diff options
Diffstat (limited to 'png')
| -rwxr-xr-x | png/ANNOUNCE | 41 | ||||
| -rwxr-xr-x | png/CHANGES | 4950 | ||||
| -rwxr-xr-x | png/CMakeLists.txt | 364 | ||||
| -rwxr-xr-x | png/INSTALL | 369 | ||||
| -rwxr-xr-x | png/Jamfile | 32 | ||||
| -rwxr-xr-x | png/LICENSE | 111 | ||||
| -rwxr-xr-x | png/README | 202 | ||||
| -rwxr-xr-x | png/TODO | 29 | ||||
| -rw-r--r-- | png/afiles | 44 | ||||
| -rwxr-xr-x | png/configure | 19 | ||||
| -rwxr-xr-x | png/example.c | 1061 | ||||
| -rwxr-xr-x | png/libpng-config.in | 127 | ||||
| -rwxr-xr-x | png/libpng-manual.txt | 5330 | ||||
| -rwxr-xr-x | png/libpng.3 | 6208 | ||||
| -rwxr-xr-x | png/libpng.pc.in | 11 | ||||
| -rwxr-xr-x | png/libpngpf.3 | 18 | ||||
| -rwxr-xr-x | png/png.5 | 74 | ||||
| -rwxr-xr-x | png/png.c | 4385 | ||||
| -rwxr-xr-x | png/png.h | 3268 | ||||
| -rwxr-xr-x | png/pngbar.jpg | bin | 0 -> 2498 bytes | |||
| -rwxr-xr-x | png/pngbar.png | bin | 0 -> 2399 bytes | |||
| -rwxr-xr-x | png/pngconf.h | 644 | ||||
| -rwxr-xr-x | png/pngdebug.h | 154 | ||||
| -rwxr-xr-x | png/pngerror.c | 961 | ||||
| -rwxr-xr-x | png/pngget.c | 1198 | ||||
| -rwxr-xr-x | png/pnginfo.h | 260 | ||||
| -rwxr-xr-x | png/pnglibconf.h | 210 | ||||
| -rwxr-xr-x | png/pngmem.c | 281 | ||||
| -rwxr-xr-x | png/pngnow.png | bin | 0 -> 2069 bytes | |||
| -rwxr-xr-x | png/pngpread.c | 1286 | ||||
| -rwxr-xr-x | png/pngpriv.h | 1940 | ||||
| -rwxr-xr-x | png/pngread.c | 4098 | ||||
| -rwxr-xr-x | png/pngrio.c | 120 | ||||
| -rwxr-xr-x | png/pngrtran.c | 4991 | ||||
| -rwxr-xr-x | png/pngrutil.c | 4469 | ||||
| -rwxr-xr-x | png/pngset.c | 1597 | ||||
| -rwxr-xr-x | png/pngstruct.h | 489 | ||||
| -rwxr-xr-x | png/pngtest.c | 1994 | ||||
| -rwxr-xr-x | png/pngtest.png | bin | 0 -> 8695 bytes | |||
| -rwxr-xr-x | png/pngtrans.c | 850 | ||||
| -rwxr-xr-x | png/pngwio.c | 168 | ||||
| -rwxr-xr-x | png/pngwrite.c | 2437 | ||||
| -rwxr-xr-x | png/pngwtran.c | 572 | ||||
| -rwxr-xr-x | png/pngwutil.c | 3026 |
44 files changed, 58388 insertions, 0 deletions
diff --git a/png/ANNOUNCE b/png/ANNOUNCE new file mode 100755 index 0000000..47181be --- /dev/null +++ b/png/ANNOUNCE @@ -0,0 +1,41 @@ + +Libpng 1.6.12 - June 12, 2014 + +This is a public release of libpng, intended for use in production codes. + +Files available for download: + +Source files with LF line endings (for Unix/Linux) and with a +"configure" script + + libpng-1.6.12.tar.xz (LZMA-compressed, recommended) + libpng-1.6.12.tar.gz + +Source files with CRLF line endings (for Windows), without the +"configure" script + + lpng1612.7z (LZMA-compressed, recommended) + lpng1612.zip + +Other information: + + libpng-1.6.12-README.txt + libpng-1.6.12-LICENSE.txt + libpng-1.6.12-*.asc (armored detached GPG signatures) + +Changes since the last public release (1.6.11): + Relocated new code from 1.6.11 in png.c to a point after the + declarations (Max Stepin). + Changed file permissions of contrib/tools/intgamma.sh, + test-driver, and compile from 0644 to 0755 (Cosmin). + Ensure "__has_attribute()" macro exists before trying to use it with + old clang compilers (MacPorts Ticket #43939). + +Send comments/corrections/commendations to png-mng-implement at lists.sf.net +(subscription required; visit +https://lists.sourceforge.net/lists/listinfo/png-mng-implement +to subscribe) +or to glennrp at users.sourceforge.net + +Glenn R-P +#endif diff --git a/png/CHANGES b/png/CHANGES new file mode 100755 index 0000000..c1951a7 --- /dev/null +++ b/png/CHANGES @@ -0,0 +1,4950 @@ +#if 0 +CHANGES - changes for libpng + +Version 0.2 + added reader into png.h + fixed small problems in stub file + +Version 0.3 + added pull reader + split up pngwrite.c to several files + added pnglib.txt + added example.c + cleaned up writer, adding a few new transformations + fixed some bugs in writer + interfaced with zlib 0.5 + added K&R support + added check for 64 KB blocks for 16-bit machines + +Version 0.4 + cleaned up code and commented code + simplified time handling into png_time + created png_color_16 and png_color_8 to handle color needs + cleaned up color type defines + fixed various bugs + made various names more consistent + interfaced with zlib 0.71 + cleaned up zTXt reader and writer (using zlib's Reset functions) + split transformations into pngrtran.c and pngwtran.c + +Version 0.5 + interfaced with zlib 0.8 + fixed many reading and writing bugs + saved using 3 spaces instead of tabs + +Version 0.6 + added png_large_malloc() and png_large_free() + added png_size_t + cleaned up some compiler warnings + added png_start_read_image() + +Version 0.7 + cleaned up lots of bugs + finished dithering and other stuff + added test program + changed name from pnglib to libpng + +Version 0.71 [June, 1995] + changed pngtest.png for zlib 0.93 + fixed error in libpng.txt and example.c + +Version 0.8 + cleaned up some bugs + added png_set_filler() + split up pngstub.c into pngmem.c, pngio.c, and pngerror.c + added #define's to remove unwanted code + moved png_info_init() to png.c + added old_size into png_realloc() + added functions to manually set filtering and compression info + changed compression parameters based on image type + optimized filter selection code + added version info + changed external functions passing floats to doubles (k&r problems?) + put all the configurable stuff in pngconf.h + enabled png_set_shift to work with paletted images on read + added png_read_update_info() - updates info structure with transformations + +Version 0.81 [August, 1995] + incorporated Tim Wegner's medium model code (thanks, Tim) + +Version 0.82 [September, 1995] + [unspecified changes] + +Version 0.85 [December, 1995] + added more medium model code (almost everything's a far) + added i/o, error, and memory callback functions + fixed some bugs (16-bit, 4-bit interlaced, etc.) + added first run progressive reader (barely tested) + +Version 0.86 [January, 1996] + fixed bugs + improved documentation + +Version 0.87 [January, 1996] + fixed medium model bugs + fixed other bugs introduced in 0.85 and 0.86 + added some minor documentation + +Version 0.88 [January, 1996] + fixed progressive bugs + replaced tabs with spaces + cleaned up documentation + added callbacks for read/write and warning/error functions + +Version 0.89 [July, 1996] + Added new initialization API to make libpng work better with shared libs + we now have png_create_read_struct(), png_create_write_struct(), + png_create_info_struct(), png_destroy_read_struct(), and + png_destroy_write_struct() instead of the separate calls to + malloc and png_read_init(), png_info_init(), and png_write_init() + Changed warning/error callback functions to fix bug - this means you + should use the new initialization API if you were using the old + png_set_message_fn() calls, and that the old API no longer exists + so that people are aware that they need to change their code + Changed filter selection API to allow selection of multiple filters + since it didn't work in previous versions of libpng anyways + Optimized filter selection code + Fixed png_set_background() to allow using an arbitrary RGB color for + paletted images + Fixed gamma and background correction for paletted images, so + png_correct_palette is not needed unless you are correcting an + external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED + in pngconf.h) - if nobody uses this, it may disappear in the future. + Fixed bug with Borland 64K memory allocation (Alexander Lehmann) + Fixed bug in interlace handling (Smarasderagd, I think) + Added more error checking for writing and image to reduce invalid files + Separated read and write functions so that they won't both be linked + into a binary when only reading or writing functionality is used + New pngtest image also has interlacing and zTXt + Updated documentation to reflect new API + +Version 0.90 [January, 1997] + Made CRC errors/warnings on critical and ancillary chunks configurable + libpng will use the zlib CRC routines by (compile-time) default + Changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner) + Added external C++ wrapper statements to png.h (Gilles Dauphin) + Allow PNG file to be read when some or all of file signature has already + been read from the beginning of the stream. ****This affects the size + of info_struct and invalidates all programs that use a shared libpng**** + Fixed png_filler() declarations + Fixed? background color conversions + Fixed order of error function pointers to match documentation + Current chunk name is now available in png_struct to reduce the number + of nearly identical error messages (will simplify multi-lingual + support when available) + Try to get ready for unknown-chunk callback functions: + - previously read critical chunks are flagged, so the chunk handling + routines can determine if the chunk is in the right place + - all chunk handling routines have the same prototypes, so we will + be able to handle all chunks via a callback mechanism + Try to fix Linux "setjmp" buffer size problems + Removed png_large_malloc, png_large_free, and png_realloc functions. + +Version 0.95 [March, 1997] + Fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never + Fixed bug in PNG file signature compares when start != 0 + Changed parameter type of png_set_filler(...filler...) from png_byte + to png_uint_32 + Added test for MACOS to ensure that both math.h and fp.h are not #included + Added macros for libpng to be compiled as a Windows DLL (Andreas Kupries) + Added "packswap" transformation, which changes the endianness of + packed-pixel bytes (Kevin Bracey) + Added "strip_alpha" transformation, which removes the alpha channel of + input images without using it (not necessarily a good idea) + Added "swap_alpha" transformation, which puts the alpha channel in front + of the color bytes instead of after + Removed all implicit variable tests which assume NULL == 0 (I think) + Changed several variables to "png_size_t" to show 16/32-bit limitations + Added new pCAL chunk read/write support + Added experimental filter selection weighting (Greg Roelofs) + Removed old png_set_rgbx() and png_set_xrgb() functions that have been + obsolete for about 2 years now (use png_set_filler() instead) + Added macros to read 16- and 32-bit ints directly from buffer, to be + used only on those systems that support it (namely PowerPC and 680x0) + With some testing, this may become the default for MACOS/PPC systems. + Only calculate CRC on data if we are going to use it + Added macros for zTXt compression type PNG_zTXt_COMPRESSION_??? + Added macros for simple libpng debugging output selectable at compile time + Removed PNG_READ_END_MODE in progressive reader (Smarasderagd) + More description of info_struct in libpng.txt and png.h + More instructions in example.c + More chunk types tested in pngtest.c + Renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be + png_set_<chunk>. We now have corresponding png_get_<chunk> + functions in pngget.c to get information in info_ptr. This isolates + the application from the internal organization of png_info_struct + (good for shared library implementations). + +Version 0.96 [May, 1997] + Fixed serious bug with < 8bpp images introduced in 0.95 + Fixed 256-color transparency bug (Greg Roelofs) + Fixed up documentation (Greg Roelofs, Laszlo Nyul) + Fixed "error" in pngconf.h for Linux setjmp() behavior + Fixed DOS medium model support (Tim Wegner) + Fixed png_check_keyword() for case with error in static string text + Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul) + Added typecasts to quiet compiler errors + Added more debugging info + +Version 0.97 [January, 1998] + Removed PNG_USE_OWN_CRC capability + Relocated png_set_crc_action from pngrutil.c to pngrtran.c + Fixed typecasts of "new_key", etc. (Andreas Dilger) + Added RFC 1152 [sic] date support + Fixed bug in gamma handling of 4-bit grayscale + Added 2-bit grayscale gamma handling (Glenn R-P) + Added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P) + Minor corrections in libpng.txt + Added simple sRGB support (Glenn R-P) + Easier conditional compiling, e.g., + define PNG_READ/WRITE_NOT_FULLY_SUPPORTED; + all configurable options can be selected from command-line instead + of having to edit pngconf.h (Glenn R-P) + Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P) + Added more conditions for png_do_background, to avoid changing + black pixels to background when a background is supplied and + no pixels are transparent + Repaired PNG_NO_STDIO behavior + Tested NODIV support and made it default behavior (Greg Roelofs) + Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler) + Regularized version numbering scheme and bumped shared-library major + version number to 2 to avoid problems with libpng 0.89 apps + (Greg Roelofs) + +Version 0.98 [January, 1998] + Cleaned up some typos in libpng.txt and in code documentation + Fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler) + Cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c + Changed recommendation about file_gamma for PC images to .51 from .45, + in example.c and libpng.txt, added comments to distinguish between + screen_gamma, viewing_gamma, and display_gamma. + Changed all references to RFC1152 to read RFC1123 and changed the + PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED + Added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent) + Changed srgb_intent from png_byte to int to avoid compiler bugs + +Version 0.99 [January 30, 1998] + Free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler) + Fixed a longstanding "packswap" bug in pngtrans.c + Fixed some inconsistencies in pngconf.h that prevented compiling with + PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined + Fixed some typos and made other minor rearrangement of libpng.txt (Andreas) + Changed recommendation about file_gamma for PC images to .50 from .51 in + example.c and libpng.txt, and changed file_gamma for sRGB images to .45 + Added a number of functions to access information from the png structure + png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit) + Added TARGET_MACOS similar to zlib-1.0.8 + Define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined + Added type casting to all png_malloc() function calls + +Version 0.99a [January 31, 1998] + Added type casts and parentheses to all returns that return a value.(Tim W.) + +Version 0.99b [February 4, 1998] + Added type cast png_uint_32 on malloc function calls where needed. + Changed type of num_hist from png_uint_32 to int (same as num_palette). + Added checks for rowbytes overflow, in case png_size_t is less than 32 bits. + Renamed makefile.elf to makefile.lnx. + +Version 0.99c [February 7, 1998] + More type casting. Removed erroneous overflow test in pngmem.c. + Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes. + Added UNIX manual pages libpng.3 (incorporating libpng.txt) and png.5. + +Version 0.99d [February 11, 1998] + Renamed "far_to_near()" "png_far_to_near()" + Revised libpng.3 + Version 99c "buffered" operations didn't work as intended. Replaced them + with png_memcpy_check() and png_memset_check(). + Added many "if (png_ptr == NULL) return" to quell compiler warnings about + unused png_ptr, mostly in pngget.c and pngset.c. + Check for overlength tRNS chunk present when indexed-color PLTE is read. + Cleaned up spelling errors in libpng.3/libpng.txt + Corrected a problem with png_get_tRNS() which returned undefined trans array + +Version 0.99e [February 28, 1998] + Corrected png_get_tRNS() again. + Add parentheses for easier reading of pngget.c, fixed "||" should be "&&". + Touched up example.c to make more of it compileable, although the entire + file still can't be compiled (Willem van Schaik) + Fixed a bug in png_do_shift() (Bryan Tsai) + Added a space in png.h prototype for png_write_chunk_start() + Replaced pngtest.png with one created with zlib 1.1.1 + Changed pngtest to report PASS even when file size is different (Jean-loup G.) + Corrected some logic errors in png_do_invert_alpha() (Chris Patterson) + +Version 0.99f [March 5, 1998] + Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey) + Moved makefiles into a "scripts" directory, and added INSTALL instruction file + Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok) + Added pointers to "note on libpng versions" in makefile.lnx and README + Added row callback feature when reading and writing nonprogressive rows + and added a test of this feature in pngtest.c + Added user transform callbacks, with test of the feature in pngtest.c + +Version 0.99g [March 6, 1998, morning] + Minor changes to pngtest.c to suppress compiler warnings. + Removed "beta" language from documentation. + +Version 0.99h [March 6, 1998, evening] + Minor changes to previous minor changes to pngtest.c + Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED + and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro + Added user transform capability + +Version 1.00 [March 7, 1998] + Changed several typedefs in pngrutil.c + Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik) + Replaced "while(1)" with "for(;;)" + Added PNGARG() to prototypes in pngtest.c and removed some prototypes + Updated some of the makefiles (Tom Lane) + Changed some typedefs (s_start, etc.) in pngrutil.c + Fixed dimensions of "short_months" array in pngwrite.c + Replaced ansi2knr.c with the one from jpeg-v6 + +Version 1.0.0 [March 8, 1998] + Changed name from 1.00 to 1.0.0 (Adam Costello) + Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert) + +Version 1.0.0a [March 9, 1998] + Fixed three bugs in pngrtran.c to make gamma+background handling consistent + (Greg Roelofs) + Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz + for major, minor, and bugfix releases. This is 10001. (Adam Costello, + Tom Lane) + Make months range from 1-12 in png_convert_to_rfc1123 + +Version 1.0.0b [March 13, 1998] + Quieted compiler complaints about two empty "for" loops in pngrutil.c + Minor changes to makefile.s2x + Removed #ifdef/#endif around a png_free() in pngread.c + +Version 1.0.1 [March 14, 1998] + Changed makefile.s2x to reduce security risk of using a relative pathname + Fixed some typos in the documentation (Greg). + Fixed a problem with value of "channels" returned by png_read_update_info() + +Version 1.0.1a [April 21, 1998] + Optimized Paeth calculations by replacing abs() function calls with intrinsics + plus other loop optimizations. Improves avg decoding speed by about 20%. + Commented out i386istic "align" compiler flags in makefile.lnx. + Reduced the default warning level in some makefiles, to make them consistent. + Removed references to IJG and JPEG in the ansi2knr.c copyright statement. + Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation. + Added grayscale and 16-bit capability to png_do_read_filler(). + Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes + too large when writing an image with bit_depth < 8 (Bob Dellaca). + Corrected some bugs in the experimental weighted filtering heuristics. + Moved a misplaced pngrutil code block that truncates tRNS if it has more + than num_palette entries -- test was done before num_palette was defined. + Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins). + Changed compiler flags in makefile.wat for better optimization + (Pawel Mrochen). + +Version 1.0.1b [May 2, 1998] + Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg). + Relocated the png_composite macros from pngrtran.c to png.h (Greg). + Added makefile.sco (contributed by Mike Hopkirk). + Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a. + Fixed a bug in pngrtran.c that would set channels=5 under some circumstances. + More work on the Paeth-filtering, achieving imperceptible speedup + (A Kleinert). + More work on loop optimization which may help when compiled with C++ + compilers. + Added warnings when people try to use transforms they've defined out. + Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran. + Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg) + +Version 1.0.1c [May 11, 1998] + Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for + filler bytes should have been 0xff instead of 0xf. + Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images. + Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED + out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h + Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED, + for consistency, in pngconf.h + Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier + to remove unwanted capabilities via the compile line + Made some corrections to grammar (which, it's) in documentation (Greg). + Corrected example.c, use of row_pointers in png_write_image(). + +Version 1.0.1d [May 24, 1998] + Corrected several statements that used side effects illegally in pngrutil.c + and pngtrans.c, that were introduced in version 1.0.1b + Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert) + More corrections to example.c, use of row_pointers in png_write_image() + and png_read_rows(). + Added pngdll.mak and pngdef.pas to scripts directory, contributed by + Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5 + Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.) + Changed several loops from count-down to count-up, for consistency. + +Version 1.0.1e [June 6, 1998] + Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and + added warnings when people try to set png_read_fn and png_write_fn in + the same structure. + Added a test such that png_do_gamma will be done when num_trans==0 + for truecolor images that have defined a background. This corrects an + error that was introduced in libpng-0.90 that can cause gamma processing + to be skipped. + Added tests in png.h to include "trans" and "trans_values" in structures + when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined. + Add png_free(png_ptr->time_buffer) in png_destroy_read_struct() + Moved png_convert_to_rfc_1123() from pngwrite.c to png.c + Added capability for user-provided malloc_fn() and free_fn() functions, + and revised pngtest.c to demonstrate their use, replacing the + PNGTEST_DEBUG_MEM feature. + Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner). + +Version 1.0.2 [June 14, 1998] + Fixed two bugs in makefile.bor . + +Version 1.0.2a [December 30, 1998] + Replaced and extended code that was removed from png_set_filler() in 1.0.1a. + Fixed a bug in png_do_filler() that made it fail to write filler bytes in + the left-most pixel of each row (Kevin Bracey). + Changed "static pngcharp tIME_string" to "static char tIME_string[30]" + in pngtest.c (Duncan Simpson). + Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk + even when no tIME chunk was present in the source file. + Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit. + Fixed a problem in png_read_push_finish_row(), which would not skip some + passes that it should skip, for images that are less than 3 pixels high. + Interchanged the order of calls to png_do_swap() and png_do_shift() + in pngwtran.c (John Cromer). + Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h . + Changed "bad adaptive filter type" from error to warning in pngrutil.c . + Fixed a documentation error about default filtering with 8-bit indexed-color. + Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO + (L. Peter Deutsch). + Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions. + Added png_get_copyright() and png_get_header_version() functions. + Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c + Added information about debugging in libpng.txt and libpng.3 . + Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and + makefile.sco. + Removed lines after Dynamic Dependencies" in makefile.aco . + Revised makefile.dec to make a shared library (Jeremie Petit). + Removed trailing blanks from all files. + +Version 1.0.2a [January 6, 1999] + Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h + Added "if" tests to silence complaints about unused png_ptr in png.h and png.c + Changed "check_if_png" function in example.c to return true (nonzero) if PNG. + Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig() + which is obsolete. + +Version 1.0.3 [January 14, 1999] + Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice) + Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO. + +Version 1.0.3a [August 12, 1999] + Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning + if an attempt is made to read an interlaced image when it's not supported. + Added check if png_ptr->trans is defined before freeing it in pngread.c + Modified the Y2K statement to include versions back to version 0.71 + Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c + Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments) + Replaced leading blanks with tab characters in makefile.hux + Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents. + Changed (float)red and (float)green to (double)red, (double)green + in png_set_rgb_to_gray() to avoid "promotion" problems in AIX. + Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey). + Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt). + Updated documentation to refer to the PNG-1.2 specification. + Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c + in makefile.knr, INSTALL, and README (L. Peter Deutsch) + Fixed bugs in calculation of the length of rowbytes when adding alpha + channels to 16-bit images, in pngrtran.c (Chris Nokleberg) + Added function png_set_user_transform_info() to store user_transform_ptr, + user_depth, and user_channels into the png_struct, and a function + png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg) + Added function png_set_empty_plte_permitted() to make libpng useable + in MNG applications. + Corrected the typedef for png_free_ptr in png.h (Jesse Jones). + Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be + consistent with PNG-1.2, and allow variance of 500 before complaining. + Added assembler code contributed by Intel in file pngvcrd.c and modified + makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation, + Gilles Vollant) + Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy. + Added some aliases for png_set_expand() in pngrtran.c, namely + png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS() + (Greg Roelofs, in "PNG: The Definitive Guide"). + Added makefile.beo for BEOS on X86, contributed by Sander Stok. + +Version 1.0.3b [August 26, 1999] + Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h + Changed leading blanks to tabs in all makefiles. + Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code. + Made alternate versions of png_set_expand() in pngrtran.c, namely + png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha + (Greg Roelofs, in "PNG: The Definitive Guide"). Deleted the 1.0.3a aliases. + Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h + Revised calculation of num_blocks in pngmem.c to avoid a potentially + negative shift distance, whose results are undefined in the C language. + Added a check in pngset.c to prevent writing multiple tIME chunks. + Added a check in pngwrite.c to detect invalid small window_bits sizes. + +Version 1.0.3d [September 4, 1999] + Fixed type casting of igamma in pngrutil.c + Added new png_expand functions to scripts/pngdef.pas and pngos2.def + Added a demo read_user_transform_fn that examines the row filters in pngtest.c + +Version 1.0.4 [September 24, 1999] + Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined + Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h + Made several minor corrections to pngtest.c + Renamed the makefiles with longer but more user friendly extensions. + Copied the PNG copyright and license to a separate LICENSE file. + Revised documentation, png.h, and example.c to remove reference to + "viewing_gamma" which no longer appears in the PNG specification. + Revised pngvcrd.c to use MMX code for interlacing only on the final pass. + Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a + Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX + assembler code) and makefile.vcwin32 (doesn't). + Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING) + Added a copy of pngnow.png to the distribution. + +Version 1.0.4a [September 25, 1999] + Increase max_pixel_depth in pngrutil.c if a user transform needs it. + Changed several division operations to right-shifts in pngvcrd.c + +Version 1.0.4b [September 30, 1999] + Added parentheses in line 3732 of pngvcrd.c + Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1 + +Version 1.0.4c [October 1, 1999] + Added a "png_check_version" function in png.c and pngtest.c that will generate + a helpful compiler error if an old png.h is found in the search path. + Changed type of png_user_transform_depth|channels from int to png_byte. + +Version 1.0.4d [October 6, 1999] + Changed 0.45 to 0.45455 in png_set_sRGB() + Removed unused PLTE entries from pngnow.png + Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly. + +Version 1.0.4e [October 10, 1999] + Fixed sign error in pngvcrd.c (Greg Roelofs) + Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P) + +Version 1.0.4f [October 15, 1999] + Surrounded example.c code with #if 0 .. #endif to prevent people from + inadvertently trying to compile it. + Changed png_get_header_version() from a function to a macro in png.h + Added type casting mostly in pngrtran.c and pngwtran.c + Removed some pointless "ptr = NULL" in pngmem.c + Added a "contrib" directory containing the source code from Greg's book. + +Version 1.0.5 [October 15, 1999] + Minor editing of the INSTALL and README files. + +Version 1.0.5a [October 23, 1999] + Added contrib/pngsuite and contrib/pngminus (Willem van Schaik) + Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans) + Further optimization and bugfix of pngvcrd.c + Revised pngset.c so that it does not allocate or free memory in the user's + text_ptr structure. Instead, it makes its own copy. + Created separate write_end_info_struct in pngtest.c for a more severe test. + Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak. + +Version 1.0.5b [November 23, 1999] + Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and + PNG_FLAG_WROTE_tIME from flags to mode. + Added png_write_info_before_PLTE() function. + Fixed some typecasting in contrib/gregbook/*.c + Updated scripts/makevms.com and added makevms.com to contrib/gregbook + and contrib/pngminus (Martin Zinser) + +Version 1.0.5c [November 26, 1999] + Moved png_get_header_version from png.h to png.c, to accommodate ansi2knr. + Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to + accommodate making DLL's: Moved usr_png_ver from global variable to function + png_get_header_ver() in png.c. Moved png_sig to png_sig_bytes in png.c and + eliminated use of png_sig in pngwutil.c. Moved the various png_CHNK arrays + into pngtypes.h. Eliminated use of global png_pass arrays. Declared the + png_CHNK and png_pass arrays to be "const". Made the global arrays + available to applications (although none are used in libpng itself) when + PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined. + Removed some extraneous "-I" from contrib/pngminus/makefile.std + Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2. + Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3 + +Version 1.0.5d [November 29, 1999] + Add type cast (png_const_charp) two places in png.c + Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays. + Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available + to applications a macro "PNG_USE_LOCAL_ARRAYS". + comment out (with #ifdef) all the new declarations when + PNG_USE_GLOBAL_ARRAYS is defined. + Added PNG_EXPORT_VAR macro to accommodate making DLL's. + +Version 1.0.5e [November 30, 1999] + Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text + structure; refactored the inflate/deflate support to make adding new chunks + with trailing compressed parts easier in the future, and added new functions + png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP, + png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond). + NOTE: Applications that write text chunks MUST define png_text->lang + before calling png_set_text(). It must be set to NULL if you want to + write tEXt or zTXt chunks. If you want your application to be able to + run with older versions of libpng, use + + #ifdef PNG_iTXt_SUPPORTED + png_text[i].lang = NULL; + #endif + + Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned + offsets (Eric S. Raymond). + Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into + PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED + macros, leaving the separate macros also available. + Removed comments on #endifs at the end of many short, non-nested #if-blocks. + +Version 1.0.5f [December 6, 1999] + Changed makefile.solaris to issue a warning about potential problems when + the ucb "ld" is in the path ahead of the ccs "ld". + Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3. + Added sCAL chunk support (Eric S. Raymond). + +Version 1.0.5g [December 7, 1999] + Fixed "png_free_spallettes" typo in png.h + Added code to handle new chunks in pngpread.c + Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block + Added "translated_key" to png_text structure and png_write_iTXt(). + Added code in pngwrite.c to work around a newly discovered zlib bug. + +Version 1.0.5h [December 10, 1999] + NOTE: regarding the note for version 1.0.5e, the following must also + be included in your code: + png_text[i].translated_key = NULL; + Unknown chunk handling is now supported. + Option to eliminate all floating point support was added. Some new + fixed-point functions such as png_set_gAMA_fixed() were added. + Expanded tabs and removed trailing blanks in source files. + +Version 1.0.5i [December 13, 1999] + Added some type casts to silence compiler warnings. + Renamed "png_free_spalette" to "png_free_spalettes" for consistency. + Removed leading blanks from a #define in pngvcrd.c + Added some parameters to the new png_set_keep_unknown_chunks() function. + Added a test for up->location != 0 in the first instance of writing + unknown chunks in pngwrite.c + Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to + prevent recursion. + Added png_free_hIST() function. + Various patches to fix bugs in the sCAL and integer cHRM processing, + and to add some convenience macros for use with sCAL. + +Version 1.0.5j [December 21, 1999] + Changed "unit" parameter of png_write_sCAL from png_byte to int, to work + around buggy compilers. + Added new type "png_fixed_point" for integers that hold float*100000 values + Restored backward compatibility of tEXt/zTXt chunk processing: + Restored the first four members of png_text to the same order as v.1.0.5d. + Added members "lang_key" and "itxt_length" to png_text struct. Set + text_length=0 when "text" contains iTXt data. Use the "compression" + member to distinguish among tEXt/zTXt/iTXt types. Added + PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros. + The "Note" above, about backward incompatibility of libpng-1.0.5e, no + longer applies. + Fixed png_read|write_iTXt() to read|write parameters in the right order, + and to write the iTXt chunk after IDAT if it appears in the end_ptr. + Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs) + Reversed the order of trying to write floating-point and fixed-point gAMA. + +Version 1.0.5k [December 27, 1999] + Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))" + Added png_handle_as_unknown() function (Glenn) + Added png_free_chunk_list() function and chunk_list and num_chunk_list members + of png_ptr. + Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE. + Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings + about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored) + Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR). + Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is. + Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP(). + +Version 1.0.5l [January 1, 2000] + Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr() + for setting a callback function to handle unknown chunks and for + retrieving the associated user pointer (Glenn). + +Version 1.0.5m [January 7, 2000] + Added high-level functions png_read_png(), png_write_png(), png_free_pixels(). + +Version 1.0.5n [January 9, 2000] + Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its + own memory for info_ptr->palette. This makes it safe for the calling + application to free its copy of the palette any time after it calls + png_set_PLTE(). + +Version 1.0.5o [January 20, 2000] + Cosmetic changes only (removed some trailing blanks and TABs) + +Version 1.0.5p [January 31, 2000] + Renamed pngdll.mak to makefile.bd32 + Cosmetic changes in pngtest.c + +Version 1.0.5q [February 5, 2000] + Relocated the makefile.solaris warning about PATH problems. + Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg) + Revised makefile.gcmmx + Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros + +Version 1.0.5r [February 7, 2000] + Removed superfluous prototype for png_get_itxt from png.h + Fixed a bug in pngrtran.c that improperly expanded the background color. + Return *num_text=0 from png_get_text() when appropriate, and fix documentation + of png_get_text() in libpng.txt/libpng.3. + +Version 1.0.5s [February 18, 2000] + Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the + new error handler that's planned for the next libpng release, and changed + example.c, pngtest.c, and contrib programs to use this macro. + Revised some of the DLL-export macros in pngconf.h (Greg Roelofs) + Fixed a bug in png_read_png() that caused it to fail to expand some images + that it should have expanded. + Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions + in pngget.c + Changed the allocation of palette, history, and trans arrays back to + the version 1.0.5 method (linking instead of copying) which restores + backward compatibility with version 1.0.5. Added some remarks about + that in example.c. Added "free_me" member to info_ptr and png_ptr + and added png_free_data() function. + Updated makefile.linux and makefile.gccmmx to make directories conditionally. + Made cosmetic changes to pngasmrd.h + Added png_set_rows() and png_get_rows(), for use with png_read|write_png(). + Modified png_read_png() to allocate info_ptr->row_pointers only if it + hasn't already been allocated. + +Version 1.0.5t [March 4, 2000] + Changed png_jmp_env() migration aiding macro to png_jmpbuf(). + Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c + Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when + PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b + Files in contrib/gregbook were revised to use png_jmpbuf() and to select + a 24-bit visual if one is available, and to allow abbreviated options. + Files in contrib/pngminus were revised to use the png_jmpbuf() macro. + Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s + +Version 1.0.5u [March 5, 2000] + Simplified the code that detects old png.h in png.c and pngtest.c + Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp) + Increased precision of rgb_to_gray calculations from 8 to 15 bits and + added png_set_rgb_to_gray_fixed() function. + Added makefile.bc32 (32-bit Borland C++, C mode) + +Version 1.0.5v [March 11, 2000] + Added some parentheses to the png_jmpbuf macro definition. + Updated references to the zlib home page, which has moved to freesoftware.com. + Corrected bugs in documentation regarding png_read_row() and png_write_row(). + Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt. + Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3, + revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin) + +Version 1.0.6 [March 20, 2000] + Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c + Added makefile.sggcc (SGI IRIX with gcc) + +Version 1.0.6d [April 7, 2000] + Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO + Added data_length parameter to png_decompress_chunk() function + Revised documentation to remove reference to abandoned png_free_chnk functions + Fixed an error in png_rgb_to_gray_fixed() + Revised example.c, usage of png_destroy_write_struct(). + Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file + Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c + Simplify png_sig_bytes() function to remove use of non-ISO-C strdup(). + +Version 1.0.6e [April 9, 2000] + Added png_data_freer() function. + In the code that checks for over-length tRNS chunks, added check of + info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann) + Minor revisions of libpng.txt/libpng.3. + Check for existing data and free it if the free_me flag is set, in png_set_*() + and png_handle_*(). + Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED + is defined. + Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c + and mentioned the purposes of the two macros in libpng.txt/libpng.3. + +Version 1.0.6f [April 14, 2000] + Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data. + Add checks in png_set_text() for NULL members of the input text structure. + Revised libpng.txt/libpng.3. + Removed superfluous prototype for png_set_iTXt from png.h + Removed "else" from pngread.c, after png_error(), and changed "0" to "length". + Changed several png_errors about malformed ancillary chunks to png_warnings. + +Version 1.0.6g [April 24, 2000] + Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined. + Relocated paragraph about png_set_background() in libpng.3/libpng.txt + and other revisions (Matthias Benckmann) + Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and + png_ptr members to restore binary compatibility with libpng-1.0.5 + (breaks compatibility with libpng-1.0.6). + +Version 1.0.6h [April 24, 2000] + Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds + libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h) + This is a temporary change for test purposes. + +Version 1.0.6i [May 2, 2000] + Rearranged some members at the end of png_info and png_struct, to put + unknown_chunks_num and free_me within the original size of the png_structs + and free_me, png_read_user_fn, and png_free_fn within the original png_info, + because some old applications allocate the structs directly instead of + using png_create_*(). + Added documentation of user memory functions in libpng.txt/libpng.3 + Modified png_read_png so that it will use user_allocated row_pointers + if present, unless free_me directs that it be freed, and added description + of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3. + Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version + 1.00) members of png_struct and png_info, to regain binary compatibility + when you define this macro. Capabilities lost in this event + are user transforms (new in version 1.0.0),the user transform pointer + (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT, + the high-level interface, and unknown chunks support (all new in 1.0.6). + This was necessary because of old applications that allocate the structs + directly as authors were instructed to do in libpng-0.88 and earlier, + instead of using png_create_*(). + Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which + can be used to detect codes that directly allocate the structs, and + code to check these modes in png_read_init() and png_write_init() and + generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED + was not defined. + Added makefile.intel and updated makefile.watcom (Pawel Mrochen) + +Version 1.0.6j [May 3, 2000] + Overloaded png_read_init() and png_write_init() with macros that convert + calls to png_read_init_2() or png_write_init_2() that check the version + and structure sizes. + +Version 1.0.7beta11 [May 7, 2000] + Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes + which are no longer used. + Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is + defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED + is defined. + Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory + overrun when old applications fill the info_ptr->text structure directly. + Added PNGAPI macro, and added it to the definitions of all exported functions. + Relocated version macro definitions ahead of the includes of zlib.h and + pngconf.h in png.h. + +Version 1.0.7beta12 [May 12, 2000] + Revised pngset.c to avoid a problem with expanding the png_debug macro. + Deleted some extraneous defines from pngconf.h + Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined. + Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined. + Added png_access_version_number() function. + Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data(). + Expanded libpng.3/libpng.txt information about png_data_freer(). + +Version 1.0.7beta14 [May 17, 2000] (beta13 was not published) + Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as + warnings instead of errors, as pngrutil.c does. + Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png() + will actually write IDATs. + Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32. + Make png_free_data() ignore its final parameter except when freeing data + that can have multiple instances (text, sPLT, unknowns). + Fixed a new bug in png_set_rows(). + Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5. + Added png_set_invalid() function. + Fixed incorrect illustrations of png_destroy_write_struct() in example.c. + +Version 1.0.7beta15 [May 30, 2000] + Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce + fewer error messages. + Rearranged checks for Z_OK to check the most likely path first in pngpread.c + and pngwutil.c. + Added checks in pngtest.c for png_create_*() returning NULL, and mentioned + in libpng.txt/libpng.3 the need for applications to check this. + Changed names of png_default_*() functions in pngtest to pngtest_*(). + Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32. + Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c + Set each pointer to NULL after freeing it in png_free_data(). + Worked around a problem in pngconf.h; AIX's strings.h defines an "index" + macro that conflicts with libpng's png_color_16.index. (Dimitri + Papadapoulos) + Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux). + +Version 1.0.7beta16 [June 4, 2000] + Revised the workaround of AIX string.h "index" bug. + Added a check for overlength PLTE chunk in pngrutil.c. + Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer + indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler. + Added a warning in png_decompress_chunk() when it runs out of data, e.g. + when it tries to read an erroneous PhotoShop iCCP chunk. + Added PNG_USE_DLL macro. + Revised the copyright/disclaimer/license notice. + Added contrib/msvctest directory + +Version 1.0.7rc1 [June 9, 2000] + Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA (0x0400 not 0x0200) + Added contrib/visupng directory (Willem van Schaik) + +Version 1.0.7beta18 [June 23, 2000] + Revised PNGAPI definition, and pngvcrd.c to work with __GCC__ + and do not redefine PNGAPI if it is passed in via a compiler directive. + Revised visupng/PngFile.c to remove returns from within the Try block. + Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros. + Updated contrib/visupng/cexcept.h to version 1.0.0. + Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks. + +Version 1.0.7rc2 [June 28, 2000] + Updated license to include disclaimers required by UCITA. + Fixed "DJBPP" typo in pnggccrd.c introduced in beta18. + +Version 1.0.7 [July 1, 2000] + Revised the definition of "trans_values" in libpng.3/libpng.txt + +Version 1.0.8beta1 [July 8, 2000] + Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks. + Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and + pngwutil.c. + Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h. + Removed unused "#include <assert.h>" from png.c + Added WindowsCE support. + Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment. + +Version 1.0.8beta2 [July 10, 2000] + Added project files to the wince directory and made further revisions + of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE. + +Version 1.0.8beta3 [July 11, 2000] + Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS() + for indexed-color input files to avoid potential double-freeing trans array + under some unusual conditions; problem was introduced in version 1.0.6f. + Further revisions to pngtest.c and files in the wince subdirectory. + +Version 1.0.8beta4 [July 14, 2000] + Added the files pngbar.png and pngbar.jpg to the distribution. + Added makefile.cygwin, and cygwin support in pngconf.h + Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory) + +Version 1.0.8rc1 [July 16, 2000] + Revised png_debug() macros and statements to eliminate compiler warnings. + +Version 1.0.8 [July 24, 2000] + Added png_flush() in pngwrite.c, after png_write_IEND(). + Updated makefile.hpux to build a shared library. + +Version 1.0.9beta1 [November 10, 2000] + Fixed typo in scripts/makefile.hpux + Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser) + Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser) + Changed "cdrom.com" in documentation to "libpng.org" + Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg). + Changed type of "params" from voidp to png_voidp in png_read|write_png(). + Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h. + Revised the 3 instances of WRITEFILE in pngtest.c. + Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory. + Updated png.rc in dll/msvc project + Revised makefile.dec to define and use LIBPATH and INCPATH + Increased size of global png_libpng_ver[] array from 12 to 18 chars. + Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const. + Removed duplicate png_crc_finish() from png_handle_bKGD() function. + Added a warning when application calls png_read_update_info() multiple times. + Revised makefile.cygwin + Fixed bugs in iCCP support in pngrutil.c and pngwutil.c. + Replaced png_set_empty_plte_permitted() with png_permit_mng_features(). + +Version 1.0.9beta2 [November 19, 2000] + Renamed the "dll" subdirectory "projects". + Added borland project files to "projects" subdirectory. + Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate. + Add error message in png_set_compression_buffer_size() when malloc fails. + +Version 1.0.9beta3 [November 23, 2000] + Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project. + Removed the png_flush() in pngwrite.c that crashes some applications + that don't set png_output_flush_fn. + Added makefile.macosx and makefile.aix to scripts directory. + +Version 1.0.9beta4 [December 1, 2000] + Change png_chunk_warning to png_warning in png_check_keyword(). + Increased the first part of msg buffer from 16 to 18 in png_chunk_error(). + +Version 1.0.9beta5 [December 15, 2000] + Added support for filter method 64 (for PNG datastreams embedded in MNG). + +Version 1.0.9beta6 [December 18, 2000] + Revised png_set_filter() to accept filter method 64 when appropriate. + Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to + help prevent applications from using MNG features in PNG datastreams. + Added png_permit_mng_features() function. + Revised libpng.3/libpng.txt. Changed "filter type" to "filter method". + +Version 1.0.9rc1 [December 23, 2000] + Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c + Fixed error handling of unknown compression type in png_decompress_chunk(). + In pngconf.h, define __cdecl when _MSC_VER is defined. + +Version 1.0.9beta7 [December 28, 2000] + Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places. + Revised memory management in png_set_hIST and png_handle_hIST in a backward + compatible manner. PLTE and tRNS were revised similarly. + Revised the iCCP chunk reader to ignore trailing garbage. + +Version 1.0.9beta8 [January 12, 2001] + Moved pngasmrd.h into pngconf.h. + Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop. + +Version 1.0.9beta9 [January 15, 2001] + Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to + wince and msvc project module definition files. + Minor revision of makefile.cygwin. + Fixed bug with progressive reading of narrow interlaced images in pngpread.c + +Version 1.0.9beta10 [January 16, 2001] + Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined. + Fixed "png_mmx_supported" typo in project definition files. + +Version 1.0.9beta11 [January 19, 2001] + Updated makefile.sgi to make shared library. + Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED + by default, for the benefit of DLL forward compatibility. These will + be re-enabled in version 1.2.0. + +Version 1.0.9rc2 [January 22, 2001] + Revised cygwin support. + +Version 1.0.9 [January 31, 2001] + Added check of cygwin's ALL_STATIC in pngconf.h + Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos. + +Version 1.0.10beta1 [March 14, 2001] + Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc. + Reformatted libpng.3 to eliminate bad line breaks. + Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c + Added prototype for png_mmx_support() near the top of pnggccrd.c + Moved some error checking from png_handle_IHDR to png_set_IHDR. + Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros. + Revised png_mmx_support() function in pnggccrd.c + Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c + Fixed memory leak in contrib/visupng/PngFile.c + Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version) + Added warnings when retrieving or setting gamma=0. + Increased the first part of msg buffer from 16 to 18 in png_chunk_warning(). + +Version 1.0.10rc1 [March 23, 2001] + Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy, + and png_strlen. + Revised png_mmx_supported() function in pnggccrd.c to return proper value. + Fixed bug in progressive reading (pngpread.c) with small images (height < 8). + +Version 1.0.10 [March 30, 2001] + Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin + Added beos project files (Chris Herborth) + +Version 1.0.11beta1 [April 3, 2001] + Added type casts on several png_malloc() calls (Dimitri Papadapoulos). + Removed a no-longer needed AIX work-around from pngconf.h + Changed several "//" single-line comments to C-style in pnggccrd.c + +Version 1.0.11beta2 [April 11, 2001] + Removed PNGAPI from several functions whose prototypes did not have PNGAPI. + Updated scripts/pngos2.def + +Version 1.0.11beta3 [April 14, 2001] + Added checking the results of many instances of png_malloc() for NULL + +Version 1.0.11beta4 [April 20, 2001] + Undid the changes from version 1.0.11beta3. Added a check for NULL return + from user's malloc_fn(). + Removed some useless type casts of the NULL pointer. + Added makefile.netbsd + +Version 1.0.11 [April 27, 2001] + Revised makefile.netbsd + +Version 1.0.12beta1 [May 14, 2001] + Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot) + Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h + Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings. + Eliminated the png_error about apps using png_read|write_init(). Instead, + libpng will reallocate the png_struct and info_struct if they are too small. + This retains future binary compatibility for old applications written for + libpng-0.88 and earlier. + +Version 1.2.0beta1 [May 6, 2001] + Bumped DLLNUM to 2. + Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED + by default. + Added runtime selection of MMX features. + Added png_set_strip_error_numbers function and related macros. + +Version 1.2.0beta2 [May 7, 2001] + Finished merging 1.2.0beta1 with version 1.0.11 + Added a check for attempts to read or write PLTE in grayscale PNG datastreams. + +Version 1.2.0beta3 [May 17, 2001] + Enabled user memory function by default. + Modified png_create_struct so it passes user mem_ptr to user memory allocator. + Increased png_mng_features flag from png_byte to png_uint_32. + Bumped shared-library (so-number) and dll-number to 3. + +Version 1.2.0beta4 [June 23, 2001] + Check for missing profile length field in iCCP chunk and free chunk_data + in case of truncated iCCP chunk. + Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc + Bumped dll-number from 2 to 3 in makefile.cygwin + Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly + if user attempts to run it on an 8-bit display. + Updated contrib/gregbook + Use png_malloc instead of png_zalloc to allocate palette in pngset.c + Updated makefile.ibmc + Added some typecasts to eliminate gcc 3.0 warnings. Changed prototypes + of png_write_oFFS width and height from png_uint_32 to png_int_32. + Updated example.c + Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c + +Version 1.2.0beta5 [August 8, 2001] + Revised contrib/gregbook + Revised makefile.gcmmx + Revised pnggccrd.c to conditionally compile some thread-unsafe code only + when PNG_THREAD_UNSAFE_OK is defined. + Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with + value exceeding 2^bit_depth-1 + Revised makefile.sgi and makefile.sggcc + Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c + Removed restriction that do_invert_mono only operate on 1-bit opaque files + +Version 1.2.0 [September 1, 2001] + Changed a png_warning() to png_debug() in pnggccrd.c + Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC(). + +Version 1.2.1beta1 [October 19, 2001] + Revised makefile.std in contrib/pngminus + Include background_1 in png_struct regardless of gamma support. + Revised makefile.netbsd and makefile.macosx, added makefile.darwin. + Revised example.c to provide more details about using row_callback(). + +Version 1.2.1beta2 [October 25, 2001] + Added type cast to each NULL appearing in a function call, except for + WINCE functions. + Added makefile.so9. + +Version 1.2.1beta3 [October 27, 2001] + Removed type casts from all NULLs. + Simplified png_create_struct_2(). + +Version 1.2.1beta4 [November 7, 2001] + Revised png_create_info_struct() and png_creat_struct_2(). + Added error message if png_write_info() was omitted. + Type cast NULLs appearing in function calls when _NO_PROTO or + PNG_TYPECAST_NULL is defined. + +Version 1.2.1rc1 [November 24, 2001] + Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL + is defined. + Changed typecast of "size" argument to png_size_t in pngmem.c calls to + the user malloc_fn, to agree with the prototype in png.h + Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev) + Updated makefile.sgi to recognize LIBPATH and INCPATH. + Updated various makefiles so "make clean" does not remove previous major + version of the shared library. + +Version 1.2.1rc2 [December 4, 2001] + Always allocate 256-entry internal palette, hist, and trans arrays, to + avoid out-of-bounds memory reference caused by invalid PNG datastreams. + Added a check for prefix_length > data_length in iCCP chunk handler. + +Version 1.2.1 [December 7, 2001] + None. + +Version 1.2.2beta1 [February 22, 2002] + Fixed a bug with reading the length of iCCP profiles (Larry Reeves). + Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate + libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h + Revised makefile.darwin to remove "-undefined suppress" option. + Added checks for gamma and chromaticity values over 21474.83, which exceed + the limit for PNG unsigned 32-bit integers when encoded. + Revised calls to png_create_read_struct() and png_create_write_struct() + for simpler debugging. + Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK) + +Version 1.2.2beta2 [February 23, 2002] + Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths. + Check for invalid image dimensions in png_get_IHDR. + Added missing "fi;" in the install target of the SGI makefiles. + Added install-static to all makefiles that make shared libraries. + Always do gamma compensation when image is partially transparent. + +Version 1.2.2beta3 [March 7, 2002] + Compute background.gray and background_1.gray even when color_type is RGB + in case image gets reduced to gray later. + Modified shared-library makefiles to install pkgconfig/libpngNN.pc. + Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown + Removed unused png_write_destroy_info prototype from png.h + Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case + Added install-shared target to all makefiles that make shared libraries. + Stopped a double free of palette, hist, and trans when not using free_me. + Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64. + +Version 1.2.2beta4 [March 8, 2002] + Compute background.gray and background_1.gray even when color_type is RGB + in case image gets reduced to gray later (Jason Summers). + Relocated a misplaced /bin/rm in the "install-shared" makefile targets + Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library. + +Version 1.2.2beta5 [March 26, 2002] + Added missing PNGAPI to several function definitions. + Check for invalid bit_depth or color_type in png_get_IHDR(), and + check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen). + Revised iTXt support to accept NULL for lang and lang_key. + Compute gamma for color components of background even when color_type is gray. + Changed "()" to "{}" in scripts/libpng.pc.in. + Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN + Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so + +Version 1.2.2beta6 [March 31, 2002] + +Version 1.0.13beta1 [March 31, 2002] + Prevent png_zalloc() from trying to memset memory that it failed to acquire. + Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate). + Ensure that the right function (user or default) is used to free the + png_struct after an error in png_create_read_struct_2(). + +Version 1.2.2rc1 [April 7, 2002] + +Version 1.0.13rc1 [April 7, 2002] + Save the ebx register in pnggccrd.c (Sami Farin) + Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner). + Updated makefiles to put headers in include/libpng and remove old include/*.h. + +Version 1.2.2 [April 15, 2002] + +Version 1.0.13 [April 15, 2002] + Revised description of png_set_filter() in libpng.3/libpng.txt. + Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd + +Version 1.0.13patch01 [April 17, 2002] + +Version 1.2.2patch01 [April 17, 2002] + Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and + makefile.sggcc + Fixed VER -> PNGVER typo in makefile.macosx and added install-static to + install + Added install: target to makefile.32sunu and makefile.64sunu + +Version 1.0.13patch03 [April 18, 2002] + +Version 1.2.2patch03 [April 18, 2002] + Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng + subdirectory to libpngNN subdirectory without the full pathname. + Moved generation of libpng.pc from "install" to "all" in 15 makefiles. + +Version 1.2.3rc1 [April 28, 2002] + Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos). + Added $(DESTDIR) feature to 24 makefiles (Tim Mooney) + Fixed bug with $prefix, should be $(prefix) in makefile.hpux. + Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin + Added a link from libpngNN.pc to libpng.pc in 15 makefiles. + Added links from include/libpngNN/*.h to include/*.h in 24 makefiles. + Revised makefile.darwin to make relative links without full pathname. + Added setjmp() at the end of png_create_*_struct_2() in case user forgets + to put one in their application. + Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and + removed them from module definition files. + +Version 1.2.3rc2 [May 1, 2002] + Fixed bug in reporting number of channels in pngget.c and pngset.c, + that was introduced in version 1.2.2beta5. + Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(), + png_default_flush(), and png_push_fill_buffer() and included them in + module definition files. + Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles. + +Version 1.2.3rc3 [May 1, 2002] + Revised prototype for png_default_flush() + Remove old libpng.pc and libpngNN.pc before installing new ones. + +Version 1.2.3rc4 [May 2, 2002] + Typos in *.def files (png_default_read|write -> png_default_read|write_data) + In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc + Added libpng-config and libpngNN-config and modified makefiles to install + them. + Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles + Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp + +Version 1.2.3rc5 [May 11, 2002] + Changed "error" and "message" in prototypes to "error_message" and + "warning_message" to avoid namespace conflict. + Revised 15 makefiles to build libpng-config from libpng-config-*.in + Once more restored png_zalloc and png_zfree to regular nonexported form. + Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer + to nonexported form, but with PNGAPI, and removed them from module def + files. + +Version 1.2.3rc6 [May 14, 2002] + Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c + Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp. + Removed leftover libpng-config "sed" script from four makefiles. + Revised libpng-config creating script in 16 makefiles. + +Version 1.2.3 [May 22, 2002] + Revised libpng-config target in makefile.cygwin. + Removed description of png_set_mem_fn() from documentation. + Revised makefile.freebsd. + Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR). + Revised projects/msvc/README.txt + Changed -lpng to -lpngNN in LDFLAGS in several makefiles. + +Version 1.2.4beta1 [May 24, 2002] + Added libpng.pc and libpng-config to "all:" target in 16 makefiles. + Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH) + Added missing "\" before closing double quote in makefile.gcmmx. + Plugged various memory leaks; added png_malloc_warn() and png_set_text_2() + functions. + +Version 1.2.4beta2 [June 25, 2002] + Plugged memory leak of png_ptr->current_text (Matt Holgate). + Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison) + Added -soname to the loader flags in makefile.dec, makefile.sgi, and + makefile.sggcc. + Added "test-installed" target to makefile.linux, makefile.gcmmx, + makefile.sgi, and makefile.sggcc. + +Version 1.2.4beta3 [June 28, 2002] + Plugged memory leak of row_buf in pngtest.c when there is a png_error(). + Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data. + Added "test-installed" target to makefile.32sunu, makefile.64sunu, + makefile.beos, makefile.darwin, makefile.dec, makefile.macosx, + makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9. + +Version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002] + Added "test-installed" target to makefile.cygwin and makefile.sco. + Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro. + +Version 1.2.4 and 1.0.14 [July 8, 2002] + Changed png_warning() to png_error() when width is too large to process. + +Version 1.2.4patch01 [July 20, 2002] + Revised makefile.cygwin to use DLL number 12 instead of 13. + +Version 1.2.5beta1 [August 6, 2002] + Added code to contrib/gregbook/readpng2.c to ignore unused chunks. + Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11) + Removed some stray *.o files from contrib/gregbook. + Changed png_error() to png_warning() about "Too much data" in pngpread.c + and about "Extra compressed data" in pngrutil.c. + Prevent png_ptr->pass from exceeding 7 in png_push_finish_row(). + Updated makefile.hpgcc + Updated png.c and pnggccrd.c handling of return from png_mmx_support() + +Version 1.2.5beta2 [August 15, 2002] + Only issue png_warning() about "Too much data" in pngpread.c when avail_in + is nonzero. + Updated makefiles to install a separate libpng.so.3 with its own rpath. + +Version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002] + Revised makefiles to not remove previous minor versions of shared libraries. + +Version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002] + Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared + library loader directive. + Added missing "$OBJSDLL" line to makefile.gcmmx. + Added missing "; fi" to makefile.32sunu. + +Version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002] + Revised libpng-config script. + +Version 1.2.5 and 1.0.15 [October 3, 2002] + Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux, + and makefile.aix. + Relocated two misplaced PNGAPI lines in pngtest.c + +Version 1.2.6beta1 [October 22, 2002] + Commented out warning about uninitialized mmx_support in pnggccrd.c. + Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h. + Relocated two more misplaced PNGAPI lines in pngtest.c + Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams, + introduced in version 1.0.2. + Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu. + +Version 1.2.6beta2 [November 1, 2002] + Added libpng-config "--ldopts" output. + Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)" + in makefiles. + +Version 1.2.6beta3 [July 18, 2004] + Reverted makefile changes from version 1.2.6beta2 and some of the changes + from version 1.2.6beta1; these will be postponed until version 1.2.7. + Version 1.2.6 is going to be a simple bugfix release. + Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile. + Fixed potential overrun in pngerror.c by using strncpy instead of memcpy. + Added "#!/bin/sh" at the top of configure, for recognition of the + 'x' flag under Cygwin (Cosmin). + Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin). + Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin). + Fixed the special memory handler for Borland C under DOS, in pngmem.c + (Cosmin). + Removed some spurious assignments in pngrutil.c (Cosmin). + Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings + on 16-bit platforms (Cosmin). + Enclosed shift op expressions in parentheses, to silence warnings (Cosmin). + Used proper type png_fixed_point, to avoid problems on 16-bit platforms, + in png_handle_sRGB() (Cosmin). + Added compression_type to png_struct, and optimized the window size + inside the deflate stream (Cosmin). + Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin). + Fixed handling of unknown chunks that come after IDAT (Cosmin). + Allowed png_error() and png_warning() to work even if png_ptr == NULL + (Cosmin). + Replaced row_info->rowbytes with row_bytes in png_write_find_filter() + (Cosmin). + Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre). + Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded + values in png.c (Simon-Pierre, Cosmin). + Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre). + Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc + (Simon-Pierre). + Moved the definition of PNG_HEADER_VERSION_STRING near the definitions + of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin). + Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin). + Updated scripts/makefile.vc(a)win32 (Cosmin). + Updated the MSVC project (Simon-Pierre, Cosmin). + Updated the Borland C++ Builder project (Cosmin). + Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin). + Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin). + Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin). + Added extra guard around inclusion of Turbo C memory headers, in pngconf.h + (Cosmin). + Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to + projects/cbuilder5/ (Cosmin). + Moved projects/visualc6/png32ms.def to scripts/pngw32.def, + and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin). + Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin). + Changed line endings to DOS style in cbuilder5 and visualc6 files, even + in the tar.* distributions (Cosmin). + Updated contrib/visupng/VisualPng.dsp (Cosmin). + Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin). + Added a separate distribution with "configure" and supporting files (Junichi). + +Version 1.2.6beta4 [July 28, 2004] + Added user ability to change png_size_t via a PNG_SIZE_T macro. + Added png_sizeof() and png_convert_size() functions. + Added PNG_SIZE_MAX (maximum value of a png_size_t variable. + Added check in png_malloc_default() for (size_t)size != (png_uint_32)size + which would indicate an overflow. + Changed sPLT failure action from png_error to png_warning and abandon chunk. + Changed sCAL and iCCP failures from png_error to png_warning and abandon. + Added png_get_uint_31(png_ptr, buf) function. + Added PNG_UINT_32_MAX macro. + Renamed PNG_MAX_UINT to PNG_UINT_31_MAX. + Made png_zalloc() issue a png_warning and return NULL on potential + overflow. + Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x + Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4. + Revised Borland portion of png_malloc() to return NULL or issue + png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK. + Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove + sequential read support. + Added some "#if PNG_WRITE_SUPPORTED" blocks. + Added #ifdef to remove some redundancy in png_malloc_default(). + Use png_malloc instead of png_zalloc to allocate the pallete. + +Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004] + Fixed buffer overflow vulnerability in png_handle_tRNS() + Fixed integer arithmetic overflow vulnerability in png_read_png(). + Fixed some harmless bugs in png_handle_sBIT, etc, that would cause + duplicate chunk types to go undetected. + Fixed some timestamps in the -config version + Rearranged order of processing of color types in png_handle_tRNS(). + Added ROWBYTES macro to calculate rowbytes without integer overflow. + Updated makefile.darwin and removed makefile.macosx from scripts directory. + Imposed default one million column, one-million row limits on the image + dimensions, and added png_set_user_limits() function to override them. + Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro. + Fixed wrong cast of returns from png_get_user_width|height_max(). + Changed some "keep the compiler happy" from empty statements to returns, + Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution + +Version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004] + Revised makefile.darwin and makefile.solaris. Removed makefile.macosx. + Revised pngtest's png_debug_malloc() to use png_malloc() instead of + png_malloc_default() which is not supposed to be exported. + Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in + pngpread.c. Bug was introduced in 1.2.6rc1. + Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1. + Fixed old bug in RGB to Gray transformation. + Fixed problem with 64-bit compilers by casting arguments to abs() + to png_int_32. + Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9). + Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin) + Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles. + Added code to update the row_info->colortype in png_do_read_filler() (MSB). + +Version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004] + Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid + trouble with some 64-bit compilers. Created PNG_OUT_OF_RANGE() macro. + Revised documentation of png_set_keep_unknown_chunks(). + Check handle_as_unknown status in pngpread.c, as in pngread.c previously. + Moved "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h + Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c + +Version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004] + Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of + "pinfo" was out of place). + +Version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004] + Moved "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED + section of png.h where they were inadvertently placed in version rc3. + +Version 1.2.6 and 1.0.16 [August 15, 2004] + Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1. + +Version 1.2.7beta1 [August 26, 2004] + Removed unused pngasmrd.h file. + Removed references to uu.net for archived files. Added references to + PNG Spec (second edition) and the PNG ISO/IEC Standard. + Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR. + Fixed bug with "optimized window size" in the IDAT datastream, that + causes libpng to write PNG files with incorrect zlib header bytes. + +Version 1.2.7beta2 [August 28, 2004] + Fixed bug with sCAL chunk and big-endian machines (David Munro). + Undid new code added in 1.2.6rc2 to update the color_type in + png_set_filler(). + Added png_set_add_alpha() that updates color type. + +Version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004] + Revised png_set_strip_filler() to not remove alpha if color_type has alpha. + +Version 1.2.7 and 1.0.17 [September 12, 2004] + Added makefile.hp64 + Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin + +Version 1.2.8beta1 [November 1, 2004] + Fixed bug in png_text_compress() that would fail to complete a large block. + Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during + strip alpha operation in png_do_strip_filler(). + Added PNG_1_2_X definition in pngconf.h + Use #ifdef to comment out png_info_init in png.c and png_read_init in + pngread.c (as of 1.3.0) + +Version 1.2.8beta2 [November 2, 2004] + Reduce color_type to a nonalpha type after strip alpha operation in + png_do_strip_filler(). + +Version 1.2.8beta3 [November 3, 2004] + Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM + +Version 1.2.8beta4 [November 12, 2004] + Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin). + Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin). + Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection + of data type in deflate (Cosmin). + Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of + PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING. + +Version 1.2.8beta5 [November 20, 2004] + Use png_ptr->flags instead of png_ptr->transformations to pass + PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI + compatibility. + Revised handling of SPECIALBUILD, PRIVATEBUILD, + PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING. + +Version 1.2.8rc1 [November 24, 2004] + Moved handling of BUILD macros from pngconf.h to png.h + Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently + omitted from beta5. + Revised scripts/pngw32.rc + Despammed mailing addresses by masking "@" with "at". + Inadvertently installed a supposedly faster test version of pngrutil.c + +Version 1.2.8rc2 [November 26, 2004] + Added two missing "\" in png.h + Change tests in pngread.c and pngpread.c to + if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA)) + png_do_read_transformations(png_ptr); + +Version 1.2.8rc3 [November 28, 2004] + Reverted pngrutil.c to version libpng-1.2.8beta5. + Added scripts/makefile.elf with supporting code in pngconf.h for symbol + versioning (John Bowler). + +Version 1.2.8rc4 [November 29, 2004] + Added projects/visualc7 (Simon-pierre). + +Version 1.2.8rc5 [November 29, 2004] + Fixed new typo in scripts/pngw32.rc + +Version 1.2.8 [December 3, 2004] + Removed projects/visualc7, added projects/visualc71. + +Version 1.2.9beta1 [February 21, 2006] + Initialized some structure members in pngwutil.c to avoid gcc-4.0.0 complaints + Revised man page and libpng.txt to make it clear that one should not call + png_read_end or png_write_end after png_read_png or png_write_png. + Updated references to png-mng-implement mailing list. + Fixed an incorrect typecast in pngrutil.c + Added PNG_NO_READ_SUPPORTED conditional for making a write-only library. + Added PNG_NO_WRITE_INTERLACING_SUPPORTED conditional. + Optimized alpha-inversion loops in pngwtran.c + Moved test for nonzero gamma outside of png_build_gamma_table() in pngrtran.c + Make sure num_trans is <= 256 before copying data in png_set_tRNS(). + Make sure num_palette is <= 256 before copying data in png_set_PLTE(). + Interchanged order of write_swap_alpha and write_invert_alpha transforms. + Added parentheses in the definition of PNG_LIBPNG_BUILD_TYPE (Cosmin). + Optimized zlib window flag (CINFO) in contrib/pngsuite/*.png (Cosmin). + Updated scripts/makefile.bc32 for Borland C++ 5.6 (Cosmin). + Exported png_get_uint_32, png_save_uint_32, png_get_uint_16, png_save_uint_16, + png_get_int_32, png_save_int_32, png_get_uint_31 (Cosmin). + Added type cast (png_byte) in png_write_sCAL() (Cosmin). + Fixed scripts/makefile.cygwin (Christian Biesinger, Cosmin). + Default iTXt support was inadvertently enabled. + +Version 1.2.9beta2 [February 21, 2006] + Check for png_rgb_to_gray and png_gray_to_rgb read transformations before + checking for png_read_dither in pngrtran.c + Revised checking of chromaticity limits to accommodate extended RGB + colorspace (John Denker). + Changed line endings in some of the project files to CRLF, even in the + "Unix" tar distributions (Cosmin). + Made png_get_int_32 and png_save_int_32 always available (Cosmin). + Updated scripts/pngos2.def, scripts/pngw32.def and projects/wince/png32ce.def + with the newly exported functions. + Eliminated distributions without the "configure" script. + Updated INSTALL instructions. + +Version 1.2.9beta3 [February 24, 2006] + Fixed CRCRLF line endings in contrib/visupng/VisualPng.dsp + Made libpng.pc respect EXEC_PREFIX (D. P. Kreil, J. Bowler) + Removed reference to pngasmrd.h from Makefile.am + Renamed CHANGES to ChangeLog. + Renamed LICENSE to COPYING. + Renamed ANNOUNCE to NEWS. + Created AUTHORS file. + +Version 1.2.9beta4 [March 3, 2006] + Changed definition of PKGCONFIG from $prefix/lib to $libdir in configure.ac + Reverted to filenames LICENSE and ANNOUNCE; removed AUTHORS and COPYING. + Removed newline from the end of some error and warning messages. + Removed test for sqrt() from configure.ac and configure. + Made swap tables in pngtrans.c PNG_CONST (Carlo Bramix). + Disabled default iTXt support that was inadvertently enabled in + libpng-1.2.9beta1. + Added "OS2" to list of systems that don't need underscores, in pnggccrd.c + Removed libpng version and date from *.c files. + +Version 1.2.9beta5 [March 4, 2006] + Removed trailing blanks from source files. + Put version and date of latest change in each source file, and changed + copyright year accordingly. + More cleanup of configure.ac, Makefile.am, and associated scripts. + Restored scripts/makefile.elf which was inadvertently deleted. + +Version 1.2.9beta6 [March 6, 2006] + Fixed typo (RELEASE) in configuration files. + +Version 1.2.9beta7 [March 7, 2006] + Removed libpng.vers and libpng.sym from libpng12_la_SOURCES in Makefile.am + Fixed inconsistent #ifdef's around png_sig_bytes() and png_set_sCAL_s() + in png.h. + Updated makefile.elf as suggested by debian. + Made cosmetic changes to some makefiles, adding LN_SF and other macros. + Made some makefiles accept "exec_prefix". + +Version 1.2.9beta8 [March 9, 2006] + Fixed some "#if defined (..." which should be "#if defined(..." + Bug introduced in libpng-1.2.8. + Fixed inconsistency in definition of png_default_read_data() + Restored blank that was lost from makefile.sggcc "clean" target in beta7. + Revised calculation of "current" and "major" for irix in ltmain.sh + Changed "mkdir" to "MKDIR_P" in some makefiles. + Separated PNG_EXPAND and PNG_EXPAND_tRNS. + Added png_set_expand_gray_1_2_4_to_8() and deprecated + png_set_gray_1_2_4_to_8() which also expands tRNS to alpha. + +Version 1.2.9beta9 [March 10, 2006] + Include "config.h" in pngconf.h when available. + Added some checks for NULL png_ptr or NULL info_ptr (timeless) + +Version 1.2.9beta10 [March 20, 2006] + Removed extra CR from contrib/visualpng/VisualPng.dsw (Cosmin) + Made pnggccrd.c PIC-compliant (Christian Aichinger). + Added makefile.mingw (Wolfgang Glas). + Revised pngconf.h MMX checking. + +Version 1.2.9beta11 [March 22, 2006] + Fixed out-of-order declaration in pngwrite.c that was introduced in beta9 + Simplified some makefiles by using LIBSO, LIBSOMAJ, and LIBSOVER macros. + +Version 1.2.9rc1 [March 31, 2006] + Defined PNG_USER_PRIVATEBUILD when including "pngusr.h" (Cosmin). + Removed nonsensical assertion check from pngtest.c (Cosmin). + +Version 1.2.9 [April 14, 2006] + Revised makefile.beos and added "none" selector in ltmain.sh + +Version 1.2.10beta1 [April 15, 2006] + Renamed "config.h" to "png_conf.h" and revised Makefile.am to add + -DPNG_BUILDING_LIBPNG to compile directive, and modified pngconf.h + to include png_conf.h only when PNG_BUILDING_LIBPNG is defined. + +Version 1.2.10beta2 [April 15, 2006] + Manually updated Makefile.in and configure. Changed png_conf.h.in + back to config.h. + +Version 1.2.10beta3 [April 15, 2006] + Change png_conf.h back to config.h in pngconf.h. + +Version 1.2.10beta4 [April 16, 2006] + Change PNG_BUILDING_LIBPNG to PNG_CONFIGURE_LIBPNG in config/Makefile*. + +Version 1.2.10beta5 [April 16, 2006] + Added a configure check for compiling assembler code in pnggccrd.c + +Version 1.2.10beta6 [April 17, 2006] + Revised the configure check for pnggccrd.c + Moved -DPNG_CONFIGURE_LIBPNG into @LIBPNG_DEFINES@ + Added @LIBPNG_DEFINES@ to arguments when building libpng.sym + +Version 1.2.10beta7 [April 18, 2006] + Change "exec_prefix=$prefix" to "exec_prefix=$(prefix)" in makefiles. + +Version 1.2.10rc1 [April 19, 2006] + Ensure pngconf.h doesn't define both PNG_USE_PNGGCCRD and PNG_USE_PNGVCRD + Fixed "LN_FS" typo in makefile.sco and makefile.solaris. + +Version 1.2.10rc2 [April 20, 2006] + Added a backslash between -DPNG_CONFIGURE_LIBPNG and -DPNG_NO_ASSEMBLER_CODE + in configure.ac and configure + Made the configure warning about versioned symbols less arrogant. + +Version 1.2.10rc3 [April 21, 2006] + Added a note in libpng.txt that png_set_sig_bytes(8) can be used when + writing an embedded PNG without the 8-byte signature. + Revised makefiles and configure to avoid making links to libpng.so.* + +Version 1.2.10 [April 23, 2006] + Reverted configure to "rc2" state. + +Version 1.2.11beta1 [May 31, 2006] + scripts/libpng.pc.in contained "configure" style version info and would + not work with makefiles. + The shared-library makefiles were linking to libpng.so.0 instead of + libpng.so.3 compatibility as the library. + +Version 1.2.11beta2 [June 2, 2006] + Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid + buffer overflow. + Fixed bug in example.c (png_set_palette_rgb -> png_set_palette_to_rgb) + +Version 1.2.11beta3 [June 5, 2006] + Prepended "#! /bin/sh" to ltmail.sh and contrib/pngminus/*.sh (Cosmin). + Removed the accidental leftover Makefile.in~ (Cosmin). + Avoided potential buffer overflow and optimized buffer in + png_write_sCAL(), png_write_sCAL_s() (Cosmin). + Removed the include directories and libraries from CFLAGS and LDFLAGS + in scripts/makefile.gcc (Nelson A. de Oliveira, Cosmin). + +Version 1.2.11beta4 [June 6, 2006] + Allow zero-length IDAT chunks after the entire zlib datastream, but not + after another intervening chunk type. + +Version 1.0.19rc1, 1.2.11rc1 [June 13, 2006] + Deleted extraneous square brackets from [config.h] in configure.ac + +Version 1.0.19rc2, 1.2.11rc2 [June 14, 2006] + Added prototypes for PNG_INCH_CONVERSIONS functions to png.h + Revised INSTALL and autogen.sh + Fixed typo in several makefiles (-W1 should be -Wl) + Added typedef for png_int_32 and png_uint_32 on 64-bit systems. + +Version 1.0.19rc3, 1.2.11rc3 [June 15, 2006] + Removed the new typedefs for 64-bit systems (delay until version 1.4.0) + Added one zero element to png_gamma_shift[] array in pngrtran.c to avoid + reading out of bounds. + +Version 1.0.19rc4, 1.2.11rc4 [June 15, 2006] + Really removed the new typedefs for 64-bit systems. + +Version 1.0.19rc5, 1.2.11rc5 [June 22, 2006] + Removed png_sig_bytes entry from scripts/pngw32.def + +Version 1.0.19, 1.2.11 [June 26, 2006] + None. + +Version 1.0.20, 1.2.12 [June 27, 2006] + Really increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid + buffer overflow. + +Version 1.2.13beta1 [October 2, 2006] + Removed AC_FUNC_MALLOC from configure.ac + Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h + Change "logical" to "bitwise" throughout documentation. + Detect and fix attempt to write wrong iCCP profile length (CVE-2006-7244) + +Version 1.0.21, 1.2.13 [November 14, 2006] + Fix potential buffer overflow in sPLT chunk handler. + Fix Makefile.am to not try to link to noexistent files. + Check all exported functions for NULL png_ptr. + +Version 1.2.14beta1 [November 17, 2006] + Relocated three misplaced tests for NULL png_ptr. + Built Makefile.in with automake-1.9.6 instead of 1.9.2. + Build configure with autoconf-2.60 instead of 2.59 + +Version 1.2.14beta2 [November 17, 2006] + Added some typecasts in png_zalloc(). + +Version 1.2.14rc1 [November 20, 2006] + Changed "strtod" to "png_strtod" in pngrutil.c + +Version 1.0.22, 1.2.14 [November 27, 2006] + Added missing "$(srcdir)" in Makefile.am and Makefile.in + +Version 1.2.15beta1 [December 3, 2006] + Generated configure with autoconf-2.61 instead of 2.60 + Revised configure.ac to update libpng.pc and libpng-config. + +Version 1.2.15beta2 [December 3, 2006] + Always export MMX asm functions, just stubs if not building pnggccrd.c + +Version 1.2.15beta3 [December 4, 2006] + Add "png_bytep" typecast to profile while calculating length in pngwutil.c + +Version 1.2.15beta4 [December 7, 2006] + Added scripts/CMakeLists.txt + Changed PNG_NO_ASSEMBLER_CODE to PNG_NO_MMX_CODE in scripts, like 1.4.0beta + +Version 1.2.15beta5 [December 7, 2006] + Changed some instances of PNG_ASSEMBLER_* to PNG_MMX_* in pnggccrd.c + Revised scripts/CMakeLists.txt + +Version 1.2.15beta6 [December 13, 2006] + Revised scripts/CMakeLists.txt and configure.ac + +Version 1.2.15rc1 [December 18, 2006] + Revised scripts/CMakeLists.txt + +Version 1.2.15rc2 [December 21, 2006] + Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers. + Added scripts/makefile.nommx + +Version 1.2.15rc3 [December 25, 2006] + Fixed shared library numbering error that was introduced in 1.2.15beta6. + +Version 1.2.15rc4 [December 27, 2006] + Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set. + +Version 1.2.15rc5 [December 31, 2006] + Revised handling of rgb_to_gray. + +Version 1.2.15 [January 5, 2007] + Added some (unsigned long) typecasts in pngtest.c to avoid printing errors. + +Version 1.2.16beta1 [January 6, 2007] + Fix bugs in makefile.nommx + +Version 1.2.16beta2 [January 16, 2007] + Revised scripts/CMakeLists.txt + +Version 1.2.16 [January 31, 2007] + No changes. + +Version 1.2.17beta1 [March 6, 2007] + Revised scripts/CMakeLists.txt to install both shared and static libraries. + Deleted a redundant line from pngset.c. + +Version 1.2.17beta2 [April 26, 2007] + Relocated misplaced test for png_ptr == NULL in pngpread.c + Change "==" to "&" for testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN + flags. + Changed remaining instances of PNG_ASSEMBLER_* to PNG_MMX_* + Added pngerror() when write_IHDR fails in deflateInit2(). + Added "const" to some array declarations. + Mention examples of libpng usage in the libpng*.txt and libpng.3 documents. + +Version 1.2.17rc1 [May 4, 2007] + No changes. + +Version 1.2.17rc2 [May 8, 2007] + Moved several PNG_HAVE_* macros out of PNG_INTERNAL because applications + calling set_unknown_chunk_location() need them. + Changed transformation flag from PNG_EXPAND_tRNS to PNG_EXPAND in + png_set_expand_gray_1_2_4_to_8(). + Added png_ptr->unknown_chunk to hold working unknown chunk data, so it + can be free'ed in case of error. Revised unknown chunk handling in + pngrutil.c and pngpread.c to use this structure. + +Version 1.2.17rc3 [May 8, 2007] + Revised symbol-handling in configure script. + +Version 1.2.17rc4 [May 10, 2007] + Revised unknown chunk handling to avoid storing unknown critical chunks. + +Version 1.0.25 [May 15, 2007] +Version 1.2.17 [May 15, 2007] + Added "png_ptr->num_trans=0" before error return in png_handle_tRNS, + to eliminate a vulnerability (CVE-2007-2445, CERT VU#684664) + +Version 1.0.26 [May 15, 2007] +Version 1.2.18 [May 15, 2007] + Reverted the libpng-1.2.17rc3 change to symbol-handling in configure script + +Version 1.2.19beta1 [May 18, 2007] + Changed "const static" to "static PNG_CONST" everywhere, mostly undoing + change of libpng-1.2.17beta2. Changed other "const" to "PNG_CONST" + Changed some handling of unused parameters, to avoid compiler warnings. + "if (unused == NULL) return;" becomes "unused = unused". + +Version 1.2.19beta2 [May 18, 2007] + Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier) + +Version 1.2.19beta3 [May 19, 2007] + Add some "png_byte" typecasts in png_check_keyword() and write new_key + instead of key in zTXt chunk (Kevin Ryde). + +Version 1.2.19beta4 [May 21, 2007] + Add png_snprintf() function and use it in place of sprint() for improved + defense against buffer overflows. + +Version 1.2.19beta5 [May 21, 2007] + Fixed png_handle_tRNS() to only use the valid bits of tRNS value. + Changed handling of more unused parameters, to avoid compiler warnings. + Removed some PNG_CONST in pngwutil.c to avoid compiler warnings. + +Version 1.2.19beta6 [May 22, 2007] + Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c + Added a special "_MSC_VER" case that defines png_snprintf to _snprintf + +Version 1.2.19beta7 [May 22, 2007] + Squelched png_squelch_warnings() in pnggccrd.c and added + an #ifdef PNG_MMX_CODE_SUPPORTED block around the declarations that caused + the warnings that png_squelch_warnings was squelching. + +Version 1.2.19beta8 [May 22, 2007] + Removed __MMX__ from test in pngconf.h. + +Version 1.2.19beta9 [May 23, 2007] + Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro. + Revised png_squelch_warnings() so it might work. + Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86. + +Version 1.2.19beta10 [May 24, 2007] + Resquelched png_squelch_warnings(), use "__attribute__((used))" instead. + +Version 1.4.0beta1 [April 20, 2006] + Enabled iTXt support (changes png_struct, thus requires so-number change). + Cleaned up PNG_ASSEMBLER_CODE_SUPPORTED vs PNG_MMX_CODE_SUPPORTED + Eliminated PNG_1_0_X and PNG_1_2_X macros. + Removed deprecated functions png_read_init, png_write_init, png_info_init, + png_permit_empty_plte, png_set_gray_1_2_4_to_8, png_check_sig, and + removed the deprecated macro PNG_MAX_UINT. + Moved "PNG_INTERNAL" parts of png.h and pngconf.h into pngintrn.h + Removed many WIN32_WCE #ifdefs (Cosmin). + Reduced dependency on C-runtime library when on Windows (Simon-Pierre) + Replaced sprintf() with png_sprintf() (Simon-Pierre) + +Version 1.4.0beta2 [April 20, 2006] + Revised makefiles and configure to avoid making links to libpng.so.* + Moved some leftover MMX-related defines from pngconf.h to pngintrn.h + Updated scripts/pngos2.def, pngw32.def, and projects/wince/png32ce.def + +Version 1.4.0beta3 [May 10, 2006] + Updated scripts/pngw32.def to comment out MMX functions. + Added PNG_NO_GET_INT_32 and PNG_NO_SAVE_INT_32 macros. + Scripts/libpng.pc.in contained "configure" style version info and would + not work with makefiles. + Revised pngconf.h and added pngconf.h.in, so makefiles and configure can + pass defines to libpng and applications. + +Version 1.4.0beta4 [May 11, 2006] + Revised configure.ac, Makefile.am, and many of the makefiles to write + their defines in pngconf.h. + +Version 1.4.0beta5 [May 15, 2006] + Added a missing semicolon in Makefile.am and Makefile.in + Deleted extraneous square brackets from configure.ac + +Version 1.4.0beta6 [June 2, 2006] + Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid + buffer overflow. + Changed sonum from 0 to 1. + Removed unused prototype for png_check_sig() from png.h + +Version 1.4.0beta7 [June 16, 2006] + Exported png_write_sig (Cosmin). + Optimized buffer in png_handle_cHRM() (Cosmin). + Set pHYs = 2835 x 2835 pixels per meter, and added + sCAL = 0.352778e-3 x 0.352778e-3 meters, in pngtest.png (Cosmin). + Added png_set_benign_errors(), png_benign_error(), png_chunk_benign_error(). + Added typedef for png_int_32 and png_uint_32 on 64-bit systems. + Added "(unsigned long)" typecast on png_uint_32 variables in printf lists. + +Version 1.4.0beta8 [June 22, 2006] + Added demonstration of user chunk support in pngtest.c, to support the + public sTER chunk and a private vpAg chunk. + +Version 1.4.0beta9 [July 3, 2006] + Removed ordinals from scripts/pngw32.def and removed png_info_int and + png_set_gray_1_2_4_to_8 entries. + Inline call of png_get_uint_32() in png_get_uint_31(). + Use png_get_uint_31() to get vpAg width and height in pngtest.c + Removed WINCE and Netware projects. + Removed standalone Y2KINFO file. + +Version 1.4.0beta10 [July 12, 2006] + Eliminated automatic copy of pngconf.h to pngconf.h.in from configure and + some makefiles, because it was not working reliably. Instead, distribute + pngconf.h.in along with pngconf.h and cause configure and some of the + makefiles to update pngconf.h from pngconf.h.in. + Added pngconf.h to DEPENDENCIES in Makefile.am + +Version 1.4.0beta11 [August 19, 2006] + Removed AC_FUNC_MALLOC from configure.ac. + Added a warning when writing iCCP profile with mismatched profile length. + Patched pnggccrd.c to assemble on x86_64 platforms. + Moved chunk header reading into a separate function png_read_chunk_header() + in pngrutil.c. The chunk header (len+sig) is now serialized in a single + operation (Cosmin). + Implemented support for I/O states. Added png_ptr member io_state, and + functions png_get_io_chunk_name() and png_get_io_state() in pngget.c + (Cosmin). + Added png_get_io_chunk_name and png_get_io_state to scripts/*.def (Cosmin). + Renamed scripts/pngw32.* to scripts/pngwin.* (Cosmin). + Removed the include directories and libraries from CFLAGS and LDFLAGS + in scripts/makefile.gcc (Cosmin). + Used png_save_uint_32() to set vpAg width and height in pngtest.c (Cosmin). + Cast to proper type when getting/setting vpAg units in pngtest.c (Cosmin). + Added pngintrn.h to the Visual C++ projects (Cosmin). + Removed scripts/list (Cosmin). + Updated copyright year in scripts/pngwin.def (Cosmin). + Removed PNG_TYPECAST_NULL and used standard NULL consistently (Cosmin). + Disallowed the user to redefine png_size_t, and enforced a consistent use + of png_size_t across libpng (Cosmin). + Changed the type of png_ptr->rowbytes, PNG_ROWBYTES() and friends + to png_size_t (Cosmin). + Removed png_convert_size() and replaced png_sizeof with sizeof (Cosmin). + Removed some unnecessary type casts (Cosmin). + Changed prototype of png_get_compression_buffer_size() and + png_set_compression_buffer_size() to work with png_size_t instead of + png_uint_32 (Cosmin). + Removed png_memcpy_check() and png_memset_check() (Cosmin). + Fixed a typo (png_byte --> png_bytep) in libpng.3 and libpng.txt (Cosmin). + Clarified that png_zalloc() does not clear the allocated memory, + and png_zalloc() and png_zfree() cannot be PNGAPI (Cosmin). + Renamed png_mem_size_t to png_alloc_size_t, fixed its definition in + pngconf.h, and used it in all memory allocation functions (Cosmin). + Renamed pngintrn.h to pngpriv.h, added a comment at the top of the file + mentioning that the symbols declared in that file are private, and + updated the scripts and the Visual C++ projects accordingly (Cosmin). + Removed circular references between pngconf.h and pngconf.h.in in + scripts/makefile.vc*win32 (Cosmin). + Removing trailing '.' from the warning and error messages (Cosmin). + Added pngdefs.h that is built by makefile or configure, instead of + pngconf.h.in (Glenn). + Detect and fix attempt to write wrong iCCP profile length. + +Version 1.4.0beta12 [October 19, 2006] + Changed "logical" to "bitwise" in the documentation. + Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h + Add a typecast to stifle compiler warning in pngrutil.c + +Version 1.4.0beta13 [November 10, 2006] + Fix potential buffer overflow in sPLT chunk handler. + Fix Makefile.am to not try to link to noexistent files. + +Version 1.4.0beta14 [November 15, 2006] + Check all exported functions for NULL png_ptr. + +Version 1.4.0beta15 [November 17, 2006] + Relocated two misplaced tests for NULL png_ptr. + Built Makefile.in with automake-1.9.6 instead of 1.9.2. + Build configure with autoconf-2.60 instead of 2.59 + Add "install: all" in Makefile.am so "configure; make install" will work. + +Version 1.4.0beta16 [November 17, 2006] + Added a typecast in png_zalloc(). + +Version 1.4.0beta17 [December 4, 2006] + Changed "new_key[79] = '\0';" to "(*new_key)[79] = '\0';" in pngwutil.c + Add "png_bytep" typecast to profile while calculating length in pngwutil.c + +Version 1.4.0beta18 [December 7, 2006] + Added scripts/CMakeLists.txt + +Version 1.4.0beta19 [May 16, 2007] + Revised scripts/CMakeLists.txt + Rebuilt configure and Makefile.in with newer tools. + Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers. + Added scripts/makefile.nommx + +Version 1.4.0beta20 [July 9, 2008] + Moved several PNG_HAVE_* macros from pngpriv.h to png.h because applications + calling set_unknown_chunk_location() need them. + Moved several macro definitions from pngpriv.h to pngconf.h + Merge with changes to the 1.2.X branch, as of 1.2.30beta04. + Deleted all use of the MMX assembler code and Intel-licensed optimizations. + Revised makefile.mingw + +Version 1.4.0beta21 [July 21, 2008] + Moved local array "chunkdata" from pngrutil.c to the png_struct, so + it will be freed by png_read_destroy() in case of a read error (Kurt + Christensen). + +Version 1.4.0beta22 [July 21, 2008] + Change "purpose" and "buffer" to png_ptr->chunkdata to avoid memory leaking. + +Version 1.4.0beta23 [July 22, 2008] + Change "chunkdata = NULL" to "png_ptr->chunkdata = NULL" several places in + png_decompress_chunk(). + +Version 1.4.0beta24 [July 25, 2008] + Change all remaining "chunkdata" to "png_ptr->chunkdata" in + png_decompress_chunk(), and remove "chunkdata" from parameter list. + Put a call to png_check_chunk_name() in png_read_chunk_header(). + Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte. + Removed two calls to png_check_chunk_name() occuring later in the process. + Define PNG_NO_ERROR_NUMBERS by default in pngconf.h + +Version 1.4.0beta25 [July 30, 2008] + Added a call to png_check_chunk_name() in pngpread.c + Reverted png_check_chunk_name() to accept a name with a lowercase 3rd byte. + Added png_push_have_buffer() function to pngpread.c + Eliminated PNG_BIG_ENDIAN_SUPPORTED and associated png_get_* macros. + Made inline expansion of png_get_*() optional with PNG_USE_READ_MACROS. + Eliminated all PNG_USELESS_TESTS and PNG_CORRECT_PALETTE_SUPPORTED code. + Synced contrib directory and configure files with libpng-1.2.30beta06. + Eliminated no-longer-used pngdefs.h (but it's still built in the makefiles) + Relocated a misplaced "#endif /* PNG_NO_WRITE_FILTER */" in pngwutil.c + +Version 1.4.0beta26 [August 4, 2008] + Removed png_push_have_buffer() function in pngpread.c. It increased the + compiled library size slightly. + Changed "-Wall" to "-W -Wall" in the CFLAGS in all makefiles (Cosmin Truta) + Declared png_ptr "volatile" in pngread.c and pngwrite.c to avoid warnings. + Updated contrib/visupng/cexcept.h to version 2.0.1 + Added PNG_LITERAL_CHARACTER macros for #, [, and ]. + +Version 1.4.0beta27 [August 5, 2008] + Revised usage of PNG_LITERAL_SHARP in pngerror.c. + Moved newline character from individual png_debug messages into the + png_debug macros. + Allow user to #define their own png_debug, png_debug1, and png_debug2. + +Version 1.4.0beta28 [August 5, 2008] + Revised usage of PNG_LITERAL_SHARP in pngerror.c. + Added PNG_STRING_NEWLINE macro + +Version 1.4.0beta29 [August 9, 2008] + Revised usage of PNG_STRING_NEWLINE to work on non-ISO compilers. + Added PNG_STRING_COPYRIGHT macro. + Added non-ISO versions of png_debug macros. + +Version 1.4.0beta30 [August 14, 2008] + Added premultiplied alpha feature (Volker Wiendl). + +Version 1.4.0beta31 [August 18, 2008] + Moved png_set_premultiply_alpha from pngtrans.c to pngrtran.c + Removed extra crc check at the end of png_handle_cHRM(). Bug introduced + in libpng-1.4.0beta20. + +Version 1.4.0beta32 [August 19, 2008] + Added PNG_WRITE_FLUSH_SUPPORTED block around new png_flush() call. + Revised PNG_NO_STDIO version of png_write_flush() + +Version 1.4.0beta33 [August 20, 2008] + Added png_get|set_chunk_cache_max() to limit the total number of sPLT, + text, and unknown chunks that can be stored. + +Version 1.4.0beta34 [September 6, 2008] + Shortened tIME_string to 29 bytes in pngtest.c + Fixed off-by-one error introduced in png_push_read_zTXt() function in + libpng-1.2.30beta04/pngpread.c (Harald van Dijk) + +Version 1.4.0beta35 [October 6, 2008] + Changed "trans_values" to "trans_color". + Changed so-number from 0 to 14. Some OS do not like 0. + Revised makefile.darwin to fix shared library numbering. + Change png_set_gray_1_2_4_to_8() to png_set_expand_gray_1_2_4_to_8() + in example.c (debian bug report) + +Version 1.4.0beta36 [October 25, 2008] + Sync with tEXt vulnerability fix in libpng-1.2.33rc02. + +Version 1.4.0beta37 [November 13, 2008] + Added png_check_cHRM in png.c and moved checking from pngget.c, pngrutil.c, + and pngwrite.c + +Version 1.4.0beta38 [November 22, 2008] + Added check for zero-area RGB cHRM triangle in png_check_cHRM() and + png_check_cHRM_fixed(). + +Version 1.4.0beta39 [November 23, 2008] + Revised png_warning() to write its message on standard output by default + when warning_fn is NULL. + +Version 1.4.0beta40 [November 24, 2008] + Eliminated png_check_cHRM(). Instead, always use png_check_cHRM_fixed(). + In png_check_cHRM_fixed(), ensure white_y is > 0, and removed redundant + check for all-zero coordinates that is detected by the triangle check. + +Version 1.4.0beta41 [November 26, 2008] + Fixed string vs pointer-to-string error in png_check_keyword(). + Rearranged test expressions in png_check_cHRM_fixed() to avoid internal + overflows. + Added PNG_NO_CHECK_cHRM conditional. + +Version 1.4.0beta42, 43 [December 1, 2008] + Merge png_debug with version 1.2.34beta04. + +Version 1.4.0beta44 [December 6, 2008] + Removed redundant check for key==NULL before calling png_check_keyword() + to ensure that new_key gets initialized and removed extra warning + (Merge with version 1.2.34beta05 -- Arvan Pritchard). + +Version 1.4.0beta45 [December 9, 2008] + In png_write_png(), respect the placement of the filler bytes in an earlier + call to png_set_filler() (Jim Barry). + +Version 1.4.0beta46 [December 10, 2008] + Undid previous change and added PNG_TRANSFORM_STRIP_FILLER_BEFORE and + PNG_TRANSFORM_STRIP_FILLER_AFTER conditionals and deprecated + PNG_TRANSFORM_STRIP_FILLER (Jim Barry). + +Version 1.4.0beta47 [December 15, 2008] + Support for dithering was disabled by default, because it has never + been well tested and doesn't work very well. The code has not + been removed, however, and can be enabled by building libpng with + PNG_READ_DITHER_SUPPORTED defined. + +Version 1.4.0beta48 [February 14, 2009] + Added new exported function png_calloc(). + Combined several instances of png_malloc(); png_memset() into png_calloc(). + Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24 + but was never defined. + +Version 1.4.0beta49 [February 28, 2009] + Added png_fileno() macro to pngconf.h, used in pngwio.c + Corrected order of #ifdef's in png_debug definition in png.h + Fixed bug introduced in libpng-1.4.0beta48 with the memset arguments + for pcal_params. + Fixed order of #ifdef directives in the png_debug defines in png.h + (bug introduced in libpng-1.2.34/1.4.0beta29). + Revised comments in png_set_read_fn() and png_set_write_fn(). + +Version 1.4.0beta50 [March 18, 2009] + Use png_calloc() instead of png_malloc() to allocate big_row_buf when + reading an interlaced file, to avoid a possible UMR. + Undid revision of PNG_NO_STDIO version of png_write_flush(). Users + having trouble with fflush() can build with PNG_NO_WRITE_FLUSH defined + or supply their own flush_fn() replacement. + Revised libpng*.txt and png.h documentation about use of png_write_flush() + and png_set_write_fn(). + Removed fflush() from pngtest.c. + Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h + +Version 1.4.0beta51 [March 21, 2009] + Removed new png_fileno() macro from pngconf.h . + +Version 1.4.0beta52 [March 27, 2009] + Relocated png_do_chop() ahead of building gamma tables in pngrtran.c + This avoids building 16-bit gamma tables unnecessarily. + Removed fflush() from pngtest.c. + Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h + Added a section on differences between 1.0.x and 1.2.x to libpng.3/libpng.txt + +Version 1.4.0beta53 [April 1, 2009] + Removed some remaining MMX macros from pngpriv.h + Fixed potential memory leak of "new_name" in png_write_iCCP() (Ralph Giles) + +Version 1.4.0beta54 [April 13, 2009] + Added "ifndef PNG_SKIP_SETJMP_CHECK" block in pngconf.h to allow + application code writers to bypass the check for multiple inclusion + of setjmp.h when they know that it is safe to ignore the situation. + Eliminated internal use of setjmp() in pngread.c and pngwrite.c + Reordered ancillary chunks in pngtest.png to be the same as what + pngtest now produces, and made some cosmetic changes to pngtest output. + Eliminated deprecated png_read_init_3() and png_write_init_3() functions. + +Version 1.4.0beta55 [April 15, 2009] + Simplified error handling in pngread.c and pngwrite.c by putting + the new png_read_cleanup() and png_write_cleanup() functions inline. + +Version 1.4.0beta56 [April 25, 2009] + Renamed "user_chunk_data" to "my_user_chunk_data" in pngtest.c to suppress + "shadowed declaration" warning from gcc-4.3.3. + Renamed "gamma" to "png_gamma" in pngset.c to avoid "shadowed declaration" + warning about a global "gamma" variable in math.h on some platforms. + +Version 1.4.0beta57 [May 2, 2009] + Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24 + but was never defined (again). + Rebuilt configure scripts with autoconf-2.63 instead of 2.62 + Removed pngprefs.h and MMX from makefiles + +Version 1.4.0beta58 [May 14, 2009] + Changed pngw32.def to pngwin.def in makefile.mingw (typo was introduced + in beta57). + Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri) + +Version 1.4.0beta59 [May 15, 2009] + Reformated sources in libpng style (3-space intentation, comment format) + Fixed typo in libpng docs (PNG_FILTER_AVE should be PNG_FILTER_AVG) + Added sections about the git repository and our coding style to the + documentation + Relocated misplaced #endif in pngwrite.c, sCAL chunk handler. + +Version 1.4.0beta60 [May 19, 2009] + Conditionally compile png_read_finish_row() which is not used by + progressive readers. + Added contrib/pngminim/preader to demonstrate building minimal progressive + decoder, based on contrib/gregbook with embedded libpng and zlib. + +Version 1.4.0beta61 [May 20, 2009] + In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there + is only one makefile in those directories, and revised the README files + accordingly. + More reformatting of comments, mostly to capitalize sentences. + +Version 1.4.0beta62 [June 2, 2009] + Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h + and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h + Reformatted several remaining "else statement" into two lines. + Added a section to the libpng documentation about using png_get_io_ptr() + in configure scripts to detect the presence of libpng. + +Version 1.4.0beta63 [June 15, 2009] + Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR() + multiple times and to specify the sample order in the tRNS chunk, + because the ISO PNG specification has a typo in the tRNS table. + Changed several PNG_UNKNOWN_CHUNK_SUPPORTED to + PNG_HANDLE_AS_UNKNOWN_SUPPORTED, to make the png_set_keep mechanism + available for ignoring known chunks even when not saving unknown chunks. + Adopted preference for consistent use of "#ifdef" and "#ifndef" versus + "#if defined()" and "if !defined()" where possible. + +Version 1.4.0beta64 [June 24, 2009] + Eliminated PNG_LEGACY_SUPPORTED code. + Moved the various unknown chunk macro definitions outside of the + PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks. + +Version 1.4.0beta65 [June 26, 2009] + Added a reference to the libpng license in each file. + +Version 1.4.0beta66 [June 27, 2009] + Refer to the libpng license instead of the libpng license in each file. + +Version 1.4.0beta67 [July 6, 2009] + Relocated INVERT_ALPHA within png_read_png() and png_write_png(). + Added high-level API transform PNG_TRANSFORM_GRAY_TO_RGB. + Added an "xcode" project to the projects directory (Alam Arias). + +Version 1.4.0beta68 [July 19, 2009] + Avoid some tests in filter selection in pngwutil.c + +Version 1.4.0beta69 [July 25, 2009] + Simplified the new filter-selection test. This runs faster in the + common "PNG_ALL_FILTERS" and PNG_FILTER_NONE cases. + Removed extraneous declaration from the new call to png_read_gray_to_rgb() + (bug introduced in libpng-1.4.0beta67). + Fixed up xcode project (Alam Arias) + Added a prototype for png_64bit_product() in png.c + +Version 1.4.0beta70 [July 27, 2009] + Avoid a possible NULL dereference in debug build, in png_set_text_2(). + (bug introduced in libpng-0.95, discovered by Evan Rouault) + +Version 1.4.0beta71 [July 29, 2009] + Rebuilt configure scripts with autoconf-2.64. + +Version 1.4.0beta72 [August 1, 2009] + Replaced *.tar.lzma with *.tar.xz in distribution. Get the xz codec + from <http://tukaani.org/xz>. + +Version 1.4.0beta73 [August 1, 2009] + Reject attempt to write iCCP chunk with negative embedded profile length + (JD Chen) (CVE-2009-5063). + +Version 1.4.0beta74 [August 8, 2009] + Changed png_ptr and info_ptr member "trans" to "trans_alpha". + +Version 1.4.0beta75 [August 21, 2009] + Removed an extra png_debug() recently added to png_write_find_filter(). + Fixed incorrect #ifdef in pngset.c regarding unknown chunk support. + +Version 1.4.0beta76 [August 22, 2009] + Moved an incorrectly located test in png_read_row() in pngread.c + +Version 1.4.0beta77 [August 27, 2009] + Removed lpXYZ.tar.bz2 (with CRLF), KNOWNBUG, libpng-x.y.z-KNOWNBUG.txt, + and the "noconfig" files from the distribution. + Moved CMakeLists.txt from scripts into the main libpng directory. + Various bugfixes and improvements to CMakeLists.txt (Philip Lowman) + +Version 1.4.0beta78 [August 31, 2009] + Converted all PNG_NO_* tests to PNG_*_SUPPORTED everywhere except pngconf.h + Eliminated PNG_NO_FREE_ME and PNG_FREE_ME_SUPPORTED macros. + Use png_malloc plus a loop instead of png_calloc() to initialize + row_pointers in png_read_png(). + +Version 1.4.0beta79 [September 1, 2009] + Eliminated PNG_GLOBAL_ARRAYS and PNG_LOCAL_ARRAYS; always use local arrays. + Eliminated PNG_CALLOC_SUPPORTED macro and always provide png_calloc(). + +Version 1.4.0beta80 [September 17, 2009] + Removed scripts/libpng.icc + Changed typecast of filler from png_byte to png_uint_16 in png_set_filler(). + (Dennis Gustafsson) + Fixed typo introduced in beta78 in pngtest.c ("#if def " should be "#ifdef ") + +Version 1.4.0beta81 [September 23, 2009] + Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h + Expanded TAB characters in pngrtran.c + Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid + compiler complaints about doubly declaring things "const". + Changed all "#if [!]defined(X)" to "if[n]def X" where possible. + Eliminated unused png_ptr->row_buf_size + +Version 1.4.0beta82 [September 25, 2009] + Moved redundant IHDR checking into new png_check_IHDR() in png.c + and report all errors found in the IHDR data. + Eliminated useless call to png_check_cHRM() from pngset.c + +Version 1.4.0beta83 [September 25, 2009] + Revised png_check_IHDR() to eliminate bogus complaint about filter_type. + +Version 1.4.0beta84 [September 30, 2009] + Fixed some inconsistent indentation in pngconf.h + Revised png_check_IHDR() to add a test for width variable less than 32-bit. + +Version 1.4.0beta85 [October 1, 2009] + Revised png_check_IHDR() again, to check info_ptr members instead of + the contents of the returned parameters. + +Version 1.4.0beta86 [October 9, 2009] + Updated the "xcode" project (Alam Arias). + Eliminated a shadowed declaration of "pp" in png_handle_sPLT(). + +Version 1.4.0rc01 [October 19, 2009] + Trivial cosmetic changes. + +Version 1.4.0beta87 [October 30, 2009] + Moved version 1.4.0 back into beta. + +Version 1.4.0beta88 [October 30, 2009] + Revised libpng*.txt section about differences between 1.2.x and 1.4.0 + because most of the new features have now been ported back to 1.2.41 + +Version 1.4.0beta89 [November 1, 2009] + More bugfixes and improvements to CMakeLists.txt (Philip Lowman) + Removed a harmless extra png_set_invert_alpha() from pngwrite.c + Apply png_user_chunk_cache_max within png_decompress_chunk(). + Merged libpng-1.2.41.txt with libpng-1.4.0.txt where appropriate. + +Version 1.4.0beta90 [November 2, 2009] + Removed all remaining WIN32_WCE #ifdefs except those involving the + time.h "tm" structure + +Version 1.4.0beta91 [November 3, 2009] + Updated scripts/pngw32.def and projects/wince/png32ce.def + Copied projects/wince/png32ce.def to the scripts directory. + Added scripts/makefile.wce + Patched ltmain.sh for wince support. + Added PNG_CONVERT_tIME_SUPPORTED macro. + +Version 1.4.0beta92 [November 4, 2009] + Make inclusion of time.h in pngconf.h depend on PNG_CONVERT_tIME_SUPPORTED + Make #define PNG_CONVERT_tIME_SUPPORTED depend on PNG_WRITE_tIME_SUPPORTED + Revised libpng*.txt to describe differences from 1.2.40 to 1.4.0 (instead + of differences from 1.2.41 to 1.4.0) + +Version 1.4.0beta93 [November 7, 2009] + Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and + PNG_ALLOCATED macros to detect deprecated direct access to the + png_struct or info_struct members and other deprecated usage in + applications (John Bowler). + Updated scripts/makefile* to add "-DPNG_CONFIGURE_LIBPNG" to CFLAGS, + to prevent warnings about direct access to png structs by libpng + functions while building libpng. They need to be tested, especially + those using compilers other than gcc. + Updated projects/visualc6 and visualc71 with "/d PNG_CONFIGURE_LIBPNG". + They should work but still need to be updated to remove + references to pnggccrd.c or pngvcrd.c and ASM building. + Added README.txt to the beos, cbuilder5, netware, and xcode projects warning + that they need to be updated, to remove references to pnggccrd.c and + pngvcrd.c and to depend on pngpriv.h + Removed three direct references to read_info_ptr members in pngtest.c + that were detected by the new PNG_DEPSTRUCT macro. + Moved the png_debug macro definitions and the png_read_destroy(), + png_write_destroy() and png_far_to_near() prototypes from png.h + to pngpriv.h (John Bowler) + Moved the synopsis lines for png_read_destroy(), png_write_destroy() + png_debug(), png_debug1(), and png_debug2() from libpng.3 to libpngpf.3. + +Version 1.4.0beta94 [November 9, 2009] + Removed the obsolete, unused pnggccrd.c and pngvcrd.c files. + Updated CMakeLists.txt to add "-DPNG_CONFIGURE_LIBPNG" to the definitions. + Removed dependency of pngtest.o on pngpriv.h in the makefiles. + Only #define PNG_DEPSTRUCT, etc. in pngconf.h if not already defined. + +Version 1.4.0beta95 [November 10, 2009] + Changed png_check_sig() to !png_sig_cmp() in contrib programs. + Added -DPNG_CONFIGURE_LIBPNG to contrib/pngminm/*/makefile + Changed png_check_sig() to !png_sig_cmp() in contrib programs. + Corrected the png_get_IHDR() call in contrib/gregbook/readpng2.c + Changed pngminim/*/gather.sh to stop trying to remove pnggccrd.c and pngvcrd.c + Added dependency on pngpriv.h in contrib/pngminim/*/makefile + +Version 1.4.0beta96 [November 12, 2009] + Renamed scripts/makefile.wce to scripts/makefile.cegcc + Revised Makefile.am to use libpng.sys while building libpng.so + so that only PNG_EXPORT functions are exported. + Removed the deprecated png_check_sig() function/macro. + Removed recently removed function names from scripts/*.def + Revised pngtest.png to put chunks in the same order written by pngtest + (evidently the same change made in libpng-1.0beta54 was lost). + Added PNG_PRIVATE macro definition in pngconf.h for possible future use. + +Version 1.4.0beta97 [November 13, 2009] + Restored pngtest.png to the libpng-1.4.0beta7 version. + Removed projects/beos and netware.txt; no one seems to be supporting them. + Revised Makefile.in + +Version 1.4.0beta98 [November 13, 2009] + Added the "xcode" project to zip distributions, + Fixed a typo in scripts/pngwin.def introduced in beta97. + +Version 1.4.0beta99 [November 14, 2009] + Moved libpng-config.in and libpng.pc-configure.in out of the scripts + directory, to libpng-config.in and libpng-pc.in, respectively, and + modified Makefile.am and configure.ac accordingly. Now "configure" + needs nothing from the "scripts" directory. + Avoid redefining PNG_CONST in pngconf.h + +Version 1.4.0beta100 [November 14, 2009] + Removed ASM builds from projects/visualc6 and projects/visualc71 + Removed scripts/makefile.nommx and makefile.vcawin32 + Revised CMakeLists.txt to account for new location of libpng-config.in + and libpng-pc.in + Updated INSTALL to reflect removal and relocation of files. + +Version 1.4.0beta101 [November 14, 2009] + Restored the binary files (*.jpg, *.png, some project files) that were + accidentally deleted from the zip and 7z distributions when the xcode + project was added. + +Version 1.4.0beta102 [November 18, 2009] + Added libpng-config.in and libpng-pc.in to the zip and 7z distributions. + Fixed a typo in projects/visualc6/pngtest.dsp, introduced in beta100. + Moved descriptions of makefiles and other scripts out of INSTALL into + scripts/README.txt + Updated the copyright year in scripts/pngwin.rc from 2006 to 2009. + +Version 1.4.0beta103 [November 21, 2009] + Removed obsolete comments about ASM from projects/visualc71/README_zlib.txt + Align row_buf on 16-byte boundary in memory. + Restored the PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED guard around the call + to png_flush() after png_write_IEND(). See 1.4.0beta32, 1.4.0beta50 + changes above and 1.2.30, 1.2.30rc01 and rc03 in 1.2.41 CHANGES. Someone + needs this feature. + Make the 'png_jmpbuf' macro expand to a call that records the correct + longjmp function as well as returning a pointer to the setjmp + jmp_buf buffer, and marked direct access to jmpbuf 'deprecated'. + (John Bowler) + +Version 1.4.0beta104 [November 22, 2009] + Removed png_longjmp_ptr from scripts/*.def and libpng.3 + Rebuilt configure scripts with autoconf-2.65 + +Version 1.4.0beta105 [November 25, 2009] + Use fast integer PNG_DIVIDE_BY_255() or PNG_DIVIDE_BY_65535() + to accomplish alpha premultiplication when + PNG_READ_COMPOSITE_NODIV_SUPPORTED is defined. + Changed "/255" to "/255.0" in background calculations to make it clear + that the 255 is used as a double. + +Version 1.4.0beta106 [November 27, 2009] + Removed premultiplied alpha feature. + +Version 1.4.0beta107 [December 4, 2009] + Updated README + Added "#define PNG_NO_PEDANTIC_WARNINGS" in the libpng source files. + Removed "-DPNG_CONFIGURE_LIBPNG" from the makefiles and projects. + Revised scripts/makefile.netbsd, makefile.openbsd, and makefile.sco + to put png.h and pngconf.h in $prefix/include, like the other scripts, + instead of in $prefix/include/libpng. Also revised makefile.sco + to put them in $prefix/include/libpng15 instead of in + $prefix/include/libpng/libpng15. + +Version 1.4.0beta108 [December 11, 2009] + Removed leftover "-DPNG_CONFIGURE_LIBPNG" from contrib/pngminim/*/makefile + Relocated png_do_chop() to its original position in pngrtran.c; the + change in version 1.2.41beta08 caused transparency to be handled wrong + in some 16-bit datastreams (Yusaku Sugai). + +Version 1.4.0beta109 [December 13, 2009] + Added "bit_depth" parameter to the private png_build_gamma_table() function. + Pass bit_depth=8 to png_build_gamma_table() when bit_depth is 16 but the + PNG_16_TO_8 transform has been set, to avoid unnecessary build of 16-bit + tables. + +Version 1.4.0rc02 [December 20, 2009] + Declared png_cleanup_needed "volatile" in pngread.c and pngwrite.c + +Version 1.4.0rc03 [December 22, 2009] + Renamed libpng-pc.in back to libpng.pc.in and revised CMakeLists.txt + (revising the change in 1.4.0beta99) + +Version 1.4.0rc04 [December 25, 2009] + Swapped PNG_UNKNOWN_CHUNKS_SUPPORTED and PNG_HANDLE_AS_UNKNOWN_SUPPORTED + in pngset.c to be consistent with other changes in version 1.2.38. + +Version 1.4.0rc05 [December 25, 2009] + Changed "libpng-pc.in" to "libpng.pc.in" in configure.ac, configure, and + Makefile.in to be consistent with changes in libpng-1.4.0rc03 + +Version 1.4.0rc06 [December 29, 2009] + Reverted the gamma_table changes from libpng-1.4.0beta109. + Fixed some indentation errors. + +Version 1.4.0rc07 [January 1, 2010] + Revised libpng*.txt and libpng.3 about 1.2.x->1.4.x differences. + Use png_calloc() instead of png_malloc(); png_memset() in pngrutil.c + Update copyright year to 2010. + +Version 1.4.0rc08 [January 2, 2010] + Avoid deprecated references to png_ptr-io_ptr and png_ptr->error_ptr + in pngtest.c + +Version 1.4.0 [January 3, 2010] + No changes. + +Version 1.4.1beta01 [January 8, 2010] + Updated CMakeLists.txt for consistent indentation and to avoid an + unclosed if-statement warning (Philip Lowman). + Revised Makefile.am and Makefile.in to remove references to Y2KINFO, + KNOWNBUG, and libpng.la (Robert Schwebel). + Revised the makefiles to install the same files and symbolic + links as configure, except for libpng.la and libpng14.la. + Make png_set|get_compression_buffer_size() available even when + PNG_WRITE_SUPPORTED is not enabled. + Revised Makefile.am and Makefile.in to simplify their maintenance. + Revised scripts/makefile.linux to install a link to libpng14.so.14.1 + +Version 1.4.1beta02 [January 9, 2010] + Revised the rest of the makefiles to install a link to libpng14.so.14.1 + +Version 1.4.1beta03 [January 10, 2010] + Removed png_set_premultiply_alpha() from scripts/*.def + +Version 1.4.1rc01 [January 16, 2010] + No changes. + +Version 1.4.1beta04 [January 23, 2010] + Revised png_decompress_chunk() to improve speed and memory usage when + decoding large chunks. + Added png_set|get_chunk_malloc_max() functions. + +Version 1.4.1beta05 [January 26, 2010] + Relocated "int k" declaration in pngtest.c to minimize its scope. + +Version 1.4.1beta06 [January 28, 2010] + Revised png_decompress_chunk() to use a two-pass method suggested by + John Bowler. + +Version 1.4.1beta07 [February 6, 2010] + Folded some long lines in the source files. + Added defineable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX, + and a PNG_USER_LIMITS_SUPPORTED flag. + Eliminated use of png_ptr->irowbytes and reused the slot in png_ptr as + png_ptr->png_user_chunk_malloc_max. + Revised png_push_save_buffer() to do fewer but larger png_malloc() calls. + +Version 1.4.1beta08 [February 6, 2010] + Minor cleanup and updating of dates and copyright year. + +Version 1.5.0beta01 [February 7, 2010] + Moved declaration of png_struct into private pngstruct.h and png_info + into pnginfo.h + +Version 1.4.1beta09 and 1.5.0beta02 [February 7, 2010] + Reverted to original png_push_save_buffer() code. + +Version 1.4.1beta10 and 1.5.0beta03 [February 8, 2010] + Return allocated "old_buffer" in png_push_save_buffer() before + calling png_error(), to avoid a potential memory leak. + Updated configure script to use SO number 15. + +Version 1.5.0beta04 [February 9, 2010] + Removed malformed "incomplete struct declaration" of png_info from png.h + +Version 1.5.0beta05 [February 12, 2010] + Removed PNG_DEPSTRUCT markup in pngstruct.h and pnginfo.h, and undid the + linewrapping that it entailed. + Revised comments in pngstruct.h and pnginfo.h and added pointers to + the libpng license. + Changed PNG_INTERNAL to PNG_EXPOSE_INTERNAL_STRUCTURES + Removed the cbuilder5 project, which has not been updated to 1.4.0. + +Version 1.4.1beta12 and 1.5.0beta06 [February 14, 2010] + Fixed type declaration of png_get_chunk_malloc_max() in pngget.c (Daisuke + Nishikawa) + +Version 1.5.0beta07 [omitted] + +Version 1.5.0beta08 [February 19, 2010] + Changed #ifdef PNG_NO_STDIO_SUPPORTED to #ifdef PNG_NO_CONSOLE_IO_SUPPORTED + wherever png_snprintf() is used to construct error and warning messages. + Noted in scripts/makefile.mingw that it expects to be run under MSYS. + Removed obsolete unused MMX-querying support from contrib/gregbook + Added exported png_longjmp() function. + Removed the AIX redefinition of jmpbuf in png.h + Added -D_ALLSOURCE in configure.ac, makefile.aix, and CMakeLists.txt + when building on AIX. + +Version 1.5.0beta09 [February 19, 2010] + Removed -D_ALLSOURCE from configure.ac, makefile.aix, and CMakeLists.txt. + Changed the name of png_ptr->jmpbuf to png_ptr->png_jmpbuf in pngstruct.h + +Version 1.5.0beta10 [February 25, 2010] + Removed unused gzio.c from contrib/pngminim gather and makefile scripts + Removed replacement error handlers from contrib/gregbook. Because of + the new png_longjmp() function they are no longer needed. + +Version 1.5.0beta11 [March 6, 2010] + Removed checking for already-included setjmp.h from pngconf.h + Fixed inconsistent indentations and made numerous cosmetic changes. + Revised the "SEE ALSO" style of libpng.3, libpngpf.3, and png.5 + +Version 1.5.0beta12 [March 9, 2010] + Moved "#include png.h" inside pngpriv.h and removed "#include png.h" from + the source files, along with "#define PNG_EXPOSE_INTERNAL_STRUCTURES" + and "#define PNG_NO_PEDANTIC_WARNINGS" (John Bowler). + Created new pngdebug.h and moved debug definitions there. + +Version 1.5.0beta13 [March 10, 2010] + Protect pngstruct.h, pnginfo.h, and pngdebug.h from being included twice. + Revise the "#ifdef" blocks in png_inflate() so it will compile when neither + PNG_USER_CHUNK_MALLOC_MAX nor PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED + is defined. + Removed unused png_measure_compressed_chunk() from pngpriv.h and libpngpf.3 + Moved the 'config.h' support from pngconf.h to pngpriv.h + Removed PNGAPI from the png_longjmp_ptr typedef. + Eliminated dependence of pngtest.c on the private pngdebug.h file. + Make all png_debug macros into *unterminated* statements or + expressions (i.e. a trailing ';' must always be added) and correct + the format statements in various png_debug messages. + +Version 1.5.0beta14 [March 14, 2010] + Removed direct access to png_ptr->io_ptr from the Windows code in pngtest.c + Revised Makefile.am to account for recent additions and replacements. + Corrected CE and OS/2 DEF files (scripts/png*def) for symbols removed and + added ordinal numbers to the Windows DEF file and corrected the duplicated + ordinal numbers on CE symbols that are commented out. + Added back in export symbols that can be present in the Windows build but + are disabled by default. + PNG_EXPORT changed to include an 'ordinal' field for DEF file generation. + PNG_CALLBACK added to make callback definitions uniform. PNGAPI split + into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks), + and appropriate changes made to all files. Cygwin builds re-hinged to + allow procedure call standard changes and to remove the need for the DEF + file (fixes build on Cygwin). + Enabled 'attribute' warnings that are relevant to library APIs and callbacks. + Changed rules for generation of the various symbol files and added a new + rule for a DEF file (which is also added to the distribution). + Updated the symbol file generation to stop it adding spurious spaces + to EOL (coming from preprocessor macro expansion). Added a facility + to join tokens in the output and rewrite *.dfn to use this. + Eliminated scripts/*.def in favor of libpng.def; updated projects/visualc71 + and removed scripts/makefile.cygwin. + Made PNG_BUILD_DLL safe: it can be set whenever a DLL is being built. + Removed the include of sys/types.h - apparently unnecessary now on the + platforms on which it happened (all but Mac OS and RISC OS). + Moved the Mac OS test into pngpriv.h (the only place it is used.) + +Version 1.5.0beta15 [March 17, 2010] + Added symbols.chk target to Makefile.am to validate the symbols in png.h + against the new DEF file scripts/symbols.def. + Changed the default DEF file back to pngwin.def. + Removed makefile.mingw. + Eliminated PNG_NO_EXTERN and PNG_ALL_EXTERN + +Version 1.5.0beta16 [April 1, 2010] + Make png_text_struct independent of PNG_iTXt_SUPPORTED, so that + fields are initialized in all configurations. The READ/WRITE + macros (PNG_(READ|WRITE)_iTXt_SUPPORTED) still function as + before to disable code to actually read or write iTXt chunks + and iTXt_SUPPORTED can be used to detect presence of either + read or write support (but it is probably better to check for + the one actually required - read or write.) + Combined multiple png_warning() calls for a single error. + Restored the macro definition of png_check_sig(). + +Version 1.5.0beta17 [April 17, 2010] + Added some "(long)" typecasts to printf calls in png_handle_cHRM(). + Documented the fact that png_set_dither() was disabled since libpng-1.4.0. + Reenabled png_set_dither() but renamed it to png_set_quantize() to reflect + more accurately what it actually does. At the same time, renamed + the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros to + PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS. + Added some "(long)" typecasts to printf calls in png_handle_cHRM(). + Freeze build-time only configuration in the build. + In all prior versions of libpng most configuration options + controlled by compiler #defines had to be repeated by the + application code that used libpng. This patch changes this + so that compilation options that can only be changed at build + time are frozen in the build. Options that are compiler + dependent (and those that are system dependent) are evaluated + each time - pngconf.h holds these. Options that can be changed + per-file in the application are in png.h. Frozen options are + in the new installed header file pnglibconf.h (John Bowler) + Removed the xcode project because it has not been updated to work + with libpng-1.5.0. + Removed the ability to include optional pngusr.h + +Version 1.5.0beta18 [April 17, 2010] + Restored the ability to include optional pngusr.h + Moved replacements for png_error() and png_warning() from the + contrib/pngminim project to pngerror.c, for use when warnings or + errors are disabled via PNG_NO_WARN or PNG_NO_ERROR_TEXT, to avoid + storing unneeded error/warning text. + Updated contrib/pngminim project to work with the new pnglibconf.h + Added some PNG_NO_* defines to contrib/pngminim/*/pngusr.h to save space. + +Version 1.5.0beta19 [April 24, 2010] + Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED. This allows the functions + to read and write ints to be disabled independently of PNG_USE_READ_MACROS, + which allows libpng to be built with the functions even though the default + is to use the macros - this allows applications to choose at app build + time whether or not to use macros (previously impossible because the + functions weren't in the default build.) + Changed Windows calling convention back to __cdecl for API functions. + For Windows/x86 platforms only: + __stdcall is no longer needed for Visual Basic, so libpng-1.5.0 uses + __cdecl throughout (both API functions and callbacks) on Windows/x86 + platforms. + Replaced visualc6 and visualc71 projects with new vstudio project + Relaxed the overly-restrictive permissions of some files. + +Version 1.5.0beta20 [April 24, 2010] + Relaxed more overly-restrictive permissions of some files. + +Version 1.5.0beta21 [April 27, 2010] + Removed some unwanted binary bytes and changed CRLF to NEWLINE in the new + vstudio project files, and some trivial editing of some files in the + scripts directory. + Set PNG_NO_READ_BGR, PNG_NO_IO_STATE, and PNG_NO_TIME_RFC1123 in + contrib/pngminim/decoder/pngusr.h to make a smaller decoder application. + +Version 1.5.0beta22 [April 28, 2010] + Fixed dependencies of GET_INT_32 - it does not require READ_INT_FUNCTIONS + because it has a macro equivalent. + Improved the options.awk script; added an "everything off" option. + Revised contrib/pngminim to use the "everything off" option in pngusr.dfa. + +Version 1.5.0beta23 [April 29, 2010] + Corrected PNG_REMOVED macro to take five arguments. + The macro was documented with two arguments (name,ordinal), however + the symbol checking .dfn files assumed five arguments. The five + argument form seems more useful so it is changed to that. + Corrected PNG_UNKNOWN_CHUNKS_SUPPORTED to PNG_HANDLE_AS_UNKNOWN_SUPPORTED + in gregbook/readpng2.c + Corrected protection of png_get_user_transform_ptr. The API declaration in + png.h is removed if both READ and WRITE USER_TRANSFORM are turned off + but was left defined in pngtrans.c + Added logunsupported=1 to cause pnglibconf.h to document disabled options. + This makes the installed pnglibconf.h more readable but causes no + other change. The intention is that users of libpng will find it + easier to understand if an API they need is missing. + Include png_reset_zstream() in png.c only when PNG_READ_SUPPORTED is defined. + Removed dummy_inflate.c from contrib/pngminim/encoder + Removed contrib/pngminim/*/gather.sh; gathering is now done in the makefile. + +Version 1.5.0beta24 [May 7, 2010] + Use bitwise "&" instead of arithmetic mod in pngrutil.c calculation of the + offset of the png_ptr->rowbuf pointer into png_ptr->big_row_buf. + Added more blank lines for readability. + +Version 1.5.0beta25 [June 18, 2010] + In pngpread.c: png_push_have_row() add check for new_row > height + Removed the now-redundant check for out-of-bounds new_row from example.c + +Version 1.5.0beta26 [June 18, 2010] + In pngpread.c: png_push_process_row() add check for too many rows. + +Version 1.5.0beta27 [June 18, 2010] + Removed the check added in beta25 as it is now redundant. + +Version 1.5.0beta28 [June 20, 2010] + Rewrote png_process_IDAT_data to consistently treat extra data as warnings + and handle end conditions more cleanly. + Removed the new (beta26) check in png_push_process_row(). + +Version 1.5.0beta29 [June 21, 2010] + Revised scripts/options.awk to work on Sunos (but still doesn't work) + Added comment to options.awk and contrib/pngminim/*/makefile to try nawk. + +Version 1.5.0beta30 [June 22, 2010] + Stop memory leak when reading a malformed sCAL chunk. + +Version 1.5.0beta31 [June 26, 2010] + Revised pngpread.c patch of beta28 to avoid an endless loop. + Removed some trailing blanks. + +Version 1.5.0beta32 [June 26, 2010] + Removed leftover scripts/options.patch and scripts/options.rej + +Version 1.5.0beta33 [July 6, 3010] + Made FIXED and FLOATING options consistent in the APIs they enable and + disable. Corrected scripts/options.awk to handle both command line + options and options specified in the .dfa files. + Changed char *msg to PNG_CONST char *msg in pngrutil.c + Make png_set_sRGB_gAMA_and_cHRM set values using either the fixed or + floating point APIs, but not both. + Reversed patch to remove error handler when the jmp_buf is stored in the + main program structure, not the png_struct. + The error handler is needed because the default handler in libpng will + always use the jmp_buf in the library control structure; this is never + set. The gregbook code is a useful example because, even though it + uses setjmp/longjmp, it shows how error handling can be implemented + using control mechanisms not directly supported by libpng. The + technique will work correctly with mechanisms such as Microsoft + Structure Exceptions or C++ exceptions (compiler willing - note that gcc + does not by default support interworking of C and C++ error handling.) + Reverted changes to call png_longjmp in contrib/gregbook where it is not + appropriate. If mainprog->jmpbuf is used by setjmp, then png_longjmp + cannot be used. + Changed "extern PNG_EXPORT" to "PNG_EXPORT" in png.h (Jan Nijtmans) + Changed "extern" to "PNG_EXTERN" in pngpriv.h (except for the 'extern "C" {') + +Version 1.5.0beta34 [July 12, 2010] + Put #ifndef PNG_EXTERN, #endif around the define PNG_EXTERN in pngpriv.h + +Version 1.5.0beta35 [July 24, 2010] + Removed some newly-added TAB characters. + Added -DNO_PNG_SNPRINTF to CFLAGS in scripts/makefile.dj2 + Moved the definition of png_snprintf() outside of the enclosing + #ifdef blocks in pngconf.h + +Version 1.5.0beta36 [July 29, 2010] + Patches by John Bowler: + Fixed point APIs are now supported throughout (no missing APIs). + Internal fixed point arithmetic support exists for all internal floating + point operations. + sCAL validates the floating point strings it is passed. + Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2 + Two new APIs exist to get the number of passes without turning on the + PNG_INTERLACE transform and to get the number of rows in the current + pass. + A new test program, pngvalid.c, validates the gamma code. + Errors in the 16-bit gamma correction (overflows) have been corrected. + cHRM chunk testing is done consistently (previously the floating point + API bypassed it, because the test really didn't work on FP, now the test + is performed on the actual values to be stored in the PNG file so it + works in the FP case too.) + Most floating point APIs now simply call the fixed point APIs after + converting the values to the fixed point form used in the PNG file. + The standard headers no longer include zlib.h, which is currently only + required for pngstruct.h and can therefore be internal. + Revised png_get_int_32 to undo the PNG two's complement representation of + negative numbers. + +Version 1.5.0beta37 [July 30, 2010] + Added a typecast in png_get_int_32() in png.h and pngrutil.h to avoid + a compiler warning. + Replaced oFFs 0,0 with oFFs -10,20 in pngtest.png + +Version 1.5.0beta38 [July 31, 2010] + Implemented remaining "_fixed" functions. + Corrected a number of recently introduced warnings mostly resulting from + safe but uncast assignments to shorter integers. Also added a zlib + VStudio release library project because the latest zlib Official Windows + build does not include such a thing. + Revised png_get_int_16() to be similar to png_get_int_32(). + Restored projects/visualc71. + +Version 1.5.0beta39 [August 2, 2010] + VisualC/GCC warning fixes, VisualC build fixes + The changes include support for function attributes in VC in addition to + those already present in GCC - necessary because without these some + warnings are unavoidable. Fixes include signed/unsigned fixes in + pngvalid and checks with gcc -Wall -Wextra -Wunused. + VC requires function attributes on function definitions as well as + declarations, PNG_FUNCTION has been added to enable this and the + relevant function definitions changed. + +Version 1.5.0beta40 [August 6, 2010] + Correct use of _WINDOWS_ in pngconf.h + Removed png_mem_ #defines; they are no longer used. + Added the sRGB chunk to pngtest.png + +Version 1.5.0beta41 [August 11, 2010] + Added the cHRM chunk to pngtest.png + Don't try to use version-script with cygwin/mingw. + Revised contrib/gregbook to work under cygwin/mingw. + +Version 1.5.0beta42 [August 18, 2010] + Add .dll.a to the list of extensions to be symlinked by Makefile.am (Yaakov) + Made all API functions that have const arguments and constant string + literal pointers declare them (John Bowler). + +Version 1.5.0beta43 [August 20, 2010] + Removed spurious tabs, shorten long lines (no source change) + Also added scripts/chkfmt to validate the format of all the files that can + reasonably be validated (it is suggested to run "make distclean" before + checking, because some machine generated files have long lines.) + Reformatted the CHANGES file to be more consistent throughout. + Made changes to address various issues identified by GCC, mostly + signed/unsigned and shortening problems on assignment but also a few + difficult to optimize (for GCC) loops. + Fixed non-GCC fixed point builds. In png.c a declaration was misplaced + in an earlier update. Fixed to declare the auto variables at the head. + Use cexcept.h in pngvalid.c. + +Version 1.5.0beta44 [August 24, 2010] + Updated CMakeLists.txt to use CMAKE_INSTALL_LIBDIR variable; useful for + installing libpng in /usr/lib64 (Funda Wang). + Revised CMakeLists.txt to put the man pages in share/man/man* not man/man* + Revised CMakeLists.txt to make symlinks instead of copies when installing. + Changed PNG_LIB_NAME from pngNN to libpngNN in CMakeLists.txt (Philip Lowman) + Implemented memory checks within pngvalid + Reformatted/rearranged pngvalid.c to assist use of progressive reader. + Check interlaced images in pngvalid + Clarified pngusr.h comments in pnglibconf.dfa + Simplified the pngvalid error-handling code now that cexcept.h is in place. + Implemented progressive reader in pngvalid.c for standard tests + Implemented progressive read in pngvalid.c gamma tests + Turn on progressive reader in pngvalid.c by default and tidy code. + +Version 1.5.0beta45 [August 26, 2010] + Added an explicit make step to projects/vstudio for pnglibconf.h + Also corrected zlib.vcxproj into which Visual Studio had introduced + what it calls an "authoring error". The change to make pnglibconf.h + simply copies the file; in the future it may actually generate the + file from scripts/pnglibconf.dfa as the other build systems do. + Changed pngvalid to work when floating point APIs are disabled + Renamed the prebuilt scripts/pnglibconf.h to scripts/pnglibconf.h.prebuilt + Supply default values for PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX + in pngpriv.h in case the user neglected to define them in their pngusr.h + +Version 1.5.0beta46 [August 28, 2010] + Added new private header files to libpng_sources in CMakeLists.txt + Added PNG_READ_16BIT, PNG_WRITE_16BIT, and PNG_16BIT options. + Added reference to scripts/pnglibconf.h.prebuilt in the visualc71 project. + +Version 1.5.0beta47 [September 11, 2010] + Fixed a number of problems with 64-bit compilation reported by Visual + Studio 2010 (John Bowler). + +Version 1.5.0beta48 [October 4, 2010] + Updated CMakeLists.txt (Philip Lowman). + Revised autogen.sh to recognize and use $AUTOCONF, $AUTOMAKE, $AUTOHEADER, + $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE + Fixed problem with symbols creation in Makefile.am which was assuming that + all versions of ccp write to standard output by default (Martin Banky). The + bug was introduced in libpng-1.2.9beta5. + Removed unused mkinstalldirs. + +Version 1.5.0beta49 [October 8, 2010] + Undid Makefile.am revision of 1.5.0beta48. + +Version 1.5.0beta50 [October 14, 2010] + Revised Makefile.in to account for mkinstalldirs being removed. + Added some "(unsigned long)" typecasts in printf statements in pngvalid.c. + Suppressed a compiler warning in png_handle_sPLT(). + Check for out-of-range text compression mode in png_set_text(). + +Version 1.5.0beta51 [October 15, 2010] + Changed embedded dates to "(PENDING RELEASE) in beta releases (and future + rc releases) to minimize the difference between releases. + +Version 1.5.0beta52 [October 16, 2010] + Restored some of the embedded dates (in png.h, png.c, documentation, etc.) + +Version 1.5.0beta53 [October 18, 2010] + Updated INSTALL to mention using "make maintainer-clean" and to remove + obsolete statement about a custom ltmain.sh + Disabled "color-tests" by default in Makefile.am so it will work with + automake versions earlier than 1.11.1 + Use document name "libpng-manual.txt" instead of "libpng-<version>.txt" + to simplify version differences. + Removed obsolete remarks about setjmp handling from INSTALL. + Revised and renamed the typedef in png.h and png.c that was designed + to catch library and header mismatch. + +Version 1.5.0beta54 [November 10, 2010] + Require 48 bytes, not 64 bytes, for big_row_buf in overflow checks. + Used a consistent structure for the pngget.c functions. + +Version 1.5.0beta55 [November 21, 2010] + Revised png_get_uint_32, png_get_int_32, png_get_uint_16 (Cosmin) + Moved reading of file signature into png_read_sig (Cosmin) + Fixed atomicity of chunk header serialization (Cosmin) + Added test for io_state in pngtest.c (Cosmin) + Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts. + Changes to remove gcc warnings (John Bowler) + Certain optional gcc warning flags resulted in warnings in libpng code. + With these changes only -Wconversion and -Wcast-qual cannot be turned on. + Changes are trivial rearrangements of code. -Wconversion is not possible + for pngrutil.c (because of the widespread use of += et al on variables + smaller than (int) or (unsigned int)) and -Wcast-qual is not possible + with pngwio.c and pngwutil.c because the 'write' callback and zlib + compression both fail to declare their input buffers with 'const'. + +Version 1.5.0beta56 [December 7, 2010] + Added the private PNG_UNUSED() macro definition in pngpriv.h. + Added some commentary about PNG_EXPORT in png.h and pngconf.h + Revised PNG_EXPORT() macro and added PNG_EXPORTA() macro, with the + objective of simplifying and improving the cosmetic appearance of png.h. + Fixed some incorrect "=" macro names in pnglibconf.dfa + Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt + +Version 1.5.0beta57 [December 9, 2010] + Documented the pngvalid gamma error summary with additional comments and + print statements. + Improved missing symbol handling in checksym.awk; symbols missing in both + the old and new files can now be optionally ignored, treated as errors + or warnings. + Removed references to pngvcrd.c and pnggccrd.c from the vstudio project. + Updated "libpng14" to "libpng15" in the visualc71 project. + Enabled the strip16 tests in pngvalid.` + Don't display test results (except PASS/FAIL) when running "make test". + Instead put them in pngtest-log.txt + Added "--with-zprefix=<string>" to configure.ac + Updated the prebuilt configuration files to autoconf version 2.68 + +Version 1.5.0beta58 [December 19, 2010] + Fixed interlace image handling and add test cases (John Bowler) + Fixed the clean rule in Makefile.am to remove pngtest-log.txt + Made minor changes to work around warnings in gcc 3.4 + +Version 1.5.0rc01 [December 27, 2010] + No changes. + +Version 1.5.0rc02 [December 27, 2010] + Eliminated references to the scripts/*.def files in project/visualc71. + +Version 1.5.0rc03 [December 28, 2010] + Eliminated scripts/*.def and revised Makefile.am accordingly + +Version 1.5.0rc04 [December 29, 2010] + Fixed bug in background transformation handling in pngrtran.c (it was + looking for the flag in png_ptr->transformations instead of in + png_ptr->flags) (David Raymond). + +Version 1.5.0rc05 [December 31, 2010] + Fixed typo in a comment in CMakeLists.txt (libpng14 => libpng15) (Cosmin) + +Version 1.5.0rc06 [January 4, 2011] + Changed the new configure option "zprefix=string" to "zlib-prefix=string" + +Version 1.5.0rc07 [January 4, 2011] + Updated copyright year. + +Version 1.5.0 [January 6, 2011] + No changes. + +version 1.5.1beta01 [January 8, 2011] + Added description of png_set_crc_action() to the manual. + Added a note in the manual that the type of the iCCP profile was changed + from png_charpp to png_bytepp in png_get_iCCP(). This change happened + in version 1.5.0beta36 but is not noted in the CHANGES. Similarly, + it was changed from png_charpp to png_const_bytepp in png_set_iCCP(). + Ensure that png_rgb_to_gray ignores palette mapped images, if libpng + internally happens to call it with one, and fixed a failure to handle + palette mapped images correctly. This fixes CVE-2690. + +Version 1.5.1beta02 [January 14, 2011] + Fixed a bug in handling of interlaced images (bero at arklinux.org). + Updated CMakeLists.txt (Clifford Yapp) + +Version 1.5.1beta03 [January 14, 2011] + Fixed typecasting of some png_debug() statements (Cosmin) + +Version 1.5.1beta04 [January 16, 2011] + Updated documentation of png_set|get_tRNS() (Thomas Klausner). + Mentioned in the documentation that applications must #include "zlib.h" + if they need access to anything in zlib.h, and that a number of + macros such as png_memset() are no longer accessible by applications. + Corrected pngvalid gamma test "sample" function to access all of the color + samples of each pixel, instead of sampling the red channel three times. + Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow" + warnings, and (mistakenly) changed png_exp() to exp(). + +Version 1.5.1beta05 [January 16, 2011] + Changed variable names png_index, png_div, png_exp, and png_gamma to + char_index, divisor, exp_b10, and gamma_val, respectively, and + changed exp() back to png_exp(). + +Version 1.5.1beta06 [January 20, 2011] + Prevent png_push_crc_skip() from hanging while reading an unknown chunk + or an over-large compressed zTXt chunk with the progressive reader. + Eliminated more GCC "shadow" warnings. + Revised png_fixed() in png.c to avoid compiler warning about reaching the + end without returning anything. + +Version 1.5.1beta07 [January 22, 2011] + In the manual, describe the png_get_IHDR() arguments in the correct order. + Added const_png_structp and const_png_infop types, and used them in + prototypes for most png_get_*() functions. + +Version 1.5.1beta08 [January 23, 2011] + Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name() + Added synopses for the IO_STATE functions and other missing synopses + to the manual. Removed the synopses from libpngpf.3 because they + were out of date and no longer useful. Better information can be + obtained by reading the prototypes and comments in pngpriv.h + Attempted to fix cpp on Solaris with S. Studio 12 cc, fix build + Added a make macro DFNCPP that is a CPP that will accept the tokens in + a .dfn file and adds configure stuff to test for such a CPP. ./configure + should fail if one is not available. + Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace. + Added png_get_current_row_number and png_get_current_pass_number for the + benefit of the user transform callback. + Added png_process_data_pause and png_process_data_skip for the benefit of + progressive readers that need to stop data processing or want to optimize + skipping of unread data (e.g., if the reader marks a chunk to be skipped.) + +Version 1.5.1beta09 [January 24, 2011] + Enhanced pngvalid, corrected an error in gray_to_rgb, corrected doc error. + pngvalid contains tests of transforms, which tests are currently disabled + because they are incompletely tested. gray_to_rgb was failing to expand + the bit depth for smaller bit depth images; this seems to be a long + standing error and resulted, apparently, in invalid output + (CVE-2011-0408, CERT VU#643140). The documentation did not accurately + describe what libpng really does when converting RGB to gray. + +Version 1.5.1beta10 [January 27, 2010] + Fixed incorrect examples of callback prototypes in the manual, that were + introduced in libpng-1.0.0. + In addition the order of the png_get_uint macros with respect to the + relevant function definitions has been reversed. This helps the + preprocessing of the symbol files be more robust. Furthermore, the + symbol file preprocessing now uses -DPNG_NO_USE_READ_MACROS even when + the library may actually be built with PNG_USE_READ_MACROS; this stops + the read macros interfering with the symbol file format. + Made the manual, synopses, and function prototypes use the function + argument names file_gamma, int_file_gamma, and srgb_intent consistently. + +Version 1.5.1beta11 [January 28, 2011] + Changed PNG_UNUSED from "param=param;" to "{if(param){}}". + Corrected local variable type in new API png_process_data_skip() + The type was self-evidently incorrect but only causes problems on 64-bit + architectures. + Added transform tests to pngvalid and simplified the arguments. + +Version 1.5.1rc01 [January 29, 2011] + No changes. + +Version 1.5.1rc02 [January 31, 2011] + Added a request in the manual that applications do not use "png_" or + "PNG_" to begin any of their own symbols. + Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h + +Version 1.5.1 [February 3, 2011] + No changes. + +Version 1.5.2beta01 [February 13, 2011] + More -Wshadow fixes for older gcc compilers. Older gcc versions apparently + check formal parameters names in function declarations (as well as + definitions) to see if they match a name in the global namespace. + Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the + old VisualC++ preprocessor. + Turned on interlace handling in png_read_png(). + Fixed gcc pendantic warnings. + Handle longjmp in Cygwin. + Fixed png_get_current_row_number() in the interlaced case. + Cleaned up ALPHA flags and transformations. + Implemented expansion to 16 bits. + +Version 1.5.2beta02 [February 19, 2011] + Fixed mistake in the descriptions of user read_transform and write_transform + function prototypes in the manual. The row_info struct is png_row_infop. + Reverted png_get_current_row_number() to previous (1.5.2beta01) behavior. + Corrected png_get_current_row_number documentation + Fixed the read/write row callback documentation. + This documents the current behavior, where the callback is called after + every row with information pertaining to the next row. + +Version 1.5.2beta03 [March 3, 2011] + Fixed scripts/makefile.vcwin32 + Updated contrib/pngsuite/README to add the word "modify". + Define PNG_ALLOCATED to blank when _MSC_VER<1300. + +Version 1.5.2rc01 [March 19, 2011] + Define remaining attributes to blank when MSC_VER<1300. + ifdef out mask arrays in pngread.c when interlacing is not supported. + +Version 1.5.2rc02 [March 22, 2011] + Added a hint to try CPP=/bin/cpp if "cpp -E" fails in scripts/pnglibconf.mak + and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed "strip" + from the makefiles. + Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail + to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill) + +Version 1.5.2rc03 [March 24, 2011] + Don't include standard header files in png.h while building the symbol table, + to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro). + +Version 1.5.2 [March 31, 2011] + No changes. + +Version 1.5.3beta01 [April 1, 2011] + Re-initialize the zlib compressor before compressing non-IDAT chunks. + Added API functions (png_set_text_compression_level() and four others) to + set parameters for zlib compression of non-IDAT chunks. + +Version 1.5.3beta02 [April 3, 2011] + Updated scripts/symbols.def with new API functions. + Only compile the new zlib re-initializing code when text or iCCP is + supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro. + Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03). + Optimize the zlib CMF byte in non-IDAT compressed chunks + +Version 1.5.3beta03 [April 16, 2011] + Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have + snprintf, and the "__STRICT_ANSI__" detects that condition more reliably + than __STDC__ (John Bowler). + Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells + the compiler that a user supplied callback (the error handler) does not + return, yet there is no guarantee in practice that the application code + will correctly implement the error handler because the compiler only + issues a warning if there is a mistake (John Bowler). + Removed the no-longer-used PNG_DEPSTRUCT macro. + Updated the zlib version to 1.2.5 in the VStudio project. + Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in + pngwutil.c (John Bowler). + Fixed bug with stripping the filler or alpha channel when writing, that + was introduced in libpng-1.5.2beta01 (bug report by Andrew Church). + +Version 1.5.3beta04 [April 27, 2011] + Updated pngtest.png with the new zlib CMF optimization. + Cleaned up conditional compilation code and of background/gamma handling + Internal changes only except a new option to avoid compiling the + png_build_grayscale_palette API (which is not used at all internally.) + The main change is to move the transform tests (READ_TRANSFORMS, + WRITE_TRANSFORMS) up one level to the caller of the APIs. This avoids + calls to spurious functions if all transforms are disabled and slightly + simplifies those functions. Pngvalid modified to handle this. + A minor change is to stop the strip_16 and expand_16 interfaces from + disabling each other; this allows the future alpha premultiplication + code to use 16-bit intermediate values while still producing 8-bit output. + png_do_background and png_do_gamma have been simplified to take a single + pointer to the png_struct rather than pointers to every item required + from the png_struct. This makes no practical difference to the internal + code. + A serious bug in the pngvalid internal routine 'standard_display_init' has + been fixed - this failed to initialize the red channel and accidentally + initialized the alpha channel twice. + Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to + avoid a possible clash with the png_jmpbuf macro on some platforms. + +Version 1.5.3beta05 [May 6, 2011] + Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the + correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and + pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs. + Removed png_snprintf and added formatted warning messages. This change adds + internal APIs to allow png_warning messages to have parameters without + requiring the host OS to implement snprintf. As a side effect the + dependency of the tIME-supporting RFC1132 code on stdio is removed and + PNG_NO_WARNINGS does actually work now. + Pass "" instead of '\0' to png_default_error() in png_err(). This mistake + was introduced in libpng-1.2.20beta01. This fixes CVE-2011-2691. + Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte + optimization configureable. + IDAT compression failed if preceded by a compressed text chunk (bug + introduced in libpng-1.5.3beta01-02). This was because the attempt to + reset the zlib stream in png_write_IDAT happened after the first IDAT + chunk had been deflated - much too late. In this change internal + functions were added to claim/release the z_stream and, hopefully, make + the code more robust. Also deflateEnd checking is added - previously + libpng would ignore an error at the end of the stream. + +Version 1.5.3beta06 [May 8, 2011] + Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt + Implemented premultiplied alpha support: png_set_alpha_mode API + +Version 1.5.3beta07 [May 11, 2011] + Added expand_16 support to the high level interface. + Added named value and 'flag' gamma support to png_set_gamma. Made a minor + change from the previous (unreleased) ABI/API to hide the exact value used + for Macs - it's not a good idea to embed this in the ABI! + Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT + from pngpriv.h to png.h because they must be visible to applications + that call png_set_unknown_chunks(). + Check for up->location !PNG_AFTER_IDAT when writing unknown chunks + before IDAT. + +Version 1.5.3beta08 [May 16, 2011] + Improved "pngvalid --speed" to exclude more of pngvalid from the time. + Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt + The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative + parameters are supplied by the caller), while in the absence of cHRM + sRGB/Rec 709 values are still used. This introduced a divide-by-zero + bug in png_handle_cHRM(). + The bKGD chunk no longer overwrites the background value set by + png_set_background(), allowing the latter to be used before the file + header is read. It never performed any useful function to override + the default anyway. + Added memory overwrite and palette image checks to pngvalid.c + Previously palette image code was poorly checked. Since the transformation + code has a special palette path in most cases this was a severe weakness. + Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When + expanding an indexed image, always expand to RGBA if transparency is + present. + +Version 1.5.3beta09 [May 17, 2011] + Reversed earlier 1.5.3 change of transformation order; move png_expand_16 + back where it was. The change doesn't work because it requires 16-bit + gamma tables when the code only generates 8-bit ones. This fails + silently; the libpng code just doesn't do any gamma correction. Moving + the tests back leaves the old, inaccurate, 8-bit gamma calculations, but + these are clearly better than none! + +Version 1.5.3beta10 [May 20, 2011] + + png_set_background() and png_expand_16() did not work together correctly. + This problem is present in 1.5.2; if png_set_background is called with + need_expand false and the matching 16 bit color libpng erroneously just + treats it as an 8-bit color because of where png_do_expand_16 is in the + transform list. This simple fix reduces the supplied colour to 8-bits, + so it gets smashed, but this is better than the current behavior. + Added tests for expand16, more fixes for palette image tests to pngvalid. + Corrects the code for palette image tests and disables attempts to + validate palette colors. + +Version 1.5.3rc01 [June 3, 2011] + No changes. + +Version 1.5.3rc02 [June 8, 2011] + Fixed uninitialized memory read in png_format_buffer() (Bug report by + Frank Busse, CVE-2011-2501, related to CVE-2004-0421). + +Version 1.5.3beta11 [June 11, 2011] + Fixed png_handle_sCAL which is broken in 1.5. This fixes CVE 2011-2692. + Added sCAL to pngtest.png + Revised documentation about png_set_user_limits() to say that it also affects + png writing. + Revised handling of png_set_user_limits() so that it can increase the + limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only + reduce it. + Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is + wrong (high by one) 25% of the time. Dividing by 257 with rounding is + wrong in 128 out of 65536 cases. Getting the right answer all the time + without division is easy. + Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro. + Added projects/owatcom, an IDE project for OpenWatcom to replace + scripts/makefile.watcom. This project works with OpenWatcom 1.9. The + IDE autogenerates appropriate makefiles (libpng.mk) for batch processing. + The project is configurable, unlike the Visual Studio project, so long + as the developer has an awk. + Changed png_set_gAMA to limit the gamma value range so that the inverse + of the stored value cannot overflow the fixed point representation, + and changed other things OpenWatcom warns about. + Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows + pngvalid to build when ALPHA_MODE is not supported, which is required if + it is to build on libpng 1.4. + Removed string/memory macros that are no longer used and are not + necessarily fully supportable, particularly png_strncpy and png_snprintf. + Added log option to pngvalid.c and attempted to improve gamma messages. + +Version 1.5.3 [omitted] + People found the presence of a beta release following an rc release + to be confusing; therefore we bump the version to libpng-1.5.4beta01 + and there will be no libpng-1.5.3 release. + +Version 1.5.4beta01 [June 14, 2011] + Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED + to get the same (inaccurate) output as libpng-1.5.2 and earlier. + Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE + outside of an unknown-chunk block in png.h because they are also + needed for other uses. + +Version 1.5.4beta02 [June 14, 2011] + Fixed and clarified LEGACY 16-to-8 scaling code. + Added png_set_chop_16() API, to match inaccurate results from previous + libpng versions. + Removed the ACCURATE and LEGACY options (they are no longer useable) + Use the old scaling method for background if png_set_chop_16() was + called. + Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED + +Version 1.5.4beta03 [June 15, 2011] + Fixed a problem in png_do_expand_palette() exposed by optimization in + 1.5.3beta06 + Also removed a spurious and confusing "trans" member ("trans") from png_info. + The palette expand optimization prevented expansion to an intermediate RGBA + form if tRNS was present but alpha was marked to be stripped; this exposed + a check for tRNS in png_do_expand_palette() which is inconsistent with the + code elsewhere in libpng. + Correction to the expand_16 code; removed extra instance of + png_set_scale_16_to_8 from pngpriv.h + +Version 1.5.4beta04 [June 16, 2011] + Added a missing "#ifdef PNG_READ_BACKGROUND_SUPPORTED/#endif" in pngrtran.c + Added PNG_TRANSFORM_CHOP_16 to the high-level read transforms. + Made PNG_READ_16_TO_8_ACCURATE_SCALE configurable again. If this is + not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built. + Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8 + +Version 1.5.4beta05 [June 16, 2011] + Renamed png_set_strip_16() to png_set_scale_16() and renamed + png_set_chop_16() to png_set_strip(16) in an attempt to minimize the + behavior changes between libpng14 and libpng15. + +Version 1.5.4beta06 [June 18, 2011] + Fixed new bug that was causing both strip_16 and scale_16 to be applied. + +Version 1.5.4beta07 [June 19, 2011] + Fixed pngvalid, simplified macros, added checking for 0 in sCAL. + The ACCURATE scale macro is no longer defined in 1.5 - call the + png_scale_16_to_8 API. Made sure that PNG_READ_16_TO_8 is still defined + if the png_strip_16_to_8 API is present. png_check_fp_number now + maintains some state so that positive, negative and zero values are + identified. sCAL uses these to be strictly spec conformant. + +Version 1.5.4beta08 [June 23, 2011] + Fixed pngvalid if ACCURATE_SCALE is defined. + Updated scripts/pnglibconf.h.prebuilt. + +Version 1.5.4rc01 [June 30, 2011] + Define PNG_ALLOCATED to "restrict" only if MSC_VER >= 1400. + +Version 1.5.4 [July 7, 2011] + No changes. + +Version 1.5.5beta01 [July 13, 2011] + Fixed some typos and made other minor changes in the manual. + Updated contrib/pngminus/makefile.std (Samuli Souminen) + +Version 1.5.5beta02 [July 14, 2011] + Revised Makefile.am and Makefile.in to look in the right directory for + pnglibconf.h.prebuilt + +Version 1.5.5beta03 [July 27, 2011] + Enabled compilation with g++ compiler. This compiler does not recognize + the file extension, so it always compiles with C++ rules. Made minor + changes to pngrutil.c to cast results where C++ expects it but C does not. + Minor editing of libpng.3 and libpng-manual.txt. + +Version 1.5.5beta04 [July 29, 2011] + Revised CMakeLists.txt (Clifford Yapp) + Updated commentary about the png_rgb_to_gray() default coefficients + in the manual and in pngrtran.c + +Version 1.5.5beta05 [August 17, 2011] + Prevent unexpected API exports from non-libpng DLLs on Windows. The "_DLL" + is removed from the test of whether a DLL is being built (this erroneously + caused the libpng APIs to be marked as DLL exports in static builds under + Microsoft Visual Studio). Almost all of the libpng building configuration + is moved from pngconf.h to pngpriv.h, but PNG_DLL_EXPORT remains in + pngconf.h, though, so that it is colocated with the import definition (it + is no longer used anywhere in the installed headers). The VStudio project + definitions have been cleaned up: "_USRDLL" has been removed from the + static library builds (this was incorrect), and PNG_USE_DLL has been added + to pngvalid to test the functionality (pngtest does not supply it, + deliberately). The spurious "_EXPORTS" has been removed from the + libpng build (all these errors were a result of copy/paste between project + configurations.) + Added new types and internal functions for CIE RGB end point handling to + pngpriv.h (functions yet to be implemented). + +Version 1.5.5beta06 [August 26, 2011] + Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set in CMakeLists.txt + (Clifford Yap) + Fixes to rgb_to_gray and cHRM XYZ APIs (John Bowler): + The rgb_to_gray code had errors when combined with gamma correction. + Some pixels were treated as true grey when they weren't and such pixels + and true grey ones were not gamma corrected (the original value of the + red component was used instead). APIs to get and set cHRM using color + space end points have been added and the rgb_to_gray code that defaults + based on cHRM, and the divide-by-zero bug in png_handle_cHRM (CERT + VU#477046, CVE-2011-3328, introduced in 1.5.4) have been corrected. + A considerable number of tests has been added to pngvalid for the + rgb_to_gray transform. + Arithmetic errors in rgb_to_gray whereby the calculated gray value was + truncated to the bit depth rather than rounded have been fixed except in + the 8-bit non-gamma-corrected case (where consistency seems more important + than correctness.) The code still has considerable inaccuracies in the + 8-bit case because 8-bit linear arithmetic is used. + +Version 1.5.5beta07 [September 7, 2011] + Added "$(ARCH)" option to makefile.darwin + Added SunOS support to configure.ac and Makefile.am + Changed png_chunk_benign_error() to png_warning() in png.c, in + png_XYZ_from_xy_checked(). + +Version 1.5.5beta08 [September 10, 2011] + Fixed 64-bit compilation errors (gcc). The errors fixed relate + to conditions where types that are 32 bits in the GCC 32-bit + world (uLong and png_size_t) become 64 bits in the 64-bit + world. This produces potential truncation errors which the + compiler correctly flags. + Relocated new HAVE_SOLARIS_LD definition in configure.ac + Constant changes for 64-bit compatibility (removal of L suffixes). The + 16-bit cases still use "L" as we don't have a 16-bit test system. + +Version 1.5.5rc01 [September 15, 2011] + Removed "L" suffixes in pngpriv.h + +Version 1.5.5 [September 22, 2011] + No changes. + +Version 1.5.6beta01 [September 22, 2011] + Fixed some 64-bit type conversion warnings in pngrtran.c + Moved row_info from png_struct to a local variable. + The various interlace mask arrays have been made into arrays of + bytes and made PNG_CONST and static (previously some arrays were + marked PNG_CONST and some weren't). + Additional checks have been added to the transform code to validate the + pixel depths after the transforms on both read and write. + Removed some redundant code from pngwrite.c, in png_destroy_write_struct(). + Changed chunk reading/writing code to use png_uint_32 instead of png_byte[4]. + This removes the need to allocate temporary strings for chunk names on + the stack in the read/write code. Unknown chunk handling still uses the + string form because this is exposed in the API. + +Version 1.5.6beta02 [September 26, 2011] + Added a note in the manual the png_read_update_info() must be called only + once with a particular info_ptr. + Fixed a typo in the definition of the new PNG_STRING_FROM_CHUNK(s,c) macro. + +Version 1.5.6beta03 [September 28, 2011] + Revised test-pngtest.sh to report FAIL when pngtest fails. + Added "--strict" option to pngtest, to report FAIL when the failure is + only because the resulting valid files are different. + Revised CMakeLists.txt to work with mingw and removed some material from + CMakeLists.txt that is no longer useful in libpng-1.5. + +Version 1.5.6beta04 [October 5, 2011] + Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")." + +Version 1.5.6beta05 [October 12, 2011] + Speed up png_combine_row() for interlaced images. This reduces the generality + of the code, allowing it to be optimized for Adam7 interlace. The masks + passed to png_combine_row() are now generated internally, avoiding + some code duplication and localizing the interlace handling somewhat. + Align png_struct::row_buf - previously it was always unaligned, caused by + a bug in the code that attempted to align it; the code needs to subtract + one from the pointer to take account of the filter byte prepended to + each row. + Optimized png_combine_row() when rows are aligned. This gains a small + percentage for 16-bit and 32-bit pixels in the typical case where the + output row buffers are appropriately aligned. The optimization was not + previously possible because the png_struct buffer was always misaligned. + Fixed bug in png_write_chunk_header() debug print, introduced in 1.5.6beta01. + +Version 1.5.6beta06 [October 17, 2011] + Removed two redundant tests for unitialized row. + Fixed a relatively harmless memory overwrite in compressed text writing + with a 1 byte zlib buffer. + Add ability to call png_read_update_info multiple times to pngvalid.c. + Fixes for multiple calls to png_read_update_info. These fixes attend to + most of the errors revealed in pngvalid, however doing the gamma work + twice results in inaccuracies that can't be easily fixed. There is now + a warning in the code if this is going to happen. + Turned on multiple png_read_update_info in pngvalid transform tests. + Prevent libpng from overwriting unused bits at the end of the image when + it is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would + overwrite the partial byte at the end of each row if the row width was not + an exact multiple of 8 bits and the image is not interlaced. + +Version 1.5.6beta07 [October 21, 2011] + Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row + (Mans Rullgard). + +Version 1.5.6rc01 [October 26, 2011] + Changed misleading "Missing PLTE before cHRM" warning to "Out of place cHRM" + +Version 1.5.6rc02 [October 27, 2011] + Added LSR() macro to defend against buggy compilers that evaluate non-taken + code branches and complain about out-of-range shifts. + +Version 1.5.6rc03 [October 28, 2011] + Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro. + Fixed compiler warnings with Intel and MSYS compilers. The logical shift + fix for Microsoft Visual C is required by other compilers, so this + enables that fix for all compilers when using compile-time constants. + Under MSYS 'byte' is a name declared in a system header file, so we + changed the name of a local variable to avoid the warnings that result. + Added #define PNG_ALIGN_TYPE PNG_ALIGN_NONE to contrib/pngminim/*/pngusr.h + +Version 1.5.6 [November 3, 2011] + No changes. + +Version 1.5.7beta01 [November 4, 2011] + Added support for ARM processor, when decoding all PNG up-filtered rows + and any other-filtered rows with 3 or 4 bytes per pixel (Mans Rullgard). + Fixed bug in pngvalid on early allocation failure; fixed type cast in + pngmem.c; pngvalid would attempt to call png_error() if the allocation + of a png_struct or png_info failed. This would probably have led to a + crash. The pngmem.c implementation of png_malloc() included a cast + to png_size_t which would fail on large allocations on 16-bit systems. + Fix for the preprocessor of the Intel C compiler. The preprocessor + splits adjacent @ signs with a space; this changes the concatentation + token from @-@-@ to PNG_JOIN; that should work with all compiler + preprocessors. + Paeth filter speed improvements from work by Siarhei Siamashka. This + changes the 'Paeth' reconstruction function to improve the GCC code + generation on x86. The changes are only part of the suggested ones; + just the changes that definitely improve speed and remain simple. + The changes also slightly increase the clarity of the code. + +Version 1.5.7beta02 [November 11, 2011] + Check compression_type parameter in png_get_iCCP and remove spurious + casts. The compression_type parameter is always assigned to, so must + be non-NULL. The cast of the profile length potentially truncated the + value unnecessarily on a 16-bit int system, so the cast of the (byte) + compression type to (int) is specified by ANSI-C anyway. + Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left + the sBIT fields in the test pixel as 0, which resulted in a floating + point division by zero which was irrelevant but causes systems where + FP exceptions cause a crash. Added code to pngvalid to turn on FP + exceptions if the appropriate glibc support is there to ensure this is + tested in the future. + Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the + new PNG_JOIN macro. + Added versioning to pnglibconf.h comments. + Simplified read/write API initial version; basic read/write tested on + a variety of images, limited documentation (in the header file.) + Installed more accurate linear to sRGB conversion tables. The slightly + modified tables reduce the number of 16-bit values that + convert to an off-by-one 8-bit value. The "makesRGB.c" code that was used + to generate the tables is now in a contrib/sRGBtables sub-directory. + +Version 1.5.7beta03 [November 17, 2011] + Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c + Added run-time detection of NEON support. + Added contrib/libtests; includes simplified API test and timing test and + a color conversion utility for rapid checking of failed 'pngstest' results. + Multiple transform bug fixes plus a work-round for double gamma correction. + libpng does not support more than one transform that requires linear data + at once - if this is tried typically the results is double gamma + correction. Since the simplified APIs can need rgb to gray combined with + a compose operation it is necessary to do one of these outside the main + libpng transform code. This check-in also contains fixes to various bugs + in the simplified APIs themselves and to some bugs in compose and rgb to + gray (on palette) itself. + Fixes for C++ compilation using g++ When libpng source is compiled + using g++. The compiler imposes C++ rules on the C source; thus it + is desireable to make the source work with either C or C++ rules + without throwing away useful error information. This change adds + png_voidcast to allow C semantic (void*) cases or the corresponding + C++ static_cast operation, as appropriate. + Added --noexecstack to assembler file compilation. GCC does not set + this on assembler compilation, even though it does on C compilation. + This creates security issues if assembler code is enabled; the + work-around is to set it by default in the flags for $(CCAS) + Work around compilers that don't support declaration of const data. Some + compilers fault 'extern const' data declarations (because the data is + not initialized); this turns on const-ness only for compilers where + this is known to work. + +Version 1.5.7beta04 [November 17, 2011] + Since the gcc driver does not recognize the --noexecstack flag, we must + use the -Wa prefix to have it passed through to the assembler. + Also removed a duplicate setting of this flag. + Added files that were omitted from the libpng-1.5.7beta03 zip distribution. + +Version 1.5.7beta05 [November 25, 2011] + Removed "zTXt" from warning in generic chunk decompression function. + Validate time settings passed to pngset() and png_convert_to_rfc1123() + (Frank Busse). + Added MINGW support to CMakeLists.txt + Reject invalid compression flag or method when reading the iTXt chunk. + Backed out 'simplified' API changes. The API seems too complex and there + is a lack of consensus or enthusiasm for the proposals. The API also + reveals significant bugs inside libpng (double gamma correction and the + known bug of being unable to retrieve a corrected palette). It seems + better to wait until the bugs, at least, are corrected. + Moved pngvalid.c into contrib/libtests + Rebuilt Makefile.in, configure, etc., with autoconf-2.68 + +Version 1.5.7rc01 [December 1, 2011] + Replaced an "#if" with "#ifdef" in pngrtran.c + Revised #if PNG_DO_BC block in png.c (use #ifdef and add #else) + +Version 1.5.7rc02 [December 5, 2011] + Revised project files and contrib/pngvalid/pngvalid.c to account for + the relocation of pngvalid into contrib/libtests. + Revised pngconf.h to use " __declspec(restrict)" only when MSC_VER >= 1400, + as in libpng-1.5.4. + Put CRLF line endings in the owatcom project files. + +Version 1.5.7rc03 [December 7, 2011] + Updated CMakeLists.txt to account for the relocation of pngvalid.c + +Version 1.5.7 [December 15, 2011] + Minor fixes to pngvalid.c for gcc 4.6.2 compatibility to remove warnings + reported by earlier versions. + Fixed minor memset/sizeof errors in pngvalid.c. + +Version 1.6.0beta01 [December 15, 2011] + Removed machine-generated configure files from the GIT repository (they will + continue to appear in the tarball distributions and in the libpng15 and + earlier GIT branches). + Restored the new 'simplified' API, which was started in libpng-1.5.7beta02 + but later deleted from libpng-1.5.7beta05. + Added example programs for the new 'simplified' API. + Added ANSI-C (C90) headers and require them, and take advantage of the + change. Also fixed some of the projects/* and contrib/* files that needed + updates for libpng16 and the move of pngvalid.c. + With this change the required ANSI-C header files are assumed to exist: the + implementation must provide float.h, limits.h, stdarg.h and stddef.h and + libpng relies on limits.h and stddef.h existing and behaving as defined + (the other two required headers aren't used). Non-ANSI systems that don't + have stddef.h or limits.h will have to provide an appropriate fake + containing the relevant types and #defines. + The use of FAR/far has been eliminated and the definition of png_alloc_size_t + is now controlled by a flag so that 'small size_t' systems can select it + if necessary. Libpng 1.6 may not currently work on such systems -- it + seems likely that it will ask 'malloc' for more than 65535 bytes with any + image that has a sufficiently large row size (rather than simply failing + to read such images). + New tools directory containing tools used to generate libpng code. + Fixed race conditions in parallel make builds. With higher degrees of + parallelism during 'make' the use of the same temporary file names such + as 'dfn*' can result in a race where a temporary file from one arm of the + build is deleted or overwritten in another arm. This changes the + temporary files for suffix rules to always use $* and ensures that the + non-suffix rules use unique file names. + +Version 1.6.0beta02 [December 21, 2011] + Correct configure builds where build and source directories are separate. + The include path of 'config.h' was erroneously made relative in pngvalid.c + in libpng 1.5.7. + +Version 1.6.0beta03 [December 22, 2011] + Start-up code size improvements, error handler flexibility. These changes + alter how the tricky allocation of the initial png_struct and png_info + structures are handled. png_info is now handled in pretty much the same + way as everything else, except that the allocations handle NULL return + silently. png_struct is changed in a similar way on allocation and on + deallocation a 'safety' error handler is put in place (which should never + be required). The error handler itself is changed to permit mismatches + in the application and libpng error buffer size; however, this means a + silent change to the API to return the jmp_buf if the size doesn't match + the size from the libpng compilation; libpng now allocates the memory and + this may fail. Overall these changes result in slight code size + reductions; however, this is a reduction in code that is always executed + so is particularly valuable. Overall on a 64-bit system the libpng DLL + decreases in code size by 1733 bytes. pngerror.o increases in size by + about 465 bytes because of the new functionality. + Added png_convert_to_rfc1123_buffer() and deprecated png_convert_to_rfc1123() + to avoid including a spurious buffer in the png_struct. + +Version 1.6.0beta04 [December 30, 2011] + Regenerated configure scripts with automake-1.11.2 + Eliminated png_info_destroy(). It is now used only in png.c and only calls + one other internal function and memset(). + Enabled png_get_sCAL_fixed() if floating point APIs are enabled. Previously + it was disabled whenever internal fixed point arithmetic was selected, + which meant it didn't exist even on systems where FP was available but not + preferred. + Added pngvalid.c compile time checks for const APIs. + Implemented 'restrict' for png_info and png_struct. Because of the way + libpng works both png_info and png_struct are always accessed via a + single pointer. This means adding C99 'restrict' to the pointer gives + the compiler some opportunity to optimize the code. This change allows + that. + Moved AC_MSG_CHECKING([if libraries can be versioned]) later to the proper + location in configure.ac (Gilles Espinasse). + Changed png_memcpy to C assignment where appropriate. Changed all those + uses of png_memcpy that were doing a simple assignment to assignments + (all those cases where the thing being copied is a non-array C L-value). + Added some error checking to png_set_*() routines. + Removed the reference to the non-exported function png_memcpy() from + example.c. + Fixed the Visual C 64-bit build - it requires jmp_buf to be aligned, but + it had become misaligned. + Revised contrib/pngminus/pnm2png.c to avoid warnings when png_uint_32 + and unsigned long are of different sizes. + +Version 1.6.0beta05 [January 15, 2012] + Updated manual with description of the simplified API (copied from png.h) + Fix bug in pngerror.c: some long warnings were being improperly truncated + (CVE-2011-3464, bug introduced in libpng-1.5.3beta05). + +Version 1.6.0beta06 [January 24, 2012] + Added palette support to the simplified APIs. This commit + changes some of the macro definitions in png.h, app code + may need corresponding changes. + Increased the formatted warning buffer to 192 bytes. + Added color-map support to simplified API. This is an initial version for + review; the documentation has not yet been updated. + Fixed Min/GW uninstall to remove libpng.dll.a + +Version 1.6.0beta07 [January 28, 2012] + Eliminated Intel icc/icl compiler warnings. The Intel (GCC derived) + compiler issues slightly different warnings from those issued by the + current vesions of GCC. This eliminates those warnings by + adding/removing casts and small code rewrites. + Updated configure.ac from autoupdate: added --enable-werror option. + Also some layout regularization and removal of introduced tab characters + (replaced with 3-character indentation). Obsolete macros identified by + autoupdate have been removed; the replacements are all in 2.59 so + the pre-req hasn't been changed. --enable-werror checks for support + for -Werror (or the given argument) in the compiler. This mimics the + gcc configure option by allowing -Werror to be turned on safely; without + the option the tests written in configure itself fail compilation because + they cause compiler warnings. + Rewrote autogen.sh to run autoreconf instead of running tools one-by-one. + Conditionalize the install rules for MINGW and CYGWIN in CMakeLists.txt and + set CMAKE_LIBRARY_OUTPUT_DIRECTORY to "lib" on all platforms (C. Yapp). + Freeze libtool files in the 'scripts' directory. This version of autogen.sh + attempts to dissuade people from running it when it is not, or should not, + be necessary. In fact, autogen.sh does not work when run in a libpng + directory extracted from a tar distribution anymore. You must run it in + a GIT clone instead. + Added two images to contrib/pngsuite (1-bit and 2-bit transparent grayscale), + and renamed three whose names were inconsistent with those in + pngsuite/README.txt. + +Version 1.6.0beta08 [February 1, 2012] + Fixed Image::colormap misalignment in pngstest.c + Check libtool/libtoolize version number (2.4.2) in configure.ac + Divide test-pngstest.sh into separate pngstest runs for basic and + transparent images. + Moved automake options to AM_INIT_AUTOMAKE in configure.ac + Added color-tests, silent-rules (Not yet implemented in Makefile.am) and + version checking to configure.ac + Improved pngstest speed by not doing redundant tests and add const to + the background parameter of png_image_finish_read. The --background + option is now done automagically only when required, so that commandline + option no longer exists. + Cleaned up pngpriv.h to consistently declare all functions and data. + Also eliminated PNG_CONST_DATA, which is apparently not needed but we + can't be sure until it is gone. + Added symbol prefixing that allows all the libpng external symbols + to be prefixed (suggested by Reuben Hawkins). + Updated "ftbb*.png" list in the owatcom and vstudio projects. + Fixed 'prefix' builds on clean systems. The generation of pngprefix.h + should not require itself. + Updated INSTALL to explain that autogen.sh must be run in a GIT clone, + not in a libpng directory extracted from a tar distribution. + +Version 1.6.0beta09 [February 1, 2012] + Reverted the prebuilt configure files to libpng-1.6.0beta05 condition. + +Version 1.6.0beta10 [February 3, 2012] + Added Z_SOLO for zlib-1.2.6+ and correct pngstest tests + Updated list of test images in CMakeLists.txt + Updated the prebuilt configure files to current condition. + Revised INSTALL information about autogen.sh; it works in tar distributions. + +Version 1.6.0beta11 [February 16, 2012] + Fix character count in pngstest command in projects/owatcom/pngstest.tgt + Revised test-pngstest.sh to report PASS/FAIL for each image. + Updated documentation about the simplified API. + Corrected estimate of error in libpng png_set_rgb_to_gray API. The API is + extremely inaccurate for sRGB conversions because it uses an 8-bit + intermediate linear value and it does not use the sRGB transform, so it + suffers from the known instability in gamma transforms for values close + to 0 (see Poynton). The net result is that the calculation has a maximum + error of 14.99/255; 0.5/255^(1/2.2). pngstest now uses 15 for the + permitted 8-bit error. This may still not be enough because of arithmetic + error. + Removed some unused arrays (with #ifdef) from png_read_push_finish_row(). + Fixed a memory overwrite bug in simplified read of RGB PNG with + non-linear gamma Also bugs in the error checking in pngread.c and changed + quite a lot of the checks in pngstest.c to be correct; either correctly + written or not over-optimistic. The pngstest changes are insufficient to + allow all possible RGB transforms to be passed; pngstest cmppixel needs + to be rewritten to make it clearer which errors it allows and then changed + to permit known inaccuracies. + Removed tests for no-longer-used *_EMPTY_PLTE_SUPPORTED from pngstruct.h + Fixed fixed/float API export conditionals. 1) If FIXED_POINT or + FLOATING_POINT options were switched off, png.h ended up with lone ';' + characters. This is not valid ANSI-C outside a function. The ';' + characters have been moved inside the definition of PNG_FP_EXPORT and + PNG_FIXED_EXPORT. 2) If either option was switched off, the declaration + of the corresponding functions were completely omitted, even though some + of them are still used internally. The result is still valid, but + produces warnings from gcc with some warning options (including -Wall). The + fix is to cause png.h to declare the functions with PNG_INTERNAL_FUNCTION + when png.h is included from pngpriv.h. + Check for invalid palette index while reading paletted PNG. When one is + found, issue a warning and increase png_ptr->num_palette accordingly. + Apps are responsible for checking to see if that happened. + +Version 1.6.0beta12 [February 18, 2012] + Do not increase num_palette on invalid_index. + Relocated check for invalid palette index to pngrtran.c, after unpacking + the sub-8-bit pixels. + Fixed CVE-2011-3026 buffer overrun bug. This bug was introduced when + iCCP chunk support was added at libpng-1.0.6. Deal more correctly with the + test on iCCP chunk length. Also removed spurious casts that may hide + problems on 16-bit systems. + +Version 1.6.0beta13 [February 24, 2012] + Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from + pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c; + now that png_ptr->buffer is inaccessible to applications, the special + handling is no longer useful. + Added PNG_SAFE_LIMITS feature to pnglibconf.dfa, pngpriv.h, and new + pngusr.dfa to reset the user limits to safe ones if PNG_SAFE_LIMITS is + defined. To enable, use "CPPFLAGS=-DPNG_SAFE_LIMITS_SUPPORTED=1" on the + configure command or put #define PNG_SAFE_LIMITS_SUPPORTED in + pnglibconf.h.prebuilt and pnglibconf.h. + +Version 1.6.0beta14 [February 27, 2012] + Added information about the new limits in the manual. + Updated Makefile.in + +Version 1.6.0beta15 [March 2, 2012] + Removed unused "current_text" members of png_struct and the png_free() + of png_ptr->current_text from pngread.c + Rewrote pngstest.c for substantial speed improvement. + Fixed transparent pixel and 16-bit rgb tests in pngstest and removed a + spurious check in pngwrite.c + Added PNG_IMAGE_FLAG_FAST for the benefit of applications that store + intermediate files, or intermediate in-memory data, while processing + image data with the simplified API. The option makes the files larger + but faster to write and read. pngstest now uses this by default; this + can be disabled with the --slow option. + Improved pngstest fine tuning of error numbers, new test file generator. + The generator generates images that test the full range of sample values, + allow the error numbers in pngstest to be tuned and checked. makepng + also allows generation of images with extra chunks, although this is + still work-in-progress. + Added check for invalid palette index while reading. + Fixed some bugs in ICC profile writing. The code should now accept + all potentially valid ICC profiles and reject obviously invalid ones. + It now uses png_error() to do so rather than casually writing a PNG + without the necessary color data. + Removed whitespace from the end of lines in all source files and scripts. + +Version 1.6.0beta16 [March 6, 2012] + Relocated palette-index checking function from pngrutil.c to pngtrans.c + Added palette-index checking while writing. + Changed png_inflate() and calling routines to avoid overflow problems. + This is an intermediate check-in that solves the immediate problems and + introduces one performance improvement (avoiding a copy via png_ptr->zbuf.) + Further changes will be made to make ICC profile handling more secure. + Fixed build warnings (MSVC, GCC, GCC v3). Cygwin GCC with default options + declares 'index' as a global, causing a warning if it is used as a local + variable. GCC 64-bit warns about assigning a (size_t) (unsigned 64-bit) + to an (int) (signed 32-bit). MSVC, however, warns about using the + unary '-' operator on an unsigned value (even though it is well defined + by ANSI-C to be ~x+1). The padding calculation was changed to use a + different method. Removed the tests on png_ptr->pass. + Added contrib/libtests/tarith.c to test internal arithmetic functions from + png.c. This is a libpng maintainer program used to validate changes to the + internal arithmetic functions. + Made read 'inflate' handling like write 'deflate' handling. The read + code now claims and releases png_ptr->zstream, like the write code. + The bug whereby the progressive reader failed to release the zstream + is now fixed, all initialization is delayed, and the code checks for + changed parameters on deflate rather than always calling + deflatedEnd/deflateInit. + Validate the zTXt strings in pngvalid. + Added code to validate the windowBits value passed to deflateInit2(). + If the call to deflateInit2() is wrong a png_warning will be issued + (in fact this is harmless, but the PNG data produced may be sub-optimal). + +Version 1.6.0beta17 [March 10, 2012] + Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition. + Reject all iCCP chunks after the first, even if the first one is invalid. + Deflate/inflate was reworked to move common zlib calls into single + functions [rw]util.c. A new shared keyword check routine was also added + and the 'zbuf' is no longer allocated on progressive read. It is now + possible to call png_inflate() incrementally. A warning is no longer + issued if the language tag or translated keyword in the iTXt chunk + has zero length. + If benign errors are disabled use maximum window on ancilliary inflate. + This works round a bug introduced in 1.5.4 where compressed ancillary + chunks could end up with a too-small windowBits value in the deflate + header. + +Version 1.6.0beta18 [March 16, 2012] + Issue a png_benign_error() instead of png_warning() about bad palette index. + In pngtest, treat benign errors as errors if "-strict" is present. + Fixed an off-by-one error in the palette index checking function. + Fixed a compiler warning under Cygwin (Windows-7, 32-bit system) + Revised example.c to put text strings in a temporary character array + instead of directly assigning string constants to png_textp members. + This avoids compiler warnings when -Wwrite-strings is enabled. + Added output flushing to aid debugging under Visual Studio. Unfortunately + this is necessary because the VS2010 output window otherwise simply loses + the error messages on error (they weren't flushed to the window before + the process exited, apparently!) + Added configuration support for benign errors and changed the read + default. Also changed some warnings in the iCCP and sRGB handling + from to benign errors. Configuration now makes read benign + errors warnings and write benign errors to errors by default (thus + changing the behavior on read). The simplified API always forces + read benign errors to warnings (regardless of the system default, unless + this is disabled in which case the simplified API can't be built.) + +Version 1.6.0beta19 [March 18, 2012] + Work around for duplicate row start calls; added warning messages. + This turns on PNG_FLAG_DETECT_UNINITIALIZED to detect app code that + fails to call one of the 'start' routines (not enabled in libpng-1.5 + because it is technically an API change, since it did normally work + before.) It also makes duplicate calls to png_read_start_row (an + internal function called at the start of the image read) benign, as + they were before changes to use png_inflate_claim. Somehow webkit is + causing this to happen; this is probably a mis-feature in the zlib + changes so this commit is only a work-round. + Removed erroneous setting of DETECT_UNINITIALIZED and added more + checks. The code now does a png_error if an attempt is made to do the + row initialization twice; this is an application error and it has + serious consequences because the transform data in png_struct is + changed by each call. + Added application error reporting and added chunk names to read + benign errors; also added --strict to pngstest - not enabled + yet because a warning is produced. + Avoid the double gamma correction warning in the simplified API. + This allows the --strict option to pass in the pngstest checks + +Version 1.6.0beta20 [March 29, 2012] + Changed chunk handler warnings into benign errors, incrementally load iCCP + Added checksum-icc.c to contrib/tools + Prevent PNG_EXPAND+PNG_SHIFT doing the shift twice. + Recognize known sRGB ICC profiles while reading; prefer writing the + iCCP profile over writing the sRGB chunk, controlled by the + PNG_sRGB_PROFILE_CHECKS option. + Revised png_set_text_2() to avoid potential memory corruption (fixes + CVE-2011-3048, also known as CVE-2012-3425). + +Version 1.6.0beta21 [April 27, 2012] + Revised scripts/makefile.darwin: use system zlib; remove quotes around + architecture list; add missing ppc architecture; add architecture options + to shared library link; don't try to create a shared lib based on missing + RELEASE variable. + Enable png_set_check_for_invalid_index() for both read and write. + Removed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpriv.h around + declaration of png_handle_unknown(). + Added -lssp_nonshared in a comment in scripts/makefile.freebsd + and changed deprecated NOOBJ and NOPROFILE to NO_OBJ and NO_PROFILE. + +Version 1.6.0beta22 [May 23, 2012] + Removed need for -Wno-cast-align with clang. clang correctly warns on + alignment increasing pointer casts when -Wcast-align is passed. This + fixes the cases that clang warns about either by eliminating the + casts from png_bytep to png_uint_16p (pngread.c), or, for pngrutil.c + where the cast is previously verified or pngstest.c where it is OK, by + introducing new png_aligncast macros to do the cast in a way that clang + accepts. + +Version 1.6.0beta23 [June 6, 2012] + Revised CMakeLists.txt to not attempt to make a symlink under mingw. + Made fixes for new optimization warnings from gcc 4.7.0. The compiler + performs an optimization which is safe; however it then warns about it. + Changing the type of 'palette_number' in pngvalid.c removes the warning. + Do not depend upon a GCC feature macro being available for use in generating + the linker mapfile symbol prefix. + Improved performance of new do_check_palette_indexes() function (only + update the value when it actually increases, move test for whether + the check is wanted out of the function. + +Version 1.6.0beta24 [June 7, 2012] + Don't check palette indexes if num_palette is 0 (as it can be in MNG files). + +Version 1.6.0beta25 [June 16, 2012] + Revised png_set_keep_unknown_chunks() so num_chunks < 0 means ignore all + unknown chunks and all known chunks except for IHDR, PLTE, tRNS, IDAT, + and IEND. Previously it only meant ignore all unknown chunks, the + same as num_chunks == 0. Revised png_image_skip_unused_chunks() to + provide a list of chunks to be processed instead of a list of chunks to + ignore. Revised contrib/gregbook/readpng2.c accordingly. + +Version 1.6.0beta26 [July 10, 2012] + Removed scripts/makefile.cegcc from the *.zip and *.7z distributions; it + depends on configure, which is not included in those archives. + Moved scripts/chkfmt to contrib/tools. + Changed "a+w" to "u+w" in Makefile.in to fix CVE-2012-3386. + +Version 1.6.0beta27 [August 11, 2012] + Do not compile PNG_DEPRECATED, PNG_ALLOC and PNG_PRIVATE when __GNUC__ < 3. + Do not use __restrict when GNUC is <= 3.1 + Removed references to png_zalloc() and png_zfree() from the manual. + Fixed configurations where floating point is completely disabled. Because + of the changes to support symbol prefixing PNG_INTERNAL_FUNCTION declares + floating point APIs during libpng builds even if they are completely + disabled. This requires the png floating point types (png_double*) to be + declared even though the functions are never actually defined. This + change provides a dummy definition so that the declarations work, yet any + implementation will fail to compile because of an incomplete type. + Re-eliminated the use of strcpy() in pngtest.c. An unncessary use of + strcpy() was accidentally re-introduced in libpng16; this change replaces + it with strncpy(). + Eliminated use of png_sizeof(); use sizeof() instead. + Use a consistent style for (sizeof type) and (sizeof (array)) + Cleanup of png_set_filler(). This function does very different things on + read and write. In libpng 1.6 the two cases can be distinguished and + considerable code cleanup, and extra error checking, is possible. This + makes calls on the write side that have no effect be ignored with a + png_app_error(), which can be disabled in the app using + png_set_benign_errors(), and removes the spurious use of usr_channels + on the read side. + Insist on autotools 1.12.1 for git builds because there are security issues + with 1.12 and insisting on anything less would allow 1.12 to be used. + Removed info_ptr->signature[8] from WRITE-only builds. + Add some conditions for compiling png_fixed(). This is a small function + but it requires "-lm" on some platforms. + Cause pngtest --strict to fail on any warning from libpng (not just errors) + and cause it not to fail at the comparison step if libpng lacks support + for writing chunks that it reads from the input (currently only implemented + for compressed text chunks). + Make all three "make check" test programs work without READ or WRITE support. + Now "make check" will succeed even if libpng is compiled with -DPNG_NO_READ + or -DPNG_NO_WRITE. The tests performed are reduced, but the basic reading + and writing of a PNG file is always tested by one or more of the tests. + Consistently use strlen(), memset(), memcpy(), and memcmp() instead of the + png_strlen(), png_memset(), png_memcpy(), and png_memcmp() macros. + Removed the png_sizeof(), png_strlen(), png_memset(), png_memcpy(), and + png_memcmp() macros. + Work around gcc 3.x and Microsoft Visual Studio 2010 complaints. Both object + to the split initialization of num_chunks. + +Version 1.6.0beta28 [August 29, 2012] + Unknown handling fixes and clean up. This adds more correct option + control of the unknown handling, corrects the pre-existing bug where + the per-chunk 'keep' setting is ignored and makes it possible to skip + IDAT chunks in the sequential reader (broken in earlier 1.6 versions). + There is a new test program, test-unknown.c, which is a work in progress + (not currently part of the test suite). Comments in the header files now + explain how the unknown handling works. + Allow fine grain control of unknown chunk APIs. This change allows + png_set_keep_unknown_chunks() to be turned off if not required and causes + both read and write to behave appropriately (on read this is only possible + if the user callback is used to handle unknown chunks). The change + also removes the support for storing unknown chunks in the info_struct + if the only unknown handling enabled is via the callback, allowing libpng + to be configured with callback reading and none of the unnecessary code. + Corrected fix for unknown handling in pngtest. This reinstates the + libpng handling of unknown chunks other than vpAg and sTER (including + unsafe-to-copy chunks which were dropped before) and eliminates the + repositioning of vpAg and sTER in pngtest.png by changing pngtest.png + (so the chunks are where libpng would put them). + Added "tunknown" test and corrected a logic error in png_handle_unknown() + when SAVE support is absent. Moved the shell test scripts for + contrib/libtests from the libpng top directory to contrib/libtests. + png_handle_unknown() must always read or skip the chunk, if + SAVE_UNKNOWN_CHUNKS is turned off *and* the application does not set + a user callback an unknown chunk will not be read, leading to a read + error, which was revealed by the "tunknown" test. + Cleaned up and corrected ICC profile handling. + contrib/libtests/makepng: corrected 'rgb' and 'gray' cases. profile_error + messages could be truncated; made a correct buffer size calculation and + adjusted pngerror.c appropriately. png_icc_check_* checking improved; + changed the functions to receive the correct color type of the PNG on read + or write and check that it matches the color space of the profile (despite + what the comments said before, there is danger in assuming the app will + cope correctly with an RGB profile on a grayscale image and, since it + violates the PNG spec, allowing it is certain to produce inconsistent + app behavior and might even cause app crashes.) Check that profiles + contain the tags needed to process the PNG (tags all required by the ICC + spec). Removed unused PNG_STATIC from pngpriv.h. + +Version 1.6.0beta29 [September 4, 2012] + Fixed the simplified API example programs to add the *colormap parameter + to several of he API and improved the error message if the version field + is not set. + Added contrib/examples/* to the *.zip and *.7z distributions. + Updated simplified API synopses and description of the png_image structure + in the manual. + Made makepng and pngtest produce identical PNGs, add "--relaxed" option + to pngtest. The "--relaxed" option turns off the benign errors that are + enabled by default in pre-RC builds. makepng can now write ICC profiles + where the length has not been extended to a multiple of 4, and pngtest + now intercepts all libpng errors, allowing the previously-introduced + "--strict test" on no warnings to actually work. + Improved ICC profile handling including cHRM chunk generation and fixed + Cygwin+MSVC build errors. The ICC profile handling now includes more + checking. Several errors that caused rejection of the profile are now + handled with a warning in such a way that the invalid profiles will be + read by default in release (but not pre-RC) builds but will not be + written by default. The easy part of handling the cHRM chunk is written, + where the ICC profile contains the required data. The more difficult + part plus guessing a gAMA value requires code to pass selected RGB values + through the profile. + +Version 1.6.0beta30 [October 24, 2012] + Changed ICC profile matrix/vector types to not depend on array type rules. + By the ANSI-C standard the new types should be identical to the previous + versions, and all known versions of gcc tested with the previous versions + except for GCC-4.2.1 work with this version. The change makes the ANSI-C + rule that const applied to an array of elements applies instead to the + elements in the array moot by explicitly applying const to the base + elements of the png_icc_matrix and png_icc_vector types. The accidental + (harmless) 'const' previously applied to the parameters of two of the + functions have also been removed. + Added a work around for GCC 4.2 optimization bug. + Marked the broken (bad white point) original HP sRGB profiles correctly and + correct comments. + Added -DZ_SOLO to contrib/pngminim/*/makefile to work with zlib-1.2.7 + Use /MDd for vstudio debug builds. Also added pngunkown to the vstudio + builds, fixed build errors and corrected a minor exit code error in + pngvalid if the 'touch' file name is invalid. + Add updated WARNING file to projects/vstudio from libpng 1.5/vstudio + Fixed build when using #define PNG_NO_READ_GAMMA in png_do_compose() in + pngrtran.c (Domani Hannes). + +Version 1.6.0beta31 [November 1, 2012] + Undid the erroneous change to vstudio/pngvalid build in libpng-1.6.0beta30. + Made pngvalid so that it will build outside the libpng source tree. + Made builds -DPNG_NO_READ_GAMMA compile (the unit tests still fail). + Made PNG_NO_READ_GAMMA switch off interfaces that depend on READ_GAMMA. + Prior to 1.6.0 switching off READ_GAMMA did unpredictable things to the + interfaces that use it (specifically, png_do_background in 1.4 would + simply display composite for grayscale images but do composition + with the incorrect arithmetic for color ones). In 1.6 the semantic + of -DPNG_NO_READ_GAMMA is changed to simply disable any interface that + depends on it; this obliges people who set it to consider whether they + really want it off if they happen to use any of the interfaces in + question (typically most users who disable it won't). + Fixed GUIDs in projects/vstudio. Some were duplicated or missing, + resulting in VS2010 having to update the files. + Removed non-working ICC profile support code that was mostly added to + libpng-1.6.0beta29 and beta30. There was too much code for too little + gain; implementing full ICC color correction may be desireable but is left + up to applications. + +Version 1.6.0beta32 [November 25, 2012] + Fixed an intermittent SEGV in pngstest due to an uninitialized array element. + Added the ability for contrib/libtests/makepng.c to make a PNG with just one + color. This is useful for debugging pngstest color inaccuracy reports. + Fixed error checking in the simplified write API (Olaf van der Spek) + Made png_user_version_check() ok to use with libpng version 1.10.x and later. + +Version 1.6.0beta33 [December 15, 2012] + Fixed typo in png.c (PNG_SET_CHUNK_MALLOC_MAX should be PNG_CHUNK_MALLOC_MAX) + that causes the MALLOC_MAX limit not to work (John Bowler) + Change png_warning() to png_app_error() in pngwrite.c and comment the + fall-through condition. + Change png_warning() to png_app_warning() in png_write_tRNS(). + Rearranged the ARM-NEON optimizations: Isolated the machine specific code + to the hardware subdirectory and added comments to pngrutil.c so that + implementors of other optimizations know what to do. + Fixed cases of unquoted DESTDIR in Makefile.am + Rebuilt Makefile.in, etc., with autoconf-2.69 and automake-1.12.5. + +Version 1.6.0beta34 [December 19, 2012] + Cleaned up whitespace in the synopsis portion of the manpage "libpng.3" + Disassembled the version number in scripts/options.awk (necessary for + building on SunOs). + +Version 1.6.0beta35 [December 23, 2012] + Made default Zlib compression settings be configurable. This adds #defines to + pnglibconf.h to control the defaults. + Fixed Windows build issues, enabled ARM compilation. Various warnings issued + by earlier versions of GCC fixed for Cygwin and Min/GW (which both use old + GCCs.) ARM support is enabled by default in zlib.props (unsupported by + Microsoft) and ARM compilation is made possible by deleting the check for + x86. The test programs cannot be run because they are not signed. + +Version 1.6.0beta36 [January 2, 2013] + Discontinued distributing libpng-1.x.x.tar.bz2. + Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar. + Rebuilt configure with autoconf-2.69 (inadvertently not done in beta33) + Fixed 'make distcheck' on SUN OS - libpng.so was not being removed + +Version 1.6.0beta37 [January 10, 2013] + Fixed conceivable but difficult to repro overflow. Also added two test + programs to generate and test a PNG which should have the problem. + +Version 1.6.0beta39 [January 19, 2013] + Again corrected attempt at overflow detection in png_set_unknown_chunks() + (CVE-2013-7353). Added overflow detection in png_set_sPLT() and + png_set_text_2() (CVE-2013-7354). + +Version 1.6.0beta40 [January 20, 2013] + Use consistent handling of overflows in text, sPLT and unknown png_set_* APIs + +Version 1.6.0rc01 [January 26, 2013] + No changes. + +Version 1.6.0rc02 [February 4, 2013] + Added png_get_palette_max() function. + +Version 1.6.0rc03 [February 5, 2013] + Fixed the png_get_palette_max API. + +Version 1.6.0rc04 [February 7, 2013] + Turn serial tests back on (recently turned off by autotools upgrade). + +Version 1.6.0rc05 [February 8, 2013] + Update manual about png_get_palette_max(). + +Version 1.6.0rc06 [February 9, 2013] + Fixed missing dependency in --prefix builds The intermediate + internal 'prefix.h' file can only be generated correctly after + pnglibconf.h, however the dependency was not in Makefile.am. The + symptoms are unpredictable depending on the order make chooses to + build pngprefix.h and pnglibconf.h, often the error goes unnoticed + because there is a system pnglibconf.h to use instead. + +Version 1.6.0rc07 [February 10, 2013] + Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED + block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly. + +Version 1.6.0rc08 [February 10, 2013] + Fix typo in png.h #ifdef + +Version 1.6.0 [February 14, 2013] + No changes. + +Version 1.6.1beta01 [February 16, 2013] + Made symbol prefixing work with the ARM neon optimizations. Also allow + pngpriv.h to be included for preprocessor definitions only, so it can + be used in non-C/C++ files. Back ported from libpng 1.7. + Made sRGB check numbers consistent. + Ported libpng 1.5 options.awk/dfn file handling to 1.6, fixed one bug. + Removed cc -E workround, corrected png_get_palette_max API Tested on + SUN OS cc 5.9, which demonstrates the tokenization problem previously + avoided by using /lib/cpp. Since all .dfn output is now protected in + double quotes unless it is to be macro substituted the fix should + work everywhere. + Enabled parallel tests - back ported from libpng-1.7. + scripts/pnglibconf.dfa formatting improvements back ported from libpng17. + Fixed a race condition in the creation of the build 'scripts' directory + while building with a parallel make. + Use approved/supported Android method to check for NEON, use Linux/POSIX + 1003.1 API to check /proc/self/auxv avoiding buffer allocation and other + library calls (ported from libpng15). + +Version 1.6.1beta02 [February 19, 2013] + Use parentheses more consistently in "#if defined(MACRO)" tests. + Folded long lines. + Reenabled code to allow zero length PLTE chunks for MNG. + +Version 1.6.1beta03 [February 22, 2013] + Fixed ALIGNED_MEMORY support. + Allow run-time ARM NEON checking to be disabled. A new configure option: + --enable-arm-neon=always will stop the run-time checks. New checks + within arm/arm_init.c will cause the code not to be compiled unless + __ARM_NEON__ is set. This should make it fail safe (if someone asks + for it on then the build will fail if it can't be done.) + Updated the INSTALL document. + +Version 1.6.1beta04 [February 27, 2013] + Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES. + Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC. + Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble + with CRLF line endings. + +Version 1.6.1beta05 [March 1, 2013] + Avoid a possible memory leak in contrib/gregbook/readpng.c + +Version 1.6.1beta06 [March 4, 2013] + Better documentation of unknown handling API interactions. + Corrected Android builds and corrected libpng.vers with symbol + prefixing This adds an API to set optimization options externally, + providing an alternative and general solution for the non-portable + run-time tests used by the ARM Neon code. It also makes those tests + compile and link on Android. + The order of settings vs options in pnglibconf.h is reversed to allow + settings to depend on options and options can now set (or override) the + defaults for settings. + +Version 1.6.1beta07 [March 7, 2013] + Corrected simplified API default gamma for color-mapped output, added + a flag to change default. In 1.6.0 when the simplified API was used + to produce color-mapped output from an input image with no gamma + information the gamma assumed for the input could be different from + that assumed for non-color-mapped output. In particular 16-bit depth + input files were assumed to be sRGB encoded, whereas in the 'direct' + case they were assumed to have linear data. This was an error. The + fix makes the simplified API treat all input files the same way and + adds a new flag to the png_image::flags member to allow the + application/user to specify that 16-bit files contain sRGB data + rather than the default linear. + Fixed bugs in the pngpixel and makepng test programs. + +Version 1.6.1beta08 [March 7, 2013] + Fixed CMakelists.txt to allow building a single variant of the library + (Claudio Bley): + Introduced a PNG_LIB_TARGETS variable that lists all activated library + targets. It is an error if this variable ends up empty, ie. you have + to build at least one library variant. + Made the *_COPY targets only depend on library targets actually being build. + Use PNG_LIB_TARGETS to unify a code path. + Changed the CREATE_SYMLINK macro to expect the full path to a file as the + first argument. When symlinking the filename component of that path is + determined and used as the link target. + Use copy_if_different in the CREATE_SYMLINK macro. + +Version 1.6.1beta09 [March 13, 2013] + Eliminated two warnings from the Intel C compiler. The warnings are + technically valid, although a reasonable treatment of division would + show it to be incorrect. + +Version 1.6.1rc01 [March 21, 2013] + No changes. + +Version 1.6.1 [March 28, 2013] + No changes. + +Version 1.6.2beta01 [April 14, 2013] + Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling. + Fixed incorrect warning of excess deflate data. End condition - the + warning would be produced if the end of the deflate stream wasn't read + in the last row. The warning is harmless. + Corrected the test on user transform changes on read. It was in the + png_set of the transform function, but that doesn't matter unless the + transform function changes the rowbuf size, and that is only valid if + transform_info is called. + Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c + (Flavio Medeiros). + Corrected length written to uncompressed iTXt chunks (Samuli Suominen). + Bug was introduced in libpng-1.6.0. + +Version 1.6.2rc01 [April 18, 2013] + Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length + written by libpng-1.6.0 and 1.6.1. + Disallow storing sRGB information when the sRGB is not supported. + +Version 1.6.2rc02 [April 18, 2013] + Merge pngtest.c with libpng-1.7.0 + +Version 1.6.2rc03 [April 22, 2013] + Trivial spelling cleanup. + +Version 1.6.2rc04 and 1.6.2rc05 [omitted] + +Version 1.6.2rc06 [April 24, 2013] + Reverted to version 1.6.2rc03. Recent changes to arm/neon support + have been ported to libpng-1.7.0beta09 and will reappear in version + 1.6.3beta01. + +Version 1.6.2 [April 25, 2013] + No changes. + +Version 1.6.3beta01 [April 25, 2013] + Revised stack marking in arm/filter_neon.S and configure.ac. + Ensure that NEON filter stuff is completely disabled when switched 'off'. + Previously the ARM NEON specific files were still built if the option + was switched 'off' as opposed to being explicitly disabled. + +Version 1.6.3beta02 [April 26, 2013] + Test for 'arm*' not just 'arm' in the host_cpu configure variable. + Rebuilt the configure scripts. + +Version 1.6.3beta03 [April 30, 2013] + Expanded manual paragraph about writing private chunks, particularly + the need to call png_set_keep_unknown_chunks() when writing them. + Avoid dereferencing NULL pointer possibly returned from + png_create_write_struct() (Andrew Church). + +Version 1.6.3beta05 [May 9, 2013] + Calculate our own zlib windowBits when decoding rather than trusting the + CMF bytes in the PNG datastream. + Added an option to force maximum window size for inflating, which was + the behavior of libpng15 and earlier. + Added png-fix-itxt and png-fix-too-far-back to the built programs and + removed warnings from the source code and timepng that are revealed as + a result. + Detect wrong libpng versions linked to png-fix-too-far-back, which currently + only works with libpng versions that can be made to reliably fail when + the deflate data contains an out-of-window reference. This means only + 1.6 and later. + Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning + message which it is easier to work round than ignore. + Updated contrib/pngminus/pnm2png.c (Paul Stewart): + Check for EOF + Ignore "#" delimited comments in input file to pnm2png.c. + Fixed whitespace handling + Added a call to png_set_packing() + Initialize dimension values so if sscanf fails at least we have known + invalid values. + Attempt to detect configuration issues with png-fix-too-far-back, which + requires both the correct libpng and the correct zlib to function + correctly. + Check ZLIB_VERNUM for mismatches, enclose #error in quotes + Added information in the documentation about problems with and fixes for + the bad CRC and bad iTXt chunk situations. + +Version 1.6.3beta06 [May 12, 2013] + Allow contrib/pngminus/pnm2png.c to compile without WRITE_INVERT and + WRITE_PACK supported (writes error message that it can't read P1 or + P4 PBM files). + Improved png-fix-too-far-back usage message, added --suffix option. + Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the + right zlib header files. + Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile + +Version 1.6.3beta07 [June 8, 2013] + Removed a redundant test in png_set_IHDR(). + Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt) + Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt + Enclose the prototypes for the simplified write API in + #ifdef PNG_STDIO_SUPPORTED/#endif + Make ARM NEON support work at compile time (not just configure time). + This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when + using a compiler that compiles for multiple architectures at one time. + Removed PNG_FILTER_OPTIMIZATIONS and PNG_ARM_NEON_SUPPORTED from + pnglibconf.h, allowing more of the decisions to be made internally + (pngpriv.h) during the compile. Without this, symbol prefixing is broken + under certain circumstances on ARM platforms. Now only the API parts of + the optimizations ('check' vs 'api') are exposed in the public header files + except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the + decision about whether or not to use the optimizations. + Protect symbol prefixing against CC/CPPFLAGS/CFLAGS useage. + Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test + on __ARM_NEON__ from configure time to compile time. This breaks symbol + prefixing because the definition of the special png_init_filter_functions + call was hidden at configure time if the relevant compiler arguments are + passed in CFLAGS as opposed to CC. This change attempts to avoid all + the confusion that would result by declaring the init function even when + it is not used, so that it will always get prefixed. + +Version 1.6.3beta08 [June 18, 2013] + Revised libpng.3 so that "doclifter" can process it. + +Version 1.6.3beta09 [June 27, 2013] + Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18 + as parameters for png_set_gamma(). These have been available since + libpng-1.5.4. + Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it + to check all compressed chunks known to libpng. + +Version 1.6.3beta10 [July 5, 2013] + Updated documentation to show default behavior of benign errors correctly. + Only compile ARM code when PNG_READ_SUPPORTED is defined. + Fixed undefined behavior in contrib/tools/pngfix.c and added new strip + option. pngfix relied on undefined behavior and even a simple change from + gcc to g++ caused it to fail. The new strip option 'unsafe' has been + implemented and is the default if --max is given. Option names have + been clarified, with --strip=transform now stripping the bKGD chunk, + which was stripped previously with --strip=unused. + Added all documented chunk types to pngpriv.h + Unified pngfix.c source with libpng17. + +Version 1.6.3rc01 [July 11, 2013] + No changes. + +Version 1.6.3 [July 18, 2013] + Revised manual about changes in iTXt chunk handling made in libpng-1.6.0. + Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings + may be erroneously issued by code-checking applications. + +Version 1.6.4beta01 [August 21, 2013] + Added information about png_set_options() to the manual. + Delay calling png_init_filter_functions() until a row with nonzero filter + is found. + +Version 1.6.4beta02 [August 30, 2013] + Fixed inconsistent conditional compilation of png_chunk_unknown_handling() + prototype, definition, and usage. Made it depend on + PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere. + +Version 1.6.4rc01 [September 5, 2013] + No changes. + +Version 1.6.4 [September 12, 2013] + No changes. + +Version 1.6.5 [September 14, 2013] + Removed two stray lines of code from arm/arm_init.c. + +Version 1.6.6 [September 16, 2013] + Removed two stray lines of code from arm/arm_init.c, again. + +Version 1.6.7beta01 [September 30, 2013] + Revised unknown chunk code to correct several bugs in the NO_SAVE_/NO_WRITE + combination + Allow HANDLE_AS_UNKNOWN to work when other options are configured off. Also + fixed the pngminim makefiles to work when $(MAKEFLAGS) contains stuff + which terminates the make options (as by default in recent versions of + Gentoo). + Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of + png_modifier are greater than that of png_store and as a consequence + compilation of pngvalid.c results in a warning about increased alignment + requirements because of the bare cast to (png_modifier*). The code is safe, + because the pointer is known to point to a stack allocated png_modifier, + but this change avoids the warning. + Fixed default behavior of ARM_NEON_API. If the ARM NEON API option was + compiled without the CHECK option it defaulted to on, not off. + Check user callback behavior in pngunknown.c. Previous versions compiled + if SAVE_UNKNOWN was not available but did nothing since the callback + was never implemented. + Merged pngunknown.c with 1.7 version and back ported 1.7 improvements/fixes + +Version 1.6.7beta02 [October 12, 2013] + Made changes for compatibility with automake 1.14: + 1) Added the 'compile' program to the list of programs that must be cleaned + in autogen.sh + 2) Added 'subdir-objects' which causes .c files in sub-directories to be + compiled such that the corresponding .o files are also in the + sub-directory. This is because automake 1.14 warns that the + current behavior of compiling to the top level directory may be removed + in the future. + 3) Updated dependencies on pnglibconf.h to match the new .o locations and + added all the files in contrib/libtests and contrib/tools that depend + on pnglibconf.h + 4) Added 'BUILD_SOURCES = pnglibconf.h'; this is the automake recommended + way of handling the dependencies of sources that are machine generated; + unfortunately it only works if the user does 'make all' or 'make check', + so the dependencies (3) are still required. + Cleaned up (char*) casts of zlib messages. The latest version of the Intel C + compiler complains about casting a string literal as (char*), so copied the + treatment of z_const from the library code into pngfix.c + Simplified error message code in pngunknown. The simplification has the + useful side effect of avoiding a bogus warning generated by the latest + version of the Intel C compiler (it objects to + condition ? string-literal : string-literal). + Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always + removing the 1.14 'compile' script but never checking for it. + +Version 1.6.7beta03 [October 19, 2013] + Added ARMv8 support (James Yu <james.yu at linaro.org>). Added file + arm/filter_neon_intrinsics.c; enable with -mfpu=neon. + Revised pngvalid to generate size images with as many filters as it can + manage, limited by the number of rows. + Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h + and detect the broken GCC compilers. + +Version 1.6.7beta04 [October 26, 2013] + Allow clang derived from older GCC versions to use ARM intrinsics. This + causes all clang builds that use -mfpu=neon to use the intrinsics code, + not the assembler code. This has only been tested on iOS 7. It may be + necessary to exclude some earlier clang versions but this seems unlikely. + Changed NEON implementation selection mechanism. This allows assembler + or intrinsics to be turned on at compile time during the build by defining + PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1). This macro + is undefined by default and the build type is selected in pngpriv.h. + +Version 1.6.7rc01 [November 2, 2013] + No changes. + +Version 1.6.7rc02 [November 7, 2013] + Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char + checking macros take an unsigned char argument, not a signed char. + +Version 1.6.7 [November 14, 2013] + No changes. + +Version 1.6.8beta01 [November 24, 2013] + Moved prototype for png_handle_unknown() in pngpriv.h outside of + the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block. + Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile + Conditionally compile some unused functions reported by -Wall in + pngminim. + Fixed 'minimal' builds. Various obviously useful minimal configurations + don't build because of missing contrib/libtests test programs and + overly complex dependencies in scripts/pnglibconf.dfa. This change + adds contrib/conftest/*.dfa files that can be used in automatic build + scripts to ensure that these configurations continue to build. + Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder. + Fixed pngvalid 'fail' function declaration on the Intel C Compiler. + This reverts to the previous 'static' implementation and works round + the 'unused static function' warning by using PNG_UNUSED(). + +Version 1.6.8beta02 [November 30, 2013] + Removed or marked PNG_UNUSED some harmless "dead assignments" reported + by clang scan-build. + Changed tabs to 3 spaces in png_debug macros and changed '"%s"m' + to '"%s" m' to improve portability among compilers. + Changed png_free_default() to free() in pngtest.c + +Version 1.6.8rc01 [December 12, 2013] + Tidied up pngfix inits and fixed pngtest no-write builds. + +Version 1.6.8rc02 [December 14, 2013] + Handle zero-length PLTE chunk or NULL palette with png_error() + instead of png_chunk_report(), which by default issues a warning + rather than an error, leading to later reading from a NULL pointer + (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954 + and VU#650142. Libpng-1.6.1 through 1.6.7 are vulnerable. + Libpng-1.6.0 and earlier do not have this bug. + +Version 1.6.8 [December 19, 2013] + No changes. + +Version 1.6.9beta01 [December 26, 2013] + Bookkeeping: Moved functions around (no changes). Moved transform + function definitions before the place where they are called so that + they can be made static. Move the intrapixel functions and the + grayscale palette builder out of the png?tran.c files. The latter + isn't a transform function and is no longer used internally, and the + former MNG specific functions are better placed in pngread/pngwrite.c + Made transform implementation functions static. This makes the internal + functions called by png_do_{read|write}_transformations static. On an + x86-64 DLL build (Gentoo Linux) this reduces the size of the text + segment of the DLL by 1208 bytes, about 0.6%. It also simplifies + maintenance by removing the declarations from pngpriv.h and allowing + easier changes to the internal interfaces. + Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69 + in the tar distributions. + +Version 1.6.9beta02 [January 1, 2014] + Added checks for libpng 1.5 to pngvalid.c. This supports the use of + this version of pngvalid in libpng 1.5 + Merged with pngvalid.c from libpng-1.7 changes to create a single + pngvalid.c + Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner). + Merged pngrio.c, pngtrans.c, pngwio.c, and pngerror.c with libpng-1.7.0 + Merged libpng-1.7.0 changes to make no-interlace configurations work + with test programs. + Revised pngvalid.c to support libpng 1.5, which does not support the + PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when appropriate in + pngvalid.c + Allow unversioned links created on install to be disabled in configure. + In configure builds 'make install' changes/adds links like png.h + and libpng.a to point to the newly installed, versioned, files (e.g. + libpng17/png.h and libpng17.a). Three new configure options and some + rearrangement of Makefile.am allow creation of these links to be disabled. + +Version 1.6.9beta03 [January 10, 2014] + Removed potentially misleading warning from png_check_IHDR(). + +Version 1.6.9beta04 [January 20, 2014] + Updated scripts/makefile.* to use CPPFLAGS (Cosmin). + Added clang attribute support (Cosmin). + +Version 1.6.9rc01 [January 28, 2014] + No changes. + +Version 1.6.9rc02 [January 30, 2014] + Quiet an uninitialized memory warning from VC2013 in png_get_png(). + +Version 1.6.9 [February 6, 2014] + +Version 1.6.10beta01 [February 9, 2014] + Backported changes from libpng-1.7.0beta30 and beta31: + Fixed a large number of instances where PNGCBAPI was omitted from + function definitions. + Added pngimage test program for png_read_png() and png_write_png() + with two new test scripts. + Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling + png_set_packing() in png_read_png(). + Fixed combination of ~alpha with shift. On read invert alpha, processing + occurred after shift processing, which causes the final values to be + outside the range that should be produced by the shift. Reversing the + order on read makes the two transforms work together correctly and mirrors + the order used on write. + Do not read invalid sBIT chunks. Previously libpng only checked sBIT + values on write, so a malicious PNG writer could therefore cause + the read code to return an invalid sBIT chunk, which might lead to + application errors or crashes. Such chunks are now skipped (with + chunk_benign_error). + Make png_read_png() and png_write_png() prototypes in png.h depend + upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED. + Support builds with unsupported PNG_TRANSFORM_* values. All of the + PNG_TRANSFORM_* values are always defined in png.h and, because they + are used for both read and write in some cases, it is not reliable + to #if out ones that are totally unsupported. This change adds error + detection in png_read_image() and png_write_image() to do a + png_app_error() if the app requests something that cannot be done + and it adds corresponding code to pngimage.c to handle such options + by not attempting to test them. + +Version 1.6.10beta02 [February 23, 2014] + Moved redefines of png_error(), png_warning(), png_chunk_error(), + and png_chunk_warning() from pngpriv.h to png.h to make them visible + to libpng-calling applications. + Moved OS dependent code from arm/arm_init.c, to allow the included + implementation of the ARM NEON discovery function to be set at + build-time and provide sample implementations from the current code in the + contrib/arm-neon subdirectory. The __linux__ code has also been changed to + compile and link on Android by using /proc/cpuinfo, and the old linux code + is in contrib/arm-neon/linux-auxv.c. The new code avoids POSIX and Linux + dependencies apart from opening /proc/cpuinfo and is C90 compliant. + Check for info_ptr == NULL early in png_read_end() so we don't need to + run all the png_handle_*() and depend on them to return if info_ptr == NULL. + This improves the performance of png_read_end(png_ptr, NULL) and makes + it more robust against future programming errors. + Check for __has_extension before using it in pngconf.h, to + support older Clang versions (Jeremy Sequoia). + Treat CRC error handling with png_set_crc_action(), instead of with + png_set_benign_errors(), which has been the case since libpng-1.6.0beta18. + Use a user warning handler in contrib/gregbook/readpng2.c instead of default, + so warnings will be put on stderr even if libpng has CONSOLE_IO disabled. + Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk + after recognizing the IDAT chunk, which avoids an infinite loop while + reading a datastream whose first IDAT chunk is of zero-length. + This fixes CERT VU#684412 and CVE-2014-0333. + Don't recognize known sRGB profiles as sRGB if they have been hacked, + but don't reject them and don't issue a copyright violation warning. + +Version 1.6.10beta03 [February 25, 2014] + Moved some documentation from png.h to libpng.3 and libpng-manual.txt + Minor editing of contrib/arm-neon/README and contrib/examples/*.c + +Version 1.6.10rc01 [February 27, 2014] + Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS + and PNG_USR_CONFIG -> PNG_USER_CONFIG). + +Version 1.6.10rc02 [February 28, 2014] + Removed unreachable return statement after png_chunk_error() + in pngrutil.c + +Version 1.6.10rc03 [March 4, 2014] + Un-deprecated png_data_freer(). + +Version 1.6.10 [March 6, 2014] + No changes. + +Version 1.6.11beta01 [March 17, 2014] + Use "if (value != 0)" instead of "if (value)" consistently. + Changed ZlibSrcDir from 1.2.5 to 1.2.8 in projects/vstudio. + Moved configuration information from the manual to the INSTALL file. + +Version 1.6.11beta02 [April 6, 2014] + Removed #if/#else/#endif from inside two pow() calls in pngvalid.c because + they were handled improperly by Portland Group's PGI-14.1 - PGI-14.3 + when using its "__builtin_pow()" function. + Silence 'unused parameter' build warnings (Cosmin Truta). + $(CP) is now used alongside $(RM_F). Also, use 'copy' instead of 'cp' + where applicable, and applied other minor makefile changes (Cosmin). + Don't warn about invalid dimensions exceeding user limits (Cosmin). + Allow an easy replacement of the default pre-built configuration + header with a custom header, via the make PNGLIBCONF_H_PREBUILT + macro (Cosmin). + +Version 1.6.11beta03 [April 6, 2014] + Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes + with "blocky" expansion of sub-8-bit interlaced PNG files (Eric Huss). + Optionally use __builtin_bswap16() in png_do_swap(). + +Version 1.6.11beta04 [April 19, 2014] + Made progressive reading of interlaced images consistent with the + behavior of the sequential reader and consistent with the manual, by + moving some code out of the PNG_READ_INTERLACING_SUPPORTED blocks. The + row_callback now receives the proper pass number and unexpanded rows, when + png_combine_row() isn't built or used, and png_set_interlace_handling() + is not called. + Allow PNG_sRGB_PROFILE_CHECKING = (-1) to mean no sRGB profile checking. + +Version 1.6.11beta05 [April 26, 2014] + Do not reject ICC V2 profiles that lack padding (Kai-Uwe Behrmann). + Relocated closing bracket of the sRGB profile test loop to avoid getting + "Not recognizing known sRGB profile that has been edited" warning for + ICC V2 profiles that lack the MD5 signature in the profile header. + +Version 1.6.11beta06 [May 19, 2014] + Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option(). + +Version 1.6.11rc01 [May 27, 2014] + No changes. + +Version 1.6.11rc02 [June 3, 2014] + Test ZLIB_VERNUM instead of PNG_ZLIB_VERNUM in contrib/tools/pngfix.c + +Version 1.6.11 [June 5, 2014] + No changes. + +Version 1.6.12rc01 [June 6, 2014] + Relocated new code from 1.6.11beta06 in png.c to a point after the + declarations (Max Stepin). + +Version 1.6.12rc02 [June 7, 2014] + Changed file permissions of contrib/tools/intgamma.sh, + test-driver, and compile from 0644 to 0755 (Cosmin). + +Version 1.6.12rc03 [June 8, 2014] + Ensure "__has_attribute()" macro exists before trying to use it with + old clang compilers (MacPorts Ticket #43939). + +Version 1.6.12 [June 12, 2014] + No changes. + +Send comments/corrections/commendations to png-mng-implement at lists.sf.net +(subscription required; visit +https://lists.sourceforge.net/lists/listinfo/png-mng-implement +to subscribe) +or to glennrp at users.sourceforge.net + +Glenn R-P +#endif diff --git a/png/CMakeLists.txt b/png/CMakeLists.txt new file mode 100755 index 0000000..f74147b --- /dev/null +++ b/png/CMakeLists.txt @@ -0,0 +1,364 @@ +# CMakeLists.txt + +# Copyright (C) 2007-2013 Glenn Randers-Pehrson + +# This code is released under the libpng license. +# For conditions of distribution and use, see the disclaimer +# and license in png.h + +cmake_minimum_required(VERSION 2.4.4) +set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS true) + +set(CMAKE_CONFIGURATION_TYPES "Release;Debug;MinSizeRel;RelWithDebInfo") + +project(libpng C) +enable_testing() + +set(PNGLIB_MAJOR 1) +set(PNGLIB_MINOR 6) +set(PNGLIB_RELEASE 12) +set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR}) +set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE}) + +# needed packages +find_package(ZLIB REQUIRED) +include_directories(${ZLIB_INCLUDE_DIR}) + +if(NOT WIN32) + find_library(M_LIBRARY + NAMES m + PATHS /usr/lib /usr/local/lib + ) + if(NOT M_LIBRARY) + message(STATUS + "math library 'libm' not found - floating point support disabled") + endif() +else() + # not needed on windows + set(M_LIBRARY "") +endif() + +# COMMAND LINE OPTIONS +if(DEFINED PNG_SHARED) + option(PNG_SHARED "Build shared lib" ${PNG_SHARED}) +else() + option(PNG_SHARED "Build shared lib" ON) +endif() +if(DEFINED PNG_STATIC) + option(PNG_STATIC "Build static lib" ${PNG_STATIC}) +else() + option(PNG_STATIC "Build static lib" ON) +endif() + +option(PNG_TESTS "Build libpng tests" YES) + +# Many more configuration options could be added here +option(PNG_DEBUG "Build with debug output" NO) +option(PNGARG "Disable ANSI-C prototypes" NO) + +# SET LIBNAME +set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR}) + +# to distinguish between debug and release lib +set(CMAKE_DEBUG_POSTFIX "d") + +# Use the prebuilt pnglibconf.h file from the scripts folder +# TODO: fix this by building with awk; without this no cmake build can be +# configured directly (to do so indirectly use your local awk to build a +# pnglibconf.h in the build directory.) +configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt + ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h) +include_directories(${CMAKE_CURRENT_BINARY_DIR}) + +# OUR SOURCES +set(libpng_public_hdrs + png.h + pngconf.h + ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h +) +set(libpng_sources + ${libpng_public_hdrs} + pngdebug.h + pnginfo.h + pngpriv.h + pngstruct.h + png.c + pngerror.c + pngget.c + pngmem.c + pngpread.c + pngread.c + pngrio.c + pngrtran.c + pngrutil.c + pngset.c + pngtrans.c + pngwio.c + pngwrite.c + pngwtran.c + pngwutil.c +) +set(pngtest_sources + pngtest.c +) +set(pngvalid_sources + contrib/libtests/pngvalid.c +) +set(pngstest_sources + contrib/libtests/pngstest.c +) +# SOME NEEDED DEFINITIONS + +if(MSVC) + add_definitions(-D_CRT_SECURE_NO_DEPRECATE) +endif(MSVC) + +if(PNG_DEBUG) + add_definitions(-DPNG_DEBUG) +endif() + +# NOW BUILD OUR TARGET +include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${ZLIB_INCLUDE_DIR}) + +unset(PNG_LIB_TARGETS) + +if(PNG_SHARED) + add_library(${PNG_LIB_NAME} SHARED ${libpng_sources}) + set(PNG_LIB_TARGETS ${PNG_LIB_NAME}) + if(MSVC) + # msvc does not append 'lib' - do it here to have consistent name + set_target_properties(${PNG_LIB_NAME} PROPERTIES PREFIX "lib") + set_target_properties(${PNG_LIB_NAME} PROPERTIES IMPORT_PREFIX "lib") + endif() + target_link_libraries(${PNG_LIB_NAME} ${ZLIB_LIBRARY} ${M_LIBRARY}) +endif() + +if(PNG_STATIC) +# does not work without changing name + set(PNG_LIB_NAME_STATIC ${PNG_LIB_NAME}_static) + add_library(${PNG_LIB_NAME_STATIC} STATIC ${libpng_sources}) + list(APPEND PNG_LIB_TARGETS ${PNG_LIB_NAME_STATIC}) + if(MSVC) + # msvc does not append 'lib' - do it here to have consistent name + set_target_properties(${PNG_LIB_NAME_STATIC} PROPERTIES PREFIX "lib") + endif() + target_link_libraries(${PNG_LIB_NAME_STATIC} ${ZLIB_LIBRARY} ${M_LIBRARY}) +endif() + +if(NOT PNG_LIB_TARGETS) + message(SEND_ERROR + "No library variant selected to build. " + "Please enable at least one of the following options: PNG_STATIC, PNG_SHARED") +endif() + +if(PNG_SHARED AND WIN32) + set_target_properties(${PNG_LIB_NAME} PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL) +endif() + +if(PNG_TESTS AND PNG_SHARED) + # does not work with msvc due to png_lib_ver issue + add_executable(pngtest ${pngtest_sources}) + target_link_libraries(pngtest ${PNG_LIB_NAME}) + add_test(pngtest ./pngtest ${CMAKE_CURRENT_SOURCE_DIR}/pngtest.png) + # + add_executable(pngvalid ${pngvalid_sources}) + target_link_libraries(pngvalid ${PNG_LIB_NAME}) + add_test(pngvalid ./pngvalid) + add_executable(pngstest ${pngstest_sources}) + target_link_libraries(pngstest ${PNG_LIB_NAME}) + add_test(pngstest ./pngstest + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g01.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g02.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g04.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn0g16.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn2c08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn2c16.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn3p01.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn3p02.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn3p04.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn3p08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn4a08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn4a16.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn6a08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/basn6a16.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn0g01.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn0g02.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn0g04.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn2c16.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbbn3p08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbgn2c16.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbgn3p08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbrn2c08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbwn0g16.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbwn3p08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftbyn3p08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftp0n0g08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftp0n2c08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftp0n3p08.png + ${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/ftp1n3p08.png + ) +endif() + +# Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set +IF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY) + SET(CMAKE_LIBRARY_OUTPUT_DIRECTORY "lib") +ENDIF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY) + +# Set a variable with CMake code which: +# Creates a symlink from src to dest (if possible) or alternatively +# copies if different. +macro(CREATE_SYMLINK SRC_FILE DEST_FILE) + FILE(REMOVE ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}) + if(WIN32 AND NOT CYGWIN AND NOT MSYS) + ADD_CUSTOM_COMMAND( + OUTPUT ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE} + COMMAND ${CMAKE_COMMAND} -E copy_if_different "${SRC_FILE}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} + COMMAND ${CMAKE_COMMAND} -E copy_if_different "${SRC_FILE}" ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE} + DEPENDS ${PNG_LIB_TARGETS} + ) + ADD_CUSTOM_TARGET(${DEST_FILE}_COPY ALL DEPENDS ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}) + else(WIN32 AND NOT CYGWIN AND NOT MSYS) + get_filename_component(LINK_TARGET "${SRC_FILE}" NAME) + execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}) + execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}) + endif(WIN32 AND NOT CYGWIN AND NOT MSYS) +endmacro() + +# libpng is a library so default to 'lib' +if(NOT DEFINED CMAKE_INSTALL_LIBDIR) + set(CMAKE_INSTALL_LIBDIR lib) +endif(NOT DEFINED CMAKE_INSTALL_LIBDIR) + +# CREATE PKGCONFIG FILES +# we use the same files like ./configure, so we have to set its vars +# Only do this on Windows for Cygwin - the files don't make much sense outside +# a UNIX look alike +if(NOT WIN32 OR CYGWIN OR MINGW) + set(prefix ${CMAKE_INSTALL_PREFIX}) + set(exec_prefix ${CMAKE_INSTALL_PREFIX}) + set(libdir ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}) + set(includedir ${CMAKE_INSTALL_PREFIX}/include) + set(LIBS "-lz -lm") + configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in + ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc @ONLY) + CREATE_SYMLINK(${PNGLIB_NAME}.pc libpng.pc) + + configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in + ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config @ONLY) + CREATE_SYMLINK(${PNGLIB_NAME}-config libpng-config) +endif(NOT WIN32 OR CYGWIN OR MINGW) + +# SET UP LINKS +if(PNG_SHARED) + set_target_properties(${PNG_LIB_NAME} PROPERTIES +# VERSION 16.${PNGLIB_RELEASE}.1.6.12 + VERSION 16.${PNGLIB_RELEASE}.0 + SOVERSION 16 + CLEAN_DIRECT_OUTPUT 1) +endif() +if(PNG_STATIC) + # MSVC doesn't use a different file extension for shared vs. static + # libs. We are able to change OUTPUT_NAME to remove the _static + # for all other platforms. + if(NOT MSVC) + set_target_properties(${PNG_LIB_NAME_STATIC} PROPERTIES + OUTPUT_NAME ${PNG_LIB_NAME} + CLEAN_DIRECT_OUTPUT 1) + endif() +endif() + +# If CMake > 2.4.x, we set a variable used below to export +# targets to an export file. +# TODO: Use VERSION_GREATER after our cmake_minimum_required >= 2.6.2 +if(CMAKE_MAJOR_VERSION GREATER 1 AND CMAKE_MINOR_VERSION GREATER 4) + set(PNG_EXPORT_RULE EXPORT libpng) +elseif(CMAKE_MAJOR_VERSION GREATER 2) # future proof + set(PNG_EXPORT_RULE EXPORT libpng) +endif() + +# INSTALL +if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL ) + install(TARGETS ${PNG_LIB_TARGETS} + ${PNG_EXPORT_RULE} + RUNTIME DESTINATION bin + LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} + ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}) + + if(PNG_SHARED) + # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin + if(CYGWIN OR MINGW) + get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME} LOCATION_${CMAKE_BUILD_TYPE}) + CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX}) + install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX} + DESTINATION ${CMAKE_INSTALL_LIBDIR}) + endif(CYGWIN OR MINGW) + + if(NOT WIN32) + get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME} LOCATION_${CMAKE_BUILD_TYPE}) + CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_SHARED_LIBRARY_SUFFIX}) + install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX} + DESTINATION ${CMAKE_INSTALL_LIBDIR}) + endif(NOT WIN32) + endif(PNG_SHARED) + + if(PNG_STATIC) + if(NOT WIN32 OR CYGWIN OR MINGW) + get_target_property(BUILD_TARGET_LOCATION ${PNG_LIB_NAME_STATIC} LOCATION_${CMAKE_BUILD_TYPE}) + CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_STATIC_LIBRARY_SUFFIX}) + install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX} + DESTINATION ${CMAKE_INSTALL_LIBDIR}) + endif(NOT WIN32 OR CYGWIN OR MINGW) + endif() +endif() + +if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL ) + install(FILES ${libpng_public_hdrs} DESTINATION include) + install(FILES ${libpng_public_hdrs} DESTINATION include/${PNGLIB_NAME}) +endif() +if(NOT SKIP_INSTALL_EXECUTABLES AND NOT SKIP_INSTALL_ALL ) + if(NOT WIN32 OR CYGWIN OR MINGW) + install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config DESTINATION bin) + install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config + DESTINATION bin) + endif(NOT WIN32 OR CYGWIN OR MINGW) +endif() + +if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL ) + # Install man pages + if(NOT PNG_MAN_DIR) + set(PNG_MAN_DIR "share/man") + endif() + install(FILES libpng.3 libpngpf.3 DESTINATION ${PNG_MAN_DIR}/man3) + install(FILES png.5 DESTINATION ${PNG_MAN_DIR}/man5) + # Install pkg-config files + if(NOT WIN32 OR CYGWIN OR MINGW) + install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc + DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig) + install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config + DESTINATION bin) + install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc + DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig) + install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config + DESTINATION bin) + endif(NOT WIN32 OR CYGWIN OR MINGW) +endif() + +# On versions of CMake that support it, create an export file CMake +# users can include() to import our targets +if(PNG_EXPORT_RULE AND NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL ) + install(EXPORT libpng DESTINATION lib/libpng FILE lib${PNG_LIB_NAME}.cmake) +endif() + +# what's with libpng-$VER%.txt and all the extra files? + +# UNINSTALL +# do we need this? + +# DIST +# do we need this? + +# to create msvc import lib for mingw compiled shared lib +# pexports libpng.dll > libpng.def +# lib /def:libpng.def /machine:x86 + diff --git a/png/INSTALL b/png/INSTALL new file mode 100755 index 0000000..b645491 --- /dev/null +++ b/png/INSTALL @@ -0,0 +1,369 @@ + +Installing libpng + +Contents + + I. Simple installation + II. Rebuilding the configure scripts + III. Using scripts/makefile* + IV. Using cmake + V. Directory structure + VI. Building with project files + VII. Building with makefiles +VIII. Configuring libpng for 16-bit platforms + IX. Configuring for DOS + X. Configuring for Medium Model + XI. Prepending a prefix to exported symbols + XII. Configuring for compiler xxx: +XIII. Removing unwanted object code + XIV. Changes to the build and configuration of libpng in libpng-1.5.x + XV. Configuring libpng for multiprocessing + XVI. Other sources of information about libpng: + +I. Simple installation + +On Unix/Linux and similar systems, you can simply type + + ./configure [--prefix=/path] + make check + make install + +and ignore the rest of this document. + +II. Rebuilding the configure scripts + +If configure does not work on your system, or if you have a need to +change configure.ac or Makefile.am, and you have a reasonably +up-to-date set of tools, running ./autogen.sh in a git clone before +running ./configure may fix the problem. To be really sure that you +aren't using any of the included pre-built scripts, you can do this: + + ./configure --enable-maintainer-mode + make maintainer-clean + ./autogen.sh --maintainer --clean + ./autogen.sh --maintainer + ./configure [--prefix=/path] [other options] + make + make install + make check + +III. Using scripts/makefile* + +Instead, you can use one of the custom-built makefiles in the +"scripts" directory + + cp scripts/pnglibconf.h.prebuilt pnglibconf.h + cp scripts/makefile.system makefile + make test + make install + +The files that are presently available in the scripts directory +are listed and described in scripts/README.txt. + +Or you can use one of the "projects" in the "projects" directory. + +Before installing libpng, you must first install zlib, if it +is not already on your system. zlib can usually be found +wherever you got libpng. zlib can be placed in another directory, +at the same level as libpng. + +If your system already has a preinstalled zlib you will still need +to have access to the zlib.h and zconf.h include files that +correspond to the version of zlib that's installed. + +If you wish to test with a particular zlib that is not first in the +standard library search path, put ZLIBLIB, ZLIBINC, CPPFLAGS, LDFLAGS, +and LD_LIBRARY_PATH in your environment before running "make test" +or "make distcheck": + +ZLIBLIB=/path/to/lib export ZLIBLIB +ZLIBINC=/path/to/include export ZLIBINC +CPPFLAGS="-I$ZLIBINC" export CPPFLAGS +LDFLAGS="-L$ZLIBLIB" export LDFLAGS +LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH + +If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC +in your environment and type "make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test". + +IV. Using cmake + +If you want to use "cmake" (see www.cmake.org), type + + cmake . -DCMAKE_INSTALL_PREFIX=/path + make + make install + +V. Directory structure + +You can rename the directories that you downloaded (they +might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.8" +or "zlib128") so that you have directories called "zlib" and "libpng". + +Your directory structure should look like this: + + .. (the parent directory) + libpng (this directory) + INSTALL (this file) + README + *.h + *.c + CMakeLists.txt => "cmake" script + configuration files: + configure.ac, configure, Makefile.am, Makefile.in, + autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in, + libpng-config.in, aclocal.m4, config.h.in, config.sub, + depcomp, install-sh, mkinstalldirs, test-pngtest.sh + contrib + gregbook + libtests + pngminim + pngminus + pngsuite + visupng + projects + visualc71 + vstudio + scripts + makefile.* + *.def (module definition files) + etc. + pngtest.png + etc. + zlib + README + *.h + *.c + contrib + etc. + +If the line endings in the files look funny, you may wish to get the other +distribution of libpng. It is available in both tar.gz (UNIX style line +endings) and zip (DOS style line endings) formats. + +VI. Building with project files + +If you are building libpng with MSVC, you can enter the +libpng projects\visualc6 or visualc71 directory and follow the instructions +in README.txt. + +Otherwise enter the zlib directory and follow the instructions in zlib/README, +then come back here and run "configure" or choose the appropriate +makefile.sys in the scripts directory. + +VII. Building with makefiles + +Copy the file (or files) that you need from the +scripts directory into this directory, for example + + MSDOS example: copy scripts\makefile.msc makefile + copy scripts\pnglibconf.h.prebuilt pnglibconf.h + UNIX example: cp scripts/makefile.std makefile + cp scripts/pnglibconf.h.prebuilt pnglibconf.h + +Read the makefile to see if you need to change any source or +target directories to match your preferences. + +Then read pnglibconf.dfa to see if you want to make any configuration +changes. + +Then just run "make" which will create the libpng library in +this directory and "make test" which will run a quick test that reads +the "pngtest.png" file and writes a "pngout.png" file that should be +identical to it. Look for "9782 zero samples" in the output of the +test. For more confidence, you can run another test by typing +"pngtest pngnow.png" and looking for "289 zero samples" in the output. +Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare +your output with the result shown in contrib/pngsuite/README. + +Most of the makefiles will allow you to run "make install" to +put the library in its final resting place (if you want to +do that, run "make install" in the zlib directory first if necessary). +Some also allow you to run "make test-installed" after you have +run "make install". + +VIII. Configuring libpng for 16-bit platforms + +You will want to look into zconf.h to tell zlib (and thus libpng) that +it cannot allocate more then 64K at a time. Even if you can, the memory +won't be accessible. So limit zlib and libpng to 64K by defining MAXSEG_64K. + +IX. Configuring for DOS + +For DOS users who only have access to the lower 640K, you will +have to limit zlib's memory usage via a png_set_compression_mem_level() +call. See zlib.h or zconf.h in the zlib library for more information. + +X. Configuring for Medium Model + +Libpng's support for medium model has been tested on most of the popular +compilers. Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets +defined, and FAR gets defined to far in pngconf.h, and you should be +all set. Everything in the library (except for zlib's structure) is +expecting far data. You must use the typedefs with the p or pp on +the end for pointers (or at least look at them and be careful). Make +note that the rows of data are defined as png_bytepp, which is +an "unsigned char far * far *". + +XI. Prepending a prefix to exported symbols + +Starting with libpng-1.6.0, you can configure libpng (when using the +"configure" script) to prefix all exported symbols by means of the +configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any +string beginning with a letter and containing only uppercase +and lowercase letters, digits, and the underscore (i.e., a C language +identifier). This creates a set of macros in pnglibconf.h, so this is +transparent to applications; their function calls get transformed by +the macros to use the modified names. + +XII. Configuring for compiler xxx: + +All includes for libpng are in pngconf.h. If you need to add, change +or delete an include, this is the place to do it. +The includes that are not needed outside libpng are placed in pngpriv.h, +which is only used by the routines inside libpng itself. +The files in libpng proper only include pngpriv.h and png.h, which +in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h. +As of libpng-1.5.0, pngpriv.h also includes three other private header +files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material +that previously appeared in the public headers. + +XIII. Removing unwanted object code + +There are a bunch of #define's in pngconf.h that control what parts of +libpng are compiled. All the defines end in _SUPPORTED. If you are +never going to use a capability, you can change the #define to #undef +before recompiling libpng and save yourself code and data space, or +you can turn off individual capabilities with defines that begin with +PNG_NO_. + +In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead. + +You can also turn all of the transforms and ancillary chunk capabilities +off en masse with compiler directives that define +PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS, +or all four, along with directives to turn on any of the capabilities that +you do want. The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the +extra transformations but still leave the library fully capable of reading +and writing PNG files with all known public chunks. Use of the +PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library +that is incapable of reading or writing ancillary chunks. If you are +not using the progressive reading capability, you can turn that off +with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING +capability, which you'll still have). + +All the reading and writing specific code are in separate files, so the +linker should only grab the files it needs. However, if you want to +make sure, or if you are building a stand alone library, all the +reading files start with "pngr" and all the writing files start with "pngw". +The files that don't match either (like png.c, pngtrans.c, etc.) +are used for both reading and writing, and always need to be included. +The progressive reader is in pngpread.c + +If you are creating or distributing a dynamically linked library (a .so +or DLL file), you should not remove or disable any parts of the library, +as this will cause applications linked with different versions of the +library to fail if they call functions not available in your library. +The size of the library itself should not be an issue, because only +those sections that are actually used will be loaded into memory. + +XIV. Changes to the build and configuration of libpng in libpng-1.5.x + +Details of internal changes to the library code can be found in the CHANGES +file and in the GIT repository logs. These will be of no concern to the vast +majority of library users or builders; however, the few who configure libpng +to a non-default feature set may need to change how this is done. + +There should be no need for library builders to alter build scripts if +these use the distributed build support - configure or the makefiles - +however, users of the makefiles may care to update their build scripts +to build pnglibconf.h where the corresponding makefile does not do so. + +Building libpng with a non-default configuration has changed completely. +The old method using pngusr.h should still work correctly even though the +way pngusr.h is used in the build has been changed; however, library +builders will probably want to examine the changes to take advantage of +new capabilities and to simplify their build system. + +A. Specific changes to library configuration capabilities + +The exact mechanism used to control attributes of API functions has +changed. A single set of operating system independent macro definitions +is used and operating system specific directives are defined in +pnglibconf.h + +As part of this the mechanism used to choose procedure call standards on +those systems that allow a choice has been changed. At present this only +affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems +running on Intel processors. As before, PNGAPI is defined where required +to control the exported API functions; however, two new macros, PNGCBAPI +and PNGCAPI, are used instead for callback functions (PNGCBAPI) and +(PNGCAPI) for functions that must match a C library prototype (currently +only png_longjmp_ptr, which must match the C longjmp function.) The new +approach is documented in pngconf.h + +Despite these changes, libpng 1.5.0 only supports the native C function +calling standard on those platforms tested so far (__cdecl on Microsoft +Windows). This is because the support requirements for alternative +calling conventions seem to no longer exist. Developers who find it +necessary to set PNG_API_RULE to 1 should advise the mailing list +(png-mng-implement) of this and library builders who use Openwatcom and +therefore set PNG_API_RULE to 2 should also contact the mailing list. + +B. Changes to the configuration mechanism + +Prior to libpng-1.5.0 library builders who needed to configure libpng +had either to modify the exported pngconf.h header file to add system +specific configuration or had to write feature selection macros into +pngusr.h and cause this to be included into pngconf.h by defining +PNG_USER_CONFIG. The latter mechanism had the disadvantage that an +application built without PNG_USER_CONFIG defined would see the +unmodified, default, libpng API and thus would probably fail to link. + +These mechanisms still work in the configure build and in any makefile +build that builds pnglibconf.h, although the feature selection macros +have changed somewhat as described above. In 1.5.0, however, pngusr.h is +processed only once, when the exported header file pnglibconf.h is built. +pngconf.h no longer includes pngusr.h, therefore pngusr.h is ignored after the +build of pnglibconf.h and it is never included in an application build. + +The rarely used alternative of adding a list of feature macros to the +CPPFLAGS setting in the build also still works; however, the macros will be +copied to pnglibconf.h and this may produce macro redefinition warnings +when the individual C files are compiled. + +All configuration now only works if pnglibconf.h is built from +scripts/pnglibconf.dfa. This requires the program awk. Brian Kernighan +(the original author of awk) maintains C source code of that awk and this +and all known later implementations (often called by subtly different +names - nawk and gawk for example) are adequate to build pnglibconf.h. +The Sun Microsystems (now Oracle) program 'awk' is an earlier version +and does not work; this may also apply to other systems that have a +functioning awk called 'nawk'. + +Configuration options are now documented in scripts/pnglibconf.dfa. This +file also includes dependency information that ensures a configuration is +consistent; that is, if a feature is switched off dependent features are +also removed. As a recommended alternative to using feature macros in +pngusr.h a system builder may also define equivalent options in pngusr.dfa +(or, indeed, any file) and add that to the configuration by setting +DFA_XTRA to the file name. The makefiles in contrib/pngminim illustrate +how to do this, and a case where pngusr.h is still required. + +XV. Configuring libpng for multiprocessing + +Libpng uses setjmp()/longjmp() for error handling. Unfortunately setjmp() +is known to be not thread-safe on some platforms and we don't know of +any platform where it is guaranteed to be thread-safe. Therefore, if +your application is going to be using multiple threads, you should +configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with +-DPNG_NO_SETJMP on your compile line, or with + + #undef PNG_SETJMP_SUPPORTED + +in your pnglibconf.h or pngusr.h. + +XVI. Other sources of information about libpng: + +Further information can be found in the README and libpng-manual.txt +files, in the individual makefiles, in png.h, and the manual pages +libpng.3 and png.5. diff --git a/png/Jamfile b/png/Jamfile new file mode 100755 index 0000000..def7495 --- /dev/null +++ b/png/Jamfile @@ -0,0 +1,32 @@ + +#PREF_CCFLAGS = $(CCOPTFLAG) ; # Turn optimisation on +PREF_CCFLAGS = $(CCDEBUGFLAG) ; # Debugging flags +PREF_LINKFLAGS = $(LINKDEBUGFLAG) ; + +Libraries = libpng ; +Executables = ; +Headers = png.h ; + +HDRS = $(ZINC) ; + +# png library +LIBSRCS = + png.c + pngerror.c + pngget.c + pngmem.c + pngpread.c + pngread.c + pngrio.c + pngrtran.c + pngrutil.c + pngset.c + pngtrans.c + pngwio.c + pngwrite.c + pngwtran.c + pngwutil.c + ; + +Library libpng : $(LIBSRCS) ; + diff --git a/png/LICENSE b/png/LICENSE new file mode 100755 index 0000000..b77abdd --- /dev/null +++ b/png/LICENSE @@ -0,0 +1,111 @@ + +This copy of the libpng notices is provided for your convenience. In case of +any discrepancy between this copy and the notices in the file png.h that is +included in the libpng distribution, the latter shall prevail. + +COPYRIGHT NOTICE, DISCLAIMER, and LICENSE: + +If you modify libpng you may insert additional notices immediately following +this sentence. + +This code is released under the libpng license. + +libpng versions 1.2.6, August 15, 2004, through 1.6.12, June 12, 2014, are +Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are +distributed according to the same disclaimer and license as libpng-1.2.5 +with the following individual added to the list of Contributing Authors + + Cosmin Truta + +libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are +Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are +distributed according to the same disclaimer and license as libpng-1.0.6 +with the following individuals added to the list of Contributing Authors + + Simon-Pierre Cadieux + Eric S. Raymond + Gilles Vollant + +and with the following additions to the disclaimer: + + There is no warranty against interference with your enjoyment of the + library or against infringement. There is no warranty that our + efforts or the library will fulfill any of your particular purposes + or needs. This library is provided with all faults, and the entire + risk of satisfactory quality, performance, accuracy, and effort is with + the user. + +libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are +Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are +distributed according to the same disclaimer and license as libpng-0.96, +with the following individuals added to the list of Contributing Authors: + + Tom Lane + Glenn Randers-Pehrson + Willem van Schaik + +libpng versions 0.89, June 1996, through 0.96, May 1997, are +Copyright (c) 1996, 1997 Andreas Dilger +Distributed according to the same disclaimer and license as libpng-0.88, +with the following individuals added to the list of Contributing Authors: + + John Bowler + Kevin Bracey + Sam Bushell + Magnus Holmgren + Greg Roelofs + Tom Tanner + +libpng versions 0.5, May 1995, through 0.88, January 1996, are +Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc. + +For the purposes of this copyright and license, "Contributing Authors" +is defined as the following set of individuals: + + Andreas Dilger + Dave Martindale + Guy Eric Schalnat + Paul Schmidt + Tim Wegner + +The PNG Reference Library is supplied "AS IS". The Contributing Authors +and Group 42, Inc. disclaim all warranties, expressed or implied, +including, without limitation, the warranties of merchantability and of +fitness for any purpose. The Contributing Authors and Group 42, Inc. +assume no liability for direct, indirect, incidental, special, exemplary, +or consequential damages, which may result from the use of the PNG +Reference Library, even if advised of the possibility of such damage. + +Permission is hereby granted to use, copy, modify, and distribute this +source code, or portions hereof, for any purpose, without fee, subject +to the following restrictions: + +1. The origin of this source code must not be misrepresented. + +2. Altered versions must be plainly marked as such and must not + be misrepresented as being the original source. + +3. This Copyright notice may not be removed or altered from any + source or altered source distribution. + +The Contributing Authors and Group 42, Inc. specifically permit, without +fee, and encourage the use of this source code as a component to +supporting the PNG file format in commercial products. If you use this +source code in a product, acknowledgment is not required but would be +appreciated. + + +A "png_get_copyright" function is available, for convenient use in "about" +boxes and the like: + + printf("%s",png_get_copyright(NULL)); + +Also, the PNG logo (in PNG format, of course) is supplied in the +files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31). + +Libpng is OSI Certified Open Source Software. OSI Certified Open Source is a +certification mark of the Open Source Initiative. + +Glenn Randers-Pehrson +glennrp at users.sourceforge.net +June 12, 2014 diff --git a/png/README b/png/README new file mode 100755 index 0000000..dc6c00b --- /dev/null +++ b/png/README @@ -0,0 +1,202 @@ +README for libpng version 1.6.12 - June 12, 2014 (shared library 16.0) +See the note about version numbers near the top of png.h + +See INSTALL for instructions on how to install libpng. + +Libpng comes in several distribution formats. Get libpng-*.tar.gz or +libpng-*.tar.xz or if you want UNIX-style line endings in the text files, +or lpng*.7z or lpng*.zip if you want DOS-style line endings. + +Version 0.89 was the first official release of libpng. Don't let the +fact that it's the first release fool you. The libpng library has been in +extensive use and testing since mid-1995. By late 1997 it had +finally gotten to the stage where there hadn't been significant +changes to the API in some time, and people have a bad feeling about +libraries with versions < 1.0. Version 1.0.0 was released in +March 1998. + +**** +Note that some of the changes to the png_info structure render this +version of the library binary incompatible with libpng-0.89 or +earlier versions if you are using a shared library. The type of the +"filler" parameter for png_set_filler() has changed from png_byte to +png_uint_32, which will affect shared-library applications that use +this function. + +To avoid problems with changes to the internals of png_info_struct, +new APIs have been made available in 0.95 to avoid direct application +access to info_ptr. These functions are the png_set_<chunk> and +png_get_<chunk> functions. These functions should be used when +accessing/storing the info_struct data, rather than manipulating it +directly, to avoid such problems in the future. + +It is important to note that the APIs do not make current programs +that access the info struct directly incompatible with the new +library. However, it is strongly suggested that new programs use +the new APIs (as shown in example.c and pngtest.c), and older programs +be converted to the new format, to facilitate upgrades in the future. +**** + +Additions since 0.90 include the ability to compile libpng as a +Windows DLL, and new APIs for accessing data in the info struct. +Experimental functions include the ability to set weighting and cost +factors for row filter selection, direct reads of integers from buffers +on big-endian processors that support misaligned data access, faster +methods of doing alpha composition, and more accurate 16->8 bit color +conversion. + +The additions since 0.89 include the ability to read from a PNG stream +which has had some (or all) of the signature bytes read by the calling +application. This also allows the reading of embedded PNG streams that +do not have the PNG file signature. As well, it is now possible to set +the library action on the detection of chunk CRC errors. It is possible +to set different actions based on whether the CRC error occurred in a +critical or an ancillary chunk. + +The changes made to the library, and bugs fixed are based on discussions +on the PNG-implement mailing list and not on material submitted +privately to Guy, Andreas, or Glenn. They will forward any good +suggestions to the list. + +For a detailed description on using libpng, read libpng-manual.txt. For +examples of libpng in a program, see example.c and pngtest.c. For usage +information and restrictions (what little they are) on libpng, see +png.h. For a description on using zlib (the compression library used by +libpng) and zlib's restrictions, see zlib.h + +I have included a general makefile, as well as several machine and +compiler specific ones, but you may have to modify one for your own needs. + +You should use zlib 1.0.4 or later to run this, but it MAY work with +versions as old as zlib 0.95. Even so, there are bugs in older zlib +versions which can cause the output of invalid compression streams for +some images. You will definitely need zlib 1.0.4 or later if you are +taking advantage of the MS-DOS "far" structure allocation for the small +and medium memory models. You should also note that zlib is a +compression library that is useful for more things than just PNG files. +You can use zlib as a drop-in replacement for fread() and fwrite() if +you are so inclined. + +zlib should be available at the same place that libpng is, or at zlib.net. + +You may also want a copy of the PNG specification. It is available +as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find +these at http://www.libpng.org/pub/png/documents/ + +This code is currently being archived at libpng.sf.net in the +[DOWNLOAD] area, and at ftp://ftp.simplesystems.org. If you can't find it +in any of those places, e-mail me, and I'll help you find it. + +If you have any code changes, requests, problems, etc., please e-mail +them to me. Also, I'd appreciate any make files or project files, +and any modifications you needed to make to get libpng to compile, +along with a #define variable to tell what compiler/system you are on. +If you needed to add transformations to libpng, or wish libpng would +provide the image in a different way, drop me a note (and code, if +possible), so I can consider supporting the transformation. +Finally, if you get any warning messages when compiling libpng +(note: not zlib), and they are easy to fix, I'd appreciate the +fix. Please mention "libpng" somewhere in the subject line. Thanks. + +This release was created and will be supported by myself (of course +based in a large way on Guy's and Andreas' earlier work), and the PNG +development group. + +Send comments/corrections/commendations to png-mng-implement at +lists.sourceforge.net (subscription required; visit +https://lists.sourceforge.net/lists/listinfo/png-mng-implement +to subscribe) or to glennrp at users.sourceforge.net + +You can't reach Guy, the original libpng author, at the addresses +given in previous versions of this document. He and Andreas will +read mail addressed to the png-implement list, however. + +Please do not send general questions about PNG. Send them to +png-mng-misc at lists.sf.net (subscription required; visit +https://lists.sourceforge.net/lists/listinfo/png-mng-misc to +subscribe). If you have a question about something +in the PNG specification that is related to using libpng, send it +to me. Send me any questions that start with "I was using libpng, +and ...". If in doubt, send questions to me. I'll bounce them +to others, if necessary. + +Please do not send suggestions on how to change PNG. We have +been discussing PNG for nineteen years now, and it is official and +finished. If you have suggestions for libpng, however, I'll +gladly listen. Even if your suggestion is not used immediately, +it may be used later. + +Files in this distribution: + + ANNOUNCE => Announcement of this version, with recent changes + CHANGES => Description of changes between libpng versions + KNOWNBUG => List of known bugs and deficiencies + LICENSE => License to use and redistribute libpng + README => This file + TODO => Things not implemented in the current library + Y2KINFO => Statement of Y2K compliance + example.c => Example code for using libpng functions + libpng.3 => manual page for libpng (includes libpng-manual.txt) + libpng-manual.txt => Description of libpng and its functions + libpngpf.3 => manual page for libpng's private functions + png.5 => manual page for the PNG format + png.c => Basic interface functions common to library + png.h => Library function and interface declarations (public) + pngpriv.h => Library function and interface declarations (private) + pngconf.h => System specific library configuration (public) + pngstruct.h => png_struct declaration (private) + pnginfo.h => png_info struct declaration (private) + pngdebug.h => debugging macros (private) + pngerror.c => Error/warning message I/O functions + pngget.c => Functions for retrieving info from struct + pngmem.c => Memory handling functions + pngbar.png => PNG logo, 88x31 + pngnow.png => PNG logo, 98x31 + pngpread.c => Progressive reading functions + pngread.c => Read data/helper high-level functions + pngrio.c => Lowest-level data read I/O functions + pngrtran.c => Read data transformation functions + pngrutil.c => Read data utility functions + pngset.c => Functions for storing data into the info_struct + pngtest.c => Library test program + pngtest.png => Library test sample image + pngtrans.c => Common data transformation functions + pngwio.c => Lowest-level write I/O functions + pngwrite.c => High-level write functions + pngwtran.c => Write data transformations + pngwutil.c => Write utility functions + arm => Contains optimized code for the ARM platform + contrib => Contributions + examples => Example programs + gregbook => source code for PNG reading and writing, from + Greg Roelofs' "PNG: The Definitive Guide", + O'Reilly, 1999 + libtests => Test programs + pngminim => Minimal decoder, encoder, and progressive decoder + programs demonstrating use of pngusr.dfa + pngminus => Simple pnm2png and png2pnm programs + pngsuite => Test images + tools => Various tools + visupng => Contains a MSVC workspace for VisualPng + projects => Contains project files and workspaces for + building a DLL + owatcom => Contains a WATCOM project for building libpng + visualc71 => Contains a Microsoft Visual C++ (MSVC) + workspace for building libpng and zlib + vstudio => Contains a Microsoft Visual C++ (MSVC) + workspace for building libpng and zlib + scripts => Directory containing scripts for building libpng: + (see scripts/README.txt for the list of scripts) + +Good luck, and happy coding. + +-Glenn Randers-Pehrson (current maintainer, since 1998) + Internet: glennrp at users.sourceforge.net + +-Andreas Eric Dilger (former maintainer, 1996-1997) + Internet: adilger at enel.ucalgary.ca + Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/ + +-Guy Eric Schalnat (original author and former maintainer, 1995-1996) + (formerly of Group 42, Inc) + Internet: gschal at infinet.com diff --git a/png/TODO b/png/TODO new file mode 100755 index 0000000..7263377 --- /dev/null +++ b/png/TODO @@ -0,0 +1,29 @@ +/* +TODO - list of things to do for libpng: + +Final bug fixes. +Better C++ wrapper/full C++ implementation? +Fix problem with C++ and EXTERN "C". +cHRM transformation. +Remove setjmp/longjmp usage in favor of returning error codes. +Palette creation. +Add "grayscale->palette" transformation and "palette->grayscale" detection. +Improved dithering. +Multi-lingual error and warning message support. +Complete sRGB transformation (presently it simply uses gamma=0.45455). +Make profile checking optional via a png_set_something() call. +Man pages for function calls. +Better documentation. +Better filter selection + (counting huffman bits/precompression? filter inertia? filter costs?). +Histogram creation. +Text conversion between different code pages (Latin-1 -> Mac and DOS). +Avoid building gamma tables whenever possible. +Use greater precision when changing to linear gamma for compositing against + background and doing rgb-to-gray transformation. +Investigate pre-incremented loop counters and other loop constructions. +Add interpolated method of handling interlacing. +Switch to the simpler zlib (zlib/libpng) license if legally possible. +Extend pngvalid.c to validate more of the libpng transformations. + +*/ diff --git a/png/afiles b/png/afiles new file mode 100644 index 0000000..9e4e485 --- /dev/null +++ b/png/afiles @@ -0,0 +1,44 @@ +afiles +Jamfile +ANNOUNCE +CHANGES +CMakeLists.txt +INSTALL +LICENSE +README +TODO +configure +example.c +libpng-config.in +libpng-manual.txt +libpng.3 +libpng.pc.in +libpngpf.3 +png.5 +png.c +png.h +pngbar.jpg +pngbar.png +pngconf.h +pngdebug.h +pngerror.c +pngget.c +pnginfo.h +pnglibconf.h +pngmem.c +pngnow.png +pngpread.c +pngpriv.h +pngread.c +pngrio.c +pngrtran.c +pngrutil.c +pngset.c +pngstruct.h +pngtest.c +pngtest.png +pngtrans.c +pngwio.c +pngwrite.c +pngwtran.c +pngwutil.c diff --git a/png/configure b/png/configure new file mode 100755 index 0000000..9406e1f --- /dev/null +++ b/png/configure @@ -0,0 +1,19 @@ + +echo " + There is no \"configure\" script in this distribution (*.zip or *.7z) of + libpng-1.6.12. + + Instead, please copy the appropriate makefile for your system from the + \"scripts\" directory. Read the INSTALL file for more details. + + Update, July 2004: you can get a \"configure\" based distribution + from the libpng distribution sites. Download the file + libpng-1.6.12.tar.gz, libpng-1.6.12.tar.xz, or libpng-1.6.12.tar.bz2 + + If the line endings in the files look funny, which is likely to be the + case if you were trying to run \"configure\" on a Linux machine, you may + wish to get the other distribution of libpng. It is available in both + tar.gz/tar.xz (UNIX style line endings, with \"configure\") and .7z/.zip + (DOS style line endings, without \"configure\") formats. +" + diff --git a/png/example.c b/png/example.c new file mode 100755 index 0000000..e9747a8 --- /dev/null +++ b/png/example.c @@ -0,0 +1,1061 @@ + +#if 0 /* in case someone actually tries to compile this */ + +/* example.c - an example of using libpng + * Last changed in libpng 1.6.11 [June 12, 2014] + * Maintained 1998-2014 Glenn Randers-Pehrson + * Maintained 1996, 1997 Andreas Dilger) + * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * To the extent possible under law, the authors have waived + * all copyright and related or neighboring rights to this file. + * This work is published from: United States. + */ + +/* This is an example of how to use libpng to read and write PNG files. + * The file libpng-manual.txt is much more verbose then this. If you have not + * read it, do so first. This was designed to be a starting point of an + * implementation. This is not officially part of libpng, is hereby placed + * in the public domain, and therefore does not require a copyright notice. + * + * This file does not currently compile, because it is missing certain + * parts, like allocating memory to hold an image. You will have to + * supply these parts to get it to compile. For an example of a minimal + * working PNG reader/writer, see pngtest.c, included in this distribution; + * see also the programs in the contrib directory. + */ + +/* The simple, but restricted, approach to reading a PNG file or data stream + * just requires two function calls, as in the following complete program. + * Writing a file just needs one function call, so long as the data has an + * appropriate layout. + * + * The following code reads PNG image data from a file and writes it, in a + * potentially new format, to a new file. While this code will compile there is + * minimal (insufficient) error checking; for a more realistic version look at + * contrib/examples/pngtopng.c + */ +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <png.h> +#include <zlib.h> + +int main(int argc, const char **argv) +{ + if (argc == 3) + { + png_image image; /* The control structure used by libpng */ + + /* Initialize the 'png_image' structure. */ + memset(&image, 0, (sizeof image)); + image.version = PNG_IMAGE_VERSION; + + /* The first argument is the file to read: */ + if (png_image_begin_read_from_file(&image, argv[1])) + { + png_bytep buffer; + + /* Set the format in which to read the PNG file; this code chooses a + * simple sRGB format with a non-associated alpha channel, adequate to + * store most images. + */ + image.format = PNG_FORMAT_RGBA; + + /* Now allocate enough memory to hold the image in this format; the + * PNG_IMAGE_SIZE macro uses the information about the image (width, + * height and format) stored in 'image'. + */ + buffer = malloc(PNG_IMAGE_SIZE(image)); + + /* If enough memory was available read the image in the desired format + * then write the result out to the new file. 'background' is not + * necessary when reading the image because the alpha channel is + * preserved; if it were to be removed, for example if we requested + * PNG_FORMAT_RGB, then either a solid background color would have to + * be supplied or the output buffer would have to be initialized to the + * actual background of the image. + * + * The fourth argument to png_image_finish_read is the 'row_stride' - + * this is the number of components allocated for the image in each + * row. It has to be at least as big as the value returned by + * PNG_IMAGE_ROW_STRIDE, but if you just allocate space for the + * default, minimum, size using PNG_IMAGE_SIZE as above you can pass + * zero. + * + * The final argument is a pointer to a buffer for the colormap; + * colormaps have exactly the same format as a row of image pixels (so + * you choose what format to make the colormap by setting + * image.format). A colormap is only returned if + * PNG_FORMAT_FLAG_COLORMAP is also set in image.format, so in this + * case NULL is passed as the final argument. If you do want to force + * all images into an index/color-mapped format then you can use: + * + * PNG_IMAGE_COLORMAP_SIZE(image) + * + * to find the maximum size of the colormap in bytes. + */ + if (buffer != NULL && + png_image_finish_read(&image, NULL/*background*/, buffer, + 0/*row_stride*/, NULL/*colormap*/)) + { + /* Now write the image out to the second argument. In the write + * call 'convert_to_8bit' allows 16-bit data to be squashed down to + * 8 bits; this isn't necessary here because the original read was + * to the 8-bit format. + */ + if (png_image_write_to_file(&image, argv[2], 0/*convert_to_8bit*/, + buffer, 0/*row_stride*/, NULL/*colormap*/)) + { + /* The image has been written successfully. */ + exit(0); + } + } + + else + { + /* Calling png_free_image is optional unless the simplified API was + * not run to completion. In this case if there wasn't enough + * memory for 'buffer' we didn't complete the read, so we must free + * the image: + */ + if (buffer == NULL) + png_free_image(&image); + + else + free(buffer); + } + + /* Something went wrong reading or writing the image. libpng stores a + * textual message in the 'png_image' structure: + */ + fprintf(stderr, "pngtopng: error: %s\n", image.message); + exit (1); + } + + fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n"); + exit(1); +} + +/* That's it ;-) Of course you probably want to do more with PNG files than + * just converting them all to 32-bit RGBA PNG files; you can do that between + * the call to png_image_finish_read and png_image_write_to_file. You can also + * ask for the image data to be presented in a number of different formats. You + * do this by simply changing the 'format' parameter set before allocating the + * buffer. + * + * The format parameter consists of five flags that define various aspects of + * the image, you can simply add these together to get the format or you can use + * one of the predefined macros from png.h (as above): + * + * PNG_FORMAT_FLAG_COLOR: if set the image will have three color components per + * pixel (red, green and blue), if not set the image will just have one + * luminance (grayscale) component. + * + * PNG_FORMAT_FLAG_ALPHA: if set each pixel in the image will have an additional + * alpha value; a linear value that describes the degree the image pixel + * covers (overwrites) the contents of the existing pixel on the display. + * + * PNG_FORMAT_FLAG_LINEAR: if set the components of each pixel will be returned + * as a series of 16-bit linear values, if not set the components will be + * returned as a series of 8-bit values encoded according to the 'sRGB' + * standard. The 8-bit format is the normal format for images intended for + * direct display, because almost all display devices do the inverse of the + * sRGB transformation to the data they receive. The 16-bit format is more + * common for scientific data and image data that must be further processed; + * because it is linear simple math can be done on the component values. + * Regardless of the setting of this flag the alpha channel is always linear, + * although it will be 8 bits or 16 bits wide as specified by the flag. + * + * PNG_FORMAT_FLAG_BGR: if set the components of a color pixel will be returned + * in the order blue, then green, then red. If not set the pixel components + * are in the order red, then green, then blue. + * + * PNG_FORMAT_FLAG_AFIRST: if set the alpha channel (if present) precedes the + * color or grayscale components. If not set the alpha channel follows the + * components. + * + * You do not have to read directly from a file. You can read from memory or, + * on systems that support it, from a <stdio.h> FILE*. This is controlled by + * the particular png_image_read_from_ function you call at the start. Likewise + * on write you can write to a FILE* if your system supports it. Check the + * macro PNG_STDIO_SUPPORTED to see if stdio support has been included in your + * libpng build. + * + * If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data you may need to write it in + * the 8-bit format for display. You do this by setting the convert_to_8bit + * flag to 'true'. + * + * Don't repeatedly convert between the 8-bit and 16-bit forms. There is + * significant data loss when 16-bit data is converted to the 8-bit encoding and + * the current libpng implementation of convertion to 16-bit is also + * significantly lossy. The latter will be fixed in the future, but the former + * is unavoidable - the 8-bit format just doesn't have enough resolution. + */ + +/* If your program needs more information from the PNG data it reads, or if you + * need to do more complex transformations, or minimise transformations, on the + * data you read, then you must use one of the several lower level libpng + * interfaces. + * + * All these interfaces require that you do your own error handling - your + * program must be able to arrange for control to return to your own code any + * time libpng encounters a problem. There are several ways to do this, but the + * standard way is to use the ANSI-C (C90) <setjmp.h> interface to establish a + * return point within your own code. You must do this if you do not use the + * simplified interface (above). + * + * The first step is to include the header files you need, including the libpng + * header file. Include any standard headers and feature test macros your + * program requires before including png.h: + */ +#include <png.h> + + /* The png_jmpbuf() macro, used in error handling, became available in + * libpng version 1.0.6. If you want to be able to run your code with older + * versions of libpng, you must define the macro yourself (but only if it + * is not already defined by libpng!). + */ + +#ifndef png_jmpbuf +# define png_jmpbuf(png_ptr) ((png_ptr)->png_jmpbuf) +#endif + +/* Check to see if a file is a PNG file using png_sig_cmp(). png_sig_cmp() + * returns zero if the image is a PNG and nonzero if it isn't a PNG. + * + * The function check_if_png() shown here, but not used, returns nonzero (true) + * if the file can be opened and is a PNG, 0 (false) otherwise. + * + * If this call is successful, and you are going to keep the file open, + * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once + * you have created the png_ptr, so that libpng knows your application + * has read that many bytes from the start of the file. Make sure you + * don't call png_set_sig_bytes() with more than 8 bytes read or give it + * an incorrect number of bytes read, or you will either have read too + * many bytes (your fault), or you are telling libpng to read the wrong + * number of magic bytes (also your fault). + * + * Many applications already read the first 2 or 4 bytes from the start + * of the image to determine the file type, so it would be easiest just + * to pass the bytes to png_sig_cmp() or even skip that if you know + * you have a PNG file, and call png_set_sig_bytes(). + */ +#define PNG_BYTES_TO_CHECK 4 +int check_if_png(char *file_name, FILE **fp) +{ + char buf[PNG_BYTES_TO_CHECK]; + + /* Open the prospective PNG file. */ + if ((*fp = fopen(file_name, "rb")) == NULL) + return 0; + + /* Read in some of the signature bytes */ + if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK) + return 0; + + /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature. + Return nonzero (true) if they match */ + + return(!png_sig_cmp(buf, (png_size_t)0, PNG_BYTES_TO_CHECK)); +} + +/* Read a PNG file. You may want to return an error code if the read + * fails (depending upon the failure). There are two "prototypes" given + * here - one where we are given the filename, and we need to open the + * file, and the other where we are given an open file (possibly with + * some or all of the magic bytes read - see comments above). + */ +#ifdef open_file /* prototype 1 */ +void read_png(char *file_name) /* We need to open the file */ +{ + png_structp png_ptr; + png_infop info_ptr; + unsigned int sig_read = 0; + png_uint_32 width, height; + int bit_depth, color_type, interlace_type; + FILE *fp; + + if ((fp = fopen(file_name, "rb")) == NULL) + return (ERROR); + +#else no_open_file /* prototype 2 */ +void read_png(FILE *fp, unsigned int sig_read) /* File is already open */ +{ + png_structp png_ptr; + png_infop info_ptr; + png_uint_32 width, height; + int bit_depth, color_type, interlace_type; +#endif no_open_file /* Only use one prototype! */ + + /* Create and initialize the png_struct with the desired error handler + * functions. If you want to use the default stderr and longjump method, + * you can supply NULL for the last three parameters. We also supply the + * the compiler header file version, so that we know if the application + * was compiled with a compatible version of the library. REQUIRED + */ + png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, + png_voidp user_error_ptr, user_error_fn, user_warning_fn); + + if (png_ptr == NULL) + { + fclose(fp); + return (ERROR); + } + + /* Allocate/initialize the memory for image information. REQUIRED. */ + info_ptr = png_create_info_struct(png_ptr); + if (info_ptr == NULL) + { + fclose(fp); + png_destroy_read_struct(&png_ptr, NULL, NULL); + return (ERROR); + } + + /* Set error handling if you are using the setjmp/longjmp method (this is + * the normal method of doing things with libpng). REQUIRED unless you + * set up your own error handlers in the png_create_read_struct() earlier. + */ + + if (setjmp(png_jmpbuf(png_ptr))) + { + /* Free all of the memory associated with the png_ptr and info_ptr */ + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + fclose(fp); + /* If we get here, we had a problem reading the file */ + return (ERROR); + } + + /* One of the following I/O initialization methods is REQUIRED */ +#ifdef streams /* PNG file I/O method 1 */ + /* Set up the input control if you are using standard C streams */ + png_init_io(png_ptr, fp); + +#else no_streams /* PNG file I/O method 2 */ + /* If you are using replacement read functions, instead of calling + * png_init_io() here you would call: + */ + png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn); + /* where user_io_ptr is a structure you want available to the callbacks */ +#endif no_streams /* Use only one I/O method! */ + + /* If we have already read some of the signature */ + png_set_sig_bytes(png_ptr, sig_read); + +#ifdef hilevel + /* + * If you have enough memory to read in the entire image at once, + * and you need to specify only transforms that can be controlled + * with one of the PNG_TRANSFORM_* bits (this presently excludes + * quantizing, filling, setting background, and doing gamma + * adjustment), then you can read the entire image (including + * pixels) into the info structure with this call: + */ + png_read_png(png_ptr, info_ptr, png_transforms, NULL); + +#else + /* OK, you're doing it the hard way, with the lower-level functions */ + + /* The call to png_read_info() gives us all of the information from the + * PNG file before the first IDAT (image data chunk). REQUIRED + */ + png_read_info(png_ptr, info_ptr); + + png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, + &interlace_type, NULL, NULL); + + /* Set up the data transformations you want. Note that these are all + * optional. Only call them if you want/need them. Many of the + * transformations only work on specific types of images, and many + * are mutually exclusive. + */ + + /* Tell libpng to strip 16 bit/color files down to 8 bits/color. + * Use accurate scaling if it's available, otherwise just chop off the + * low byte. + */ +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + png_set_scale_16(png_ptr); +#else + png_set_strip_16(png_ptr); +#endif + + /* Strip alpha bytes from the input data without combining with the + * background (not recommended). + */ + png_set_strip_alpha(png_ptr); + + /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single + * byte into separate bytes (useful for paletted and grayscale images). + */ + png_set_packing(png_ptr); + + /* Change the order of packed pixels to least significant bit first + * (not useful if you are using png_set_packing). */ + png_set_packswap(png_ptr); + + /* Expand paletted colors into true RGB triplets */ + if (color_type == PNG_COLOR_TYPE_PALETTE) + png_set_palette_to_rgb(png_ptr); + + /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */ + if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) + png_set_expand_gray_1_2_4_to_8(png_ptr); + + /* Expand paletted or RGB images with transparency to full alpha channels + * so the data will be available as RGBA quartets. + */ + if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) + png_set_tRNS_to_alpha(png_ptr); + + /* Set the background color to draw transparent and alpha images over. + * It is possible to set the red, green, and blue components directly + * for paletted images instead of supplying a palette index. Note that + * even if the PNG file supplies a background, you are not required to + * use it - you should use the (solid) application background if it has one. + */ + + png_color_16 my_background, *image_background; + + if (png_get_bKGD(png_ptr, info_ptr, &image_background)) + png_set_background(png_ptr, image_background, + PNG_BACKGROUND_GAMMA_FILE, 1, 1.0); + else + png_set_background(png_ptr, &my_background, + PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0); + + /* Some suggestions as to how to get a screen gamma value + * + * Note that screen gamma is the display_exponent, which includes + * the CRT_exponent and any correction for viewing conditions + */ + if (/* We have a user-defined screen gamma value */) + { + screen_gamma = user-defined screen_gamma; + } + /* This is one way that applications share the same screen gamma value */ + else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL) + { + screen_gamma = atof(gamma_str); + } + /* If we don't have another value */ + else + { + screen_gamma = PNG_DEFAULT_sRGB; /* A good guess for a PC monitor + in a dimly lit room */ + screen_gamma = PNG_GAMMA_MAC_18 or 1.0; /* Good guesses for Mac systems */ + } + + /* Tell libpng to handle the gamma conversion for you. The final call + * is a good guess for PC generated images, but it should be configurable + * by the user at run time by the user. It is strongly suggested that + * your application support gamma correction. + */ + + int intent; + + if (png_get_sRGB(png_ptr, info_ptr, &intent)) + png_set_gamma(png_ptr, screen_gamma, PNG_DEFAULT_sRGB); + else + { + double image_gamma; + if (png_get_gAMA(png_ptr, info_ptr, &image_gamma)) + png_set_gamma(png_ptr, screen_gamma, image_gamma); + else + png_set_gamma(png_ptr, screen_gamma, 0.45455); + } + +#ifdef PNG_READ_QUANTIZE_SUPPORTED + /* Quantize RGB files down to 8 bit palette or reduce palettes + * to the number of colors available on your screen. + */ + if (color_type & PNG_COLOR_MASK_COLOR) + { + int num_palette; + png_colorp palette; + + /* This reduces the image to the application supplied palette */ + if (/* We have our own palette */) + { + /* An array of colors to which the image should be quantized */ + png_color std_color_cube[MAX_SCREEN_COLORS]; + + png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS, + MAX_SCREEN_COLORS, NULL, 0); + } + /* This reduces the image to the palette supplied in the file */ + else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette)) + { + png_uint_16p histogram = NULL; + + png_get_hIST(png_ptr, info_ptr, &histogram); + + png_set_quantize(png_ptr, palette, num_palette, + max_screen_colors, histogram, 0); + } + } +#endif /* PNG_READ_QUANTIZE_SUPPORTED */ + + /* Invert monochrome files to have 0 as white and 1 as black */ + png_set_invert_mono(png_ptr); + + /* If you want to shift the pixel values from the range [0,255] or + * [0,65535] to the original [0,7] or [0,31], or whatever range the + * colors were originally in: + */ + if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT)) + { + png_color_8p sig_bit_p; + + png_get_sBIT(png_ptr, info_ptr, &sig_bit_p); + png_set_shift(png_ptr, sig_bit_p); + } + + /* Flip the RGB pixels to BGR (or RGBA to BGRA) */ + if (color_type & PNG_COLOR_MASK_COLOR) + png_set_bgr(png_ptr); + + /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */ + png_set_swap_alpha(png_ptr); + + /* Swap bytes of 16 bit files to least significant byte first */ + png_set_swap(png_ptr); + + /* Add filler (or alpha) byte (before/after each RGB triplet) */ + png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER); + +#ifdef PNG_READ_INTERLACING_SUPPORTED + /* Turn on interlace handling. REQUIRED if you are not using + * png_read_image(). To see how to handle interlacing passes, + * see the png_read_row() method below: + */ + number_passes = png_set_interlace_handling(png_ptr); +#else + number_passes = 1; +#endif /* PNG_READ_INTERLACING_SUPPORTED */ + + + /* Optional call to gamma correct and add the background to the palette + * and update info structure. REQUIRED if you are expecting libpng to + * update the palette for you (ie you selected such a transform above). + */ + png_read_update_info(png_ptr, info_ptr); + + /* Allocate the memory to hold the image using the fields of info_ptr. */ + + /* The easiest way to read the image: */ + png_bytep row_pointers[height]; + + /* Clear the pointer array */ + for (row = 0; row < height; row++) + row_pointers[row] = NULL; + + for (row = 0; row < height; row++) + row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr, + info_ptr)); + + /* Now it's time to read the image. One of these methods is REQUIRED */ +#ifdef entire /* Read the entire image in one go */ + png_read_image(png_ptr, row_pointers); + +#else no_entire /* Read the image one or more scanlines at a time */ + /* The other way to read images - deal with interlacing: */ + + for (pass = 0; pass < number_passes; pass++) + { +#ifdef single /* Read the image a single row at a time */ + for (y = 0; y < height; y++) + { + png_read_rows(png_ptr, &row_pointers[y], NULL, 1); + } + +#else no_single /* Read the image several rows at a time */ + for (y = 0; y < height; y += number_of_rows) + { +#ifdef sparkle /* Read the image using the "sparkle" effect. */ + png_read_rows(png_ptr, &row_pointers[y], NULL, + number_of_rows); +#else no_sparkle /* Read the image using the "rectangle" effect */ + png_read_rows(png_ptr, NULL, &row_pointers[y], + number_of_rows); +#endif no_sparkle /* Use only one of these two methods */ + } + + /* If you want to display the image after every pass, do so here */ +#endif no_single /* Use only one of these two methods */ + } +#endif no_entire /* Use only one of these two methods */ + + /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */ + png_read_end(png_ptr, info_ptr); +#endif hilevel + + /* At this point you have read the entire image */ + + /* Clean up after the read, and free any memory allocated - REQUIRED */ + png_destroy_read_struct(&png_ptr, &info_ptr, NULL); + + /* Close the file */ + fclose(fp); + + /* That's it */ + return (OK); +} + +/* Progressively read a file */ + +int +initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr) +{ + /* Create and initialize the png_struct with the desired error handler + * functions. If you want to use the default stderr and longjump method, + * you can supply NULL for the last three parameters. We also check that + * the library version is compatible in case we are using dynamically + * linked libraries. + */ + *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, + png_voidp user_error_ptr, user_error_fn, user_warning_fn); + + if (*png_ptr == NULL) + { + *info_ptr = NULL; + return (ERROR); + } + + *info_ptr = png_create_info_struct(png_ptr); + + if (*info_ptr == NULL) + { + png_destroy_read_struct(png_ptr, info_ptr, NULL); + return (ERROR); + } + + if (setjmp(png_jmpbuf((*png_ptr)))) + { + png_destroy_read_struct(png_ptr, info_ptr, NULL); + return (ERROR); + } + + /* This one's new. You will need to provide all three + * function callbacks, even if you aren't using them all. + * If you aren't using all functions, you can specify NULL + * parameters. Even when all three functions are NULL, + * you need to call png_set_progressive_read_fn(). + * These functions shouldn't be dependent on global or + * static variables if you are decoding several images + * simultaneously. You should store stream specific data + * in a separate struct, given as the second parameter, + * and retrieve the pointer from inside the callbacks using + * the function png_get_progressive_ptr(png_ptr). + */ + png_set_progressive_read_fn(*png_ptr, (void *)stream_data, + info_callback, row_callback, end_callback); + + return (OK); +} + +int +process_data(png_structp *png_ptr, png_infop *info_ptr, + png_bytep buffer, png_uint_32 length) +{ + if (setjmp(png_jmpbuf((*png_ptr)))) + { + /* Free the png_ptr and info_ptr memory on error */ + png_destroy_read_struct(png_ptr, info_ptr, NULL); + return (ERROR); + } + + /* This one's new also. Simply give it chunks of data as + * they arrive from the data stream (in order, of course). + * On segmented machines, don't give it any more than 64K. + * The library seems to run fine with sizes of 4K, although + * you can give it much less if necessary (I assume you can + * give it chunks of 1 byte, but I haven't tried with less + * than 256 bytes yet). When this function returns, you may + * want to display any rows that were generated in the row + * callback, if you aren't already displaying them there. + */ + png_process_data(*png_ptr, *info_ptr, buffer, length); + return (OK); +} + +info_callback(png_structp png_ptr, png_infop info) +{ + /* Do any setup here, including setting any of the transformations + * mentioned in the Reading PNG files section. For now, you _must_ + * call either png_start_read_image() or png_read_update_info() + * after all the transformations are set (even if you don't set + * any). You may start getting rows before png_process_data() + * returns, so this is your last chance to prepare for that. + */ +} + +row_callback(png_structp png_ptr, png_bytep new_row, + png_uint_32 row_num, int pass) +{ + /* + * This function is called for every row in the image. If the + * image is interlaced, and you turned on the interlace handler, + * this function will be called for every row in every pass. + * + * In this function you will receive a pointer to new row data from + * libpng called new_row that is to replace a corresponding row (of + * the same data format) in a buffer allocated by your application. + * + * The new row data pointer "new_row" may be NULL, indicating there is + * no new data to be replaced (in cases of interlace loading). + * + * If new_row is not NULL then you need to call + * png_progressive_combine_row() to replace the corresponding row as + * shown below: + */ + + /* Get pointer to corresponding row in our + * PNG read buffer. + */ + png_bytep old_row = ((png_bytep *)our_data)[row_num]; + +#ifdef PNG_READ_INTERLACING_SUPPORTED + /* If both rows are allocated then copy the new row + * data to the corresponding row data. + */ + if ((old_row != NULL) && (new_row != NULL)) + png_progressive_combine_row(png_ptr, old_row, new_row); + + /* + * The rows and passes are called in order, so you don't really + * need the row_num and pass, but I'm supplying them because it + * may make your life easier. + * + * For the non-NULL rows of interlaced images, you must call + * png_progressive_combine_row() passing in the new row and the + * old row, as demonstrated above. You can call this function for + * NULL rows (it will just return) and for non-interlaced images + * (it just does the memcpy for you) if it will make the code + * easier. Thus, you can just do this for all cases: + */ + + png_progressive_combine_row(png_ptr, old_row, new_row); + + /* where old_row is what was displayed for previous rows. Note + * that the first pass (pass == 0 really) will completely cover + * the old row, so the rows do not have to be initialized. After + * the first pass (and only for interlaced images), you will have + * to pass the current row as new_row, and the function will combine + * the old row and the new row. + */ +#endif /* PNG_READ_INTERLACING_SUPPORTED */ +} + +end_callback(png_structp png_ptr, png_infop info) +{ + /* This function is called when the whole image has been read, + * including any chunks after the image (up to and including + * the IEND). You will usually have the same info chunk as you + * had in the header, although some data may have been added + * to the comments and time fields. + * + * Most people won't do much here, perhaps setting a flag that + * marks the image as finished. + */ +} + +/* Write a png file */ +void write_png(char *file_name /* , ... other image information ... */) +{ + FILE *fp; + png_structp png_ptr; + png_infop info_ptr; + png_colorp palette; + + /* Open the file */ + fp = fopen(file_name, "wb"); + if (fp == NULL) + return (ERROR); + + /* Create and initialize the png_struct with the desired error handler + * functions. If you want to use the default stderr and longjump method, + * you can supply NULL for the last three parameters. We also check that + * the library version is compatible with the one used at compile time, + * in case we are using dynamically linked libraries. REQUIRED. + */ + png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, + png_voidp user_error_ptr, user_error_fn, user_warning_fn); + + if (png_ptr == NULL) + { + fclose(fp); + return (ERROR); + } + + /* Allocate/initialize the image information data. REQUIRED */ + info_ptr = png_create_info_struct(png_ptr); + if (info_ptr == NULL) + { + fclose(fp); + png_destroy_write_struct(&png_ptr, NULL); + return (ERROR); + } + + /* Set error handling. REQUIRED if you aren't supplying your own + * error handling functions in the png_create_write_struct() call. + */ + if (setjmp(png_jmpbuf(png_ptr))) + { + /* If we get here, we had a problem writing the file */ + fclose(fp); + png_destroy_write_struct(&png_ptr, &info_ptr); + return (ERROR); + } + + /* One of the following I/O initialization functions is REQUIRED */ + +#ifdef streams /* I/O initialization method 1 */ + /* Set up the output control if you are using standard C streams */ + png_init_io(png_ptr, fp); + +#else no_streams /* I/O initialization method 2 */ + /* If you are using replacement write functions, instead of calling + * png_init_io() here you would call + */ + png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn, + user_IO_flush_function); + /* where user_io_ptr is a structure you want available to the callbacks */ +#endif no_streams /* Only use one initialization method */ + +#ifdef hilevel + /* This is the easy way. Use it if you already have all the + * image info living in the structure. You could "|" many + * PNG_TRANSFORM flags into the png_transforms integer here. + */ + png_write_png(png_ptr, info_ptr, png_transforms, NULL); + +#else + /* This is the hard way */ + + /* Set the image information here. Width and height are up to 2^31, + * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on + * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY, + * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB, + * or PNG_COLOR_TYPE_RGB_ALPHA. interlace is either PNG_INTERLACE_NONE or + * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST + * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED + */ + png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, PNG_COLOR_TYPE_???, + PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); + + /* Set the palette if there is one. REQUIRED for indexed-color images */ + palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH + * (sizeof (png_color))); + /* ... Set palette colors ... */ + png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH); + /* You must not free palette here, because png_set_PLTE only makes a link to + * the palette that you malloced. Wait until you are about to destroy + * the png structure. + */ + + /* Optional significant bit (sBIT) chunk */ + png_color_8 sig_bit; + + /* If we are dealing with a grayscale image then */ + sig_bit.gray = true_bit_depth; + + /* Otherwise, if we are dealing with a color image then */ + sig_bit.red = true_red_bit_depth; + sig_bit.green = true_green_bit_depth; + sig_bit.blue = true_blue_bit_depth; + + /* If the image has an alpha channel then */ + sig_bit.alpha = true_alpha_bit_depth; + + png_set_sBIT(png_ptr, info_ptr, &sig_bit); + + + /* Optional gamma chunk is strongly suggested if you have any guess + * as to the correct gamma of the image. + */ + png_set_gAMA(png_ptr, info_ptr, gamma); + + /* Optionally write comments into the image */ + { + png_text text_ptr[3]; + + char key0[]="Title"; + char text0[]="Mona Lisa"; + text_ptr[0].key = key0; + text_ptr[0].text = text0; + text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE; + text_ptr[0].itxt_length = 0; + text_ptr[0].lang = NULL; + text_ptr[0].lang_key = NULL; + + char key1[]="Author"; + char text1[]="Leonardo DaVinci"; + text_ptr[1].key = key1; + text_ptr[1].text = text1; + text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE; + text_ptr[1].itxt_length = 0; + text_ptr[1].lang = NULL; + text_ptr[1].lang_key = NULL; + + char key2[]="Description"; + char text2[]="<long text>"; + text_ptr[2].key = key2; + text_ptr[2].text = text2; + text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt; + text_ptr[2].itxt_length = 0; + text_ptr[2].lang = NULL; + text_ptr[2].lang_key = NULL; + + png_set_text(write_ptr, write_info_ptr, text_ptr, 3); + } + + /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs */ + + /* Note that if sRGB is present the gAMA and cHRM chunks must be ignored + * on read and, if your application chooses to write them, they must + * be written in accordance with the sRGB profile + */ + + /* Write the file header information. REQUIRED */ + png_write_info(png_ptr, info_ptr); + + /* If you want, you can write the info in two steps, in case you need to + * write your private chunk ahead of PLTE: + * + * png_write_info_before_PLTE(write_ptr, write_info_ptr); + * write_my_chunk(); + * png_write_info(png_ptr, info_ptr); + * + * However, given the level of known- and unknown-chunk support in 1.2.0 + * and up, this should no longer be necessary. + */ + + /* Once we write out the header, the compression type on the text + * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or + * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again + * at the end. + */ + + /* Set up the transformations you want. Note that these are + * all optional. Only call them if you want them. + */ + + /* Invert monochrome pixels */ + png_set_invert_mono(png_ptr); + + /* Shift the pixels up to a legal bit depth and fill in + * as appropriate to correctly scale the image. + */ + png_set_shift(png_ptr, &sig_bit); + + /* Pack pixels into bytes */ + png_set_packing(png_ptr); + + /* Swap location of alpha bytes from ARGB to RGBA */ + png_set_swap_alpha(png_ptr); + + /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into + * RGB (4 channels -> 3 channels). The second parameter is not used. + */ + png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE); + + /* Flip BGR pixels to RGB */ + png_set_bgr(png_ptr); + + /* Swap bytes of 16-bit files to most significant byte first */ + png_set_swap(png_ptr); + + /* Swap bits of 1, 2, 4 bit packed pixel formats */ + png_set_packswap(png_ptr); + + /* Turn on interlace handling if you are not using png_write_image() */ + if (interlacing != 0) + number_passes = png_set_interlace_handling(png_ptr); + + else + number_passes = 1; + + /* The easiest way to write the image (you may have a different memory + * layout, however, so choose what fits your needs best). You need to + * use the first method if you aren't handling interlacing yourself. + */ + png_uint_32 k, height, width; + + /* In this example, "image" is a one-dimensional array of bytes */ + png_byte image[height*width*bytes_per_pixel]; + + png_bytep row_pointers[height]; + + if (height > PNG_UINT_32_MAX/(sizeof (png_bytep))) + png_error (png_ptr, "Image is too tall to process in memory"); + + /* Set up pointers into your "image" byte array */ + for (k = 0; k < height; k++) + row_pointers[k] = image + k*width*bytes_per_pixel; + + /* One of the following output methods is REQUIRED */ + +#ifdef entire /* Write out the entire image data in one call */ + png_write_image(png_ptr, row_pointers); + + /* The other way to write the image - deal with interlacing */ + +#else no_entire /* Write out the image data by one or more scanlines */ + + /* The number of passes is either 1 for non-interlaced images, + * or 7 for interlaced images. + */ + for (pass = 0; pass < number_passes; pass++) + { + /* Write a few rows at a time. */ + png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows); + + /* If you are only writing one row at a time, this works */ + for (y = 0; y < height; y++) + png_write_rows(png_ptr, &row_pointers[y], 1); + } +#endif no_entire /* Use only one output method */ + + /* You can write optional chunks like tEXt, zTXt, and tIME at the end + * as well. Shouldn't be necessary in 1.2.0 and up as all the public + * chunks are supported and you can use png_set_unknown_chunks() to + * register unknown chunks into the info structure to be written out. + */ + + /* It is REQUIRED to call this to finish writing the rest of the file */ + png_write_end(png_ptr, info_ptr); +#endif hilevel + + /* If you png_malloced a palette, free it here (don't free info_ptr->palette, + * as recommended in versions 1.0.5m and earlier of this example; if + * libpng mallocs info_ptr->palette, libpng will free it). If you + * allocated it with malloc() instead of png_malloc(), use free() instead + * of png_free(). + */ + png_free(png_ptr, palette); + palette = NULL; + + /* Similarly, if you png_malloced any data that you passed in with + * png_set_something(), such as a hist or trans array, free it here, + * when you can be sure that libpng is through with it. + */ + png_free(png_ptr, trans); + trans = NULL; + /* Whenever you use png_free() it is a good idea to set the pointer to + * NULL in case your application inadvertently tries to png_free() it + * again. When png_free() sees a NULL it returns without action, thus + * avoiding the double-free security problem. + */ + + /* Clean up after the write, and free any memory allocated */ + png_destroy_write_struct(&png_ptr, &info_ptr); + + /* Close the file */ + fclose(fp); + + /* That's it */ + return (OK); +} + +#endif /* if 0 */ diff --git a/png/libpng-config.in b/png/libpng-config.in new file mode 100755 index 0000000..69bf8e3 --- /dev/null +++ b/png/libpng-config.in @@ -0,0 +1,127 @@ +#! /bin/sh + +# libpng-config +# provides configuration info for libpng. + +# Copyright (C) 2002, 2004, 2006, 2007 Glenn Randers-Pehrson + +# This code is released under the libpng license. +# For conditions of distribution and use, see the disclaimer +# and license in png.h + +# Modeled after libxml-config. + +version="@PNGLIB_VERSION@" +prefix="@prefix@" +exec_prefix="@exec_prefix@" +libdir="@libdir@" +includedir="@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@" +libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@" +all_libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ @LIBS@" +I_opts="-I${includedir}" +L_opts="-L${libdir}" +R_opts="" +cppflags="" +ccopts="" +ldopts="" + +usage() +{ + cat <<EOF +Usage: $0 [OPTION] ... + +Known values for OPTION are: + + --prefix print libpng prefix + --libdir print path to directory containing library + --libs print library linking information + --ccopts print compiler options + --cppflags print pre-processor flags + --cflags print preprocessor flags, I_opts, and compiler options + --I_opts print "-I" include options + --L_opts print linker "-L" flags for dynamic linking + --R_opts print dynamic linker "-R" or "-rpath" flags + --ldopts print linker options + --ldflags print linker flags (ldopts, L_opts, R_opts, and libs) + --static revise subsequent outputs for static linking + --help print this help and exit + --version print version information +EOF + + exit $1 +} + +if test $# -eq 0; then + usage 1 +fi + +while test $# -gt 0; do + case "$1" in + + --prefix) + echo ${prefix} + ;; + + --version) + echo ${version} + exit 0 + ;; + + --help) + usage 0 + ;; + + --ccopts) + echo ${ccopts} + ;; + + --cppflags) + echo ${cppflags} + ;; + + --cflags) + echo ${I_opts} ${cppflags} ${ccopts} + ;; + + --libdir) + echo ${libdir} + ;; + + --libs) + echo ${libs} + ;; + + --I_opts) + echo ${I_opts} + ;; + + --L_opts) + echo ${L_opts} + ;; + + --R_opts) + echo ${R_opts} + ;; + + --ldopts) + echo ${ldopts} + ;; + + --ldflags) + echo ${ldopts} ${L_opts} ${R_opts} ${libs} + ;; + + --static) + R_opts="" + libs=${all_libs} + ;; + + *) + usage + exit 1 + ;; + esac + shift +done + +exit 0 diff --git a/png/libpng-manual.txt b/png/libpng-manual.txt new file mode 100755 index 0000000..f79ca7e --- /dev/null +++ b/png/libpng-manual.txt @@ -0,0 +1,5330 @@ +libpng-manual.txt - A description on how to use and modify libpng + + libpng version 1.6.12 - June 12, 2014 + Updated and distributed by Glenn Randers-Pehrson + <glennrp at users.sourceforge.net> + Copyright (c) 1998-2014 Glenn Randers-Pehrson + + This document is released under the libpng license. + For conditions of distribution and use, see the disclaimer + and license in png.h + + Based on: + + libpng versions 0.97, January 1998, through 1.6.12 - June 12, 2014 + Updated and distributed by Glenn Randers-Pehrson + Copyright (c) 1998-2014 Glenn Randers-Pehrson + + libpng 1.0 beta 6 - version 0.96 - May 28, 1997 + Updated and distributed by Andreas Dilger + Copyright (c) 1996, 1997 Andreas Dilger + + libpng 1.0 beta 2 - version 0.88 - January 26, 1996 + For conditions of distribution and use, see copyright + notice in png.h. Copyright (c) 1995, 1996 Guy Eric + Schalnat, Group 42, Inc. + + Updated/rewritten per request in the libpng FAQ + Copyright (c) 1995, 1996 Frank J. T. Wojcik + December 18, 1995 & January 20, 1996 + + TABLE OF CONTENTS + + I. Introduction + II. Structures + III. Reading + IV. Writing + V. Simplified API + VI. Modifying/Customizing libpng + VII. MNG support + VIII. Changes to Libpng from version 0.88 + IX. Changes to Libpng from version 1.0.x to 1.2.x + X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x + XI. Changes to Libpng from version 1.4.x to 1.5.x + XII. Changes to Libpng from version 1.5.x to 1.6.x + XIII. Detecting libpng + XIV. Source code repository + XV. Coding style + XVI. Y2K Compliance in libpng + +I. Introduction + +This file describes how to use and modify the PNG reference library +(known as libpng) for your own use. In addition to this +file, example.c is a good starting point for using the library, as +it is heavily commented and should include everything most people +will need. We assume that libpng is already installed; see the +INSTALL file for instructions on how to configure and install libpng. + +For examples of libpng usage, see the files "example.c", "pngtest.c", +and the files in the "contrib" directory, all of which are included in +the libpng distribution. + +Libpng was written as a companion to the PNG specification, as a way +of reducing the amount of time and effort it takes to support the PNG +file format in application programs. + +The PNG specification (second edition), November 2003, is available as +a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at +<http://www.w3.org/TR/2003/REC-PNG-20031110/ +The W3C and ISO documents have identical technical content. + +The PNG-1.2 specification is available at +<http://www.libpng.org/pub/png/documents/>. It is technically equivalent +to the PNG specification (second edition) but has some additional material. + +The PNG-1.0 specification is available +as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a +W3C Recommendation <http://www.w3.org/TR/REC.png.html>. + +Some additional chunks are described in the special-purpose public chunks +documents at <http://www.libpng.org/pub/png/documents/>. + +Other information +about PNG, and the latest version of libpng, can be found at the PNG home +page, <http://www.libpng.org/pub/png/>. + +Most users will not have to modify the library significantly; advanced +users may want to modify it more. All attempts were made to make it as +complete as possible, while keeping the code easy to understand. +Currently, this library only supports C. Support for other languages +is being considered. + +Libpng has been designed to handle multiple sessions at one time, +to be easily modifiable, to be portable to the vast majority of +machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy +to use. The ultimate goal of libpng is to promote the acceptance of +the PNG file format in whatever way possible. While there is still +work to be done (see the TODO file), libpng should cover the +majority of the needs of its users. + +Libpng uses zlib for its compression and decompression of PNG files. +Further information about zlib, and the latest version of zlib, can +be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>. +The zlib compression utility is a general purpose utility that is +useful for more than PNG files, and can be used without libpng. +See the documentation delivered with zlib for more details. +You can usually find the source files for the zlib utility wherever you +find the libpng source files. + +Libpng is thread safe, provided the threads are using different +instances of the structures. Each thread should have its own +png_struct and png_info instances, and thus its own image. +Libpng does not protect itself against two threads using the +same instance of a structure. + +II. Structures + +There are two main structures that are important to libpng, png_struct +and png_info. Both are internal structures that are no longer exposed +in the libpng interface (as of libpng 1.5.0). + +The png_info structure is designed to provide information about the +PNG file. At one time, the fields of png_info were intended to be +directly accessible to the user. However, this tended to cause problems +with applications using dynamically loaded libraries, and as a result +a set of interface functions for png_info (the png_get_*() and png_set_*() +functions) was developed, and direct access to the png_info fields was +deprecated.. + +The png_struct structure is the object used by the library to decode a +single image. As of 1.5.0 this structure is also not exposed. + +Almost all libpng APIs require a pointer to a png_struct as the first argument. +Many (in particular the png_set and png_get APIs) also require a pointer +to png_info as the second argument. Some application visible macros +defined in png.h designed for basic data access (reading and writing +integers in the PNG format) don't take a png_info pointer, but it's almost +always safe to assume that a (png_struct*) has to be passed to call an API +function. + +You can have more than one png_info structure associated with an image, +as illustrated in pngtest.c, one for information valid prior to the +IDAT chunks and another (called "end_info" below) for things after them. + +The png.h header file is an invaluable reference for programming with libpng. +And while I'm on the topic, make sure you include the libpng header file: + +#include <png.h> + +and also (as of libpng-1.5.0) the zlib header file, if you need it: + +#include <zlib.h> + +Types + +The png.h header file defines a number of integral types used by the +APIs. Most of these are fairly obvious; for example types corresponding +to integers of particular sizes and types for passing color values. + +One exception is how non-integral numbers are handled. For application +convenience most APIs that take such numbers have C (double) arguments; +however, internally PNG, and libpng, use 32 bit signed integers and encode +the value by multiplying by 100,000. As of libpng 1.5.0 a convenience +macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point) +which is simply (png_int_32). + +All APIs that take (double) arguments also have a matching API that +takes the corresponding fixed point integer arguments. The fixed point +API has the same name as the floating point one with "_fixed" appended. +The actual range of values permitted in the APIs is frequently less than +the full range of (png_fixed_point) (-21474 to +21474). When APIs require +a non-negative argument the type is recorded as png_uint_32 above. Consult +the header file and the text below for more information. + +Special care must be take with sCAL chunk handling because the chunk itself +uses non-integral values encoded as strings containing decimal floating point +numbers. See the comments in the header file. + +Configuration + +The main header file function declarations are frequently protected by C +preprocessing directives of the form: + + #ifdef PNG_feature_SUPPORTED + declare-function + #endif + ... + #ifdef PNG_feature_SUPPORTED + use-function + #endif + +The library can be built without support for these APIs, although a +standard build will have all implemented APIs. Application programs +should check the feature macros before using an API for maximum +portability. From libpng 1.5.0 the feature macros set during the build +of libpng are recorded in the header file "pnglibconf.h" and this file +is always included by png.h. + +If you don't need to change the library configuration from the default, skip to +the next section ("Reading"). + +Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all +of the build project files in the 'projects' directory simply copy +scripts/pnglibconf.h.prebuilt to pnglibconf.h. This means that these build +systems do not permit easy auto-configuration of the library - they only +support the default configuration. + +The easiest way to make minor changes to the libpng configuration when +auto-configuration is supported is to add definitions to the command line +using (typically) CPPFLAGS. For example: + +CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC + +will change the internal libpng math implementation for gamma correction and +other arithmetic calculations to fixed point, avoiding the need for fast +floating point support. The result can be seen in the generated pnglibconf.h - +make sure it contains the changed feature macro setting. + +If you need to make more extensive configuration changes - more than one or two +feature macro settings - you can either add -DPNG_USER_CONFIG to the build +command line and put a list of feature macro settings in pngusr.h or you can set +DFA_XTRA (a makefile variable) to a file containing the same information in the +form of 'option' settings. + +A. Changing pnglibconf.h + +A variety of methods exist to build libpng. Not all of these support +reconfiguration of pnglibconf.h. To reconfigure pnglibconf.h it must either be +rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand. + +Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to +pnglibconf.h and changing the lines defining the supported features, paying +very close attention to the 'option' information in scripts/pnglibconf.dfa +that describes those features and their requirements. This is easy to get +wrong. + +B. Configuration using DFA_XTRA + +Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later +variant such as 'nawk' or 'gawk', is available. The configure build will +automatically find an appropriate awk and build pnglibconf.h. +The scripts/pnglibconf.mak file contains a set of make rules for doing the +same thing if configure is not used, and many of the makefiles in the scripts +directory use this approach. + +When rebuilding simply write a new file containing changed options and set +DFA_XTRA to the name of this file. This causes the build to append the new file +to the end of scripts/pnglibconf.dfa. The pngusr.dfa file should contain lines +of the following forms: + +everything = off + +This turns all optional features off. Include it at the start of pngusr.dfa to +make it easier to build a minimal configuration. You will need to turn at least +some features on afterward to enable either reading or writing code, or both. + +option feature on +option feature off + +Enable or disable a single feature. This will automatically enable other +features required by a feature that is turned on or disable other features that +require a feature which is turned off. Conflicting settings will cause an error +message to be emitted by awk. + +setting feature default value + +Changes the default value of setting 'feature' to 'value'. There are a small +number of settings listed at the top of pnglibconf.h, they are documented in the +source code. Most of these values have performance implications for the library +but most of them have no visible effect on the API. Some can also be overridden +from the API. + +This method of building a customized pnglibconf.h is illustrated in +contrib/pngminim/*. See the "$(PNGCONF):" target in the makefile and +pngusr.dfa in these directories. + +C. Configuration using PNG_USER_CONFIG + +If -DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built, +the file pngusr.h will automatically be included before the options in +scripts/pnglibconf.dfa are processed. Your pngusr.h file should contain only +macro definitions turning features on or off or setting settings. + +Apart from the global setting "everything = off" all the options listed above +can be set using macros in pngusr.h: + +#define PNG_feature_SUPPORTED + +is equivalent to: + +option feature on + +#define PNG_NO_feature + +is equivalent to: + +option feature off + +#define PNG_feature value + +is equivalent to: + +setting feature default value + +Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the +pngusr file you supply override the contents of scripts/pnglibconf.dfa + +If confusing or incomprehensible behavior results it is possible to +examine the intermediate file pnglibconf.dfn to find the full set of +dependency information for each setting and option. Simply locate the +feature in the file and read the C comments that precede it. + +This method is also illustrated in the contrib/pngminim/* makefiles and +pngusr.h. + +III. Reading + +We'll now walk you through the possible functions to call when reading +in a PNG file sequentially, briefly explaining the syntax and purpose +of each one. See example.c and png.h for more detail. While +progressive reading is covered in the next section, you will still +need some of the functions discussed in this section to read a PNG +file. + +Setup + +You will want to do the I/O initialization(*) before you get into libpng, +so if it doesn't work, you don't have much to undo. Of course, you +will also want to insure that you are, in fact, dealing with a PNG +file. Libpng provides a simple check to see if a file is a PNG file. +To use it, pass in the first 1 to 8 bytes of the file to the function +png_sig_cmp(), and it will return 0 (false) if the bytes match the +corresponding bytes of the PNG signature, or nonzero (true) otherwise. +Of course, the more bytes you pass in, the greater the accuracy of the +prediction. + +If you are intending to keep the file pointer open for use in libpng, +you must ensure you don't read more than 8 bytes from the beginning +of the file, and you also have to make a call to png_set_sig_bytes_read() +with the number of bytes you read from the beginning. Libpng will +then only check the bytes (if any) that your program didn't read. + +(*): If you are not using the standard I/O functions, you will need +to replace them with custom functions. See the discussion under +Customizing libpng. + + + FILE *fp = fopen(file_name, "rb"); + if (!fp) + { + return (ERROR); + } + + fread(header, 1, number, fp); + is_png = !png_sig_cmp(header, 0, number); + + if (!is_png) + { + return (NOT_PNG); + } + + +Next, png_struct and png_info need to be allocated and initialized. In +order to ensure that the size of these structures is correct even with a +dynamically linked libpng, there are functions to initialize and +allocate the structures. We also pass the library version, optional +pointers to error handling functions, and a pointer to a data struct for +use by the error functions, if necessary (the pointer and functions can +be NULL if the default error handlers are to be used). See the section +on Changes to Libpng below regarding the old initialization functions. +The structure allocation functions quietly return NULL if they fail to +create the structure, so your application should check for that. + + png_structp png_ptr = png_create_read_struct + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn); + + if (!png_ptr) + return (ERROR); + + png_infop info_ptr = png_create_info_struct(png_ptr); + + if (!info_ptr) + { + png_destroy_read_struct(&png_ptr, + (png_infopp)NULL, (png_infopp)NULL); + return (ERROR); + } + +If you want to use your own memory allocation routines, +use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use +png_create_read_struct_2() instead of png_create_read_struct(): + + png_structp png_ptr = png_create_read_struct_2 + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn, (png_voidp) + user_mem_ptr, user_malloc_fn, user_free_fn); + +The error handling routines passed to png_create_read_struct() +and the memory alloc/free routines passed to png_create_struct_2() +are only necessary if you are not using the libpng supplied error +handling and memory alloc/free functions. + +When libpng encounters an error, it expects to longjmp back +to your routine. Therefore, you will need to call setjmp and pass +your png_jmpbuf(png_ptr). If you read the file from different +routines, you will need to update the longjmp buffer every time you enter +a new routine that will call a png_*() function. + +See your documentation of setjmp/longjmp for your compiler for more +information on setjmp/longjmp. See the discussion on libpng error +handling in the Customizing Libpng section below for more information +on the libpng error handling. If an error occurs, and libpng longjmp's +back to your setjmp, you will want to call png_destroy_read_struct() to +free any memory. + + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_read_struct(&png_ptr, &info_ptr, + &end_info); + fclose(fp); + return (ERROR); + } + +Pass (png_infopp)NULL instead of &end_info if you didn't create +an end_info structure. + +If you would rather avoid the complexity of setjmp/longjmp issues, +you can compile libpng with PNG_NO_SETJMP, in which case +errors will result in a call to PNG_ABORT() which defaults to abort(). + +You can #define PNG_ABORT() to a function that does something +more useful than abort(), as long as your function does not +return. + +Now you need to set up the input code. The default for libpng is to +use the C function fread(). If you use this, you will need to pass a +valid FILE * in the function png_init_io(). Be sure that the file is +opened in binary mode. If you wish to handle reading data in another +way, you need not call the png_init_io() function, but you must then +implement the libpng I/O methods discussed in the Customizing Libpng +section below. + + png_init_io(png_ptr, fp); + +If you had previously opened the file and read any of the signature from +the beginning in order to see if this was a PNG file, you need to let +libpng know that there are some bytes missing from the start of the file. + + png_set_sig_bytes(png_ptr, number); + +You can change the zlib compression buffer size to be used while +reading compressed data with + + png_set_compression_buffer_size(png_ptr, buffer_size); + +where the default size is 8192 bytes. Note that the buffer size +is changed immediately and the buffer is reallocated immediately, +instead of setting a flag to be acted upon later. + +If you want CRC errors to be handled in a different manner than +the default, use + + png_set_crc_action(png_ptr, crit_action, ancil_action); + +The values for png_set_crc_action() say how libpng is to handle CRC errors in +ancillary and critical chunks, and whether to use the data contained +therein. Note that it is impossible to "discard" data in a critical +chunk. + +Choices for (int) crit_action are + PNG_CRC_DEFAULT 0 error/quit + PNG_CRC_ERROR_QUIT 1 error/quit + PNG_CRC_WARN_USE 3 warn/use data + PNG_CRC_QUIET_USE 4 quiet/use data + PNG_CRC_NO_CHANGE 5 use the current value + +Choices for (int) ancil_action are + PNG_CRC_DEFAULT 0 error/quit + PNG_CRC_ERROR_QUIT 1 error/quit + PNG_CRC_WARN_DISCARD 2 warn/discard data + PNG_CRC_WARN_USE 3 warn/use data + PNG_CRC_QUIET_USE 4 quiet/use data + PNG_CRC_NO_CHANGE 5 use the current value + +Setting up callback code + +You can set up a callback function to handle any unknown chunks in the +input stream. You must supply the function + + read_chunk_callback(png_structp png_ptr, + png_unknown_chunkp chunk); + { + /* The unknown chunk structure contains your + chunk data, along with similar data for any other + unknown chunks: */ + + png_byte name[5]; + png_byte *data; + png_size_t size; + + /* Note that libpng has already taken care of + the CRC handling */ + + /* put your code here. Search for your chunk in the + unknown chunk structure, process it, and return one + of the following: */ + + return (-n); /* chunk had an error */ + return (0); /* did not recognize */ + return (n); /* success */ + } + +(You can give your function another name that you like instead of +"read_chunk_callback") + +To inform libpng about your function, use + + png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr, + read_chunk_callback); + +This names not only the callback function, but also a user pointer that +you can retrieve with + + png_get_user_chunk_ptr(png_ptr); + +If you call the png_set_read_user_chunk_fn() function, then all unknown +chunks which the callback does not handle will be saved when read. You can +cause them to be discarded by returning '1' ("handled") instead of '0'. This +behavior will change in libpng 1.7 and the default handling set by the +png_set_keep_unknown_chunks() function, described below, will be used when the +callback returns 0. If you want the existing behavior you should set the global +default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current +versions of libpng and with 1.7. Libpng 1.6 issues a warning if you keep the +default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0. + +At this point, you can set up a callback function that will be +called after each row has been read, which you can use to control +a progress meter or the like. It's demonstrated in pngtest.c. +You must supply a function + + void read_row_callback(png_structp png_ptr, + png_uint_32 row, int pass); + { + /* put your code here */ + } + +(You can give it another name that you like instead of "read_row_callback") + +To inform libpng about your function, use + + png_set_read_status_fn(png_ptr, read_row_callback); + +When this function is called the row has already been completely processed and +the 'row' and 'pass' refer to the next row to be handled. For the +non-interlaced case the row that was just handled is simply one less than the +passed in row number, and pass will always be 0. For the interlaced case the +same applies unless the row value is 0, in which case the row just handled was +the last one from one of the preceding passes. Because interlacing may skip a +pass you cannot be sure that the preceding pass is just 'pass-1', if you really +need to know what the last pass is record (row,pass) from the callback and use +the last recorded value each time. + +As with the user transform you can find the output row using the +PNG_ROW_FROM_PASS_ROW macro. + +Unknown-chunk handling + +Now you get to set the way the library processes unknown chunks in the +input PNG stream. Both known and unknown chunks will be read. Normal +behavior is that known chunks will be parsed into information in +various info_ptr members while unknown chunks will be discarded. This +behavior can be wasteful if your application will never use some known +chunk types. To change this, you can call: + + png_set_keep_unknown_chunks(png_ptr, keep, + chunk_list, num_chunks); + + keep - 0: default unknown chunk handling + 1: ignore; do not keep + 2: keep only if safe-to-copy + 3: keep even if unsafe-to-copy + + You can use these definitions: + PNG_HANDLE_CHUNK_AS_DEFAULT 0 + PNG_HANDLE_CHUNK_NEVER 1 + PNG_HANDLE_CHUNK_IF_SAFE 2 + PNG_HANDLE_CHUNK_ALWAYS 3 + + chunk_list - list of chunks affected (a byte string, + five bytes per chunk, NULL or '\0' if + num_chunks is positive; ignored if + numchunks <= 0). + + num_chunks - number of chunks affected; if 0, all + unknown chunks are affected. If positive, + only the chunks in the list are affected, + and if negative all unknown chunks and + all known chunks except for the IHDR, + PLTE, tRNS, IDAT, and IEND chunks are + affected. + +Unknown chunks declared in this way will be saved as raw data onto a +list of png_unknown_chunk structures. If a chunk that is normally +known to libpng is named in the list, it will be handled as unknown, +according to the "keep" directive. If a chunk is named in successive +instances of png_set_keep_unknown_chunks(), the final instance will +take precedence. The IHDR and IEND chunks should not be named in +chunk_list; if they are, libpng will process them normally anyway. +If you know that your application will never make use of some particular +chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below. + +Here is an example of the usage of png_set_keep_unknown_chunks(), +where the private "vpAg" chunk will later be processed by a user chunk +callback function: + + png_byte vpAg[5]={118, 112, 65, 103, (png_byte) '\0'}; + + #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) + png_byte unused_chunks[]= + { + 104, 73, 83, 84, (png_byte) '\0', /* hIST */ + 105, 84, 88, 116, (png_byte) '\0', /* iTXt */ + 112, 67, 65, 76, (png_byte) '\0', /* pCAL */ + 115, 67, 65, 76, (png_byte) '\0', /* sCAL */ + 115, 80, 76, 84, (png_byte) '\0', /* sPLT */ + 116, 73, 77, 69, (png_byte) '\0', /* tIME */ + }; + #endif + + ... + + #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) + /* ignore all unknown chunks + * (use global setting "2" for libpng16 and earlier): + */ + png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0); + + /* except for vpAg: */ + png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1); + + /* also ignore unused known chunks: */ + png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks, + (int)(sizeof unused_chunks)/5); + #endif + +User limits + +The PNG specification allows the width and height of an image to be as +large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns. +Since very few applications really need to process such large images, +we have imposed an arbitrary 1-million limit on rows and columns. +Larger images will be rejected immediately with a png_error() call. If +you wish to change this limit, you can use + + png_set_user_limits(png_ptr, width_max, height_max); + +to set your own limits, or use width_max = height_max = 0x7fffffffL +to allow all valid dimensions (libpng may reject some very large images +anyway because of potential buffer overflow conditions). + +You should put this statement after you create the PNG structure and +before calling png_read_info(), png_read_png(), or png_process_data(). + +When writing a PNG datastream, put this statement before calling +png_write_info() or png_write_png(). + +If you need to retrieve the limits that are being applied, use + + width_max = png_get_user_width_max(png_ptr); + height_max = png_get_user_height_max(png_ptr); + +The PNG specification sets no limit on the number of ancillary chunks +allowed in a PNG datastream. You can impose a limit on the total number +of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with + + png_set_chunk_cache_max(png_ptr, user_chunk_cache_max); + +where 0x7fffffffL means unlimited. You can retrieve this limit with + + chunk_cache_max = png_get_chunk_cache_max(png_ptr); + +You can also set a limit on the amount of memory that a compressed chunk +other than IDAT can occupy, with + + png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max); + +and you can retrieve the limit with + + chunk_malloc_max = png_get_chunk_malloc_max(png_ptr); + +Any chunks that would cause either of these limits to be exceeded will +be ignored. + +Information about your system + +If you intend to display the PNG or to incorporate it in other image data you +need to tell libpng information about your display or drawing surface so that +libpng can convert the values in the image to match the display. + +From libpng-1.5.4 this information can be set before reading the PNG file +header. In earlier versions png_set_gamma() existed but behaved incorrectly if +called before the PNG file header had been read and png_set_alpha_mode() did not +exist. + +If you need to support versions prior to libpng-1.5.4 test the version number +as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures +described in the appropriate manual page. + +You give libpng the encoding expected by your system expressed as a 'gamma' +value. You can also specify a default encoding for the PNG file in +case the required information is missing from the file. By default libpng +assumes that the PNG data matches your system, to keep this default call: + + png_set_gamma(png_ptr, screen_gamma, output_gamma); + +or you can use the fixed point equivalent: + + png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma, + PNG_FP_1*output_gamma); + +If you don't know the gamma for your system it is probably 2.2 - a good +approximation to the IEC standard for display systems (sRGB). If images are +too contrasty or washed out you got the value wrong - check your system +documentation! + +Many systems permit the system gamma to be changed via a lookup table in the +display driver, a few systems, including older Macs, change the response by +default. As of 1.5.4 three special values are available to handle common +situations: + + PNG_DEFAULT_sRGB: Indicates that the system conforms to the + IEC 61966-2-1 standard. This matches almost + all systems. + PNG_GAMMA_MAC_18: Indicates that the system is an older + (pre Mac OS 10.6) Apple Macintosh system with + the default settings. + PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates + that the system expects data with no gamma + encoding. + +You would use the linear (unencoded) value if you need to process the pixel +values further because this avoids the need to decode and re-encode each +component value whenever arithmetic is performed. A lot of graphics software +uses linear values for this reason, often with higher precision component values +to preserve overall accuracy. + + +The output_gamma value expresses how to decode the output values, not how +they are encoded. The values used correspond to the normal numbers used to +describe the overall gamma of a computer display system; for example 2.2 for +an sRGB conformant system. The values are scaled by 100000 in the _fixed +version of the API (so 220000 for sRGB.) + +The inverse of the value is always used to provide a default for the PNG file +encoding if it has no gAMA chunk and if png_set_gamma() has not been called +to override the PNG gamma information. + +When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode +opaque pixels however pixels with lower alpha values are not encoded, +regardless of the output gamma setting. + +When the standard Porter Duff handling is requested with mode 1 the output +encoding is set to be linear and the output_gamma value is only relevant +as a default for input data that has no gamma information. The linear output +encoding will be overridden if png_set_gamma() is called - the results may be +highly unexpected! + +The following numbers are derived from the sRGB standard and the research +behind it. sRGB is defined to be approximated by a PNG gAMA chunk value of +0.45455 (1/2.2) for PNG. The value implicitly includes any viewing +correction required to take account of any differences in the color +environment of the original scene and the intended display environment; the +value expresses how to *decode* the image for display, not how the original +data was *encoded*. + +sRGB provides a peg for the PNG standard by defining a viewing environment. +sRGB itself, and earlier TV standards, actually use a more complex transform +(a linear portion then a gamma 2.4 power law) than PNG can express. (PNG is +limited to simple power laws.) By saying that an image for direct display on +an sRGB conformant system should be stored with a gAMA chunk value of 45455 +(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification +makes it possible to derive values for other display systems and +environments. + +The Mac value is deduced from the sRGB based on an assumption that the actual +extra viewing correction used in early Mac display systems was implemented as +a power 1.45 lookup table. + +Any system where a programmable lookup table is used or where the behavior of +the final display device characteristics can be changed requires system +specific code to obtain the current characteristic. However this can be +difficult and most PNG gamma correction only requires an approximate value. + +By default, if png_set_alpha_mode() is not called, libpng assumes that all +values are unencoded, linear, values and that the output device also has a +linear characteristic. This is only very rarely correct - it is invariably +better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the +default if you don't know what the right answer is! + +The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS +10.6) which used a correction table to implement a somewhat lower gamma on an +otherwise sRGB system. + +Both these values are reserved (not simple gamma values) in order to allow +more precise correction internally in the future. + +NOTE: the values can be passed to either the fixed or floating +point APIs, but the floating point API will also accept floating point +values. + +The second thing you may need to tell libpng about is how your system handles +alpha channel information. Some, but not all, PNG files contain an alpha +channel. To display these files correctly you need to compose the data onto a +suitable background, as described in the PNG specification. + +Libpng only supports composing onto a single color (using png_set_background; +see below). Otherwise you must do the composition yourself and, in this case, +you may need to call png_set_alpha_mode: + + #if PNG_LIBPNG_VER >= 10504 + png_set_alpha_mode(png_ptr, mode, screen_gamma); + #else + png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma); + #endif + +The screen_gamma value is the same as the argument to png_set_gamma; however, +how it affects the output depends on the mode. png_set_alpha_mode() sets the +file gamma default to 1/screen_gamma, so normally you don't need to call +png_set_gamma. If you need different defaults call png_set_gamma() before +png_set_alpha_mode() - if you call it after it will override the settings made +by png_set_alpha_mode(). + +The mode is as follows: + + PNG_ALPHA_PNG: The data is encoded according to the PNG +specification. Red, green and blue, or gray, components are +gamma encoded color values and are not premultiplied by the +alpha value. The alpha value is a linear measure of the +contribution of the pixel to the corresponding final output pixel. + +You should normally use this format if you intend to perform +color correction on the color values; most, maybe all, color +correction software has no handling for the alpha channel and, +anyway, the math to handle pre-multiplied component values is +unnecessarily complex. + +Before you do any arithmetic on the component values you need +to remove the gamma encoding and multiply out the alpha +channel. See the PNG specification for more detail. It is +important to note that when an image with an alpha channel is +scaled, linear encoded, pre-multiplied component values must +be used! + +The remaining modes assume you don't need to do any further color correction or +that if you do, your color correction software knows all about alpha (it +probably doesn't!). They 'associate' the alpha with the color information by +storing color channel values that have been scaled by the alpha. The +advantage is that the color channels can be resampled (the image can be +scaled) in this form. The disadvantage is that normal practice is to store +linear, not (gamma) encoded, values and this requires 16-bit channels for +still images rather than the 8-bit channels that are just about sufficient if +gamma encoding is used. In addition all non-transparent pixel values, +including completely opaque ones, must be gamma encoded to produce the final +image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes +described below (the latter being the two common names for associated alpha +color channels). Note that PNG files always contain non-associated color +channels; png_set_alpha_mode() with one of the modes causes the decoder to +convert the pixels to an associated form before returning them to your +application. + +Since it is not necessary to perform arithmetic on opaque color values so +long as they are not to be resampled and are in the final color space it is +possible to optimize the handling of alpha by storing the opaque pixels in +the PNG format (adjusted for the output color space) while storing partially +opaque pixels in the standard, linear, format. The accuracy required for +standard alpha composition is relatively low, because the pixels are +isolated, therefore typically the accuracy loss in storing 8-bit linear +values is acceptable. (This is not true if the alpha channel is used to +simulate transparency over large areas - use 16 bits or the PNG mode in +this case!) This is the 'OPTIMIZED' mode. For this mode a pixel is +treated as opaque only if the alpha value is equal to the maximum value. + + PNG_ALPHA_STANDARD: The data libpng produces is encoded in the +standard way assumed by most correctly written graphics software. +The gamma encoding will be removed by libpng and the +linear component values will be pre-multiplied by the +alpha channel. + +With this format the final image must be re-encoded to +match the display gamma before the image is displayed. +If your system doesn't do that, yet still seems to +perform arithmetic on the pixels without decoding them, +it is broken - check out the modes below. + +With PNG_ALPHA_STANDARD libpng always produces linear +component values, whatever screen_gamma you supply. The +screen_gamma value is, however, used as a default for +the file gamma if the PNG file has no gamma information. + +If you call png_set_gamma() after png_set_alpha_mode() you +will override the linear encoding. Instead the +pre-multiplied pixel values will be gamma encoded but +the alpha channel will still be linear. This may +actually match the requirements of some broken software, +but it is unlikely. + +While linear 8-bit data is often used it has +insufficient precision for any image with a reasonable +dynamic range. To avoid problems, and if your software +supports it, use png_set_expand_16() to force all +components to 16 bits. + + PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD +except that completely opaque pixels are gamma encoded according to +the screen_gamma value. Pixels with alpha less than 1.0 +will still have linear components. + +Use this format if you have control over your +compositing software and so don't do other arithmetic +(such as scaling) on the data you get from libpng. Your +compositing software can simply copy opaque pixels to +the output but still has linear values for the +non-opaque pixels. + +In normal compositing, where the alpha channel encodes +partial pixel coverage (as opposed to broad area +translucency), the inaccuracies of the 8-bit +representation of non-opaque pixels are irrelevant. + +You can also try this format if your software is broken; +it might look better. + + PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component +values, including the alpha channel are gamma encoded. This is +broken because, in practice, no implementation that uses this choice +correctly undoes the encoding before handling alpha composition. Use this +choice only if other serious errors in the software or hardware you use +mandate it. In most cases of broken software or hardware the bug in the +final display manifests as a subtle halo around composited parts of the +image. You may not even perceive this as a halo; the composited part of +the image may simply appear separate from the background, as though it had +been cut out of paper and pasted on afterward. + +If you don't have to deal with bugs in software or hardware, or if you can fix +them, there are three recommended ways of using png_set_alpha_mode(): + + png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG, + screen_gamma); + +You can do color correction on the result (libpng does not currently +support color correction internally). When you handle the alpha channel +you need to undo the gamma encoding and multiply out the alpha. + + png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD, + screen_gamma); + png_set_expand_16(png_ptr); + +If you are using the high level interface, don't call png_set_expand_16(); +instead pass PNG_TRANSFORM_EXPAND_16 to the interface. + +With this mode you can't do color correction, but you can do arithmetic, +including composition and scaling, on the data without further processing. + + png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED, + screen_gamma); + +You can avoid the expansion to 16-bit components with this mode, but you +lose the ability to scale the image or perform other linear arithmetic. +All you can do is compose the result onto a matching output. Since this +mode is libpng-specific you also need to write your own composition +software. + +The following are examples of calls to png_set_alpha_mode to achieve the +required overall gamma correction and, where necessary, alpha +premultiplication. + + png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); + +This is the default libpng handling of the alpha channel - it is not +pre-multiplied into the color components. In addition the call states +that the output is for a sRGB system and causes all PNG files without gAMA +chunks to be assumed to be encoded using sRGB. + + png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); + +In this case the output is assumed to be something like an sRGB conformant +display preceeded by a power-law lookup table of power 1.45. This is how +early Mac systems behaved. + + png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR); + +This is the classic Jim Blinn approach and will work in academic +environments where everything is done by the book. It has the shortcoming +of assuming that input PNG data with no gamma information is linear - this +is unlikely to be correct unless the PNG files where generated locally. +Most of the time the output precision will be so low as to show +significant banding in dark areas of the image. + + png_set_expand_16(pp); + png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB); + +This is a somewhat more realistic Jim Blinn inspired approach. PNG files +are assumed to have the sRGB encoding if not marked with a gamma value and +the output is always 16 bits per component. This permits accurate scaling +and processing of the data. If you know that your input PNG files were +generated locally you might need to replace PNG_DEFAULT_sRGB with the +correct value for your system. + + png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB); + +If you just need to composite the PNG image onto an existing background +and if you control the code that does this you can use the optimization +setting. In this case you just copy completely opaque pixels to the +output. For pixels that are not completely transparent (you just skip +those) you do the composition math using png_composite or png_composite_16 +below then encode the resultant 8-bit or 16-bit values to match the output +encoding. + + Other cases + +If neither the PNG nor the standard linear encoding work for you because +of the software or hardware you use then you have a big problem. The PNG +case will probably result in halos around the image. The linear encoding +will probably result in a washed out, too bright, image (it's actually too +contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably +substantially reduce the halos. Alternatively try: + + png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB); + +This option will also reduce the halos, but there will be slight dark +halos round the opaque parts of the image where the background is light. +In the OPTIMIZED mode the halos will be light halos where the background +is dark. Take your pick - the halos are unavoidable unless you can get +your hardware/software fixed! (The OPTIMIZED approach is slightly +faster.) + +When the default gamma of PNG files doesn't match the output gamma. +If you have PNG files with no gamma information png_set_alpha_mode allows +you to provide a default gamma, but it also sets the ouput gamma to the +matching value. If you know your PNG files have a gamma that doesn't +match the output you can take advantage of the fact that +png_set_alpha_mode always sets the output gamma but only sets the PNG +default if it is not already set: + + png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); + png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); + +The first call sets both the default and the output gamma values, the +second call overrides the output gamma without changing the default. This +is easier than achieving the same effect with png_set_gamma. You must use +PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will +fire if more than one call to png_set_alpha_mode and png_set_background is +made in the same read operation, however multiple calls with PNG_ALPHA_PNG +are ignored. + +If you don't need, or can't handle, the alpha channel you can call +png_set_background() to remove it by compositing against a fixed color. Don't +call png_set_strip_alpha() to do this - it will leave spurious pixel values in +transparent parts of this image. + + png_set_background(png_ptr, &background_color, + PNG_BACKGROUND_GAMMA_SCREEN, 0, 1); + +The background_color is an RGB or grayscale value according to the data format +libpng will produce for you. Because you don't yet know the format of the PNG +file, if you call png_set_background at this point you must arrange for the +format produced by libpng to always have 8-bit or 16-bit components and then +store the color as an 8-bit or 16-bit color as appropriate. The color contains +separate gray and RGB component values, so you can let libpng produce gray or +RGB output according to the input format, but low bit depth grayscale images +must always be converted to at least 8-bit format. (Even though low bit depth +grayscale images can't have an alpha channel they can have a transparent +color!) + +You set the transforms you need later, either as flags to the high level +interface or libpng API calls for the low level interface. For reference the +settings and API calls required are: + +8-bit values: + PNG_TRANSFORM_SCALE_16 | PNG_EXPAND + png_set_expand(png_ptr); png_set_scale_16(png_ptr); + + If you must get exactly the same inaccurate results + produced by default in versions prior to libpng-1.5.4, + use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr) + instead. + +16-bit values: + PNG_TRANSFORM_EXPAND_16 + png_set_expand_16(png_ptr); + +In either case palette image data will be expanded to RGB. If you just want +color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr) +to the list. + +Calling png_set_background before the PNG file header is read will not work +prior to libpng-1.5.4. Because the failure may result in unexpected warnings or +errors it is therefore much safer to call png_set_background after the head has +been read. Unfortunately this means that prior to libpng-1.5.4 it cannot be +used with the high level interface. + +The high-level read interface + +At this point there are two ways to proceed; through the high-level +read interface, or through a sequence of low-level read operations. +You can use the high-level interface if (a) you are willing to read +the entire image into memory, and (b) the input transformations +you want to do are limited to the following set: + + PNG_TRANSFORM_IDENTITY No transformation + PNG_TRANSFORM_SCALE_16 Strip 16-bit samples to + 8-bit accurately + PNG_TRANSFORM_STRIP_16 Chop 16-bit samples to + 8-bit less accurately + PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel + PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit + samples to bytes + PNG_TRANSFORM_PACKSWAP Change order of packed + pixels to LSB first + PNG_TRANSFORM_EXPAND Perform set_expand() + PNG_TRANSFORM_INVERT_MONO Invert monochrome images + PNG_TRANSFORM_SHIFT Normalize pixels to the + sBIT depth + PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA + to BGRA + PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA + to AG + PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity + to transparency + PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples + PNG_TRANSFORM_GRAY_TO_RGB Expand grayscale samples + to RGB (or GA to RGBA) + PNG_TRANSFORM_EXPAND_16 Expand samples to 16 bits + +(This excludes setting a background color, doing gamma transformation, +quantizing, and setting filler.) If this is the case, simply do this: + + png_read_png(png_ptr, info_ptr, png_transforms, NULL) + +where png_transforms is an integer containing the bitwise OR of some +set of transformation flags. This call is equivalent to png_read_info(), +followed the set of transformations indicated by the transform mask, +then png_read_image(), and finally png_read_end(). + +(The final parameter of this call is not yet used. Someday it might point +to transformation parameters required by some future input transform.) + +You must use png_transforms and not call any png_set_transform() functions +when you use png_read_png(). + +After you have called png_read_png(), you can retrieve the image data +with + + row_pointers = png_get_rows(png_ptr, info_ptr); + +where row_pointers is an array of pointers to the pixel data for each row: + + png_bytep row_pointers[height]; + +If you know your image size and pixel size ahead of time, you can allocate +row_pointers prior to calling png_read_png() with + + if (height > PNG_UINT_32_MAX/(sizeof (png_byte))) + png_error (png_ptr, + "Image is too tall to process in memory"); + + if (width > PNG_UINT_32_MAX/pixel_size) + png_error (png_ptr, + "Image is too wide to process in memory"); + + row_pointers = png_malloc(png_ptr, + height*(sizeof (png_bytep))); + + for (int i=0; i<height, i++) + row_pointers[i]=NULL; /* security precaution */ + + for (int i=0; i<height, i++) + row_pointers[i]=png_malloc(png_ptr, + width*pixel_size); + + png_set_rows(png_ptr, info_ptr, &row_pointers); + +Alternatively you could allocate your image in one big block and define +row_pointers[i] to point into the proper places in your block. + +If you use png_set_rows(), the application is responsible for freeing +row_pointers (and row_pointers[i], if they were separately allocated). + +If you don't allocate row_pointers ahead of time, png_read_png() will +do it, and it'll be free'ed by libpng when you call png_destroy_*(). + +The low-level read interface + +If you are going the low-level route, you are now ready to read all +the file information up to the actual image data. You do this with a +call to png_read_info(). + + png_read_info(png_ptr, info_ptr); + +This will process all chunks up to but not including the image data. + +This also copies some of the data from the PNG file into the decode structure +for use in later transformations. Important information copied in is: + +1) The PNG file gamma from the gAMA chunk. This overwrites the default value +provided by an earlier call to png_set_gamma or png_set_alpha_mode. + +2) Prior to libpng-1.5.4 the background color from a bKGd chunk. This +damages the information provided by an earlier call to png_set_background +resulting in unexpected behavior. Libpng-1.5.4 no longer does this. + +3) The number of significant bits in each component value. Libpng uses this to +optimize gamma handling by reducing the internal lookup table sizes. + +4) The transparent color information from a tRNS chunk. This can be modified by +a later call to png_set_tRNS. + +Querying the info structure + +Functions are used to get the information from the info_ptr once it +has been read. Note that these fields may not be completely filled +in until png_read_end() has read the chunk data following the image. + + png_get_IHDR(png_ptr, info_ptr, &width, &height, + &bit_depth, &color_type, &interlace_type, + &compression_type, &filter_method); + + width - holds the width of the image + in pixels (up to 2^31). + + height - holds the height of the image + in pixels (up to 2^31). + + bit_depth - holds the bit depth of one of the + image channels. (valid values are + 1, 2, 4, 8, 16 and depend also on + the color_type. See also + significant bits (sBIT) below). + + color_type - describes which color/alpha channels + are present. + PNG_COLOR_TYPE_GRAY + (bit depths 1, 2, 4, 8, 16) + PNG_COLOR_TYPE_GRAY_ALPHA + (bit depths 8, 16) + PNG_COLOR_TYPE_PALETTE + (bit depths 1, 2, 4, 8) + PNG_COLOR_TYPE_RGB + (bit_depths 8, 16) + PNG_COLOR_TYPE_RGB_ALPHA + (bit_depths 8, 16) + + PNG_COLOR_MASK_PALETTE + PNG_COLOR_MASK_COLOR + PNG_COLOR_MASK_ALPHA + + interlace_type - (PNG_INTERLACE_NONE or + PNG_INTERLACE_ADAM7) + + compression_type - (must be PNG_COMPRESSION_TYPE_BASE + for PNG 1.0) + + filter_method - (must be PNG_FILTER_TYPE_BASE + for PNG 1.0, and can also be + PNG_INTRAPIXEL_DIFFERENCING if + the PNG datastream is embedded in + a MNG-1.0 datastream) + + Any or all of interlace_type, compression_type, or + filter_method can be NULL if you are + not interested in their values. + + Note that png_get_IHDR() returns 32-bit data into + the application's width and height variables. + This is an unsafe situation if these are 16-bit + variables. In such situations, the + png_get_image_width() and png_get_image_height() + functions described below are safer. + + width = png_get_image_width(png_ptr, + info_ptr); + + height = png_get_image_height(png_ptr, + info_ptr); + + bit_depth = png_get_bit_depth(png_ptr, + info_ptr); + + color_type = png_get_color_type(png_ptr, + info_ptr); + + interlace_type = png_get_interlace_type(png_ptr, + info_ptr); + + compression_type = png_get_compression_type(png_ptr, + info_ptr); + + filter_method = png_get_filter_type(png_ptr, + info_ptr); + + channels = png_get_channels(png_ptr, info_ptr); + + channels - number of channels of info for the + color type (valid values are 1 (GRAY, + PALETTE), 2 (GRAY_ALPHA), 3 (RGB), + 4 (RGB_ALPHA or RGB + filler byte)) + + rowbytes = png_get_rowbytes(png_ptr, info_ptr); + + rowbytes - number of bytes needed to hold a row + + signature = png_get_signature(png_ptr, info_ptr); + + signature - holds the signature read from the + file (if any). The data is kept in + the same offset it would be if the + whole signature were read (i.e. if an + application had already read in 4 + bytes of signature before starting + libpng, the remaining 4 bytes would + be in signature[4] through signature[7] + (see png_set_sig_bytes())). + +These are also important, but their validity depends on whether the chunk +has been read. The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and +png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the +data has been read, or zero if it is missing. The parameters to the +png_get_<chunk> are set directly if they are simple data types, or a +pointer into the info_ptr is returned for any complex types. + +The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks +is simply returned to give the application information about how the +image was encoded. Libpng itself only does transformations using the file +gamma when combining semitransparent pixels with the background color, and, +since libpng-1.6.0, when converting between 8-bit sRGB and 16-bit linear pixels +within the simplified API. Libpng also uses the file gamma when converting +RGB to gray, beginning with libpng-1.0.5, if the application calls +png_set_rgb_to_gray()). + + png_get_PLTE(png_ptr, info_ptr, &palette, + &num_palette); + + palette - the palette for the file + (array of png_color) + + num_palette - number of entries in the palette + + png_get_gAMA(png_ptr, info_ptr, &file_gamma); + png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma); + + file_gamma - the gamma at which the file is + written (PNG_INFO_gAMA) + + int_file_gamma - 100,000 times the gamma at which the + file is written + + png_get_cHRM(png_ptr, info_ptr, &white_x, &white_y, &red_x, + &red_y, &green_x, &green_y, &blue_x, &blue_y) + png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z, + &green_X, &green_Y, &green_Z, &blue_X, &blue_Y, + &blue_Z) + png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x, + &int_white_y, &int_red_x, &int_red_y, + &int_green_x, &int_green_y, &int_blue_x, + &int_blue_y) + png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y, + &int_red_Z, &int_green_X, &int_green_Y, + &int_green_Z, &int_blue_X, &int_blue_Y, + &int_blue_Z) + + {white,red,green,blue}_{x,y} + A color space encoding specified using the + chromaticities of the end points and the + white point. (PNG_INFO_cHRM) + + {red,green,blue}_{X,Y,Z} + A color space encoding specified using the + encoding end points - the CIE tristimulus + specification of the intended color of the red, + green and blue channels in the PNG RGB data. + The white point is simply the sum of the three + end points. (PNG_INFO_cHRM) + + png_get_sRGB(png_ptr, info_ptr, &srgb_intent); + + srgb_intent - the rendering intent (PNG_INFO_sRGB) + The presence of the sRGB chunk + means that the pixel data is in the + sRGB color space. This chunk also + implies specific values of gAMA and + cHRM. + + png_get_iCCP(png_ptr, info_ptr, &name, + &compression_type, &profile, &proflen); + + name - The profile name. + + compression_type - The compression type; always + PNG_COMPRESSION_TYPE_BASE for PNG 1.0. + You may give NULL to this argument to + ignore it. + + profile - International Color Consortium color + profile data. May contain NULs. + + proflen - length of profile data in bytes. + + png_get_sBIT(png_ptr, info_ptr, &sig_bit); + + sig_bit - the number of significant bits for + (PNG_INFO_sBIT) each of the gray, + red, green, and blue channels, + whichever are appropriate for the + given color type (png_color_16) + + png_get_tRNS(png_ptr, info_ptr, &trans_alpha, + &num_trans, &trans_color); + + trans_alpha - array of alpha (transparency) + entries for palette (PNG_INFO_tRNS) + + num_trans - number of transparent entries + (PNG_INFO_tRNS) + + trans_color - graylevel or color sample values of + the single transparent color for + non-paletted images (PNG_INFO_tRNS) + + png_get_hIST(png_ptr, info_ptr, &hist); + (PNG_INFO_hIST) + + hist - histogram of palette (array of + png_uint_16) + + png_get_tIME(png_ptr, info_ptr, &mod_time); + + mod_time - time image was last modified + (PNG_VALID_tIME) + + png_get_bKGD(png_ptr, info_ptr, &background); + + background - background color (of type + png_color_16p) (PNG_VALID_bKGD) + valid 16-bit red, green and blue + values, regardless of color_type + + num_comments = png_get_text(png_ptr, info_ptr, + &text_ptr, &num_text); + + num_comments - number of comments + + text_ptr - array of png_text holding image + comments + + text_ptr[i].compression - type of compression used + on "text" PNG_TEXT_COMPRESSION_NONE + PNG_TEXT_COMPRESSION_zTXt + PNG_ITXT_COMPRESSION_NONE + PNG_ITXT_COMPRESSION_zTXt + + text_ptr[i].key - keyword for comment. Must contain + 1-79 characters. + + text_ptr[i].text - text comments for current + keyword. Can be empty. + + text_ptr[i].text_length - length of text string, + after decompression, 0 for iTXt + + text_ptr[i].itxt_length - length of itxt string, + after decompression, 0 for tEXt/zTXt + + text_ptr[i].lang - language of comment (empty + string for unknown). + + text_ptr[i].lang_key - keyword in UTF-8 + (empty string for unknown). + + Note that the itxt_length, lang, and lang_key + members of the text_ptr structure only exist when the + library is built with iTXt chunk support. Prior to + libpng-1.4.0 the library was built by default without + iTXt support. Also note that when iTXt is supported, + they contain NULL pointers when the "compression" + field contains PNG_TEXT_COMPRESSION_NONE or + PNG_TEXT_COMPRESSION_zTXt. + + num_text - number of comments (same as + num_comments; you can put NULL here + to avoid the duplication) + + Note while png_set_text() will accept text, language, + and translated keywords that can be NULL pointers, the + structure returned by png_get_text will always contain + regular zero-terminated C strings. They might be + empty strings but they will never be NULL pointers. + + num_spalettes = png_get_sPLT(png_ptr, info_ptr, + &palette_ptr); + + num_spalettes - number of sPLT chunks read. + + palette_ptr - array of palette structures holding + contents of one or more sPLT chunks + read. + + png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y, + &unit_type); + + offset_x - positive offset from the left edge + of the screen (can be negative) + + offset_y - positive offset from the top edge + of the screen (can be negative) + + unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER + + png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y, + &unit_type); + + res_x - pixels/unit physical resolution in + x direction + + res_y - pixels/unit physical resolution in + x direction + + unit_type - PNG_RESOLUTION_UNKNOWN, + PNG_RESOLUTION_METER + + png_get_sCAL(png_ptr, info_ptr, &unit, &width, + &height) + + unit - physical scale units (an integer) + + width - width of a pixel in physical scale units + + height - height of a pixel in physical scale units + (width and height are doubles) + + png_get_sCAL_s(png_ptr, info_ptr, &unit, &width, + &height) + + unit - physical scale units (an integer) + + width - width of a pixel in physical scale units + (expressed as a string) + + height - height of a pixel in physical scale units + (width and height are strings like "2.54") + + num_unknown_chunks = png_get_unknown_chunks(png_ptr, + info_ptr, &unknowns) + + unknowns - array of png_unknown_chunk + structures holding unknown chunks + + unknowns[i].name - name of unknown chunk + + unknowns[i].data - data of unknown chunk + + unknowns[i].size - size of unknown chunk's data + + unknowns[i].location - position of chunk in file + + The value of "i" corresponds to the order in which the + chunks were read from the PNG file or inserted with the + png_set_unknown_chunks() function. + + The value of "location" is a bitwise "or" of + + PNG_HAVE_IHDR (0x01) + PNG_HAVE_PLTE (0x02) + PNG_AFTER_IDAT (0x08) + +The data from the pHYs chunk can be retrieved in several convenient +forms: + + res_x = png_get_x_pixels_per_meter(png_ptr, + info_ptr) + + res_y = png_get_y_pixels_per_meter(png_ptr, + info_ptr) + + res_x_and_y = png_get_pixels_per_meter(png_ptr, + info_ptr) + + res_x = png_get_x_pixels_per_inch(png_ptr, + info_ptr) + + res_y = png_get_y_pixels_per_inch(png_ptr, + info_ptr) + + res_x_and_y = png_get_pixels_per_inch(png_ptr, + info_ptr) + + aspect_ratio = png_get_pixel_aspect_ratio(png_ptr, + info_ptr) + + Each of these returns 0 [signifying "unknown"] if + the data is not present or if res_x is 0; + res_x_and_y is 0 if res_x != res_y + + Note that because of the way the resolutions are + stored internally, the inch conversions won't + come out to exactly even number. For example, + 72 dpi is stored as 0.28346 pixels/meter, and + when this is retrieved it is 71.9988 dpi, so + be sure to round the returned value appropriately + if you want to display a reasonable-looking result. + +The data from the oFFs chunk can be retrieved in several convenient +forms: + + x_offset = png_get_x_offset_microns(png_ptr, info_ptr); + + y_offset = png_get_y_offset_microns(png_ptr, info_ptr); + + x_offset = png_get_x_offset_inches(png_ptr, info_ptr); + + y_offset = png_get_y_offset_inches(png_ptr, info_ptr); + + Each of these returns 0 [signifying "unknown" if both + x and y are 0] if the data is not present or if the + chunk is present but the unit is the pixel. The + remark about inexact inch conversions applies here + as well, because a value in inches can't always be + converted to microns and back without some loss + of precision. + +For more information, see the +PNG specification for chunk contents. Be careful with trusting +rowbytes, as some of the transformations could increase the space +needed to hold a row (expand, filler, gray_to_rgb, etc.). +See png_read_update_info(), below. + +A quick word about text_ptr and num_text. PNG stores comments in +keyword/text pairs, one pair per chunk, with no limit on the number +of text chunks, and a 2^31 byte limit on their size. While there are +suggested keywords, there is no requirement to restrict the use to these +strings. It is strongly suggested that keywords and text be sensible +to humans (that's the point), so don't use abbreviations. Non-printing +symbols are not allowed. See the PNG specification for more details. +There is also no requirement to have text after the keyword. + +Keywords should be limited to 79 Latin-1 characters without leading or +trailing spaces, but non-consecutive spaces are allowed within the +keyword. It is possible to have the same keyword any number of times. +The text_ptr is an array of png_text structures, each holding a +pointer to a language string, a pointer to a keyword and a pointer to +a text string. The text string, language code, and translated +keyword may be empty or NULL pointers. The keyword/text +pairs are put into the array in the order that they are received. +However, some or all of the text chunks may be after the image, so, to +make sure you have read all the text chunks, don't mess with these +until after you read the stuff after the image. This will be +mentioned again below in the discussion that goes with png_read_end(). + +Input transformations + +After you've read the header information, you can set up the library +to handle any special transformations of the image data. The various +ways to transform the data will be described in the order that they +should occur. This is important, as some of these change the color +type and/or bit depth of the data, and some others only work on +certain color types and bit depths. + +Transformations you request are ignored if they don't have any meaning for a +particular input data format. However some transformations can have an effect +as a result of a previous transformation. If you specify a contradictory set of +transformations, for example both adding and removing the alpha channel, you +cannot predict the final result. + +The color used for the transparency values should be supplied in the same +format/depth as the current image data. It is stored in the same format/depth +as the image data in a tRNS chunk, so this is what libpng expects for this data. + +The color used for the background value depends on the need_expand argument as +described below. + +Data will be decoded into the supplied row buffers packed into bytes +unless the library has been told to transform it into another format. +For example, 4 bit/pixel paletted or grayscale data will be returned +2 pixels/byte with the leftmost pixel in the high-order bits of the +byte, unless png_set_packing() is called. 8-bit RGB data will be stored +in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha() +is called to insert filler bytes, either before or after each RGB triplet. +16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant +byte of the color value first, unless png_set_scale_16() is called to +transform it to regular RGB RGB triplets, or png_set_filler() or +png_set_add alpha() is called to insert filler bytes, either before or +after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can +be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(), +or png_set_scale_16(). + +The following code transforms grayscale images of less than 8 to 8 bits, +changes paletted images to RGB, and adds a full alpha channel if there is +transparency information in a tRNS chunk. This is most useful on +grayscale images with bit depths of 2 or 4 or if there is a multiple-image +viewing application that wishes to treat all images in the same way. + + if (color_type == PNG_COLOR_TYPE_PALETTE) + png_set_palette_to_rgb(png_ptr); + + if (png_get_valid(png_ptr, info_ptr, + PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr); + + if (color_type == PNG_COLOR_TYPE_GRAY && + bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr); + +The first two functions are actually aliases for png_set_expand(), added +in libpng version 1.0.4, with the function names expanded to improve code +readability. In some future version they may actually do different +things. + +As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was +added. It expands the sample depth without changing tRNS to alpha. + +As of libpng version 1.5.2, png_set_expand_16() was added. It behaves as +png_set_expand(); however, the resultant channels have 16 bits rather than 8. +Use this when the output color or gray channels are made linear to avoid fairly +severe accuracy loss. + + if (bit_depth < 16) + png_set_expand_16(png_ptr); + +PNG can have files with 16 bits per channel. If you only can handle +8 bits per channel, this will strip the pixels down to 8-bit. + + if (bit_depth == 16) +#if PNG_LIBPNG_VER >= 10504 + png_set_scale_16(png_ptr); +#else + png_set_strip_16(png_ptr); +#endif + +(The more accurate "png_set_scale_16()" API became available in libpng version +1.5.4). + +If you need to process the alpha channel on the image separately from the image +data (for example if you convert it to a bitmap mask) it is possible to have +libpng strip the channel leaving just RGB or gray data: + + if (color_type & PNG_COLOR_MASK_ALPHA) + png_set_strip_alpha(png_ptr); + +If you strip the alpha channel you need to find some other way of dealing with +the information. If, instead, you want to convert the image to an opaque +version with no alpha channel use png_set_background; see below. + +As of libpng version 1.5.2, almost all useful expansions are supported, the +major ommissions are conversion of grayscale to indexed images (which can be +done trivially in the application) and conversion of indexed to grayscale (which +can be done by a trivial manipulation of the palette.) + +In the following table, the 01 means grayscale with depth<8, 31 means +indexed with depth<8, other numerals represent the color type, "T" means +the tRNS chunk is present, A means an alpha channel is present, and O +means tRNS or alpha is present but all pixels in the image are opaque. + + FROM 01 31 0 0T 0O 2 2T 2O 3 3T 3O 4A 4O 6A 6O + TO + 01 - [G] - - - - - - - - - - - - - + 31 [Q] Q [Q] [Q] [Q] Q Q Q Q Q Q [Q] [Q] Q Q + 0 1 G + . . G G G G G G B B GB GB + 0T lt Gt t + . Gt G G Gt G G Bt Bt GBt GBt + 0O lt Gt t . + Gt Gt G Gt Gt G Bt Bt GBt GBt + 2 C P C C C + . . C - - CB CB B B + 2T Ct - Ct C C t + t - - - CBt CBt Bt Bt + 2O Ct - Ct C C t t + - - - CBt CBt Bt Bt + 3 [Q] p [Q] [Q] [Q] Q Q Q + . . [Q] [Q] Q Q + 3T [Qt] p [Qt][Q] [Q] Qt Qt Qt t + t [Qt][Qt] Qt Qt + 3O [Qt] p [Qt][Q] [Q] Qt Qt Qt t t + [Qt][Qt] Qt Qt + 4A lA G A T T GA GT GT GA GT GT + BA G GBA + 4O lA GBA A T T GA GT GT GA GT GT BA + GBA G + 6A CA PA CA C C A T tT PA P P C CBA + BA + 6O CA PBA CA C C A tT T PA P P CBA C BA + + +Within the matrix, + "+" identifies entries where 'from' and 'to' are the same. + "-" means the transformation is not supported. + "." means nothing is necessary (a tRNS chunk can just be ignored). + "t" means the transformation is obtained by png_set_tRNS. + "A" means the transformation is obtained by png_set_add_alpha(). + "X" means the transformation is obtained by png_set_expand(). + "1" means the transformation is obtained by + png_set_expand_gray_1_2_4_to_8() (and by png_set_expand() + if there is no transparency in the original or the final + format). + "C" means the transformation is obtained by png_set_gray_to_rgb(). + "G" means the transformation is obtained by png_set_rgb_to_gray(). + "P" means the transformation is obtained by + png_set_expand_palette_to_rgb(). + "p" means the transformation is obtained by png_set_packing(). + "Q" means the transformation is obtained by png_set_quantize(). + "T" means the transformation is obtained by + png_set_tRNS_to_alpha(). + "B" means the transformation is obtained by + png_set_background(), or png_strip_alpha(). + +When an entry has multiple transforms listed all are required to cause the +right overall transformation. When two transforms are separated by a comma +either will do the job. When transforms are enclosed in [] the transform should +do the job but this is currently unimplemented - a different format will result +if the suggested transformations are used. + +In PNG files, the alpha channel in an image +is the level of opacity. If you need the alpha channel in an image to +be the level of transparency instead of opacity, you can invert the +alpha channel (or the tRNS chunk data) after it's read, so that 0 is +fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit +images) is fully transparent, with + + png_set_invert_alpha(png_ptr); + +PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as +they can, resulting in, for example, 8 pixels per byte for 1 bit +files. This code expands to 1 pixel per byte without changing the +values of the pixels: + + if (bit_depth < 8) + png_set_packing(png_ptr); + +PNG files have possible bit depths of 1, 2, 4, 8, and 16. All pixels +stored in a PNG image have been "scaled" or "shifted" up to the next +higher possible bit depth (e.g. from 5 bits/sample in the range [0,31] +to 8 bits/sample in the range [0, 255]). However, it is also possible +to convert the PNG pixel data back to the original bit depth of the +image. This call reduces the pixels back down to the original bit depth: + + png_color_8p sig_bit; + + if (png_get_sBIT(png_ptr, info_ptr, &sig_bit)) + png_set_shift(png_ptr, sig_bit); + +PNG files store 3-color pixels in red, green, blue order. This code +changes the storage of the pixels to blue, green, red: + + if (color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_RGB_ALPHA) + png_set_bgr(png_ptr); + +PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them +into 4 or 8 bytes for windowing systems that need them in this format: + + if (color_type == PNG_COLOR_TYPE_RGB) + png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE); + +where "filler" is the 8 or 16-bit number to fill with, and the location is +either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether +you want the filler before the RGB or after. This transformation +does not affect images that already have full alpha channels. To add an +opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which +will generate RGBA pixels. + +Note that png_set_filler() does not change the color type. If you want +to do that, you can add a true alpha channel with + + if (color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_GRAY) + png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER); + +where "filler" contains the alpha value to assign to each pixel. +This function was added in libpng-1.2.7. + +If you are reading an image with an alpha channel, and you need the +data as ARGB instead of the normal PNG format RGBA: + + if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) + png_set_swap_alpha(png_ptr); + +For some uses, you may want a grayscale image to be represented as +RGB. This code will do that conversion: + + if (color_type == PNG_COLOR_TYPE_GRAY || + color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + png_set_gray_to_rgb(png_ptr); + +Conversely, you can convert an RGB or RGBA image to grayscale or grayscale +with alpha. + + if (color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_RGB_ALPHA) + png_set_rgb_to_gray(png_ptr, error_action, + double red_weight, double green_weight); + + error_action = 1: silently do the conversion + + error_action = 2: issue a warning if the original + image has any pixel where + red != green or red != blue + + error_action = 3: issue an error and abort the + conversion if the original + image has any pixel where + red != green or red != blue + + red_weight: weight of red component + + green_weight: weight of green component + If either weight is negative, default + weights are used. + +In the corresponding fixed point API the red_weight and green_weight values are +simply scaled by 100,000: + + png_set_rgb_to_gray(png_ptr, error_action, + png_fixed_point red_weight, + png_fixed_point green_weight); + +If you have set error_action = 1 or 2, you can +later check whether the image really was gray, after processing +the image rows, with the png_get_rgb_to_gray_status(png_ptr) function. +It will return a png_byte that is zero if the image was gray or +1 if there were any non-gray pixels. Background and sBIT data +will be silently converted to grayscale, using the green channel +data for sBIT, regardless of the error_action setting. + +The default values come from the PNG file cHRM chunk if present; otherwise, the +defaults correspond to the ITU-R recommendation 709, and also the sRGB color +space, as recommended in the Charles Poynton's Colour FAQ, +<http://www.poynton.com/>, in section 9: + + <http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9> + + Y = 0.2126 * R + 0.7152 * G + 0.0722 * B + +Previous versions of this document, 1998 through 2002, recommended a slightly +different formula: + + Y = 0.212671 * R + 0.715160 * G + 0.072169 * B + +Libpng uses an integer approximation: + + Y = (6968 * R + 23434 * G + 2366 * B)/32768 + +The calculation is done in a linear colorspace, if the image gamma +can be determined. + +The png_set_background() function has been described already; it tells libpng to +composite images with alpha or simple transparency against the supplied +background color. For compatibility with versions of libpng earlier than +libpng-1.5.4 it is recommended that you call the function after reading the file +header, even if you don't want to use the color in a bKGD chunk, if one exists. + +If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid), +you may use this color, or supply another color more suitable for +the current display (e.g., the background color from a web page). You +need to tell libpng how the color is represented, both the format of the +component values in the color (the number of bits) and the gamma encoding of the +color. The function takes two arguments, background_gamma_mode and need_expand +to convey this information; however, only two combinations are likely to be +useful: + + png_color_16 my_background; + png_color_16p image_background; + + if (png_get_bKGD(png_ptr, info_ptr, &image_background)) + png_set_background(png_ptr, image_background, + PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1); + else + png_set_background(png_ptr, &my_background, + PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1); + +The second call was described above - my_background is in the format of the +final, display, output produced by libpng. Because you now know the format of +the PNG it is possible to avoid the need to choose either 8-bit or 16-bit +output and to retain palette images (the palette colors will be modified +appropriately and the tRNS chunk removed.) However, if you are doing this, +take great care not to ask for transformations without checking first that +they apply! + +In the first call the background color has the original bit depth and color type +of the PNG file. So, for palette images the color is supplied as a palette +index and for low bit greyscale images the color is a reduced bit value in +image_background->gray. + +If you didn't call png_set_gamma() before reading the file header, for example +if you need your code to remain compatible with older versions of libpng prior +to libpng-1.5.4, this is the place to call it. + +Do not call it if you called png_set_alpha_mode(); doing so will damage the +settings put in place by png_set_alpha_mode(). (If png_set_alpha_mode() is +supported then you can certainly do png_set_gamma() before reading the PNG +header.) + +This API unconditionally sets the screen and file gamma values, so it will +override the value in the PNG file unless it is called before the PNG file +reading starts. For this reason you must always call it with the PNG file +value when you call it in this position: + + if (png_get_gAMA(png_ptr, info_ptr, &file_gamma)) + png_set_gamma(png_ptr, screen_gamma, file_gamma); + + else + png_set_gamma(png_ptr, screen_gamma, 0.45455); + +If you need to reduce an RGB file to a paletted file, or if a paletted +file has more entries then will fit on your screen, png_set_quantize() +will do that. Note that this is a simple match quantization that merely +finds the closest color available. This should work fairly well with +optimized palettes, but fairly badly with linear color cubes. If you +pass a palette that is larger than maximum_colors, the file will +reduce the number of colors in the palette so it will fit into +maximum_colors. If there is a histogram, libpng will use it to make +more intelligent choices when reducing the palette. If there is no +histogram, it may not do as good a job. + + if (color_type & PNG_COLOR_MASK_COLOR) + { + if (png_get_valid(png_ptr, info_ptr, + PNG_INFO_PLTE)) + { + png_uint_16p histogram = NULL; + + png_get_hIST(png_ptr, info_ptr, + &histogram); + png_set_quantize(png_ptr, palette, num_palette, + max_screen_colors, histogram, 1); + } + + else + { + png_color std_color_cube[MAX_SCREEN_COLORS] = + { ... colors ... }; + + png_set_quantize(png_ptr, std_color_cube, + MAX_SCREEN_COLORS, MAX_SCREEN_COLORS, + NULL,0); + } + } + +PNG files describe monochrome as black being zero and white being one. +The following code will reverse this (make black be one and white be +zero): + + if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY) + png_set_invert_mono(png_ptr); + +This function can also be used to invert grayscale and gray-alpha images: + + if (color_type == PNG_COLOR_TYPE_GRAY || + color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + png_set_invert_mono(png_ptr); + +PNG files store 16-bit pixels in network byte order (big-endian, +ie. most significant bits first). This code changes the storage to the +other way (little-endian, i.e. least significant bits first, the +way PCs store them): + + if (bit_depth == 16) + png_set_swap(png_ptr); + +If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you +need to change the order the pixels are packed into bytes, you can use: + + if (bit_depth < 8) + png_set_packswap(png_ptr); + +Finally, you can write your own transformation function if none of +the existing ones meets your needs. This is done by setting a callback +with + + png_set_read_user_transform_fn(png_ptr, + read_transform_fn); + +You must supply the function + + void read_transform_fn(png_structp png_ptr, png_row_infop + row_info, png_bytep data) + +See pngtest.c for a working example. Your function will be called +after all of the other transformations have been processed. Take care with +interlaced images if you do the interlace yourself - the width of the row is the +width in 'row_info', not the overall image width. + +If supported, libpng provides two information routines that you can use to find +where you are in processing the image: + + png_get_current_pass_number(png_structp png_ptr); + png_get_current_row_number(png_structp png_ptr); + +Don't try using these outside a transform callback - firstly they are only +supported if user transforms are supported, secondly they may well return +unexpected results unless the row is actually being processed at the moment they +are called. + +With interlaced +images the value returned is the row in the input sub-image image. Use +PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to +find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass). + +The discussion of interlace handling above contains more information on how to +use these values. + +You can also set up a pointer to a user structure for use by your +callback function, and you can inform libpng that your transform +function will change the number of channels or bit depth with the +function + + png_set_user_transform_info(png_ptr, user_ptr, + user_depth, user_channels); + +The user's application, not libpng, is responsible for allocating and +freeing any memory required for the user structure. + +You can retrieve the pointer via the function +png_get_user_transform_ptr(). For example: + + voidp read_user_transform_ptr = + png_get_user_transform_ptr(png_ptr); + +The last thing to handle is interlacing; this is covered in detail below, +but you must call the function here if you want libpng to handle expansion +of the interlaced image. + + number_of_passes = png_set_interlace_handling(png_ptr); + +After setting the transformations, libpng can update your png_info +structure to reflect any transformations you've requested with this +call. + + png_read_update_info(png_ptr, info_ptr); + +This is most useful to update the info structure's rowbytes +field so you can use it to allocate your image memory. This function +will also update your palette with the correct screen_gamma and +background if these have been given with the calls above. You may +only call png_read_update_info() once with a particular info_ptr. + +After you call png_read_update_info(), you can allocate any +memory you need to hold the image. The row data is simply +raw byte data for all forms of images. As the actual allocation +varies among applications, no example will be given. If you +are allocating one large chunk, you will need to build an +array of pointers to each row, as it will be needed for some +of the functions below. + +Remember: Before you call png_read_update_info(), the png_get_*() +functions return the values corresponding to the original PNG image. +After you call png_read_update_info the values refer to the image +that libpng will output. Consequently you must call all the png_set_ +functions before you call png_read_update_info(). This is particularly +important for png_set_interlace_handling() - if you are going to call +png_read_update_info() you must call png_set_interlace_handling() before +it unless you want to receive interlaced output. + +Reading image data + +After you've allocated memory, you can read the image data. +The simplest way to do this is in one function call. If you are +allocating enough memory to hold the whole image, you can just +call png_read_image() and libpng will read in all the image data +and put it in the memory area supplied. You will need to pass in +an array of pointers to each row. + +This function automatically handles interlacing, so you don't +need to call png_set_interlace_handling() (unless you call +png_read_update_info()) or call this function multiple times, or any +of that other stuff necessary with png_read_rows(). + + png_read_image(png_ptr, row_pointers); + +where row_pointers is: + + png_bytep row_pointers[height]; + +You can point to void or char or whatever you use for pixels. + +If you don't want to read in the whole image at once, you can +use png_read_rows() instead. If there is no interlacing (check +interlace_type == PNG_INTERLACE_NONE), this is simple: + + png_read_rows(png_ptr, row_pointers, NULL, + number_of_rows); + +where row_pointers is the same as in the png_read_image() call. + +If you are doing this just one row at a time, you can do this with +a single row_pointer instead of an array of row_pointers: + + png_bytep row_pointer = row; + png_read_row(png_ptr, row_pointer, NULL); + +If the file is interlaced (interlace_type != 0 in the IHDR chunk), things +get somewhat harder. The only current (PNG Specification version 1.2) +interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7); +a somewhat complicated 2D interlace scheme, known as Adam7, that +breaks down an image into seven smaller images of varying size, based +on an 8x8 grid. This number is defined (from libpng 1.5) as +PNG_INTERLACE_ADAM7_PASSES in png.h + +libpng can fill out those images or it can give them to you "as is". +It is almost always better to have libpng handle the interlacing for you. +If you want the images filled out, there are two ways to do that. The one +mentioned in the PNG specification is to expand each pixel to cover +those pixels that have not been read yet (the "rectangle" method). +This results in a blocky image for the first pass, which gradually +smooths out as more pixels are read. The other method is the "sparkle" +method, where pixels are drawn only in their final locations, with the +rest of the image remaining whatever colors they were initialized to +before the start of the read. The first method usually looks better, +but tends to be slower, as there are more pixels to put in the rows. + +If, as is likely, you want libpng to expand the images, call this before +calling png_start_read_image() or png_read_update_info(): + + if (interlace_type == PNG_INTERLACE_ADAM7) + number_of_passes + = png_set_interlace_handling(png_ptr); + +This will return the number of passes needed. Currently, this is seven, +but may change if another interlace type is added. This function can be +called even if the file is not interlaced, where it will return one pass. +You then need to read the whole image 'number_of_passes' times. Each time +will distribute the pixels from the current pass to the correct place in +the output image, so you need to supply the same rows to png_read_rows in +each pass. + +If you are not going to display the image after each pass, but are +going to wait until the entire image is read in, use the sparkle +effect. This effect is faster and the end result of either method +is exactly the same. If you are planning on displaying the image +after each pass, the "rectangle" effect is generally considered the +better looking one. + +If you only want the "sparkle" effect, just call png_read_rows() as +normal, with the third parameter NULL. Make sure you make pass over +the image number_of_passes times, and you don't change the data in the +rows between calls. You can change the locations of the data, just +not the data. Each pass only writes the pixels appropriate for that +pass, and assumes the data from previous passes is still valid. + + png_read_rows(png_ptr, row_pointers, NULL, + number_of_rows); + +If you only want the first effect (the rectangles), do the same as +before except pass the row buffer in the third parameter, and leave +the second parameter NULL. + + png_read_rows(png_ptr, NULL, row_pointers, + number_of_rows); + +If you don't want libpng to handle the interlacing details, just call +png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images. +Each of the images is a valid image by itself; however, you will almost +certainly need to distribute the pixels from each sub-image to the +correct place. This is where everything gets very tricky. + +If you want to retrieve the separate images you must pass the correct +number of rows to each successive call of png_read_rows(). The calculation +gets pretty complicated for small images, where some sub-images may +not even exist because either their width or height ends up zero. +libpng provides two macros to help you in 1.5 and later versions: + + png_uint_32 width = PNG_PASS_COLS(image_width, pass_number); + png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number); + +Respectively these tell you the width and height of the sub-image +corresponding to the numbered pass. 'pass' is in in the range 0 to 6 - +this can be confusing because the specification refers to the same passes +as 1 to 7! Be careful, you must check both the width and height before +calling png_read_rows() and not call it for that pass if either is zero. + +You can, of course, read each sub-image row by row. If you want to +produce optimal code to make a pixel-by-pixel transformation of an +interlaced image this is the best approach; read each row of each pass, +transform it, and write it out to a new interlaced image. + +If you want to de-interlace the image yourself libpng provides further +macros to help that tell you where to place the pixels in the output image. +Because the interlacing scheme is rectangular - sub-image pixels are always +arranged on a rectangular grid - all you need to know for each pass is the +starting column and row in the output image of the first pixel plus the +spacing between each pixel. As of libpng 1.5 there are four macros to +retrieve this information: + + png_uint_32 x = PNG_PASS_START_COL(pass); + png_uint_32 y = PNG_PASS_START_ROW(pass); + png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass); + png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass); + +These allow you to write the obvious loop: + + png_uint_32 input_y = 0; + png_uint_32 output_y = PNG_PASS_START_ROW(pass); + + while (output_y < output_image_height) + { + png_uint_32 input_x = 0; + png_uint_32 output_x = PNG_PASS_START_COL(pass); + + while (output_x < output_image_width) + { + image[output_y][output_x] = + subimage[pass][input_y][input_x++]; + + output_x += xStep; + } + + ++input_y; + output_y += yStep; + } + +Notice that the steps between successive output rows and columns are +returned as shifts. This is possible because the pixels in the subimages +are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original +image. In practice you may need to directly calculate the output coordinate +given an input coordinate. libpng provides two further macros for this +purpose: + + png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass); + png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass); + +Finally a pair of macros are provided to tell you if a particular image +row or column appears in a given pass: + + int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass); + int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass); + +Bear in mind that you will probably also need to check the width and height +of the pass in addition to the above to be sure the pass even exists! + +With any luck you are convinced by now that you don't want to do your own +interlace handling. In reality normally the only good reason for doing this +is if you are processing PNG files on a pixel-by-pixel basis and don't want +to load the whole file into memory when it is interlaced. + +libpng includes a test program, pngvalid, that illustrates reading and +writing of interlaced images. If you can't get interlacing to work in your +code and don't want to leave it to libpng (the recommended approach), see +how pngvalid.c does it. + +Finishing a sequential read + +After you are finished reading the image through the +low-level interface, you can finish reading the file. + +If you want to use a different crc action for handling CRC errors in +chunks after the image data, you can call png_set_crc_action() +again at this point. + +If you are interested in comments or time, which may be stored either +before or after the image data, you should pass the separate png_info +struct if you want to keep the comments from before and after the image +separate. + + png_infop end_info = png_create_info_struct(png_ptr); + + if (!end_info) + { + png_destroy_read_struct(&png_ptr, &info_ptr, + (png_infopp)NULL); + return (ERROR); + } + + png_read_end(png_ptr, end_info); + +If you are not interested, you should still call png_read_end() +but you can pass NULL, avoiding the need to create an end_info structure. +If you do this, libpng will not process any chunks after IDAT other than +skipping over them and perhaps (depending on whether you have called +png_set_crc_action) checking their CRCs while looking for the IEND chunk. + + png_read_end(png_ptr, (png_infop)NULL); + +If you don't call png_read_end(), then your file pointer will be +left pointing to the first chunk after the last IDAT, which is probably +not what you want if you expect to read something beyond the end of +the PNG datastream. + +When you are done, you can free all memory allocated by libpng like this: + + png_destroy_read_struct(&png_ptr, &info_ptr, + &end_info); + +or, if you didn't create an end_info structure, + + png_destroy_read_struct(&png_ptr, &info_ptr, + (png_infopp)NULL); + +It is also possible to individually free the info_ptr members that +point to libpng-allocated storage with the following function: + + png_free_data(png_ptr, info_ptr, mask, seq) + + mask - identifies data to be freed, a mask + containing the bitwise OR of one or + more of + PNG_FREE_PLTE, PNG_FREE_TRNS, + PNG_FREE_HIST, PNG_FREE_ICCP, + PNG_FREE_PCAL, PNG_FREE_ROWS, + PNG_FREE_SCAL, PNG_FREE_SPLT, + PNG_FREE_TEXT, PNG_FREE_UNKN, + or simply PNG_FREE_ALL + + seq - sequence number of item to be freed + (-1 for all items) + +This function may be safely called when the relevant storage has +already been freed, or has not yet been allocated, or was allocated +by the user and not by libpng, and will in those cases do nothing. +The "seq" parameter is ignored if only one item of the selected data +type, such as PLTE, is allowed. If "seq" is not -1, and multiple items +are allowed for the data type identified in the mask, such as text or +sPLT, only the n'th item in the structure is freed, where n is "seq". + +The default behavior is only to free data that was allocated internally +by libpng. This can be changed, so that libpng will not free the data, +or so that it will free data that was allocated by the user with png_malloc() +or png_calloc() and passed in via a png_set_*() function, with + + png_data_freer(png_ptr, info_ptr, freer, mask) + + freer - one of + PNG_DESTROY_WILL_FREE_DATA + PNG_SET_WILL_FREE_DATA + PNG_USER_WILL_FREE_DATA + + mask - which data elements are affected + same choices as in png_free_data() + +This function only affects data that has already been allocated. +You can call this function after reading the PNG data but before calling +any png_set_*() functions, to control whether the user or the png_set_*() +function is responsible for freeing any existing data that might be present, +and again after the png_set_*() functions to control whether the user +or png_destroy_*() is supposed to free the data. When the user assumes +responsibility for libpng-allocated data, the application must use +png_free() to free it, and when the user transfers responsibility to libpng +for data that the user has allocated, the user must have used png_malloc() +or png_calloc() to allocate it. + +If you allocated your row_pointers in a single block, as suggested above in +the description of the high level read interface, you must not transfer +responsibility for freeing it to the png_set_rows or png_read_destroy function, +because they would also try to free the individual row_pointers[i]. + +If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword +separately, do not transfer responsibility for freeing text_ptr to libpng, +because when libpng fills a png_text structure it combines these members with +the key member, and png_free_data() will free only text_ptr.key. Similarly, +if you transfer responsibility for free'ing text_ptr from libpng to your +application, your application must not separately free those members. + +The png_free_data() function will turn off the "valid" flag for anything +it frees. If you need to turn the flag off for a chunk that was freed by +your application instead of by libpng, you can use + + png_set_invalid(png_ptr, info_ptr, mask); + + mask - identifies the chunks to be made invalid, + containing the bitwise OR of one or + more of + PNG_INFO_gAMA, PNG_INFO_sBIT, + PNG_INFO_cHRM, PNG_INFO_PLTE, + PNG_INFO_tRNS, PNG_INFO_bKGD, + PNG_INFO_hIST, PNG_INFO_pHYs, + PNG_INFO_oFFs, PNG_INFO_tIME, + PNG_INFO_pCAL, PNG_INFO_sRGB, + PNG_INFO_iCCP, PNG_INFO_sPLT, + PNG_INFO_sCAL, PNG_INFO_IDAT + +For a more compact example of reading a PNG image, see the file example.c. + +Reading PNG files progressively + +The progressive reader is slightly different from the non-progressive +reader. Instead of calling png_read_info(), png_read_rows(), and +png_read_end(), you make one call to png_process_data(), which calls +callbacks when it has the info, a row, or the end of the image. You +set up these callbacks with png_set_progressive_read_fn(). You don't +have to worry about the input/output functions of libpng, as you are +giving the library the data directly in png_process_data(). I will +assume that you have read the section on reading PNG files above, +so I will only highlight the differences (although I will show +all of the code). + +png_structp png_ptr; +png_infop info_ptr; + + /* An example code fragment of how you would + initialize the progressive reader in your + application. */ + int + initialize_png_reader() + { + png_ptr = png_create_read_struct + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn); + + if (!png_ptr) + return (ERROR); + + info_ptr = png_create_info_struct(png_ptr); + + if (!info_ptr) + { + png_destroy_read_struct(&png_ptr, + (png_infopp)NULL, (png_infopp)NULL); + return (ERROR); + } + + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_read_struct(&png_ptr, &info_ptr, + (png_infopp)NULL); + return (ERROR); + } + + /* This one's new. You can provide functions + to be called when the header info is valid, + when each row is completed, and when the image + is finished. If you aren't using all functions, + you can specify NULL parameters. Even when all + three functions are NULL, you need to call + png_set_progressive_read_fn(). You can use + any struct as the user_ptr (cast to a void pointer + for the function call), and retrieve the pointer + from inside the callbacks using the function + + png_get_progressive_ptr(png_ptr); + + which will return a void pointer, which you have + to cast appropriately. + */ + png_set_progressive_read_fn(png_ptr, (void *)user_ptr, + info_callback, row_callback, end_callback); + + return 0; + } + + /* A code fragment that you call as you receive blocks + of data */ + int + process_data(png_bytep buffer, png_uint_32 length) + { + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_read_struct(&png_ptr, &info_ptr, + (png_infopp)NULL); + return (ERROR); + } + + /* This one's new also. Simply give it a chunk + of data from the file stream (in order, of + course). On machines with segmented memory + models machines, don't give it any more than + 64K. The library seems to run fine with sizes + of 4K. Although you can give it much less if + necessary (I assume you can give it chunks of + 1 byte, I haven't tried less then 256 bytes + yet). When this function returns, you may + want to display any rows that were generated + in the row callback if you don't already do + so there. + */ + png_process_data(png_ptr, info_ptr, buffer, length); + + /* At this point you can call png_process_data_skip if + you want to handle data the library will skip yourself; + it simply returns the number of bytes to skip (and stops + libpng skipping that number of bytes on the next + png_process_data call). + return 0; + } + + /* This function is called (as set by + png_set_progressive_read_fn() above) when enough data + has been supplied so all of the header has been + read. + */ + void + info_callback(png_structp png_ptr, png_infop info) + { + /* Do any setup here, including setting any of + the transformations mentioned in the Reading + PNG files section. For now, you _must_ call + either png_start_read_image() or + png_read_update_info() after all the + transformations are set (even if you don't set + any). You may start getting rows before + png_process_data() returns, so this is your + last chance to prepare for that. + + This is where you turn on interlace handling, + assuming you don't want to do it yourself. + + If you need to you can stop the processing of + your original input data at this point by calling + png_process_data_pause. This returns the number + of unprocessed bytes from the last png_process_data + call - it is up to you to ensure that the next call + sees these bytes again. If you don't want to bother + with this you can get libpng to cache the unread + bytes by setting the 'save' parameter (see png.h) but + then libpng will have to copy the data internally. + */ + } + + /* This function is called when each row of image + data is complete */ + void + row_callback(png_structp png_ptr, png_bytep new_row, + png_uint_32 row_num, int pass) + { + /* If the image is interlaced, and you turned + on the interlace handler, this function will + be called for every row in every pass. Some + of these rows will not be changed from the + previous pass. When the row is not changed, + the new_row variable will be NULL. The rows + and passes are called in order, so you don't + really need the row_num and pass, but I'm + supplying them because it may make your life + easier. + + If you did not turn on interlace handling then + the callback is called for each row of each + sub-image when the image is interlaced. In this + case 'row_num' is the row in the sub-image, not + the row in the output image as it is in all other + cases. + + For the non-NULL rows of interlaced images when + you have switched on libpng interlace handling, + you must call png_progressive_combine_row() + passing in the row and the old row. You can + call this function for NULL rows (it will just + return) and for non-interlaced images (it just + does the memcpy for you) if it will make the + code easier. Thus, you can just do this for + all cases if you switch on interlace handling; + */ + + png_progressive_combine_row(png_ptr, old_row, + new_row); + + /* where old_row is what was displayed + previously for the row. Note that the first + pass (pass == 0, really) will completely cover + the old row, so the rows do not have to be + initialized. After the first pass (and only + for interlaced images), you will have to pass + the current row, and the function will combine + the old row and the new row. + + You can also call png_process_data_pause in this + callback - see above. + */ + } + + void + end_callback(png_structp png_ptr, png_infop info) + { + /* This function is called after the whole image + has been read, including any chunks after the + image (up to and including the IEND). You + will usually have the same info chunk as you + had in the header, although some data may have + been added to the comments and time fields. + + Most people won't do much here, perhaps setting + a flag that marks the image as finished. + */ + } + + + +IV. Writing + +Much of this is very similar to reading. However, everything of +importance is repeated here, so you won't have to constantly look +back up in the reading section to understand writing. + +Setup + +You will want to do the I/O initialization before you get into libpng, +so if it doesn't work, you don't have anything to undo. If you are not +using the standard I/O functions, you will need to replace them with +custom writing functions. See the discussion under Customizing libpng. + + FILE *fp = fopen(file_name, "wb"); + + if (!fp) + return (ERROR); + +Next, png_struct and png_info need to be allocated and initialized. +As these can be both relatively large, you may not want to store these +on the stack, unless you have stack space to spare. Of course, you +will want to check if they return NULL. If you are also reading, +you won't want to name your read structure and your write structure +both "png_ptr"; you can call them anything you like, such as +"read_ptr" and "write_ptr". Look at pngtest.c, for example. + + png_structp png_ptr = png_create_write_struct + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn); + + if (!png_ptr) + return (ERROR); + + png_infop info_ptr = png_create_info_struct(png_ptr); + if (!info_ptr) + { + png_destroy_write_struct(&png_ptr, + (png_infopp)NULL); + return (ERROR); + } + +If you want to use your own memory allocation routines, +define PNG_USER_MEM_SUPPORTED and use +png_create_write_struct_2() instead of png_create_write_struct(): + + png_structp png_ptr = png_create_write_struct_2 + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn, (png_voidp) + user_mem_ptr, user_malloc_fn, user_free_fn); + +After you have these structures, you will need to set up the +error handling. When libpng encounters an error, it expects to +longjmp() back to your routine. Therefore, you will need to call +setjmp() and pass the png_jmpbuf(png_ptr). If you +write the file from different routines, you will need to update +the png_jmpbuf(png_ptr) every time you enter a new routine that will +call a png_*() function. See your documentation of setjmp/longjmp +for your compiler for more information on setjmp/longjmp. See +the discussion on libpng error handling in the Customizing Libpng +section below for more information on the libpng error handling. + + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_write_struct(&png_ptr, &info_ptr); + fclose(fp); + return (ERROR); + } + ... + return; + +If you would rather avoid the complexity of setjmp/longjmp issues, +you can compile libpng with PNG_NO_SETJMP, in which case +errors will result in a call to PNG_ABORT() which defaults to abort(). + +You can #define PNG_ABORT() to a function that does something +more useful than abort(), as long as your function does not +return. + +Checking for invalid palette index on write was added at libpng +1.5.10. If a pixel contains an invalid (out-of-range) index libpng issues +a benign error. This is enabled by default because this condition is an +error according to the PNG specification, Clause 11.3.2, but the error can +be ignored in each png_ptr with + + png_set_check_for_invalid_index(png_ptr, 0); + +If the error is ignored, or if png_benign_error() treats it as a warning, +any invalid pixels are written as-is by the encoder, resulting in an +invalid PNG datastream as output. In this case the application is +responsible for ensuring that the pixel indexes are in range when it writes +a PLTE chunk with fewer entries than the bit depth would allow. + +Now you need to set up the output code. The default for libpng is to +use the C function fwrite(). If you use this, you will need to pass a +valid FILE * in the function png_init_io(). Be sure that the file is +opened in binary mode. Again, if you wish to handle writing data in +another way, see the discussion on libpng I/O handling in the Customizing +Libpng section below. + + png_init_io(png_ptr, fp); + +If you are embedding your PNG into a datastream such as MNG, and don't +want libpng to write the 8-byte signature, or if you have already +written the signature in your application, use + + png_set_sig_bytes(png_ptr, 8); + +to inform libpng that it should not write a signature. + +Write callbacks + +At this point, you can set up a callback function that will be +called after each row has been written, which you can use to control +a progress meter or the like. It's demonstrated in pngtest.c. +You must supply a function + + void write_row_callback(png_structp png_ptr, png_uint_32 row, + int pass); + { + /* put your code here */ + } + +(You can give it another name that you like instead of "write_row_callback") + +To inform libpng about your function, use + + png_set_write_status_fn(png_ptr, write_row_callback); + +When this function is called the row has already been completely processed and +it has also been written out. The 'row' and 'pass' refer to the next row to be +handled. For the +non-interlaced case the row that was just handled is simply one less than the +passed in row number, and pass will always be 0. For the interlaced case the +same applies unless the row value is 0, in which case the row just handled was +the last one from one of the preceding passes. Because interlacing may skip a +pass you cannot be sure that the preceding pass is just 'pass-1', if you really +need to know what the last pass is record (row,pass) from the callback and use +the last recorded value each time. + +As with the user transform you can find the output row using the +PNG_ROW_FROM_PASS_ROW macro. + +You now have the option of modifying how the compression library will +run. The following functions are mainly for testing, but may be useful +in some cases, like if you need to write PNG files extremely fast and +are willing to give up some compression, or if you want to get the +maximum possible compression at the expense of slower writing. If you +have no special needs in this area, let the library do what it wants by +not calling this function at all, as it has been tuned to deliver a good +speed/compression ratio. The second parameter to png_set_filter() is +the filter method, for which the only valid values are 0 (as of the +July 1999 PNG specification, version 1.2) or 64 (if you are writing +a PNG datastream that is to be embedded in a MNG datastream). The third +parameter is a flag that indicates which filter type(s) are to be tested +for each scanline. See the PNG specification for details on the specific +filter types. + + + /* turn on or off filtering, and/or choose + specific filters. You can use either a single + PNG_FILTER_VALUE_NAME or the bitwise OR of one + or more PNG_FILTER_NAME masks. + */ + png_set_filter(png_ptr, 0, + PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE | + PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB | + PNG_FILTER_UP | PNG_FILTER_VALUE_UP | + PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG | + PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH| + PNG_ALL_FILTERS); + +If an application wants to start and stop using particular filters during +compression, it should start out with all of the filters (to ensure that +the previous row of pixels will be stored in case it's needed later), +and then add and remove them after the start of compression. + +If you are writing a PNG datastream that is to be embedded in a MNG +datastream, the second parameter can be either 0 or 64. + +The png_set_compression_*() functions interface to the zlib compression +library, and should mostly be ignored unless you really know what you are +doing. The only generally useful call is png_set_compression_level() +which changes how much time zlib spends on trying to compress the image +data. See the Compression Library (zlib.h and algorithm.txt, distributed +with zlib) for details on the compression levels. + + #include zlib.h + + /* Set the zlib compression level */ + png_set_compression_level(png_ptr, + Z_BEST_COMPRESSION); + + /* Set other zlib parameters for compressing IDAT */ + png_set_compression_mem_level(png_ptr, 8); + png_set_compression_strategy(png_ptr, + Z_DEFAULT_STRATEGY); + png_set_compression_window_bits(png_ptr, 15); + png_set_compression_method(png_ptr, 8); + png_set_compression_buffer_size(png_ptr, 8192) + + /* Set zlib parameters for text compression + * If you don't call these, the parameters + * fall back on those defined for IDAT chunks + */ + png_set_text_compression_mem_level(png_ptr, 8); + png_set_text_compression_strategy(png_ptr, + Z_DEFAULT_STRATEGY); + png_set_text_compression_window_bits(png_ptr, 15); + png_set_text_compression_method(png_ptr, 8); + +Setting the contents of info for output + +You now need to fill in the png_info structure with all the data you +wish to write before the actual image. Note that the only thing you +are allowed to write after the image is the text chunks and the time +chunk (as of PNG Specification 1.2, anyway). See png_write_end() and +the latest PNG specification for more information on that. If you +wish to write them before the image, fill them in now, and flag that +data as being valid. If you want to wait until after the data, don't +fill them until png_write_end(). For all the fields in png_info and +their data types, see png.h. For explanations of what the fields +contain, see the PNG specification. + +Some of the more important parts of the png_info are: + + png_set_IHDR(png_ptr, info_ptr, width, height, + bit_depth, color_type, interlace_type, + compression_type, filter_method) + + width - holds the width of the image + in pixels (up to 2^31). + + height - holds the height of the image + in pixels (up to 2^31). + + bit_depth - holds the bit depth of one of the + image channels. + (valid values are 1, 2, 4, 8, 16 + and depend also on the + color_type. See also significant + bits (sBIT) below). + + color_type - describes which color/alpha + channels are present. + PNG_COLOR_TYPE_GRAY + (bit depths 1, 2, 4, 8, 16) + PNG_COLOR_TYPE_GRAY_ALPHA + (bit depths 8, 16) + PNG_COLOR_TYPE_PALETTE + (bit depths 1, 2, 4, 8) + PNG_COLOR_TYPE_RGB + (bit_depths 8, 16) + PNG_COLOR_TYPE_RGB_ALPHA + (bit_depths 8, 16) + + PNG_COLOR_MASK_PALETTE + PNG_COLOR_MASK_COLOR + PNG_COLOR_MASK_ALPHA + + interlace_type - PNG_INTERLACE_NONE or + PNG_INTERLACE_ADAM7 + + compression_type - (must be + PNG_COMPRESSION_TYPE_DEFAULT) + + filter_method - (must be PNG_FILTER_TYPE_DEFAULT + or, if you are writing a PNG to + be embedded in a MNG datastream, + can also be + PNG_INTRAPIXEL_DIFFERENCING) + +If you call png_set_IHDR(), the call must appear before any of the +other png_set_*() functions, because they might require access to some of +the IHDR settings. The remaining png_set_*() functions can be called +in any order. + +If you wish, you can reset the compression_type, interlace_type, or +filter_method later by calling png_set_IHDR() again; if you do this, the +width, height, bit_depth, and color_type must be the same in each call. + + png_set_PLTE(png_ptr, info_ptr, palette, + num_palette); + + palette - the palette for the file + (array of png_color) + num_palette - number of entries in the palette + + png_set_gAMA(png_ptr, info_ptr, file_gamma); + png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma); + + file_gamma - the gamma at which the image was + created (PNG_INFO_gAMA) + + int_file_gamma - 100,000 times the gamma at which + the image was created + + png_set_cHRM(png_ptr, info_ptr, white_x, white_y, red_x, red_y, + green_x, green_y, blue_x, blue_y) + png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X, + green_Y, green_Z, blue_X, blue_Y, blue_Z) + png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y, + int_red_x, int_red_y, int_green_x, int_green_y, + int_blue_x, int_blue_y) + png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y, + int_red_Z, int_green_X, int_green_Y, int_green_Z, + int_blue_X, int_blue_Y, int_blue_Z) + + {white,red,green,blue}_{x,y} + A color space encoding specified using the chromaticities + of the end points and the white point. + + {red,green,blue}_{X,Y,Z} + A color space encoding specified using the encoding end + points - the CIE tristimulus specification of the intended + color of the red, green and blue channels in the PNG RGB + data. The white point is simply the sum of the three end + points. + + png_set_sRGB(png_ptr, info_ptr, srgb_intent); + + srgb_intent - the rendering intent + (PNG_INFO_sRGB) The presence of + the sRGB chunk means that the pixel + data is in the sRGB color space. + This chunk also implies specific + values of gAMA and cHRM. Rendering + intent is the CSS-1 property that + has been defined by the International + Color Consortium + (http://www.color.org). + It can be one of + PNG_sRGB_INTENT_SATURATION, + PNG_sRGB_INTENT_PERCEPTUAL, + PNG_sRGB_INTENT_ABSOLUTE, or + PNG_sRGB_INTENT_RELATIVE. + + + png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, + srgb_intent); + + srgb_intent - the rendering intent + (PNG_INFO_sRGB) The presence of the + sRGB chunk means that the pixel + data is in the sRGB color space. + This function also causes gAMA and + cHRM chunks with the specific values + that are consistent with sRGB to be + written. + + png_set_iCCP(png_ptr, info_ptr, name, compression_type, + profile, proflen); + + name - The profile name. + + compression_type - The compression type; always + PNG_COMPRESSION_TYPE_BASE for PNG 1.0. + You may give NULL to this argument to + ignore it. + + profile - International Color Consortium color + profile data. May contain NULs. + + proflen - length of profile data in bytes. + + png_set_sBIT(png_ptr, info_ptr, sig_bit); + + sig_bit - the number of significant bits for + (PNG_INFO_sBIT) each of the gray, red, + green, and blue channels, whichever are + appropriate for the given color type + (png_color_16) + + png_set_tRNS(png_ptr, info_ptr, trans_alpha, + num_trans, trans_color); + + trans_alpha - array of alpha (transparency) + entries for palette (PNG_INFO_tRNS) + + num_trans - number of transparent entries + (PNG_INFO_tRNS) + + trans_color - graylevel or color sample values + (in order red, green, blue) of the + single transparent color for + non-paletted images (PNG_INFO_tRNS) + + png_set_hIST(png_ptr, info_ptr, hist); + + hist - histogram of palette (array of + png_uint_16) (PNG_INFO_hIST) + + png_set_tIME(png_ptr, info_ptr, mod_time); + + mod_time - time image was last modified + (PNG_VALID_tIME) + + png_set_bKGD(png_ptr, info_ptr, background); + + background - background color (of type + png_color_16p) (PNG_VALID_bKGD) + + png_set_text(png_ptr, info_ptr, text_ptr, num_text); + + text_ptr - array of png_text holding image + comments + + text_ptr[i].compression - type of compression used + on "text" PNG_TEXT_COMPRESSION_NONE + PNG_TEXT_COMPRESSION_zTXt + PNG_ITXT_COMPRESSION_NONE + PNG_ITXT_COMPRESSION_zTXt + text_ptr[i].key - keyword for comment. Must contain + 1-79 characters. + text_ptr[i].text - text comments for current + keyword. Can be NULL or empty. + text_ptr[i].text_length - length of text string, + after decompression, 0 for iTXt + text_ptr[i].itxt_length - length of itxt string, + after decompression, 0 for tEXt/zTXt + text_ptr[i].lang - language of comment (NULL or + empty for unknown). + text_ptr[i].translated_keyword - keyword in UTF-8 (NULL + or empty for unknown). + + Note that the itxt_length, lang, and lang_key + members of the text_ptr structure only exist when the + library is built with iTXt chunk support. Prior to + libpng-1.4.0 the library was built by default without + iTXt support. Also note that when iTXt is supported, + they contain NULL pointers when the "compression" + field contains PNG_TEXT_COMPRESSION_NONE or + PNG_TEXT_COMPRESSION_zTXt. + + num_text - number of comments + + png_set_sPLT(png_ptr, info_ptr, &palette_ptr, + num_spalettes); + + palette_ptr - array of png_sPLT_struct structures + to be added to the list of palettes + in the info structure. + num_spalettes - number of palette structures to be + added. + + png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, + unit_type); + + offset_x - positive offset from the left + edge of the screen + + offset_y - positive offset from the top + edge of the screen + + unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER + + png_set_pHYs(png_ptr, info_ptr, res_x, res_y, + unit_type); + + res_x - pixels/unit physical resolution + in x direction + + res_y - pixels/unit physical resolution + in y direction + + unit_type - PNG_RESOLUTION_UNKNOWN, + PNG_RESOLUTION_METER + + png_set_sCAL(png_ptr, info_ptr, unit, width, height) + + unit - physical scale units (an integer) + + width - width of a pixel in physical scale units + + height - height of a pixel in physical scale units + (width and height are doubles) + + png_set_sCAL_s(png_ptr, info_ptr, unit, width, height) + + unit - physical scale units (an integer) + + width - width of a pixel in physical scale units + expressed as a string + + height - height of a pixel in physical scale units + (width and height are strings like "2.54") + + png_set_unknown_chunks(png_ptr, info_ptr, &unknowns, + num_unknowns) + + unknowns - array of png_unknown_chunk + structures holding unknown chunks + unknowns[i].name - name of unknown chunk + unknowns[i].data - data of unknown chunk + unknowns[i].size - size of unknown chunk's data + unknowns[i].location - position to write chunk in file + 0: do not write chunk + PNG_HAVE_IHDR: before PLTE + PNG_HAVE_PLTE: before IDAT + PNG_AFTER_IDAT: after IDAT + +The "location" member is set automatically according to +what part of the output file has already been written. +You can change its value after calling png_set_unknown_chunks() +as demonstrated in pngtest.c. Within each of the "locations", +the chunks are sequenced according to their position in the +structure (that is, the value of "i", which is the order in which +the chunk was either read from the input file or defined with +png_set_unknown_chunks). + +A quick word about text and num_text. text is an array of png_text +structures. num_text is the number of valid structures in the array. +Each png_text structure holds a language code, a keyword, a text value, +and a compression type. + +The compression types have the same valid numbers as the compression +types of the image data. Currently, the only valid number is zero. +However, you can store text either compressed or uncompressed, unlike +images, which always have to be compressed. So if you don't want the +text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE. +Because tEXt and zTXt chunks don't have a language field, if you +specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt +any language code or translated keyword will not be written out. + +Until text gets around a few hundred bytes, it is not worth compressing it. +After the text has been written out to the file, the compression type +is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR, +so that it isn't written out again at the end (in case you are calling +png_write_end() with the same struct). + +The keywords that are given in the PNG Specification are: + + Title Short (one line) title or + caption for image + + Author Name of image's creator + + Description Description of image (possibly long) + + Copyright Copyright notice + + Creation Time Time of original image creation + (usually RFC 1123 format, see below) + + Software Software used to create the image + + Disclaimer Legal disclaimer + + Warning Warning of nature of content + + Source Device used to create the image + + Comment Miscellaneous comment; conversion + from other image format + +The keyword-text pairs work like this. Keywords should be short +simple descriptions of what the comment is about. Some typical +keywords are found in the PNG specification, as is some recommendations +on keywords. You can repeat keywords in a file. You can even write +some text before the image and some after. For example, you may want +to put a description of the image before the image, but leave the +disclaimer until after, so viewers working over modem connections +don't have to wait for the disclaimer to go over the modem before +they start seeing the image. Finally, keywords should be full +words, not abbreviations. Keywords and text are in the ISO 8859-1 +(Latin-1) character set (a superset of regular ASCII) and can not +contain NUL characters, and should not contain control or other +unprintable characters. To make the comments widely readable, stick +with basic ASCII, and avoid machine specific character set extensions +like the IBM-PC character set. The keyword must be present, but +you can leave off the text string on non-compressed pairs. +Compressed pairs must have a text string, as only the text string +is compressed anyway, so the compression would be meaningless. + +PNG supports modification time via the png_time structure. Two +conversion routines are provided, png_convert_from_time_t() for +time_t and png_convert_from_struct_tm() for struct tm. The +time_t routine uses gmtime(). You don't have to use either of +these, but if you wish to fill in the png_time structure directly, +you should provide the time in universal time (GMT) if possible +instead of your local time. Note that the year number is the full +year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and +that months start with 1. + +If you want to store the time of the original image creation, you should +use a plain tEXt chunk with the "Creation Time" keyword. This is +necessary because the "creation time" of a PNG image is somewhat vague, +depending on whether you mean the PNG file, the time the image was +created in a non-PNG format, a still photo from which the image was +scanned, or possibly the subject matter itself. In order to facilitate +machine-readable dates, it is recommended that the "Creation Time" +tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"), +although this isn't a requirement. Unlike the tIME chunk, the +"Creation Time" tEXt chunk is not expected to be automatically changed +by the software. To facilitate the use of RFC 1123 dates, a function +png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to +convert from PNG time to an RFC 1123 format string. The caller must provide +a writeable buffer of at least 29 bytes. + +Writing unknown chunks + +You can use the png_set_unknown_chunks function to queue up private chunks +for writing. You give it a chunk name, location, raw data, and a size. You +also must use png_set_keep_unknown_chunks() to ensure that libpng will +handle them. That's all there is to it. The chunks will be written by the +next following png_write_info_before_PLTE, png_write_info, or png_write_end +function, depending upon the specified location. Any chunks previously +read into the info structure's unknown-chunk list will also be written out +in a sequence that satisfies the PNG specification's ordering rules. + +Here is an example of writing two private chunks, prVt and miNE: + + #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + /* Set unknown chunk data */ + png_unknown_chunk unk_chunk[2]; + strcpy((char *) unk_chunk[0].name, "prVt"; + unk_chunk[0].data = (unsigned char *) "PRIVATE DATA"; + unk_chunk[0].size = strlen(unk_chunk[0].data)+1; + unk_chunk[0].location = PNG_HAVE_IHDR; + strcpy((char *) unk_chunk[1].name, "miNE"; + unk_chunk[1].data = (unsigned char *) "MY CHUNK DATA"; + unk_chunk[1].size = strlen(unk_chunk[0].data)+1; + unk_chunk[1].location = PNG_AFTER_IDAT; + png_set_unknown_chunks(write_ptr, write_info_ptr, + unk_chunk, 2); + /* Needed because miNE is not safe-to-copy */ + png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS, + (png_bytep) "miNE", 1); + # if PNG_LIBPNG_VER < 10600 + /* Deal with unknown chunk location bug in 1.5.x and earlier */ + png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR); + png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT); + # endif + # if PNG_LIBPNG_VER < 10500 + /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0, + * one before IDAT and another after IDAT, so don't use it; only use + * PNG_HAVE_IHDR location. This call resets the location previously + * set by assignment and png_set_unknown_chunk_location() for chunk 1. + */ + png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR); + # endif + #endif + +The high-level write interface + +At this point there are two ways to proceed; through the high-level +write interface, or through a sequence of low-level write operations. +You can use the high-level interface if your image data is present +in the info structure. All defined output +transformations are permitted, enabled by the following masks. + + PNG_TRANSFORM_IDENTITY No transformation + PNG_TRANSFORM_PACKING Pack 1, 2 and 4-bit samples + PNG_TRANSFORM_PACKSWAP Change order of packed + pixels to LSB first + PNG_TRANSFORM_INVERT_MONO Invert monochrome images + PNG_TRANSFORM_SHIFT Normalize pixels to the + sBIT depth + PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA + to BGRA + PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA + to AG + PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity + to transparency + PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples + PNG_TRANSFORM_STRIP_FILLER Strip out filler + bytes (deprecated). + PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading + filler bytes + PNG_TRANSFORM_STRIP_FILLER_AFTER Strip out trailing + filler bytes + +If you have valid image data in the info structure (you can use +png_set_rows() to put image data in the info structure), simply do this: + + png_write_png(png_ptr, info_ptr, png_transforms, NULL) + +where png_transforms is an integer containing the bitwise OR of some set of +transformation flags. This call is equivalent to png_write_info(), +followed the set of transformations indicated by the transform mask, +then png_write_image(), and finally png_write_end(). + +(The final parameter of this call is not yet used. Someday it might point +to transformation parameters required by some future output transform.) + +You must use png_transforms and not call any png_set_transform() functions +when you use png_write_png(). + +The low-level write interface + +If you are going the low-level route instead, you are now ready to +write all the file information up to the actual image data. You do +this with a call to png_write_info(). + + png_write_info(png_ptr, info_ptr); + +Note that there is one transformation you may need to do before +png_write_info(). In PNG files, the alpha channel in an image is the +level of opacity. If your data is supplied as a level of transparency, +you can invert the alpha channel before you write it, so that 0 is +fully transparent and 255 (in 8-bit or paletted images) or 65535 +(in 16-bit images) is fully opaque, with + + png_set_invert_alpha(png_ptr); + +This must appear before png_write_info() instead of later with the +other transformations because in the case of paletted images the tRNS +chunk data has to be inverted before the tRNS chunk is written. If +your image is not a paletted image, the tRNS data (which in such cases +represents a single color to be rendered as transparent) won't need to +be changed, and you can safely do this transformation after your +png_write_info() call. + +If you need to write a private chunk that you want to appear before +the PLTE chunk when PLTE is present, you can write the PNG info in +two steps, and insert code to write your own chunk between them: + + png_write_info_before_PLTE(png_ptr, info_ptr); + png_set_unknown_chunks(png_ptr, info_ptr, ...); + png_write_info(png_ptr, info_ptr); + +After you've written the file information, you can set up the library +to handle any special transformations of the image data. The various +ways to transform the data will be described in the order that they +should occur. This is important, as some of these change the color +type and/or bit depth of the data, and some others only work on +certain color types and bit depths. Even though each transformation +checks to see if it has data that it can do something with, you should +make sure to only enable a transformation if it will be valid for the +data. For example, don't swap red and blue on grayscale data. + +PNG files store RGB pixels packed into 3 or 6 bytes. This code tells +the library to strip input data that has 4 or 8 bytes per pixel down +to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2 +bytes per pixel). + + png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE); + +where the 0 is unused, and the location is either PNG_FILLER_BEFORE or +PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel +is stored XRGB or RGBX. + +PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as +they can, resulting in, for example, 8 pixels per byte for 1 bit files. +If the data is supplied at 1 pixel per byte, use this code, which will +correctly pack the pixels into a single byte: + + png_set_packing(png_ptr); + +PNG files reduce possible bit depths to 1, 2, 4, 8, and 16. If your +data is of another bit depth, you can write an sBIT chunk into the +file so that decoders can recover the original data if desired. + + /* Set the true bit depth of the image data */ + if (color_type & PNG_COLOR_MASK_COLOR) + { + sig_bit.red = true_bit_depth; + sig_bit.green = true_bit_depth; + sig_bit.blue = true_bit_depth; + } + + else + { + sig_bit.gray = true_bit_depth; + } + + if (color_type & PNG_COLOR_MASK_ALPHA) + { + sig_bit.alpha = true_bit_depth; + } + + png_set_sBIT(png_ptr, info_ptr, &sig_bit); + +If the data is stored in the row buffer in a bit depth other than +one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG), +this will scale the values to appear to be the correct bit depth as +is required by PNG. + + png_set_shift(png_ptr, &sig_bit); + +PNG files store 16-bit pixels in network byte order (big-endian, +ie. most significant bits first). This code would be used if they are +supplied the other way (little-endian, i.e. least significant bits +first, the way PCs store them): + + if (bit_depth > 8) + png_set_swap(png_ptr); + +If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you +need to change the order the pixels are packed into bytes, you can use: + + if (bit_depth < 8) + png_set_packswap(png_ptr); + +PNG files store 3 color pixels in red, green, blue order. This code +would be used if they are supplied as blue, green, red: + + png_set_bgr(png_ptr); + +PNG files describe monochrome as black being zero and white being +one. This code would be used if the pixels are supplied with this reversed +(black being one and white being zero): + + png_set_invert_mono(png_ptr); + +Finally, you can write your own transformation function if none of +the existing ones meets your needs. This is done by setting a callback +with + + png_set_write_user_transform_fn(png_ptr, + write_transform_fn); + +You must supply the function + + void write_transform_fn(png_structp png_ptr, png_row_infop + row_info, png_bytep data) + +See pngtest.c for a working example. Your function will be called +before any of the other transformations are processed. If supported +libpng also supplies an information routine that may be called from +your callback: + + png_get_current_row_number(png_ptr); + png_get_current_pass_number(png_ptr); + +This returns the current row passed to the transform. With interlaced +images the value returned is the row in the input sub-image image. Use +PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to +find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass). + +The discussion of interlace handling above contains more information on how to +use these values. + +You can also set up a pointer to a user structure for use by your +callback function. + + png_set_user_transform_info(png_ptr, user_ptr, 0, 0); + +The user_channels and user_depth parameters of this function are ignored +when writing; you can set them to zero as shown. + +You can retrieve the pointer via the function png_get_user_transform_ptr(). +For example: + + voidp write_user_transform_ptr = + png_get_user_transform_ptr(png_ptr); + +It is possible to have libpng flush any pending output, either manually, +or automatically after a certain number of lines have been written. To +flush the output stream a single time call: + + png_write_flush(png_ptr); + +and to have libpng flush the output stream periodically after a certain +number of scanlines have been written, call: + + png_set_flush(png_ptr, nrows); + +Note that the distance between rows is from the last time png_write_flush() +was called, or the first row of the image if it has never been called. +So if you write 50 lines, and then png_set_flush 25, it will flush the +output on the next scanline, and every 25 lines thereafter, unless +png_write_flush() is called before 25 more lines have been written. +If nrows is too small (less than about 10 lines for a 640 pixel wide +RGB image) the image compression may decrease noticeably (although this +may be acceptable for real-time applications). Infrequent flushing will +only degrade the compression performance by a few percent over images +that do not use flushing. + +Writing the image data + +That's it for the transformations. Now you can write the image data. +The simplest way to do this is in one function call. If you have the +whole image in memory, you can just call png_write_image() and libpng +will write the image. You will need to pass in an array of pointers to +each row. This function automatically handles interlacing, so you don't +need to call png_set_interlace_handling() or call this function multiple +times, or any of that other stuff necessary with png_write_rows(). + + png_write_image(png_ptr, row_pointers); + +where row_pointers is: + + png_byte *row_pointers[height]; + +You can point to void or char or whatever you use for pixels. + +If you don't want to write the whole image at once, you can +use png_write_rows() instead. If the file is not interlaced, +this is simple: + + png_write_rows(png_ptr, row_pointers, + number_of_rows); + +row_pointers is the same as in the png_write_image() call. + +If you are just writing one row at a time, you can do this with +a single row_pointer instead of an array of row_pointers: + + png_bytep row_pointer = row; + + png_write_row(png_ptr, row_pointer); + +When the file is interlaced, things can get a good deal more complicated. +The only currently (as of the PNG Specification version 1.2, dated July +1999) defined interlacing scheme for PNG files is the "Adam7" interlace +scheme, that breaks down an image into seven smaller images of varying +size. libpng will build these images for you, or you can do them +yourself. If you want to build them yourself, see the PNG specification +for details of which pixels to write when. + +If you don't want libpng to handle the interlacing details, just +use png_set_interlace_handling() and call png_write_rows() the +correct number of times to write all the sub-images +(png_set_interlace_handling() returns the number of sub-images.) + +If you want libpng to build the sub-images, call this before you start +writing any rows: + + number_of_passes = png_set_interlace_handling(png_ptr); + +This will return the number of passes needed. Currently, this is seven, +but may change if another interlace type is added. + +Then write the complete image number_of_passes times. + + png_write_rows(png_ptr, row_pointers, number_of_rows); + +Think carefully before you write an interlaced image. Typically code that +reads such images reads all the image data into memory, uncompressed, before +doing any processing. Only code that can display an image on the fly can +take advantage of the interlacing and even then the image has to be exactly +the correct size for the output device, because scaling an image requires +adjacent pixels and these are not available until all the passes have been +read. + +If you do write an interlaced image you will hardly ever need to handle +the interlacing yourself. Call png_set_interlace_handling() and use the +approach described above. + +The only time it is conceivable that you will really need to write an +interlaced image pass-by-pass is when you have read one pass by pass and +made some pixel-by-pixel transformation to it, as described in the read +code above. In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros +to determine the size of each sub-image in turn and simply write the rows +you obtained from the read code. + +Finishing a sequential write + +After you are finished writing the image, you should finish writing +the file. If you are interested in writing comments or time, you should +pass an appropriately filled png_info pointer. If you are not interested, +you can pass NULL. + + png_write_end(png_ptr, info_ptr); + +When you are done, you can free all memory used by libpng like this: + + png_destroy_write_struct(&png_ptr, &info_ptr); + +It is also possible to individually free the info_ptr members that +point to libpng-allocated storage with the following function: + + png_free_data(png_ptr, info_ptr, mask, seq) + + mask - identifies data to be freed, a mask + containing the bitwise OR of one or + more of + PNG_FREE_PLTE, PNG_FREE_TRNS, + PNG_FREE_HIST, PNG_FREE_ICCP, + PNG_FREE_PCAL, PNG_FREE_ROWS, + PNG_FREE_SCAL, PNG_FREE_SPLT, + PNG_FREE_TEXT, PNG_FREE_UNKN, + or simply PNG_FREE_ALL + + seq - sequence number of item to be freed + (-1 for all items) + +This function may be safely called when the relevant storage has +already been freed, or has not yet been allocated, or was allocated +by the user and not by libpng, and will in those cases do nothing. +The "seq" parameter is ignored if only one item of the selected data +type, such as PLTE, is allowed. If "seq" is not -1, and multiple items +are allowed for the data type identified in the mask, such as text or +sPLT, only the n'th item in the structure is freed, where n is "seq". + +If you allocated data such as a palette that you passed in to libpng +with png_set_*, you must not free it until just before the call to +png_destroy_write_struct(). + +The default behavior is only to free data that was allocated internally +by libpng. This can be changed, so that libpng will not free the data, +or so that it will free data that was allocated by the user with png_malloc() +or png_calloc() and passed in via a png_set_*() function, with + + png_data_freer(png_ptr, info_ptr, freer, mask) + + freer - one of + PNG_DESTROY_WILL_FREE_DATA + PNG_SET_WILL_FREE_DATA + PNG_USER_WILL_FREE_DATA + + mask - which data elements are affected + same choices as in png_free_data() + +For example, to transfer responsibility for some data from a read structure +to a write structure, you could use + + png_data_freer(read_ptr, read_info_ptr, + PNG_USER_WILL_FREE_DATA, + PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST) + + png_data_freer(write_ptr, write_info_ptr, + PNG_DESTROY_WILL_FREE_DATA, + PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST) + +thereby briefly reassigning responsibility for freeing to the user but +immediately afterwards reassigning it once more to the write_destroy +function. Having done this, it would then be safe to destroy the read +structure and continue to use the PLTE, tRNS, and hIST data in the write +structure. + +This function only affects data that has already been allocated. +You can call this function before calling after the png_set_*() functions +to control whether the user or png_destroy_*() is supposed to free the data. +When the user assumes responsibility for libpng-allocated data, the +application must use +png_free() to free it, and when the user transfers responsibility to libpng +for data that the user has allocated, the user must have used png_malloc() +or png_calloc() to allocate it. + +If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword +separately, do not transfer responsibility for freeing text_ptr to libpng, +because when libpng fills a png_text structure it combines these members with +the key member, and png_free_data() will free only text_ptr.key. Similarly, +if you transfer responsibility for free'ing text_ptr from libpng to your +application, your application must not separately free those members. +For a more compact example of writing a PNG image, see the file example.c. + +V. Simplified API + +The simplified API, which became available in libpng-1.6.0, hides the details +of both libpng and the PNG file format itself. +It allows PNG files to be read into a very limited number of +in-memory bitmap formats or to be written from the same formats. If these +formats do not accommodate your needs then you can, and should, use the more +sophisticated APIs above - these support a wide variety of in-memory formats +and a wide variety of sophisticated transformations to those formats as well +as a wide variety of APIs to manipulate ancilliary information. + +To read a PNG file using the simplified API: + + 1) Declare a 'png_image' structure (see below) on the + stack and memset() it to all zero. + + 2) Call the appropriate png_image_begin_read... function. + + 3) Set the png_image 'format' member to the required + format and allocate a buffer for the image. + + 4) Call png_image_finish_read to read the image into + your buffer. + +There are no restrictions on the format of the PNG input itself; all valid +color types, bit depths, and interlace methods are acceptable, and the +input image is transformed as necessary to the requested in-memory format +during the png_image_finish_read() step. + +To write a PNG file using the simplified API: + + 1) Declare a 'png_image' structure on the stack and memset() + it to all zero. + + 2) Initialize the members of the structure that describe the + image, setting the 'format' member to the format of the + image in memory. + + 3) Call the appropriate png_image_write... function with a + pointer to the image to write the PNG data. + +png_image is a structure that describes the in-memory format of an image +when it is being read or define the in-memory format of an image that you +need to write. The "png_image" structure contains the following members: + + png_uint_32 version Set to PNG_IMAGE_VERSION + png_uint_32 width Image width in pixels (columns) + png_uint_32 height Image height in pixels (rows) + png_uint_32 format Image format as defined below + png_uint_32 flags A bit mask containing informational flags + png_controlp opaque Initialize to NULL, free with png_image_free + png_uint_32 colormap_entries; Number of entries in the color-map + png_uint_32 warning_or_error; + char message[64]; + +In the event of an error or warning the following field warning_or_error +field will be set to a non-zero value and the 'message' field will contain +a '\0' terminated string with the libpng error or warning message. If both +warnings and an error were encountered, only the error is recorded. If there +are multiple warnings, only the first one is recorded. + +The upper 30 bits of this value are reserved; the low two bits contain +a two bit code such that a value more than 1 indicates a failure in the API +just called: + + 0 - no warning or error + 1 - warning + 2 - error + 3 - error preceded by warning + +The pixels (samples) of the image have one to four channels whose components +have original values in the range 0 to 1.0: + + 1: A single gray or luminance channel (G). + 2: A gray/luminance channel and an alpha channel (GA). + 3: Three red, green, blue color channels (RGB). + 4: Three color channels and an alpha channel (RGBA). + +The channels are encoded in one of two ways: + + a) As a small integer, value 0..255, contained in a single byte. For the +alpha channel the original value is simply value/255. For the color or +luminance channels the value is encoded according to the sRGB specification +and matches the 8-bit format expected by typical display devices. + +The color/gray channels are not scaled (pre-multiplied) by the alpha +channel and are suitable for passing to color management software. + + b) As a value in the range 0..65535, contained in a 2-byte integer, in +the native byte order of the platform on which the application is running. +All channels can be converted to the original value by dividing by 65535; all +channels are linear. Color channels use the RGB encoding (RGB end-points) of +the sRGB specification. This encoding is identified by the +PNG_FORMAT_FLAG_LINEAR flag below. + +When an alpha channel is present it is expected to denote pixel coverage +of the color or luminance channels and is returned as an associated alpha +channel: the color/gray channels are scaled (pre-multiplied) by the alpha +value. + +When a color-mapped image is used as a result of calling +png_image_read_colormap or png_image_write_colormap the channels are encoded +in the color-map and the descriptions above apply to the color-map entries. +The image data is encoded as small integers, value 0..255, that index the +entries in the color-map. One integer (one byte) is stored for each pixel. + +PNG_FORMAT_* + +The #defines to be used in png_image::format. Each #define identifies a +particular layout of channel data and, if present, alpha values. There are +separate defines for each of the two channel encodings. + +A format is built up using single bit flag values. Not all combinations are +valid: use the bit flag values below for testing a format returned by the +read APIs, but set formats from the derived values. + +When reading or writing color-mapped images the format should be set to the +format of the entries in the color-map then png_image_{read,write}_colormap +called to read or write the color-map and set the format correctly for the +image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly! + +NOTE: libpng can be built with particular features disabled, if you see +compiler errors because the definition of one of the following flags has been +compiled out it is because libpng does not have the required support. It is +possible, however, for the libpng configuration to enable the format on just +read or just write; in that case you may see an error at run time. You can +guard against this by checking for the definition of: + + PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED + + PNG_FORMAT_FLAG_ALPHA 0x01 format with an alpha channel + PNG_FORMAT_FLAG_COLOR 0x02 color format: otherwise grayscale + PNG_FORMAT_FLAG_LINEAR 0x04 png_uint_16 channels else png_byte + PNG_FORMAT_FLAG_COLORMAP 0x08 libpng use only + PNG_FORMAT_FLAG_BGR 0x10 BGR colors, else order is RGB + PNG_FORMAT_FLAG_AFIRST 0x20 alpha channel comes first + +Supported formats are as follows. Future versions of libpng may support more +formats; for compatibility with older versions simply check if the format +macro is defined using #ifdef. These defines describe the in-memory layout +of the components of the pixels of the image. + +First the single byte formats: + + PNG_FORMAT_GRAY 0 + PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA + PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST) + PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR + PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR) + PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA) + PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST) + PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA) + PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST) + +Then the linear 2-byte formats. When naming these "Y" is used to +indicate a luminance (gray) channel. The component order within the pixel +is always the same - there is no provision for swapping the order of the +components in the linear format. The components are 16-bit integers in +the native byte order for your platform, and there is no provision for +swapping the bytes to a different endian condition. + + PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR + PNG_FORMAT_LINEAR_Y_ALPHA + (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA) + PNG_FORMAT_LINEAR_RGB + (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR) + PNG_FORMAT_LINEAR_RGB_ALPHA + (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR| + PNG_FORMAT_FLAG_ALPHA) + +Color-mapped formats are obtained by calling png_image_{read,write}_colormap, +as appropriate after setting png_image::format to the format of the color-map +to be read or written. Applications may check the value of +PNG_FORMAT_FLAG_COLORMAP to see if they have called the colormap API. The +format of the color-map may be extracted using the following macro. + + PNG_FORMAT_OF_COLORMAP(fmt) ((fmt) & ~PNG_FORMAT_FLAG_COLORMAP) + +PNG_IMAGE macros + +These are convenience macros to derive information from a png_image +structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the +actual image sample values - either the entries in the color-map or the +pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values +for the pixels and will always return 1 after a call to +png_image_{read,write}_colormap. The remaining macros return information +about the rows in the image and the complete image. + +NOTE: All the macros that take a png_image::format parameter are compile time +constants if the format parameter is, itself, a constant. Therefore these +macros can be used in array declarations and case labels where required. +Similarly the macros are also pre-processor constants (sizeof is not used) so +they can be used in #if tests. + +First the information about the samples. + + PNG_IMAGE_SAMPLE_CHANNELS(fmt) + Returns the total number of channels in a given format: 1..4 + + PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt) + Returns the size in bytes of a single component of a pixel or color-map + entry (as appropriate) in the image. + + PNG_IMAGE_SAMPLE_SIZE(fmt) + This is the size of the sample data for one sample. If the image is + color-mapped it is the size of one color-map entry (and image pixels are + one byte in size), otherwise it is the size of one image pixel. + + PNG_IMAGE_COLORMAP_SIZE(fmt) + The size of the color-map required by the format; this is the size of the + color-map buffer passed to the png_image_{read,write}_colormap APIs, it is + a fixed number determined by the format so can easily be allocated on the + stack if necessary. + +#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\ + (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256) + /* The maximum size of the color-map required by the format expressed in a + * count of components. This can be used to compile-time allocate a + * color-map: + * + * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)]; + * + * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)]; + * + * Alternatively, use the PNG_IMAGE_COLORMAP_SIZE macro below to use the + * information from one of the png_image_begin_read_ APIs and dynamically + * allocate the required memory. + */ + + +Corresponding information about the pixels + + PNG_IMAGE_PIXEL_(test,fmt) + + PNG_IMAGE_PIXEL_CHANNELS(fmt) + The number of separate channels (components) in a pixel; 1 for a + color-mapped image. + + PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\ + The size, in bytes, of each component in a pixel; 1 for a color-mapped + image. + + PNG_IMAGE_PIXEL_SIZE(fmt) + The size, in bytes, of a complete pixel; 1 for a color-mapped image. + +Information about the whole row, or whole image + + PNG_IMAGE_ROW_STRIDE(image) + Returns the total number of components in a single row of the image; this + is the minimum 'row stride', the minimum count of components between each + row. For a color-mapped image this is the minimum number of bytes in a + row. + + If you need the stride measured in bytes, row_stride_bytes is + PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt) + plus any padding bytes that your application might need, for example + to start the next row on a 4-byte boundary. + + PNG_IMAGE_BUFFER_SIZE(image, row_stride) + Returns the size, in bytes, of an image buffer given a png_image and a row + stride - the number of components to leave space for in each row. This + macro takes care of multiplying row_stride by PNG_IMAGE_PIXEL_COMONENT_SIZE + when the image has 2-byte components. + + PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01 + This indicates the the RGB values of the in-memory bitmap do not + correspond to the red, green and blue end-points defined by sRGB. + + PNG_IMAGE_FLAG_COLORMAP == 0x02 + The PNG is color-mapped. If this flag is set png_image_read_colormap + can be used without further loss of image information. If it is not set + png_image_read_colormap will cause significant loss if the image has any + +READ APIs + + The png_image passed to the read APIs must have been initialized by setting + the png_controlp field 'opaque' to NULL (or, better, memset the whole thing.) + + int png_image_begin_read_from_file( png_imagep image, + const char *file_name) + + The named file is opened for read and the image header + is filled in from the PNG header in the file. + + int png_image_begin_read_from_stdio (png_imagep image, + FILE* file) + + The PNG header is read from the stdio FILE object. + + int png_image_begin_read_from_memory(png_imagep image, + png_const_voidp memory, png_size_t size) + + The PNG header is read from the given memory buffer. + + int png_image_finish_read(png_imagep image, + png_colorp background, void *buffer, + png_int_32 row_stride, void *colormap)); + + Finish reading the image into the supplied buffer and + clean up the png_image structure. + + row_stride is the step, in png_byte or png_uint_16 units + as appropriate, between adjacent rows. A positive stride + indicates that the top-most row is first in the buffer - + the normal top-down arrangement. A negative stride + indicates that the bottom-most row is first in the buffer. + + background need only be supplied if an alpha channel must + be removed from a png_byte format and the removal is to be + done by compositing on a solid color; otherwise it may be + NULL and any composition will be done directly onto the + buffer. The value is an sRGB color to use for the + background, for grayscale output the green channel is used. + + For linear output removing the alpha channel is always done + by compositing on black. + + void png_image_free(png_imagep image) + + Free any data allocated by libpng in image->opaque, + setting the pointer to NULL. May be called at any time + after the structure is initialized. + +When the simplified API needs to convert between sRGB and linear colorspaces, +the actual sRGB transfer curve defined in the sRGB specification (see the +article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2 +approximation used elsewhere in libpng. + +WRITE APIS + +For write you must initialize a png_image structure to describe the image to +be written: + + version: must be set to PNG_IMAGE_VERSION + opaque: must be initialized to NULL + width: image width in pixels + height: image height in rows + format: the format of the data you wish to write + flags: set to 0 unless one of the defined flags applies; set + PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images + where the RGB values do not correspond to the colors in sRGB. + colormap_entries: set to the number of entries in the color-map (0 to 256) + + int png_image_write_to_file, (png_imagep image, + const char *file, int convert_to_8bit, const void *buffer, + png_int_32 row_stride, const void *colormap)); + + Write the image to the named file. + + int png_image_write_to_stdio(png_imagep image, FILE *file, + int convert_to_8_bit, const void *buffer, + png_int_32 row_stride, const void *colormap) + + Write the image to the given (FILE*). + +With all write APIs if image is in one of the linear formats with +(png_uint_16) data then setting convert_to_8_bit will cause the output to be +a (png_byte) PNG gamma encoded according to the sRGB specification, otherwise +a 16-bit linear encoded PNG file is written. + +With all APIs row_stride is handled as in the read APIs - it is the spacing +from one row to the next in component sized units (float) and if negative +indicates a bottom-up row layout in the buffer. + +Note that the write API does not support interlacing, sub-8-bit pixels, +and indexed (paletted) images. + +VI. Modifying/Customizing libpng + +There are two issues here. The first is changing how libpng does +standard things like memory allocation, input/output, and error handling. +The second deals with more complicated things like adding new chunks, +adding new transformations, and generally changing how libpng works. +Both of those are compile-time issues; that is, they are generally +determined at the time the code is written, and there is rarely a need +to provide the user with a means of changing them. + +Memory allocation, input/output, and error handling + +All of the memory allocation, input/output, and error handling in libpng +goes through callbacks that are user-settable. The default routines are +in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively. To change +these functions, call the appropriate png_set_*_fn() function. + +Memory allocation is done through the functions png_malloc(), png_calloc(), +and png_free(). The png_malloc() and png_free() functions currently just +call the standard C functions and png_calloc() calls png_malloc() and then +clears the newly allocated memory to zero; note that png_calloc(png_ptr, size) +is not the same as the calloc(number, size) function provided by stdlib.h. +There is limited support for certain systems with segmented memory +architectures and the types of pointers declared by png.h match this; you +will have to use appropriate pointers in your application. If you prefer +to use a different method of allocating and freeing data, you can use +png_create_read_struct_2() or png_create_write_struct_2() to register your +own functions as described above. These functions also provide a void +pointer that can be retrieved via + + mem_ptr=png_get_mem_ptr(png_ptr); + +Your replacement memory functions must have prototypes as follows: + + png_voidp malloc_fn(png_structp png_ptr, + png_alloc_size_t size); + + void free_fn(png_structp png_ptr, png_voidp ptr); + +Your malloc_fn() must return NULL in case of failure. The png_malloc() +function will normally call png_error() if it receives a NULL from the +system memory allocator or from your replacement malloc_fn(). + +Your free_fn() will never be called with a NULL ptr, since libpng's +png_free() checks for NULL before calling free_fn(). + +Input/Output in libpng is done through png_read() and png_write(), +which currently just call fread() and fwrite(). The FILE * is stored in +png_struct and is initialized via png_init_io(). If you wish to change +the method of I/O, the library supplies callbacks that you can set +through the function png_set_read_fn() and png_set_write_fn() at run +time, instead of calling the png_init_io() function. These functions +also provide a void pointer that can be retrieved via the function +png_get_io_ptr(). For example: + + png_set_read_fn(png_structp read_ptr, + voidp read_io_ptr, png_rw_ptr read_data_fn) + + png_set_write_fn(png_structp write_ptr, + voidp write_io_ptr, png_rw_ptr write_data_fn, + png_flush_ptr output_flush_fn); + + voidp read_io_ptr = png_get_io_ptr(read_ptr); + voidp write_io_ptr = png_get_io_ptr(write_ptr); + +The replacement I/O functions must have prototypes as follows: + + void user_read_data(png_structp png_ptr, + png_bytep data, png_size_t length); + + void user_write_data(png_structp png_ptr, + png_bytep data, png_size_t length); + + void user_flush_data(png_structp png_ptr); + +The user_read_data() function is responsible for detecting and +handling end-of-data errors. + +Supplying NULL for the read, write, or flush functions sets them back +to using the default C stream functions, which expect the io_ptr to +point to a standard *FILE structure. It is probably a mistake +to use NULL for one of write_data_fn and output_flush_fn but not both +of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined. +It is an error to read from a write stream, and vice versa. + +Error handling in libpng is done through png_error() and png_warning(). +Errors handled through png_error() are fatal, meaning that png_error() +should never return to its caller. Currently, this is handled via +setjmp() and longjmp() (unless you have compiled libpng with +PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()), +but you could change this to do things like exit() if you should wish, +as long as your function does not return. + +On non-fatal errors, png_warning() is called +to print a warning message, and then control returns to the calling code. +By default png_error() and png_warning() print a message on stderr via +fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined +(because you don't want the messages) or PNG_NO_STDIO defined (because +fprintf() isn't available). If you wish to change the behavior of the error +functions, you will need to set up your own message callbacks. These +functions are normally supplied at the time that the png_struct is created. +It is also possible to redirect errors and warnings to your own replacement +functions after png_create_*_struct() has been called by calling: + + png_set_error_fn(png_structp png_ptr, + png_voidp error_ptr, png_error_ptr error_fn, + png_error_ptr warning_fn); + + png_voidp error_ptr = png_get_error_ptr(png_ptr); + +If NULL is supplied for either error_fn or warning_fn, then the libpng +default function will be used, calling fprintf() and/or longjmp() if a +problem is encountered. The replacement error functions should have +parameters as follows: + + void user_error_fn(png_structp png_ptr, + png_const_charp error_msg); + + void user_warning_fn(png_structp png_ptr, + png_const_charp warning_msg); + +The motivation behind using setjmp() and longjmp() is the C++ throw and +catch exception handling methods. This makes the code much easier to write, +as there is no need to check every return code of every function call. +However, there are some uncertainties about the status of local variables +after a longjmp, so the user may want to be careful about doing anything +after setjmp returns non-zero besides returning itself. Consult your +compiler documentation for more details. For an alternative approach, you +may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net), +which is illustrated in pngvalid.c and in contrib/visupng. + +Beginning in libpng-1.4.0, the png_set_benign_errors() API became available. +You can use this to handle certain errors (normally handled as errors) +as warnings. + + png_set_benign_errors (png_ptr, int allowed); + + allowed: 0: treat png_benign_error() as an error. + 1: treat png_benign_error() as a warning. + +As of libpng-1.6.0, the default condition is to treat benign errors as +warnings while reading and as errors while writing. + +Custom chunks + +If you need to read or write custom chunks, you may need to get deeper +into the libpng code. The library now has mechanisms for storing +and writing chunks of unknown type; you can even declare callbacks +for custom chunks. However, this may not be good enough if the +library code itself needs to know about interactions between your +chunk and existing `intrinsic' chunks. + +If you need to write a new intrinsic chunk, first read the PNG +specification. Acquire a first level of understanding of how it works. +Pay particular attention to the sections that describe chunk names, +and look at how other chunks were designed, so you can do things +similarly. Second, check out the sections of libpng that read and +write chunks. Try to find a chunk that is similar to yours and use +it as a template. More details can be found in the comments inside +the code. It is best to handle private or unknown chunks in a generic method, +via callback functions, instead of by modifying libpng functions. This +is illustrated in pngtest.c, which uses a callback function to handle a +private "vpAg" chunk and the new "sTER" chunk, which are both unknown to +libpng. + +If you wish to write your own transformation for the data, look through +the part of the code that does the transformations, and check out some of +the simpler ones to get an idea of how they work. Try to find a similar +transformation to the one you want to add and copy off of it. More details +can be found in the comments inside the code itself. + +Configuring for gui/windowing platforms: + +You will need to write new error and warning functions that use the GUI +interface, as described previously, and set them to be the error and +warning functions at the time that png_create_*_struct() is called, +in order to have them available during the structure initialization. +They can be changed later via png_set_error_fn(). On some compilers, +you may also have to change the memory allocators (png_malloc, etc.). + +Configuring zlib: + +There are special functions to configure the compression. Perhaps the +most useful one changes the compression level, which currently uses +input compression values in the range 0 - 9. The library normally +uses the default compression level (Z_DEFAULT_COMPRESSION = 6). Tests +have shown that for a large majority of images, compression values in +the range 3-6 compress nearly as well as higher levels, and do so much +faster. For online applications it may be desirable to have maximum speed +(Z_BEST_SPEED = 1). With versions of zlib after v0.99, you can also +specify no compression (Z_NO_COMPRESSION = 0), but this would create +files larger than just storing the raw bitmap. You can specify the +compression level by calling: + + #include zlib.h + png_set_compression_level(png_ptr, level); + +Another useful one is to reduce the memory level used by the library. +The memory level defaults to 8, but it can be lowered if you are +short on memory (running DOS, for example, where you only have 640K). +Note that the memory level does have an effect on compression; among +other things, lower levels will result in sections of incompressible +data being emitted in smaller stored blocks, with a correspondingly +larger relative overhead of up to 15% in the worst case. + + #include zlib.h + png_set_compression_mem_level(png_ptr, level); + +The other functions are for configuring zlib. They are not recommended +for normal use and may result in writing an invalid PNG file. See +zlib.h for more information on what these mean. + + #include zlib.h + png_set_compression_strategy(png_ptr, + strategy); + + png_set_compression_window_bits(png_ptr, + window_bits); + + png_set_compression_method(png_ptr, method); + +This controls the size of the IDAT chunks (default 8192): + + png_set_compression_buffer_size(png_ptr, size); + +As of libpng version 1.5.4, additional APIs became +available to set these separately for non-IDAT +compressed chunks such as zTXt, iTXt, and iCCP: + + #include zlib.h + #if PNG_LIBPNG_VER >= 10504 + png_set_text_compression_level(png_ptr, level); + + png_set_text_compression_mem_level(png_ptr, level); + + png_set_text_compression_strategy(png_ptr, + strategy); + + png_set_text_compression_window_bits(png_ptr, + window_bits); + + png_set_text_compression_method(png_ptr, method); + #endif + +Controlling row filtering + +If you want to control whether libpng uses filtering or not, which +filters are used, and how it goes about picking row filters, you +can call one of these functions. The selection and configuration +of row filters can have a significant impact on the size and +encoding speed and a somewhat lesser impact on the decoding speed +of an image. Filtering is enabled by default for RGB and grayscale +images (with and without alpha), but not for paletted images nor +for any images with bit depths less than 8 bits/pixel. + +The 'method' parameter sets the main filtering method, which is +currently only '0' in the PNG 1.2 specification. The 'filters' +parameter sets which filter(s), if any, should be used for each +scanline. Possible values are PNG_ALL_FILTERS and PNG_NO_FILTERS +to turn filtering on and off, respectively. + +Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB, +PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise +ORed together with '|' to specify one or more filters to use. +These filters are described in more detail in the PNG specification. +If you intend to change the filter type during the course of writing +the image, you should start with flags set for all of the filters +you intend to use so that libpng can initialize its internal +structures appropriately for all of the filter types. (Note that this +means the first row must always be adaptively filtered, because libpng +currently does not allocate the filter buffers until png_write_row() +is called for the first time.) + + filters = PNG_FILTER_NONE | PNG_FILTER_SUB + PNG_FILTER_UP | PNG_FILTER_AVG | + PNG_FILTER_PAETH | PNG_ALL_FILTERS; + + png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, + filters); + The second parameter can also be + PNG_INTRAPIXEL_DIFFERENCING if you are + writing a PNG to be embedded in a MNG + datastream. This parameter must be the + same as the value of filter_method used + in png_set_IHDR(). + +It is also possible to influence how libpng chooses from among the +available filters. This is done in one or both of two ways - by +telling it how important it is to keep the same filter for successive +rows, and by telling it the relative computational costs of the filters. + + double weights[3] = {1.5, 1.3, 1.1}, + costs[PNG_FILTER_VALUE_LAST] = + {1.0, 1.3, 1.3, 1.5, 1.7}; + + png_set_filter_heuristics(png_ptr, + PNG_FILTER_HEURISTIC_WEIGHTED, 3, + weights, costs); + +The weights are multiplying factors that indicate to libpng that the +row filter should be the same for successive rows unless another row filter +is that many times better than the previous filter. In the above example, +if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a +"sum of absolute differences" 1.5 x 1.3 times higher than other filters +and still be chosen, while the NONE filter could have a sum 1.1 times +higher than other filters and still be chosen. Unspecified weights are +taken to be 1.0, and the specified weights should probably be declining +like those above in order to emphasize recent filters over older filters. + +The filter costs specify for each filter type a relative decoding cost +to be considered when selecting row filters. This means that filters +with higher costs are less likely to be chosen over filters with lower +costs, unless their "sum of absolute differences" is that much smaller. +The costs do not necessarily reflect the exact computational speeds of +the various filters, since this would unduly influence the final image +size. + +Note that the numbers above were invented purely for this example and +are given only to help explain the function usage. Little testing has +been done to find optimum values for either the costs or the weights. + +Requesting debug printout + +The macro definition PNG_DEBUG can be used to request debugging +printout. Set it to an integer value in the range 0 to 3. Higher +numbers result in increasing amounts of debugging information. The +information is printed to the "stderr" file, unless another file +name is specified in the PNG_DEBUG_FILE macro definition. + +When PNG_DEBUG > 0, the following functions (macros) become available: + + png_debug(level, message) + png_debug1(level, message, p1) + png_debug2(level, message, p1, p2) + +in which "level" is compared to PNG_DEBUG to decide whether to print +the message, "message" is the formatted string to be printed, +and p1 and p2 are parameters that are to be embedded in the string +according to printf-style formatting directives. For example, + + png_debug1(2, "foo=%d", foo); + +is expanded to + + if (PNG_DEBUG > 2) + fprintf(PNG_DEBUG_FILE, "foo=%d\n", foo); + +When PNG_DEBUG is defined but is zero, the macros aren't defined, but you +can still use PNG_DEBUG to control your own debugging: + + #ifdef PNG_DEBUG + fprintf(stderr, ... + #endif + +When PNG_DEBUG = 1, the macros are defined, but only png_debug statements +having level = 0 will be printed. There aren't any such statements in +this version of libpng, but if you insert some they will be printed. + +VII. MNG support + +The MNG specification (available at http://www.libpng.org/pub/mng) allows +certain extensions to PNG for PNG images that are embedded in MNG datastreams. +Libpng can support some of these extensions. To enable them, use the +png_permit_mng_features() function: + + feature_set = png_permit_mng_features(png_ptr, mask) + + mask is a png_uint_32 containing the bitwise OR of the + features you want to enable. These include + PNG_FLAG_MNG_EMPTY_PLTE + PNG_FLAG_MNG_FILTER_64 + PNG_ALL_MNG_FEATURES + + feature_set is a png_uint_32 that is the bitwise AND of + your mask with the set of MNG features that is + supported by the version of libpng that you are using. + +It is an error to use this function when reading or writing a standalone +PNG file with the PNG 8-byte signature. The PNG datastream must be wrapped +in a MNG datastream. As a minimum, it must have the MNG 8-byte signature +and the MHDR and MEND chunks. Libpng does not provide support for these +or any other MNG chunks; your application must provide its own support for +them. You may wish to consider using libmng (available at +http://www.libmng.com) instead. + +VIII. Changes to Libpng from version 0.88 + +It should be noted that versions of libpng later than 0.96 are not +distributed by the original libpng author, Guy Schalnat, nor by +Andreas Dilger, who had taken over from Guy during 1996 and 1997, and +distributed versions 0.89 through 0.96, but rather by another member +of the original PNG Group, Glenn Randers-Pehrson. Guy and Andreas are +still alive and well, but they have moved on to other things. + +The old libpng functions png_read_init(), png_write_init(), +png_info_init(), png_read_destroy(), and png_write_destroy() have been +moved to PNG_INTERNAL in version 0.95 to discourage their use. These +functions will be removed from libpng version 1.4.0. + +The preferred method of creating and initializing the libpng structures is +via the png_create_read_struct(), png_create_write_struct(), and +png_create_info_struct() because they isolate the size of the structures +from the application, allow version error checking, and also allow the +use of custom error handling routines during the initialization, which +the old functions do not. The functions png_read_destroy() and +png_write_destroy() do not actually free the memory that libpng +allocated for these structs, but just reset the data structures, so they +can be used instead of png_destroy_read_struct() and +png_destroy_write_struct() if you feel there is too much system overhead +allocating and freeing the png_struct for each image read. + +Setting the error callbacks via png_set_message_fn() before +png_read_init() as was suggested in libpng-0.88 is no longer supported +because this caused applications that do not use custom error functions +to fail if the png_ptr was not initialized to zero. It is still possible +to set the error callbacks AFTER png_read_init(), or to change them with +png_set_error_fn(), which is essentially the same function, but with a new +name to force compilation errors with applications that try to use the old +method. + +Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6; +however, iTXt support was not enabled by default. + +Starting with version 1.0.7, you can find out which version of the library +you are using at run-time: + + png_uint_32 libpng_vn = png_access_version_number(); + +The number libpng_vn is constructed from the major version, minor +version with leading zero, and release number with leading zero, +(e.g., libpng_vn for version 1.0.7 is 10007). + +Note that this function does not take a png_ptr, so you can call it +before you've created one. + +You can also check which version of png.h you used when compiling your +application: + + png_uint_32 application_vn = PNG_LIBPNG_VER; + +IX. Changes to Libpng from version 1.0.x to 1.2.x + +Support for user memory management was enabled by default. To +accomplish this, the functions png_create_read_struct_2(), +png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(), +png_malloc_default(), and png_free_default() were added. + +Support for the iTXt chunk has been enabled by default as of +version 1.2.41. + +Support for certain MNG features was enabled. + +Support for numbered error messages was added. However, we never got +around to actually numbering the error messages. The function +png_set_strip_error_numbers() was added (Note: the prototype for this +function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE +builds of libpng-1.2.15. It was restored in libpng-1.2.36). + +The png_malloc_warn() function was added at libpng-1.2.3. This issues +a png_warning and returns NULL instead of aborting when it fails to +acquire the requested memory allocation. + +Support for setting user limits on image width and height was enabled +by default. The functions png_set_user_limits(), png_get_user_width_max(), +and png_get_user_height_max() were added at libpng-1.2.6. + +The png_set_add_alpha() function was added at libpng-1.2.7. + +The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9. +Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the +tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is +deprecated. + +A number of macro definitions in support of runtime selection of +assembler code features (especially Intel MMX code support) were +added at libpng-1.2.0: + + PNG_ASM_FLAG_MMX_SUPPORT_COMPILED + PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU + PNG_ASM_FLAG_MMX_READ_COMBINE_ROW + PNG_ASM_FLAG_MMX_READ_INTERLACE + PNG_ASM_FLAG_MMX_READ_FILTER_SUB + PNG_ASM_FLAG_MMX_READ_FILTER_UP + PNG_ASM_FLAG_MMX_READ_FILTER_AVG + PNG_ASM_FLAG_MMX_READ_FILTER_PAETH + PNG_ASM_FLAGS_INITIALIZED + PNG_MMX_READ_FLAGS + PNG_MMX_FLAGS + PNG_MMX_WRITE_FLAGS + PNG_MMX_FLAGS + +We added the following functions in support of runtime +selection of assembler code features: + + png_get_mmx_flagmask() + png_set_mmx_thresholds() + png_get_asm_flags() + png_get_mmx_bitdepth_threshold() + png_get_mmx_rowbytes_threshold() + png_set_asm_flags() + +We replaced all of these functions with simple stubs in libpng-1.2.20, +when the Intel assembler code was removed due to a licensing issue. + +These macros are deprecated: + + PNG_READ_TRANSFORMS_NOT_SUPPORTED + PNG_PROGRESSIVE_READ_NOT_SUPPORTED + PNG_NO_SEQUENTIAL_READ_SUPPORTED + PNG_WRITE_TRANSFORMS_NOT_SUPPORTED + PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED + PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED + +They have been replaced, respectively, by: + + PNG_NO_READ_TRANSFORMS + PNG_NO_PROGRESSIVE_READ + PNG_NO_SEQUENTIAL_READ + PNG_NO_WRITE_TRANSFORMS + PNG_NO_READ_ANCILLARY_CHUNKS + PNG_NO_WRITE_ANCILLARY_CHUNKS + +PNG_MAX_UINT was replaced with PNG_UINT_31_MAX. It has been +deprecated since libpng-1.0.16 and libpng-1.2.6. + +The function + png_check_sig(sig, num) +was replaced with + !png_sig_cmp(sig, 0, num) +It has been deprecated since libpng-0.90. + +The function + png_set_gray_1_2_4_to_8() +which also expands tRNS to alpha was replaced with + png_set_expand_gray_1_2_4_to_8() +which does not. It has been deprecated since libpng-1.0.18 and 1.2.9. + +X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x + +Private libpng prototypes and macro definitions were moved from +png.h and pngconf.h into a new pngpriv.h header file. + +Functions png_set_benign_errors(), png_benign_error(), and +png_chunk_benign_error() were added. + +Support for setting the maximum amount of memory that the application +will allocate for reading chunks was added, as a security measure. +The functions png_set_chunk_cache_max() and png_get_chunk_cache_max() +were added to the library. + +We implemented support for I/O states by adding png_ptr member io_state +and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c + +We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level +input transforms. + +Checking for and reporting of errors in the IHDR chunk is more thorough. + +Support for global arrays was removed, to improve thread safety. + +Some obsolete/deprecated macros and functions have been removed. + +Typecasted NULL definitions such as + #define png_voidp_NULL (png_voidp)NULL +were eliminated. If you used these in your application, just use +NULL instead. + +The png_struct and info_struct members "trans" and "trans_values" were +changed to "trans_alpha" and "trans_color", respectively. + +The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles +were removed. + +The PNG_1_0_X and PNG_1_2_X macros were eliminated. + +The PNG_LEGACY_SUPPORTED macro was eliminated. + +Many WIN32_WCE #ifdefs were removed. + +The functions png_read_init(info_ptr), png_write_init(info_ptr), +png_info_init(info_ptr), png_read_destroy(), and png_write_destroy() +have been removed. They have been deprecated since libpng-0.95. + +The png_permit_empty_plte() was removed. It has been deprecated +since libpng-1.0.9. Use png_permit_mng_features() instead. + +We removed the obsolete stub functions png_get_mmx_flagmask(), +png_set_mmx_thresholds(), png_get_asm_flags(), +png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(), +png_set_asm_flags(), and png_mmx_supported() + +We removed the obsolete png_check_sig(), png_memcpy_check(), and +png_memset_check() functions. Instead use !png_sig_cmp(), memcpy(), +and memset(), respectively. + +The function png_set_gray_1_2_4_to_8() was removed. It has been +deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with +png_set_expand_gray_1_2_4_to_8() because the former function also +expanded any tRNS chunk to an alpha channel. + +Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32 +were added and are used by default instead of the corresponding +functions. Unfortunately, +from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the +function) incorrectly returned a value of type png_uint_32. + +We changed the prototype for png_malloc() from + png_malloc(png_structp png_ptr, png_uint_32 size) +to + png_malloc(png_structp png_ptr, png_alloc_size_t size) + +This also applies to the prototype for the user replacement malloc_fn(). + +The png_calloc() function was added and is used in place of +of "png_malloc(); memset();" except in the case in png_read_png() +where the array consists of pointers; in this case a "for" loop is used +after the png_malloc() to set the pointers to NULL, to give robust. +behavior in case the application runs out of memory part-way through +the process. + +We changed the prototypes of png_get_compression_buffer_size() and +png_set_compression_buffer_size() to work with png_size_t instead of +png_uint_32. + +Support for numbered error messages was removed by default, since we +never got around to actually numbering the error messages. The function +png_set_strip_error_numbers() was removed from the library by default. + +The png_zalloc() and png_zfree() functions are no longer exported. +The png_zalloc() function no longer zeroes out the memory that it +allocates. Applications that called png_zalloc(png_ptr, number, size) +can call png_calloc(png_ptr, number*size) instead, and can call +png_free() instead of png_zfree(). + +Support for dithering was disabled by default in libpng-1.4.0, because +it has not been well tested and doesn't actually "dither". +The code was not +removed, however, and could be enabled by building libpng with +PNG_READ_DITHER_SUPPORTED defined. In libpng-1.4.2, this support +was re-enabled, but the function was renamed png_set_quantize() to +reflect more accurately what it actually does. At the same time, +the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to +PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED +was renamed to PNG_READ_QUANTIZE_SUPPORTED. + +We removed the trailing '.' from the warning and error messages. + +XI. Changes to Libpng from version 1.4.x to 1.5.x + +From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the +function) incorrectly returned a value of type png_uint_32. +The incorrect macro was removed from libpng-1.4.5. + +Checking for invalid palette index on write was added at libpng +1.5.10. If a pixel contains an invalid (out-of-range) index libpng issues +a benign error. This is enabled by default because this condition is an +error according to the PNG specification, Clause 11.3.2, but the error can +be ignored in each png_ptr with + + png_set_check_for_invalid_index(png_ptr, allowed); + + allowed - one of + 0: disable benign error (accept the + invalid data without warning). + 1: enable benign error (treat the + invalid data as an error or a + warning). + +If the error is ignored, or if png_benign_error() treats it as a warning, +any invalid pixels are decoded as opaque black by the decoder and written +as-is by the encoder. + +Retrieving the maximum palette index found was added at libpng-1.5.15. +This statement must appear after png_read_png() or png_read_image() while +reading, and after png_write_png() or png_write_image() while writing. + + int max_palette = png_get_palette_max(png_ptr, info_ptr); + +This will return the maximum palette index found in the image, or "-1" if +the palette was not checked, or "0" if no palette was found. Note that this +does not account for any palette index used by ancillary chunks such as the +bKGD chunk; you must check those separately to determine the maximum +palette index actually used. + +There are no substantial API changes between the non-deprecated parts of +the 1.4.5 API and the 1.5.0 API; however, the ability to directly access +members of the main libpng control structures, png_struct and png_info, +deprecated in earlier versions of libpng, has been completely removed from +libpng 1.5. + +We no longer include zlib.h in png.h. The include statement has been moved +to pngstruct.h, where it is not accessible by applications. Applications that +need access to information in zlib.h will need to add the '#include "zlib.h"' +directive. It does not matter whether this is placed prior to or after +the '"#include png.h"' directive. + +The png_sprintf(), png_strcpy(), and png_strncpy() macros are no longer used +and were removed. + +We moved the png_strlen(), png_memcpy(), png_memset(), and png_memcmp() +macros into a private header file (pngpriv.h) that is not accessible to +applications. + +In png_get_iCCP, the type of "profile" was changed from png_charpp +to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep. + +There are changes of form in png.h, including new and changed macros to +declare parts of the API. Some API functions with arguments that are +pointers to data not modified within the function have been corrected to +declare these arguments with PNG_CONST. + +Much of the internal use of C macros to control the library build has also +changed and some of this is visible in the exported header files, in +particular the use of macros to control data and API elements visible +during application compilation may require significant revision to +application code. (It is extremely rare for an application to do this.) + +Any program that compiled against libpng 1.4 and did not use deprecated +features or access internal library structures should compile and work +against libpng 1.5, except for the change in the prototype for +png_get_iCCP() and png_set_iCCP() API functions mentioned above. + +libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of +interlaced images. The macros return the number of rows and columns in +each pass and information that can be used to de-interlace and (if +absolutely necessary) interlace an image. + +libpng 1.5.0 adds an API png_longjmp(png_ptr, value). This API calls +the application-provided png_longjmp_ptr on the internal, but application +initialized, longjmp buffer. It is provided as a convenience to avoid +the need to use the png_jmpbuf macro, which had the unnecessary side +effect of resetting the internal png_longjmp_ptr value. + +libpng 1.5.0 includes a complete fixed point API. By default this is +present along with the corresponding floating point API. In general the +fixed point API is faster and smaller than the floating point one because +the PNG file format used fixed point, not floating point. This applies +even if the library uses floating point in internal calculations. A new +macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library +uses floating point arithmetic (the default) or fixed point arithmetic +internally for performance critical calculations such as gamma correction. +In some cases, the gamma calculations may produce slightly different +results. This has changed the results in png_rgb_to_gray and in alpha +composition (png_set_background for example). This applies even if the +original image was already linear (gamma == 1.0) and, therefore, it is +not necessary to linearize the image. This is because libpng has *not* +been changed to optimize that case correctly, yet. + +Fixed point support for the sCAL chunk comes with an important caveat; +the sCAL specification uses a decimal encoding of floating point values +and the accuracy of PNG fixed point values is insufficient for +representation of these values. Consequently a "string" API +(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading +arbitrary sCAL chunks in the absence of either the floating point API or +internal floating point calculations. Starting with libpng-1.5.0, both +of these functions are present when PNG_sCAL_SUPPORTED is defined. Prior +to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED +being defined and PNG_FLOATING_POINT_SUPPORTED not being defined. + +Applications no longer need to include the optional distribution header +file pngusr.h or define the corresponding macros during application +build in order to see the correct variant of the libpng API. From 1.5.0 +application code can check for the corresponding _SUPPORTED macro: + +#ifdef PNG_INCH_CONVERSIONS_SUPPORTED + /* code that uses the inch conversion APIs. */ +#endif + +This macro will only be defined if the inch conversion functions have been +compiled into libpng. The full set of macros, and whether or not support +has been compiled in, are available in the header file pnglibconf.h. +This header file is specific to the libpng build. Notice that prior to +1.5.0 the _SUPPORTED macros would always have the default definition unless +reset by pngusr.h or by explicit settings on the compiler command line. +These settings may produce compiler warnings or errors in 1.5.0 because +of macro redefinition. + +Applications can now choose whether to use these macros or to call the +corresponding function by defining PNG_USE_READ_MACROS or +PNG_NO_USE_READ_MACROS before including png.h. Notice that this is +only supported from 1.5.0; defining PNG_NO_USE_READ_MACROS prior to 1.5.0 +will lead to a link failure. + +Prior to libpng-1.5.4, the zlib compressor used the same set of parameters +when compressing the IDAT data and textual data such as zTXt and iCCP. +In libpng-1.5.4 we reinitialized the zlib stream for each type of data. +We added five png_set_text_*() functions for setting the parameters to +use with textual data. + +Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED +option was off by default, and slightly inaccurate scaling occurred. +This option can no longer be turned off, and the choice of accurate +or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8() +API for accurate scaling or the old png_set_strip_16_to_8() API for simple +chopping. In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED +macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8 +macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two +png_set_*_16_to_8() functions separately. + +Prior to libpng-1.5.4, the png_set_user_limits() function could only be +used to reduce the width and height limits from the value of +PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said +that it could be used to override them. Now this function will reduce or +increase the limits. + +Starting in libpng-1.5.10, the user limits can be set en masse with the +configuration option PNG_SAFE_LIMITS_SUPPORTED. If this option is enabled, +a set of "safe" limits is applied in pngpriv.h. These can be overridden by +application calls to png_set_user_limits(), png_set_user_chunk_cache_max(), +and/or png_set_user_malloc_max() that increase or decrease the limits. Also, +in libpng-1.5.10 the default width and height limits were increased +from 1,000,000 to 0x7ffffff (i.e., made unlimited). Therefore, the +limits are now + default safe + png_user_width_max 0x7fffffff 1,000,000 + png_user_height_max 0x7fffffff 1,000,000 + png_user_chunk_cache_max 0 (unlimited) 128 + png_user_chunk_malloc_max 0 (unlimited) 8,000,000 + +The png_set_option() function (and the "options" member of the png struct) was +added to libpng-1.5.15. + +The library now supports a complete fixed point implementation and can +thus be used on systems that have no floating point support or very +limited or slow support. Previously gamma correction, an essential part +of complete PNG support, required reasonably fast floating point. + +As part of this the choice of internal implementation has been made +independent of the choice of fixed versus floating point APIs and all the +missing fixed point APIs have been implemented. + +The exact mechanism used to control attributes of API functions has +changed, as described in the INSTALL file. + +A new test program, pngvalid, is provided in addition to pngtest. +pngvalid validates the arithmetic accuracy of the gamma correction +calculations and includes a number of validations of the file format. +A subset of the full range of tests is run when "make check" is done +(in the 'configure' build.) pngvalid also allows total allocated memory +usage to be evaluated and performs additional memory overwrite validation. + +Many changes to individual feature macros have been made. The following +are the changes most likely to be noticed by library builders who +configure libpng: + +1) All feature macros now have consistent naming: + +#define PNG_NO_feature turns the feature off +#define PNG_feature_SUPPORTED turns the feature on + +pnglibconf.h contains one line for each feature macro which is either: + +#define PNG_feature_SUPPORTED + +if the feature is supported or: + +/*#undef PNG_feature_SUPPORTED*/ + +if it is not. Library code consistently checks for the 'SUPPORTED' macro. +It does not, and libpng applications should not, check for the 'NO' macro +which will not normally be defined even if the feature is not supported. +The 'NO' macros are only used internally for setting or not setting the +corresponding 'SUPPORTED' macros. + +Compatibility with the old names is provided as follows: + +PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED + +And the following definitions disable the corresponding feature: + +PNG_SETJMP_NOT_SUPPORTED disables SETJMP +PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS +PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV +PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS +PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS +PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS + +Library builders should remove use of the above, inconsistent, names. + +2) Warning and error message formatting was previously conditional on +the STDIO feature. The library has been changed to use the +CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled +the library no longer uses the printf(3) functions, even though the +default read/write implementations use (FILE) style stdio.h functions. + +3) Three feature macros now control the fixed/floating point decisions: + +PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs + +PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in +practice these are normally required internally anyway (because the PNG +file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT +merely stops the function from being exported. + +PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating +point implementation or the fixed point one. Typically the fixed point +implementation is larger and slower than the floating point implementation +on a system that supports floating point; however, it may be faster on a +system which lacks floating point hardware and therefore uses a software +emulation. + +4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED. This allows the +functions to read and write ints to be disabled independently of +PNG_USE_READ_MACROS, which allows libpng to be built with the functions +even though the default is to use the macros - this allows applications +to choose at app buildtime whether or not to use macros (previously +impossible because the functions weren't in the default build.) + +XII. Changes to Libpng from version 1.5.x to 1.6.x + +A "simplified API" has been added (see documentation in png.h and a simple +example in contrib/examples/pngtopng.c). The new publicly visible API +includes the following: + + macros: + PNG_FORMAT_* + PNG_IMAGE_* + structures: + png_control + png_image + read functions + png_image_begin_read_from_file() + png_image_begin_read_from_stdio() + png_image_begin_read_from_memory() + png_image_finish_read() + png_image_free() + write functions + png_image_write_to_file() + png_image_write_to_stdio() + +Starting with libpng-1.6.0, you can configure libpng to prefix all exported +symbols, using the PNG_PREFIX macro. + +We no longer include string.h in png.h. The include statement has been moved +to pngpriv.h, where it is not accessible by applications. Applications that +need access to information in string.h must add an '#include <string.h>' +directive. It does not matter whether this is placed prior to or after +the '#include "png.h"' directive. + +The following API are now DEPRECATED: + png_info_init_3() + png_convert_to_rfc1123() which has been replaced + with png_convert_to_rfc1123_buffer() + png_malloc_default() + png_free_default() + png_reset_zstream() + +The following have been removed: + png_get_io_chunk_name(), which has been replaced + with png_get_io_chunk_type(). The new + function returns a 32-bit integer instead of + a string. + The png_sizeof(), png_strlen(), png_memcpy(), png_memcmp(), and + png_memset() macros are no longer used in the libpng sources and + have been removed. These had already been made invisible to applications + (i.e., defined in the private pngpriv.h header file) since libpng-1.5.0. + +The signatures of many exported functions were changed, such that + png_structp became png_structrp or png_const_structrp + png_infop became png_inforp or png_const_inforp +where "rp" indicates a "restricted pointer". + +Error detection in some chunks has improved; in particular the iCCP chunk +reader now does pretty complete validation of the basic format. Some bad +profiles that were previously accepted are now accepted with a warning or +rejected, depending upon the png_set_benign_errors() setting, in particular the +very old broken Microsoft/HP 3144-byte sRGB profile. Starting with +libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by +means of + + #ifdef PNG_SKIP_sRGB_CHECK_PROFILE + png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE, + PNG_OPTION_ON); + #endif + +It's not a good idea to do this if you are using the "simplified API", +which needs to be able to recognize an sRGB profile conveyed via the iCCP +chunk. + +The PNG spec requirement that only grayscale profiles may appear in images +with color type 0 or 4 and that even if the image only contains gray pixels, +only RGB profiles may appear in images with color type 2, 3, or 6, is now +enforced. The sRGB chunk is allowed to appear in images with any color type +and is interpreted by libpng to convey a one-tracer-curve profile or a +three-tracer-curve profile as appropriate. + +Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained +an empty language field or an empty translated keyword. Both of these +are allowed by the PNG specification, so these warnings are no longer issued. + +The library now issues an error if the application attempts to set a +transform after it calls png_read_update_info() or if it attempts to call +both png_read_update_info() and png_start_read_image() or to call either +of them more than once. + +The default condition for benign_errors is now to treat benign errors as +warnings while reading and as errors while writing. + +The library now issues a warning if both background processing and RGB to +gray are used when gamma correction happens. As with previous versions of +the library the results are numerically very incorrect in this case. + +There are some minor arithmetic changes in some transforms such as +png_set_background(), that might be detected by certain regression tests. + +Unknown chunk handling has been improved internally, without any API change. +This adds more correct option control of the unknown handling, corrects +a pre-existing bug where the per-chunk 'keep' setting is ignored, and makes +it possible to skip IDAT chunks in the sequential reader. + +The machine-generated configure files are no longer included in branches +libpng16 and later of the GIT repository. They continue to be included +in the tarball releases, however. + +Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT +stream to set the size of the sliding window for reading instead of using the +default 32-kbyte sliding window size. It was discovered that there are +hundreds of PNG files in the wild that have incorrect CMF bytes that caused +zlib to issue the "invalid distance too far back" error and reject the file. +Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions, +provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes +and using a 32-kbyte sliding window), by using + + png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW, + PNG_OPTION_ON); + +and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while +optimizing the CMF bytes in its IDAT chunk correctly. + +Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong +length, which resulted in PNG files that cannot be read beyond the bad iTXt +chunk. This error was fixed in libpng-1.6.3, and a tool (called +contrib/tools/png-fix-itxt) has been added to the libpng distribution. + +XIII. Detecting libpng + +The png_get_io_ptr() function has been present since libpng-0.88, has never +changed, and is unaffected by conditional compilation macros. It is the +best choice for use in configure scripts for detecting the presence of any +libpng version since 0.88. In an autoconf "configure.in" you could use + + AC_CHECK_LIB(png, png_get_io_ptr, ... + +XV. Source code repository + +Since about February 2009, version 1.2.34, libpng has been under "git" source +control. The git repository was built from old libpng-x.y.z.tar.gz files +going back to version 0.70. You can access the git repository (read only) +at + + git://git.code.sf.net/p/libpng/code + +or you can browse it with a web browser by selecting the "code" button at + + https://sourceforge.net/projects/libpng + +Patches can be sent to glennrp at users.sourceforge.net or to +png-mng-implement at lists.sourceforge.net or you can upload them to +the libpng bug tracker at + + http://libpng.sourceforge.net + +We also accept patches built from the tar or zip distributions, and +simple verbal discriptions of bug fixes, reported either to the +SourceForge bug tracker, to the png-mng-implement at lists.sf.net +mailing list, or directly to glennrp. + +XV. Coding style + +Our coding style is similar to the "Allman" style +(See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly +braces on separate lines: + + if (condition) + { + action; + } + + else if (another condition) + { + another action; + } + +The braces can be omitted from simple one-line actions: + + if (condition) + return (0); + +We use 3-space indentation, except for continued statements which +are usually indented the same as the first line of the statement +plus four more spaces. + +For macro definitions we use 2-space indentation, always leaving the "#" +in the first column. + + #ifndef PNG_NO_FEATURE + # ifndef PNG_FEATURE_SUPPORTED + # define PNG_FEATURE_SUPPORTED + # endif + #endif + +Comments appear with the leading "/*" at the same indentation as +the statement that follows the comment: + + /* Single-line comment */ + statement; + + /* This is a multiple-line + * comment. + */ + statement; + +Very short comments can be placed after the end of the statement +to which they pertain: + + statement; /* comment */ + +We don't use C++ style ("//") comments. We have, however, +used them in the past in some now-abandoned MMX assembler +code. + +Functions and their curly braces are not indented, and +exported functions are marked with PNGAPI: + + /* This is a public function that is visible to + * application programmers. It does thus-and-so. + */ + void PNGAPI + png_exported_function(png_ptr, png_info, foo) + { + body; + } + +The return type and decorations are placed on a separate line +ahead of the function name, as illustrated above. + +The prototypes for all exported functions appear in png.h, +above the comment that says + + /* Maintainer: Put new public prototypes here ... */ + +We mark all non-exported functions with "/* PRIVATE */"": + + void /* PRIVATE */ + png_non_exported_function(png_ptr, png_info, foo) + { + body; + } + +The prototypes for non-exported functions (except for those in +pngtest) appear in +pngpriv.h +above the comment that says + + /* Maintainer: Put new private prototypes here ^ */ + +We put a space after the "sizeof" operator and we omit the +optional parentheses around its argument when the argument +is an expression, not a type name, and we always enclose the +sizeof operator, with its argument, in parentheses: + + (sizeof (png_uint_32)) + (sizeof array) + +Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as +though it were a function. + +To avoid polluting the global namespace, the names of all exported +functions and variables begin with "png_", and all publicly visible C +preprocessor macros begin with "PNG". We request that applications that +use libpng *not* begin any of their own symbols with either of these strings. + +We put a space after each comma and after each semicolon +in "for" statements, and we put spaces before and after each +C binary operator and after "for" or "while", and before +"?". We don't put a space between a typecast and the expression +being cast, nor do we put one between a function name and the +left parenthesis that follows it: + + for (i = 2; i > 0; --i) + y[i] = a(x) + (int)b; + +We prefer #ifdef and #ifndef to #if defined() and #if !defined() +when there is only one macro being tested. We always use parentheses +with "defined". + +We prefer to express integers that are used as bit masks in hex format, +with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100). + +We prefer to use underscores in variable names rather than camelCase, except +for a few type names that we inherit from zlib.h. + +We prefer "if (something != 0)" and "if (something == 0)" +over "if (something)" and if "(!something)", respectively. + +We do not use the TAB character for indentation in the C sources. + +Lines do not exceed 80 characters. + +Other rules can be inferred by inspecting the libpng source. + +XVI. Y2K Compliance in libpng + +June 12, 2014 + +Since the PNG Development group is an ad-hoc body, we can't make +an official declaration. + +This is your unofficial assurance that libpng from version 0.71 and +upward through 1.6.12 are Y2K compliant. It is my belief that earlier +versions were also Y2K compliant. + +Libpng only has two year fields. One is a 2-byte unsigned integer +that will hold years up to 65535. The other, which is deprecated, +holds the date in text format, and will hold years up to 9999. + +The integer is + "png_uint_16 year" in png_time_struct. + +The string is + "char time_buffer[29]" in png_struct. This is no longer used +in libpng-1.6.x and will be removed from libpng-1.7.0. + +There are seven time-related functions: + + png_convert_to_rfc_1123() in png.c + (formerly png_convert_to_rfc_1152() in error) + png_convert_from_struct_tm() in pngwrite.c, called + in pngwrite.c + png_convert_from_time_t() in pngwrite.c + png_get_tIME() in pngget.c + png_handle_tIME() in pngrutil.c, called in pngread.c + png_set_tIME() in pngset.c + png_write_tIME() in pngwutil.c, called in pngwrite.c + +All appear to handle dates properly in a Y2K environment. The +png_convert_from_time_t() function calls gmtime() to convert from system +clock time, which returns (year - 1900), which we properly convert to +the full 4-digit year. There is a possibility that applications using +libpng are not passing 4-digit years into the png_convert_to_rfc_1123() +function, or that they are incorrectly passing only a 2-digit year +instead of "year - 1900" into the png_convert_from_struct_tm() function, +but this is not under our control. The libpng documentation has always +stated that it works with 4-digit years, and the APIs have been +documented as such. + +The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned +integer to hold the year, and can hold years as large as 65535. + +zlib, upon which libpng depends, is also Y2K compliant. It contains +no date-related code. + + + Glenn Randers-Pehrson + libpng maintainer + PNG Development Group diff --git a/png/libpng.3 b/png/libpng.3 new file mode 100755 index 0000000..6ac1b6a --- /dev/null +++ b/png/libpng.3 @@ -0,0 +1,6208 @@ +.TH LIBPNG 3 "June 12, 2014" +.SH NAME +libpng \- Portable Network Graphics (PNG) Reference Library 1.6.12 +.SH SYNOPSIS +\fB +#include <png.h>\fP + +\fBpng_uint_32 png_access_version_number \fI(void\fP\fB);\fP + +\fBvoid png_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP + +\fBvoid png_build_grayscale_palette (int \fP\fIbit_depth\fP\fB, png_colorp \fIpalette\fP\fB);\fP + +\fBpng_voidp png_calloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP + +\fBvoid png_chunk_benign_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP + +\fBvoid png_chunk_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP + +\fBvoid png_chunk_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP + +\fBvoid png_convert_from_struct_tm (png_timep \fP\fIptime\fP\fB, struct tm FAR * \fIttime\fP\fB);\fP + +\fBvoid png_convert_from_time_t (png_timep \fP\fIptime\fP\fB, time_t \fIttime\fP\fB);\fP + +\fBpng_charp png_convert_to_rfc1123 (png_structp \fP\fIpng_ptr\fP\fB, png_timep \fIptime\fP\fB);\fP + +\fBpng_infop png_create_info_struct (png_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_structp png_create_read_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP + +\fBpng_structp png_create_read_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP + +\fBpng_structp png_create_write_struct (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarn_fn\fP\fB);\fP + +\fBpng_structp png_create_write_struct_2 (png_const_charp \fP\fIuser_png_ver\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fP\fIwarn_fn\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP + +\fBvoid png_data_freer (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIfreer\fP\fB, png_uint_32 \fImask)\fP\fB);\fP + +\fBvoid png_destroy_info_struct (png_structp \fP\fIpng_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP + +\fBvoid png_destroy_read_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fP\fIinfo_ptr_ptr\fP\fB, png_infopp \fIend_info_ptr_ptr\fP\fB);\fP + +\fBvoid png_destroy_write_struct (png_structpp \fP\fIpng_ptr_ptr\fP\fB, png_infopp \fIinfo_ptr_ptr\fP\fB);\fP + +\fBvoid png_err (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_error (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fIerror\fP\fB);\fP + +\fBvoid png_free (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP + +\fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_free_default (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP + +\fBvoid png_free_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum\fP\fB);\fP + +\fBpng_byte png_get_bit_depth (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_bKGD (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fI*background\fP\fB);\fP + +\fBpng_byte png_get_channels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_cHRM (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*white_x\fP\fB, double \fP\fI*white_y\fP\fB, double \fP\fI*red_x\fP\fB, double \fP\fI*red_y\fP\fB, double \fP\fI*green_x\fP\fB, double \fP\fI*green_y\fP\fB, double \fP\fI*blue_x\fP\fB, double \fI*blue_y\fP\fB);\fP + +\fBpng_uint_32 png_get_cHRM_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*white_x\fP\fB, png_uint_32 \fP\fI*white_y\fP\fB, png_uint_32 \fP\fI*red_x\fP\fB, png_uint_32 \fP\fI*red_y\fP\fB, png_uint_32 \fP\fI*green_x\fP\fB, png_uint_32 \fP\fI*green_y\fP\fB, png_uint_32 \fP\fI*blue_x\fP\fB, png_uint_32 \fI*blue_y\fP\fB);\fP + +\fBpng_uint_32 png_get_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fP\fI*red_X\fP\fB, double \fP\fI*red_Y\fP\fB, double \fP\fI*red_Z\fP\fB, double \fP\fI*green_X\fP\fB, double \fP\fI*green_Y\fP\fB, double \fP\fI*green_Z\fP\fB, double \fP\fI*blue_X\fP\fB, double \fP\fI*blue_Y\fP\fB, double \fI*blue_Z\fP\fB);\fP + +\fBpng_uint_32 png_get_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fI*int_red_X\fP\fB, png_fixed_point \fP\fI*int_red_Y\fP\fB, png_fixed_point \fP\fI*int_red_Z\fP\fB, png_fixed_point \fP\fI*int_green_X\fP\fB, png_fixed_point \fP\fI*int_green_Y\fP\fB, png_fixed_point \fP\fI*int_green_Z\fP\fB, png_fixed_point \fP\fI*int_blue_X\fP\fB, png_fixed_point \fP\fI*int_blue_Y\fP\fB, png_fixed_point \fI*int_blue_Z\fP\fB);\fP + +\fBpng_uint_32 png_get_chunk_cache_max (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_alloc_size_t png_get_chunk_malloc_max (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_byte png_get_color_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_compression_buffer_size (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_byte png_get_compression_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_byte png_get_copyright (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_current_row_number \fI(png_const_structp\fP\fB);\fP + +\fBpng_byte png_get_current_pass_number \fI(png_const_structp\fP\fB);\fP + +\fBpng_voidp png_get_error_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_byte png_get_filter_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_gAMA (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, double \fI*file_gamma\fP\fB);\fP + +\fBpng_uint_32 png_get_gAMA_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fI*int_file_gamma\fP\fB);\fP + +\fBpng_byte png_get_header_ver (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_byte png_get_header_version (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_hIST (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fI*hist\fP\fB);\fP + +\fBpng_uint_32 png_get_iCCP (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_bytepp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP + +\fBpng_uint_32 png_get_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*width\fP\fB, png_uint_32 \fP\fI*height\fP\fB, int \fP\fI*bit_depth\fP\fB, int \fP\fI*color_type\fP\fB, int \fP\fI*interlace_type\fP\fB, int \fP\fI*compression_type\fP\fB, int \fI*filter_type\fP\fB);\fP + +\fBpng_uint_32 png_get_image_height (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_image_width (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_int_32 png_get_int_32 (png_bytep \fIbuf\fP\fB);\fP + +\fBpng_byte png_get_interlace_type (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_io_chunk_type (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_voidp png_get_io_ptr (png_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_io_state (png_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_byte png_get_libpng_ver (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_voidp png_get_mem_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_oFFs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*offset_x\fP\fB, png_uint_32 \fP\fI*offset_y\fP\fB, int \fI*unit_type\fP\fB);\fP + +\fBpng_uint_32 png_get_pCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fI*purpose\fP\fB, png_int_32 \fP\fI*X0\fP\fB, png_int_32 \fP\fI*X1\fP\fB, int \fP\fI*type\fP\fB, int \fP\fI*nparams\fP\fB, png_charp \fP\fI*units\fP\fB, png_charpp \fI*params\fP\fB);\fP + +\fBpng_uint_32 png_get_pHYs (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP + +\fBfloat png_get_pixel_aspect_ratio (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_pHYs_dpi (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fI*res_x\fP\fB, png_uint_32 \fP\fI*res_y\fP\fB, int \fI*unit_type\fP\fB);\fP + +\fBpng_fixed_point png_get_pixel_aspect_ratio_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_voidp png_get_progressive_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_PLTE (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fI*palette\fP\fB, int \fI*num_palette\fP\fB);\fP + +\fBpng_byte png_get_rgb_to_gray_status (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_rowbytes (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_bytepp png_get_rows (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_sBIT (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fI*sig_bit\fP\fB);\fP + +\fBvoid png_get_sCAL (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, double* \fP\fIwidth\fP\fB, double* \fIheight\fP\fB);\fP + +\fBvoid png_get_sCAL_fixed (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_fixed_pointp \fP\fIwidth\fP\fB, png_fixed_pointp \fIheight\fP\fB);\fP + +\fBvoid png_get_sCAL_s (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int* \fP\fIunit\fP\fB, png_charpp \fP\fIwidth\fP\fB, png_charpp \fIheight\fP\fB);\fP + +\fBpng_bytep png_get_signature (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_sPLT (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fI*splt_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_sRGB (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, int \fI*file_srgb_intent\fP\fB);\fP + +\fBpng_uint_32 png_get_text (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fI*text_ptr\fP\fB, int \fI*num_text\fP\fB);\fP + +\fBpng_uint_32 png_get_tIME (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fI*mod_time\fP\fB);\fP + +\fBpng_uint_32 png_get_tRNS (png_const_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fI*trans_alpha\fP\fB, int \fP\fI*num_trans\fP\fB, png_color_16p \fI*trans_color\fP\fB);\fP + +\fB/* This function is really an inline macro. \fI*/ + +\fBpng_uint_16 png_get_uint_16 (png_bytep \fIbuf\fP\fB);\fP + +\fBpng_uint_32 png_get_uint_31 (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIbuf\fP\fB);\fP + +\fB/* This function is really an inline macro. \fI*/ + +\fBpng_uint_32 png_get_uint_32 (png_bytep \fIbuf\fP\fB);\fP + +\fBpng_uint_32 png_get_unknown_chunks (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkpp \fIunknowns\fP\fB);\fP + +\fBpng_voidp png_get_user_chunk_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_user_height_max (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_voidp png_get_user_transform_ptr (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_user_width_max (png_const_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_valid (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIflag\fP\fB);\fP + +\fBfloat png_get_x_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_fixed_point png_get_x_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_int_32 png_get_x_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_int_32 png_get_x_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_x_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_x_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBfloat png_get_y_offset_inches (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_fixed_point png_get_y_offset_inches_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_int_32 png_get_y_offset_microns (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_int_32 png_get_y_offset_pixels (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_y_pixels_per_inch (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBpng_uint_32 png_get_y_pixels_per_meter (png_const_structp \fP\fIpng_ptr\fP\fB, png_const_infop \fIinfo_ptr\fP\fB);\fP + +\fBint png_handle_as_unknown (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIchunk_name\fP\fB);\fP + +\fBint png_image_begin_read_from_file (png_imagep \fP\fIimage\fP\fB, const char \fI*file_name\fP\fB);\fP + +\fBint png_image_begin_read_from_stdio (png_imagep \fP\fIimage\fP\fB, FILE* \fIfile\fP\fB);\fP + +\fBint, png_image_begin_read_from_memory (png_imagep \fP\fIimage\fP\fB, png_const_voidp \fP\fImemory\fP\fB, png_size_t \fIsize\fP\fB);\fP + +\fBint png_image_finish_read (png_imagep \fP\fIimage\fP\fB, png_colorp \fP\fIbackground\fP\fB, void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP + +\fBvoid png_image_free (png_imagep \fIimage\fP\fB);\fP + +\fBint png_image_write_to_file (png_imagep \fP\fIimage\fP\fB, const char \fP\fI*file\fP\fB, int \fP\fIconvert_to_8bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap\fP\fB);\fP + +\fBint png_image_write_to_stdio (png_imagep \fP\fIimage\fP\fB, FILE \fP\fI*file\fP\fB, int \fP\fIconvert_to_8_bit\fP\fB, const void \fP\fI*buffer\fP\fB, png_int_32 \fP\fIrow_stride\fP\fB, void \fI*colormap)\fP\fB);\fP + +\fBvoid png_info_init_3 (png_infopp \fP\fIinfo_ptr\fP\fB, png_size_t \fIpng_info_struct_size\fP\fB);\fP + +\fBvoid png_init_io (png_structp \fP\fIpng_ptr\fP\fB, FILE \fI*fp\fP\fB);\fP + +\fBvoid png_longjmp (png_structp \fP\fIpng_ptr\fP\fB, int \fIval\fP\fB);\fP + +\fBpng_voidp png_malloc (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP + +\fBpng_voidp png_malloc_default (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP + +\fBpng_voidp png_malloc_warn (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIsize\fP\fB);\fP + +\fBpng_uint_32 png_permit_mng_features (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fImng_features_permitted\fP\fB);\fP + +\fBvoid png_process_data (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fIbuffer\fP\fB, png_size_t \fIbuffer_size\fP\fB);\fP + +\fBpng_size_t png_process_data_pause \fP\fI(png_structp\fP\fB, int \fIsave\fP\fB);\fP + +\fBpng_uint_32 png_process_data_skip \fI(png_structp\fP\fB);\fP + +\fBvoid png_progressive_combine_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIold_row\fP\fB, png_bytep \fInew_row\fP\fB);\fP + +\fBvoid png_read_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP + +\fBvoid png_read_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP + +\fBvoid png_read_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP + +\fBvoid png_read_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP + +\fBvoid png_read_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fIdisplay_row\fP\fB);\fP + +\fBvoid png_read_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_bytepp \fP\fIdisplay_row\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP + +\fBvoid png_read_update_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP + +\fBint png_reset_zstream (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_save_int_32 (png_bytep \fP\fIbuf\fP\fB, png_int_32 \fIi\fP\fB);\fP + +\fBvoid png_save_uint_16 (png_bytep \fP\fIbuf\fP\fB, unsigned int \fIi\fP\fB);\fP + +\fBvoid png_save_uint_32 (png_bytep \fP\fIbuf\fP\fB, png_uint_32 \fIi\fP\fB);\fP + +\fBvoid png_set_add_alpha (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP + +\fBvoid png_set_alpha_mode (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, double \fIoutput_gamma\fP\fB);\fP + +\fBvoid png_set_alpha_mode_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, png_fixed_point \fIoutput_gamma\fP\fB);\fP + +\fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP + +\fBvoid png_set_background_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, png_uint_32 \fIbackground_gamma\fP\fB);\fP + +\fBvoid png_set_benign_errors (png_structp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP + +\fBvoid png_set_bgr (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_bKGD (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_16p \fIbackground\fP\fB);\fP + +\fBvoid png_set_check_for_invalid_index(png_structrp \fP\fIpng_ptr\fP\fB, int \fIallowed\fP\fB);\fP + +\fBvoid png_set_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIwhite_x\fP\fB, double \fP\fIwhite_y\fP\fB, double \fP\fIred_x\fP\fB, double \fP\fIred_y\fP\fB, double \fP\fIgreen_x\fP\fB, double \fP\fIgreen_y\fP\fB, double \fP\fIblue_x\fP\fB, double \fIblue_y\fP\fB);\fP + +\fBvoid png_set_cHRM_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwhite_x\fP\fB, png_uint_32 \fP\fIwhite_y\fP\fB, png_uint_32 \fP\fIred_x\fP\fB, png_uint_32 \fP\fIred_y\fP\fB, png_uint_32 \fP\fIgreen_x\fP\fB, png_uint_32 \fP\fIgreen_y\fP\fB, png_uint_32 \fP\fIblue_x\fP\fB, png_uint_32 \fIblue_y\fP\fB);\fP + +\fBvoid png_set_cHRM_XYZ (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fP\fIred_X\fP\fB, double \fP\fIred_Y\fP\fB, double \fP\fIred_Z\fP\fB, double \fP\fIgreen_X\fP\fB, double \fP\fIgreen_Y\fP\fB, double \fP\fIgreen_Z\fP\fB, double \fP\fIblue_X\fP\fB, double \fP\fIblue_Y\fP\fB, double \fIblue_Z\fP\fB);\fP + +\fBvoid png_set_cHRM_XYZ_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_fixed_point \fP\fIint_red_X\fP\fB, png_fixed_point \fP\fIint_red_Y\fP\fB, png_fixed_point \fP\fIint_red_Z\fP\fB, png_fixed_point \fP\fIint_green_X\fP\fB, png_fixed_point \fP\fIint_green_Y\fP\fB, png_fixed_point \fP\fIint_green_Z\fP\fB, png_fixed_point \fP\fIint_blue_X\fP\fB, png_fixed_point \fP\fIint_blue_Y\fP\fB, png_fixed_point \fIint_blue_Z\fP\fB);\fP + +\fBvoid png_set_chunk_cache_max (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIuser_chunk_cache_max\fP\fB);\fP + +\fBvoid png_set_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP + +\fBvoid png_set_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP + +\fBvoid png_set_compression_method (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod\fP\fB);\fP + +\fBvoid png_set_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP + +\fBvoid png_set_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP + +\fBvoid png_set_crc_action (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIcrit_action\fP\fB, int \fIancil_action\fP\fB);\fP + +\fBvoid png_set_error_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIerror_ptr\fP\fB, png_error_ptr \fP\fIerror_fn\fP\fB, png_error_ptr \fIwarning_fn\fP\fB);\fP + +\fBvoid png_set_expand (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_expand_16 (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_expand_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_filler (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIfiller\fP\fB, int \fIflags\fP\fB);\fP + +\fBvoid png_set_filter (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImethod\fP\fB, int \fIfilters\fP\fB);\fP + +\fBvoid png_set_filter_heuristics (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_doublep \fP\fIfilter_weights\fP\fB, png_doublep \fIfilter_costs\fP\fB);\fP + +\fBvoid png_set_filter_heuristics_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIheuristic_method\fP\fB, int \fP\fInum_weights\fP\fB, png_fixed_point_p \fP\fIfilter_weights\fP\fB, png_fixed_point_p \fIfilter_costs\fP\fB);\fP + +\fBvoid png_set_flush (png_structp \fP\fIpng_ptr\fP\fB, int \fInrows\fP\fB);\fP + +\fBvoid png_set_gamma (png_structp \fP\fIpng_ptr\fP\fB, double \fP\fIscreen_gamma\fP\fB, double \fIdefault_file_gamma\fP\fB);\fP + +\fBvoid png_set_gamma_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIscreen_gamma\fP\fB, png_uint_32 \fIdefault_file_gamma\fP\fB);\fP + +\fBvoid png_set_gAMA (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, double \fIfile_gamma\fP\fB);\fP + +\fBvoid png_set_gAMA_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fIfile_gamma\fP\fB);\fP + +\fBvoid png_set_gray_1_2_4_to_8 (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_gray_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_16p \fIhist\fP\fB);\fP + +\fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_const_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_const_bytep \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP + +\fBint png_set_interlace_handling (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_invalid (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fImask\fP\fB);\fP + +\fBvoid png_set_invert_alpha (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_invert_mono (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_IHDR (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIwidth\fP\fB, png_uint_32 \fP\fIheight\fP\fB, int \fP\fIbit_depth\fP\fB, int \fP\fIcolor_type\fP\fB, int \fP\fIinterlace_type\fP\fB, int \fP\fIcompression_type\fP\fB, int \fIfilter_type\fP\fB);\fP + +\fBvoid png_set_keep_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIkeep\fP\fB, png_bytep \fP\fIchunk_list\fP\fB, int \fInum_chunks\fP\fB);\fP + +\fBjmp_buf* png_set_longjmp_fn (png_structp \fP\fIpng_ptr\fP\fB, png_longjmp_ptr \fP\fIlongjmp_fn\fP\fB, size_t \fIjmp_buf_size\fP\fB);\fP + +\fBvoid png_set_chunk_malloc_max (png_structp \fP\fIpng_ptr\fP\fB, png_alloc_size_t \fIuser_chunk_cache_max\fP\fB);\fP + +\fBvoid png_set_compression_buffer_size (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIsize\fP\fB);\fP + +\fBvoid png_set_mem_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fImem_ptr\fP\fB, png_malloc_ptr \fP\fImalloc_fn\fP\fB, png_free_ptr \fIfree_fn\fP\fB);\fP + +\fBvoid png_set_oFFs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIoffset_x\fP\fB, png_uint_32 \fP\fIoffset_y\fP\fB, int \fIunit_type\fP\fB);\fP + +\fBvoid png_set_packing (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_packswap (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_palette_to_rgb (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_pCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIpurpose\fP\fB, png_int_32 \fP\fIX0\fP\fB, png_int_32 \fP\fIX1\fP\fB, int \fP\fItype\fP\fB, int \fP\fInparams\fP\fB, png_charp \fP\fIunits\fP\fB, png_charpp \fIparams\fP\fB);\fP + +\fBvoid png_set_pHYs (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_uint_32 \fP\fIres_x\fP\fB, png_uint_32 \fP\fIres_y\fP\fB, int \fIunit_type\fP\fB);\fP + +\fBvoid png_set_progressive_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIprogressive_ptr\fP\fB, png_progressive_info_ptr \fP\fIinfo_fn\fP\fB, png_progressive_row_ptr \fP\fIrow_fn\fP\fB, png_progressive_end_ptr \fIend_fn\fP\fB);\fP + +\fBvoid png_set_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fInum_palette\fP\fB);\fP + +\fBvoid png_set_quantize (png_structp \fP\fIpng_ptr\fP\fB, png_colorp \fP\fIpalette\fP\fB, int \fP\fInum_palette\fP\fB, int \fP\fImaximum_colors\fP\fB, png_uint_16p \fP\fIhistogram\fP\fB, int \fIfull_quantize\fP\fB);\fP + +\fBvoid png_set_read_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fIread_data_fn\fP\fB);\fP + +\fBvoid png_set_read_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_read_status_ptr \fIread_row_fn\fP\fB);\fP + +\fBvoid png_set_read_user_chunk_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_chunk_ptr\fP\fB, png_user_chunk_ptr \fIread_user_chunk_fn\fP\fB);\fP + +\fBvoid png_set_read_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIread_user_transform_fn\fP\fB);\fP + +\fBvoid png_set_rgb_to_gray (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIerror_action\fP\fB, double \fP\fIred\fP\fB, double \fIgreen\fP\fB);\fP + +\fBvoid png_set_rgb_to_gray_fixed (png_structp \fP\fIpng_ptr\fP\fB, int error_action png_uint_32 \fP\fIred\fP\fB, png_uint_32 \fIgreen\fP\fB);\fP + +\fBvoid png_set_rows (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytepp \fIrow_pointers\fP\fB);\fP + +\fBvoid png_set_sBIT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_color_8p \fIsig_bit\fP\fB);\fP + +\fBvoid png_set_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, double \fP\fIwidth\fP\fB, double \fIheight\fP\fB);\fP + +\fBvoid png_set_sCAL_fixed (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_fixed_point \fP\fIwidth\fP\fB, png_fixed_point \fIheight\fP\fB);\fP + +\fBvoid png_set_sCAL_s (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIunit\fP\fB, png_charp \fP\fIwidth\fP\fB, png_charp \fIheight\fP\fB);\fP + +\fBvoid png_set_scale_16 (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_shift (png_structp \fP\fIpng_ptr\fP\fB, png_color_8p \fItrue_bits\fP\fB);\fP + +\fBvoid png_set_sig_bytes (png_structp \fP\fIpng_ptr\fP\fB, int \fInum_bytes\fP\fB);\fP + +\fBvoid png_set_sPLT (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_spalette_p \fP\fIsplt_ptr\fP\fB, int \fInum_spalettes\fP\fB);\fP + +\fBvoid png_set_sRGB (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP + +\fBvoid png_set_sRGB_gAMA_and_cHRM (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fIsrgb_intent\fP\fB);\fP + +\fBvoid png_set_strip_16 (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_strip_alpha (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_strip_error_numbers (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fIstrip_mode\fP\fB);\fP + +\fBvoid png_set_swap (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_swap_alpha (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_set_text (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_textp \fP\fItext_ptr\fP\fB, int \fInum_text\fP\fB);\fP + +\fBvoid png_set_text_compression_level (png_structp \fP\fIpng_ptr\fP\fB, int \fIlevel\fP\fB);\fP + +\fBvoid png_set_text_compression_mem_level (png_structp \fP\fIpng_ptr\fP\fB, int \fImem_level\fP\fB);\fP + +\fBvoid png_set_text_compression_strategy (png_structp \fP\fIpng_ptr\fP\fB, int \fIstrategy\fP\fB);\fP + +\fBvoid png_set_text_compression_window_bits (png_structp \fP\fIpng_ptr\fP\fB, int \fIwindow_bits\fP\fB);\fP + +\fBvoid \fP\fIpng_set_text_compression_method\fP\fB, (png_structp \fP\fIpng_ptr\fP\fB, int \fImethod)\fP\fB);\fP + +\fBvoid png_set_tIME (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_timep \fImod_time\fP\fB);\fP + +\fBvoid png_set_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_bytep \fP\fItrans_alpha\fP\fB, int \fP\fInum_trans\fP\fB, png_color_16p \fItrans_color\fP\fB);\fP + +\fBvoid png_set_tRNS_to_alpha (png_structp \fIpng_ptr\fP\fB);\fP + +\fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fP\fInum\fP\fB, int \fIlocation\fP\fB);\fP + +\fBvoid png_set_unknown_chunk_location (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fIchunk\fP\fB, int \fIlocation\fP\fB);\fP + +\fBvoid png_set_user_limits (png_structp \fP\fIpng_ptr\fP\fB, png_uint_32 \fP\fIuser_width_max\fP\fB, png_uint_32 \fIuser_height_max\fP\fB);\fP + +\fBvoid png_set_user_transform_info (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_transform_ptr\fP\fB, int \fP\fIuser_transform_depth\fP\fB, int \fIuser_transform_channels\fP\fB);\fP + +\fBvoid png_set_write_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIio_ptr\fP\fB, png_rw_ptr \fP\fIwrite_data_fn\fP\fB, png_flush_ptr \fIoutput_flush_fn\fP\fB);\fP + +\fBvoid png_set_write_status_fn (png_structp \fP\fIpng_ptr\fP\fB, png_write_status_ptr \fIwrite_row_fn\fP\fB);\fP + +\fBvoid png_set_write_user_transform_fn (png_structp \fP\fIpng_ptr\fP\fB, png_user_transform_ptr \fIwrite_user_transform_fn\fP\fB);\fP + +\fBint png_sig_cmp (png_bytep \fP\fIsig\fP\fB, png_size_t \fP\fIstart\fP\fB, png_size_t \fInum_to_check\fP\fB);\fP + +\fBvoid png_start_read_image (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_warning (png_structp \fP\fIpng_ptr\fP\fB, png_const_charp \fImessage\fP\fB);\fP + +\fBvoid png_write_chunk (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP + +\fBvoid png_write_chunk_data (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIdata\fP\fB, png_size_t \fIlength\fP\fB);\fP + +\fBvoid png_write_chunk_end (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_write_chunk_start (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIchunk_name\fP\fB, png_uint_32 \fIlength\fP\fB);\fP + +\fBvoid png_write_end (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP + +\fBvoid png_write_flush (png_structp \fIpng_ptr\fP\fB);\fP + +\fBvoid png_write_image (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fIimage\fP\fB);\fP + +\fBvoid png_write_info (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP + +\fBvoid png_write_info_before_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP + +\fBvoid png_write_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, png_voidp \fIparams\fP\fB);\fP + +\fBvoid png_write_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP + +\fBvoid png_write_rows (png_structp \fP\fIpng_ptr\fP\fB, png_bytepp \fP\fIrow\fP\fB, png_uint_32 \fInum_rows\fP\fB);\fP + +\fBvoid png_write_sig (png_structp \fIpng_ptr\fP\fB);\fP + +.SH DESCRIPTION +The +.I libpng +library supports encoding, decoding, and various manipulations of +the Portable Network Graphics (PNG) format image files. It uses the +.IR zlib(3) +compression library. +Following is a copy of the libpng-manual.txt file that accompanies libpng. +.SH LIBPNG.TXT +libpng-manual.txt - A description on how to use and modify libpng + + libpng version 1.6.12 - June 12, 2014 + Updated and distributed by Glenn Randers-Pehrson + <glennrp at users.sourceforge.net> + Copyright (c) 1998-2014 Glenn Randers-Pehrson + + This document is released under the libpng license. + For conditions of distribution and use, see the disclaimer + and license in png.h + + Based on: + + libpng versions 0.97, January 1998, through 1.6.12 - June 12, 2014 + Updated and distributed by Glenn Randers-Pehrson + Copyright (c) 1998-2014 Glenn Randers-Pehrson + + libpng 1.0 beta 6 - version 0.96 - May 28, 1997 + Updated and distributed by Andreas Dilger + Copyright (c) 1996, 1997 Andreas Dilger + + libpng 1.0 beta 2 - version 0.88 - January 26, 1996 + For conditions of distribution and use, see copyright + notice in png.h. Copyright (c) 1995, 1996 Guy Eric + Schalnat, Group 42, Inc. + + Updated/rewritten per request in the libpng FAQ + Copyright (c) 1995, 1996 Frank J. T. Wojcik + December 18, 1995 & January 20, 1996 + + TABLE OF CONTENTS + + I. Introduction + II. Structures + III. Reading + IV. Writing + V. Simplified API + VI. Modifying/Customizing libpng + VII. MNG support + VIII. Changes to Libpng from version 0.88 + IX. Changes to Libpng from version 1.0.x to 1.2.x + X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x + XI. Changes to Libpng from version 1.4.x to 1.5.x + XII. Changes to Libpng from version 1.5.x to 1.6.x + XIII. Detecting libpng + XIV. Source code repository + XV. Coding style + XVI. Y2K Compliance in libpng + +.SH I. Introduction + +This file describes how to use and modify the PNG reference library +(known as libpng) for your own use. In addition to this +file, example.c is a good starting point for using the library, as +it is heavily commented and should include everything most people +will need. We assume that libpng is already installed; see the +INSTALL file for instructions on how to configure and install libpng. + +For examples of libpng usage, see the files "example.c", "pngtest.c", +and the files in the "contrib" directory, all of which are included in +the libpng distribution. + +Libpng was written as a companion to the PNG specification, as a way +of reducing the amount of time and effort it takes to support the PNG +file format in application programs. + +The PNG specification (second edition), November 2003, is available as +a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at +<http://www.w3.org/TR/2003/REC-PNG-20031110/ +The W3C and ISO documents have identical technical content. + +The PNG-1.2 specification is available at +<http://www.libpng.org/pub/png/documents/>. It is technically equivalent +to the PNG specification (second edition) but has some additional material. + +The PNG-1.0 specification is available +as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a +W3C Recommendation <http://www.w3.org/TR/REC.png.html>. + +Some additional chunks are described in the special-purpose public chunks +documents at <http://www.libpng.org/pub/png/documents/>. + +Other information +about PNG, and the latest version of libpng, can be found at the PNG home +page, <http://www.libpng.org/pub/png/>. + +Most users will not have to modify the library significantly; advanced +users may want to modify it more. All attempts were made to make it as +complete as possible, while keeping the code easy to understand. +Currently, this library only supports C. Support for other languages +is being considered. + +Libpng has been designed to handle multiple sessions at one time, +to be easily modifiable, to be portable to the vast majority of +machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy +to use. The ultimate goal of libpng is to promote the acceptance of +the PNG file format in whatever way possible. While there is still +work to be done (see the TODO file), libpng should cover the +majority of the needs of its users. + +Libpng uses zlib for its compression and decompression of PNG files. +Further information about zlib, and the latest version of zlib, can +be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>. +The zlib compression utility is a general purpose utility that is +useful for more than PNG files, and can be used without libpng. +See the documentation delivered with zlib for more details. +You can usually find the source files for the zlib utility wherever you +find the libpng source files. + +Libpng is thread safe, provided the threads are using different +instances of the structures. Each thread should have its own +png_struct and png_info instances, and thus its own image. +Libpng does not protect itself against two threads using the +same instance of a structure. + +.SH II. Structures + +There are two main structures that are important to libpng, png_struct +and png_info. Both are internal structures that are no longer exposed +in the libpng interface (as of libpng 1.5.0). + +The png_info structure is designed to provide information about the +PNG file. At one time, the fields of png_info were intended to be +directly accessible to the user. However, this tended to cause problems +with applications using dynamically loaded libraries, and as a result +a set of interface functions for png_info (the png_get_*() and png_set_*() +functions) was developed, and direct access to the png_info fields was +deprecated.. + +The png_struct structure is the object used by the library to decode a +single image. As of 1.5.0 this structure is also not exposed. + +Almost all libpng APIs require a pointer to a png_struct as the first argument. +Many (in particular the png_set and png_get APIs) also require a pointer +to png_info as the second argument. Some application visible macros +defined in png.h designed for basic data access (reading and writing +integers in the PNG format) don't take a png_info pointer, but it's almost +always safe to assume that a (png_struct*) has to be passed to call an API +function. + +You can have more than one png_info structure associated with an image, +as illustrated in pngtest.c, one for information valid prior to the +IDAT chunks and another (called "end_info" below) for things after them. + +The png.h header file is an invaluable reference for programming with libpng. +And while I'm on the topic, make sure you include the libpng header file: + +#include <png.h> + +and also (as of libpng-1.5.0) the zlib header file, if you need it: + +#include <zlib.h> + +.SS Types + +The png.h header file defines a number of integral types used by the +APIs. Most of these are fairly obvious; for example types corresponding +to integers of particular sizes and types for passing color values. + +One exception is how non-integral numbers are handled. For application +convenience most APIs that take such numbers have C (double) arguments; +however, internally PNG, and libpng, use 32 bit signed integers and encode +the value by multiplying by 100,000. As of libpng 1.5.0 a convenience +macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point) +which is simply (png_int_32). + +All APIs that take (double) arguments also have a matching API that +takes the corresponding fixed point integer arguments. The fixed point +API has the same name as the floating point one with "_fixed" appended. +The actual range of values permitted in the APIs is frequently less than +the full range of (png_fixed_point) (\-21474 to +21474). When APIs require +a non-negative argument the type is recorded as png_uint_32 above. Consult +the header file and the text below for more information. + +Special care must be take with sCAL chunk handling because the chunk itself +uses non-integral values encoded as strings containing decimal floating point +numbers. See the comments in the header file. + +.SS Configuration + +The main header file function declarations are frequently protected by C +preprocessing directives of the form: + + #ifdef PNG_feature_SUPPORTED + declare-function + #endif + ... + #ifdef PNG_feature_SUPPORTED + use-function + #endif + +The library can be built without support for these APIs, although a +standard build will have all implemented APIs. Application programs +should check the feature macros before using an API for maximum +portability. From libpng 1.5.0 the feature macros set during the build +of libpng are recorded in the header file "pnglibconf.h" and this file +is always included by png.h. + +If you don't need to change the library configuration from the default, skip to +the next section ("Reading"). + +Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all +of the build project files in the 'projects' directory simply copy +scripts/pnglibconf.h.prebuilt to pnglibconf.h. This means that these build +systems do not permit easy auto-configuration of the library - they only +support the default configuration. + +The easiest way to make minor changes to the libpng configuration when +auto-configuration is supported is to add definitions to the command line +using (typically) CPPFLAGS. For example: + +CPPFLAGS=\-DPNG_NO_FLOATING_ARITHMETIC + +will change the internal libpng math implementation for gamma correction and +other arithmetic calculations to fixed point, avoiding the need for fast +floating point support. The result can be seen in the generated pnglibconf.h - +make sure it contains the changed feature macro setting. + +If you need to make more extensive configuration changes - more than one or two +feature macro settings - you can either add \-DPNG_USER_CONFIG to the build +command line and put a list of feature macro settings in pngusr.h or you can set +DFA_XTRA (a makefile variable) to a file containing the same information in the +form of 'option' settings. + +A. Changing pnglibconf.h + +A variety of methods exist to build libpng. Not all of these support +reconfiguration of pnglibconf.h. To reconfigure pnglibconf.h it must either be +rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand. + +Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to +pnglibconf.h and changing the lines defining the supported features, paying +very close attention to the 'option' information in scripts/pnglibconf.dfa +that describes those features and their requirements. This is easy to get +wrong. + +B. Configuration using DFA_XTRA + +Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later +variant such as 'nawk' or 'gawk', is available. The configure build will +automatically find an appropriate awk and build pnglibconf.h. +The scripts/pnglibconf.mak file contains a set of make rules for doing the +same thing if configure is not used, and many of the makefiles in the scripts +directory use this approach. + +When rebuilding simply write a new file containing changed options and set +DFA_XTRA to the name of this file. This causes the build to append the new file +to the end of scripts/pnglibconf.dfa. The pngusr.dfa file should contain lines +of the following forms: + +everything = off + +This turns all optional features off. Include it at the start of pngusr.dfa to +make it easier to build a minimal configuration. You will need to turn at least +some features on afterward to enable either reading or writing code, or both. + +option feature on +option feature off + +Enable or disable a single feature. This will automatically enable other +features required by a feature that is turned on or disable other features that +require a feature which is turned off. Conflicting settings will cause an error +message to be emitted by awk. + +setting feature default value + +Changes the default value of setting 'feature' to 'value'. There are a small +number of settings listed at the top of pnglibconf.h, they are documented in the +source code. Most of these values have performance implications for the library +but most of them have no visible effect on the API. Some can also be overridden +from the API. + +This method of building a customized pnglibconf.h is illustrated in +contrib/pngminim/*. See the "$(PNGCONF):" target in the makefile and +pngusr.dfa in these directories. + +C. Configuration using PNG_USER_CONFIG + +If \-DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built, +the file pngusr.h will automatically be included before the options in +scripts/pnglibconf.dfa are processed. Your pngusr.h file should contain only +macro definitions turning features on or off or setting settings. + +Apart from the global setting "everything = off" all the options listed above +can be set using macros in pngusr.h: + +#define PNG_feature_SUPPORTED + +is equivalent to: + +option feature on + +#define PNG_NO_feature + +is equivalent to: + +option feature off + +#define PNG_feature value + +is equivalent to: + +setting feature default value + +Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the +pngusr file you supply override the contents of scripts/pnglibconf.dfa + +If confusing or incomprehensible behavior results it is possible to +examine the intermediate file pnglibconf.dfn to find the full set of +dependency information for each setting and option. Simply locate the +feature in the file and read the C comments that precede it. + +This method is also illustrated in the contrib/pngminim/* makefiles and +pngusr.h. + +.SH III. Reading + +We'll now walk you through the possible functions to call when reading +in a PNG file sequentially, briefly explaining the syntax and purpose +of each one. See example.c and png.h for more detail. While +progressive reading is covered in the next section, you will still +need some of the functions discussed in this section to read a PNG +file. + +.SS Setup + +You will want to do the I/O initialization(*) before you get into libpng, +so if it doesn't work, you don't have much to undo. Of course, you +will also want to insure that you are, in fact, dealing with a PNG +file. Libpng provides a simple check to see if a file is a PNG file. +To use it, pass in the first 1 to 8 bytes of the file to the function +png_sig_cmp(), and it will return 0 (false) if the bytes match the +corresponding bytes of the PNG signature, or nonzero (true) otherwise. +Of course, the more bytes you pass in, the greater the accuracy of the +prediction. + +If you are intending to keep the file pointer open for use in libpng, +you must ensure you don't read more than 8 bytes from the beginning +of the file, and you also have to make a call to png_set_sig_bytes_read() +with the number of bytes you read from the beginning. Libpng will +then only check the bytes (if any) that your program didn't read. + +(*): If you are not using the standard I/O functions, you will need +to replace them with custom functions. See the discussion under +Customizing libpng. + + + FILE *fp = fopen(file_name, "rb"); + if (!fp) + { + return (ERROR); + } + + fread(header, 1, number, fp); + is_png = !png_sig_cmp(header, 0, number); + + if (!is_png) + { + return (NOT_PNG); + } + + +Next, png_struct and png_info need to be allocated and initialized. In +order to ensure that the size of these structures is correct even with a +dynamically linked libpng, there are functions to initialize and +allocate the structures. We also pass the library version, optional +pointers to error handling functions, and a pointer to a data struct for +use by the error functions, if necessary (the pointer and functions can +be NULL if the default error handlers are to be used). See the section +on Changes to Libpng below regarding the old initialization functions. +The structure allocation functions quietly return NULL if they fail to +create the structure, so your application should check for that. + + png_structp png_ptr = png_create_read_struct + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn); + + if (!png_ptr) + return (ERROR); + + png_infop info_ptr = png_create_info_struct(png_ptr); + + if (!info_ptr) + { + png_destroy_read_struct(&png_ptr, + (png_infopp)NULL, (png_infopp)NULL); + return (ERROR); + } + +If you want to use your own memory allocation routines, +use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use +png_create_read_struct_2() instead of png_create_read_struct(): + + png_structp png_ptr = png_create_read_struct_2 + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn, (png_voidp) + user_mem_ptr, user_malloc_fn, user_free_fn); + +The error handling routines passed to png_create_read_struct() +and the memory alloc/free routines passed to png_create_struct_2() +are only necessary if you are not using the libpng supplied error +handling and memory alloc/free functions. + +When libpng encounters an error, it expects to longjmp back +to your routine. Therefore, you will need to call setjmp and pass +your png_jmpbuf(png_ptr). If you read the file from different +routines, you will need to update the longjmp buffer every time you enter +a new routine that will call a png_*() function. + +See your documentation of setjmp/longjmp for your compiler for more +information on setjmp/longjmp. See the discussion on libpng error +handling in the Customizing Libpng section below for more information +on the libpng error handling. If an error occurs, and libpng longjmp's +back to your setjmp, you will want to call png_destroy_read_struct() to +free any memory. + + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_read_struct(&png_ptr, &info_ptr, + &end_info); + fclose(fp); + return (ERROR); + } + +Pass (png_infopp)NULL instead of &end_info if you didn't create +an end_info structure. + +If you would rather avoid the complexity of setjmp/longjmp issues, +you can compile libpng with PNG_NO_SETJMP, in which case +errors will result in a call to PNG_ABORT() which defaults to abort(). + +You can #define PNG_ABORT() to a function that does something +more useful than abort(), as long as your function does not +return. + +Now you need to set up the input code. The default for libpng is to +use the C function fread(). If you use this, you will need to pass a +valid FILE * in the function png_init_io(). Be sure that the file is +opened in binary mode. If you wish to handle reading data in another +way, you need not call the png_init_io() function, but you must then +implement the libpng I/O methods discussed in the Customizing Libpng +section below. + + png_init_io(png_ptr, fp); + +If you had previously opened the file and read any of the signature from +the beginning in order to see if this was a PNG file, you need to let +libpng know that there are some bytes missing from the start of the file. + + png_set_sig_bytes(png_ptr, number); + +You can change the zlib compression buffer size to be used while +reading compressed data with + + png_set_compression_buffer_size(png_ptr, buffer_size); + +where the default size is 8192 bytes. Note that the buffer size +is changed immediately and the buffer is reallocated immediately, +instead of setting a flag to be acted upon later. + +If you want CRC errors to be handled in a different manner than +the default, use + + png_set_crc_action(png_ptr, crit_action, ancil_action); + +The values for png_set_crc_action() say how libpng is to handle CRC errors in +ancillary and critical chunks, and whether to use the data contained +therein. Note that it is impossible to "discard" data in a critical +chunk. + +Choices for (int) crit_action are + PNG_CRC_DEFAULT 0 error/quit + PNG_CRC_ERROR_QUIT 1 error/quit + PNG_CRC_WARN_USE 3 warn/use data + PNG_CRC_QUIET_USE 4 quiet/use data + PNG_CRC_NO_CHANGE 5 use the current value + +Choices for (int) ancil_action are + PNG_CRC_DEFAULT 0 error/quit + PNG_CRC_ERROR_QUIT 1 error/quit + PNG_CRC_WARN_DISCARD 2 warn/discard data + PNG_CRC_WARN_USE 3 warn/use data + PNG_CRC_QUIET_USE 4 quiet/use data + PNG_CRC_NO_CHANGE 5 use the current value + +.SS Setting up callback code + +You can set up a callback function to handle any unknown chunks in the +input stream. You must supply the function + + read_chunk_callback(png_structp png_ptr, + png_unknown_chunkp chunk); + { + /* The unknown chunk structure contains your + chunk data, along with similar data for any other + unknown chunks: */ + + png_byte name[5]; + png_byte *data; + png_size_t size; + + /* Note that libpng has already taken care of + the CRC handling */ + + /* put your code here. Search for your chunk in the + unknown chunk structure, process it, and return one + of the following: */ + + return (\-n); /* chunk had an error */ + return (0); /* did not recognize */ + return (n); /* success */ + } + +(You can give your function another name that you like instead of +"read_chunk_callback") + +To inform libpng about your function, use + + png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr, + read_chunk_callback); + +This names not only the callback function, but also a user pointer that +you can retrieve with + + png_get_user_chunk_ptr(png_ptr); + +If you call the png_set_read_user_chunk_fn() function, then all unknown +chunks which the callback does not handle will be saved when read. You can +cause them to be discarded by returning '1' ("handled") instead of '0'. This +behavior will change in libpng 1.7 and the default handling set by the +png_set_keep_unknown_chunks() function, described below, will be used when the +callback returns 0. If you want the existing behavior you should set the global +default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current +versions of libpng and with 1.7. Libpng 1.6 issues a warning if you keep the +default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0. + +At this point, you can set up a callback function that will be +called after each row has been read, which you can use to control +a progress meter or the like. It's demonstrated in pngtest.c. +You must supply a function + + void read_row_callback(png_structp png_ptr, + png_uint_32 row, int pass); + { + /* put your code here */ + } + +(You can give it another name that you like instead of "read_row_callback") + +To inform libpng about your function, use + + png_set_read_status_fn(png_ptr, read_row_callback); + +When this function is called the row has already been completely processed and +the 'row' and 'pass' refer to the next row to be handled. For the +non-interlaced case the row that was just handled is simply one less than the +passed in row number, and pass will always be 0. For the interlaced case the +same applies unless the row value is 0, in which case the row just handled was +the last one from one of the preceding passes. Because interlacing may skip a +pass you cannot be sure that the preceding pass is just 'pass\-1', if you really +need to know what the last pass is record (row,pass) from the callback and use +the last recorded value each time. + +As with the user transform you can find the output row using the +PNG_ROW_FROM_PASS_ROW macro. + +.SS Unknown-chunk handling + +Now you get to set the way the library processes unknown chunks in the +input PNG stream. Both known and unknown chunks will be read. Normal +behavior is that known chunks will be parsed into information in +various info_ptr members while unknown chunks will be discarded. This +behavior can be wasteful if your application will never use some known +chunk types. To change this, you can call: + + png_set_keep_unknown_chunks(png_ptr, keep, + chunk_list, num_chunks); + + keep - 0: default unknown chunk handling + 1: ignore; do not keep + 2: keep only if safe-to-copy + 3: keep even if unsafe-to-copy + + You can use these definitions: + PNG_HANDLE_CHUNK_AS_DEFAULT 0 + PNG_HANDLE_CHUNK_NEVER 1 + PNG_HANDLE_CHUNK_IF_SAFE 2 + PNG_HANDLE_CHUNK_ALWAYS 3 + + chunk_list - list of chunks affected (a byte string, + five bytes per chunk, NULL or '\0' if + num_chunks is positive; ignored if + numchunks <= 0). + + num_chunks - number of chunks affected; if 0, all + unknown chunks are affected. If positive, + only the chunks in the list are affected, + and if negative all unknown chunks and + all known chunks except for the IHDR, + PLTE, tRNS, IDAT, and IEND chunks are + affected. + +Unknown chunks declared in this way will be saved as raw data onto a +list of png_unknown_chunk structures. If a chunk that is normally +known to libpng is named in the list, it will be handled as unknown, +according to the "keep" directive. If a chunk is named in successive +instances of png_set_keep_unknown_chunks(), the final instance will +take precedence. The IHDR and IEND chunks should not be named in +chunk_list; if they are, libpng will process them normally anyway. +If you know that your application will never make use of some particular +chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below. + +Here is an example of the usage of png_set_keep_unknown_chunks(), +where the private "vpAg" chunk will later be processed by a user chunk +callback function: + + png_byte vpAg[5]={118, 112, 65, 103, (png_byte) '\0'}; + + #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) + png_byte unused_chunks[]= + { + 104, 73, 83, 84, (png_byte) '\0', /* hIST */ + 105, 84, 88, 116, (png_byte) '\0', /* iTXt */ + 112, 67, 65, 76, (png_byte) '\0', /* pCAL */ + 115, 67, 65, 76, (png_byte) '\0', /* sCAL */ + 115, 80, 76, 84, (png_byte) '\0', /* sPLT */ + 116, 73, 77, 69, (png_byte) '\0', /* tIME */ + }; + #endif + + ... + + #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED) + /* ignore all unknown chunks + * (use global setting "2" for libpng16 and earlier): + */ + png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0); + + /* except for vpAg: */ + png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1); + + /* also ignore unused known chunks: */ + png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks, + (int)(sizeof unused_chunks)/5); + #endif + +.SS User limits + +The PNG specification allows the width and height of an image to be as +large as 2^(31\-1 (0x7fffffff), or about 2.147 billion rows and columns. +Since very few applications really need to process such large images, +we have imposed an arbitrary 1-million limit on rows and columns. +Larger images will be rejected immediately with a png_error() call. If +you wish to change this limit, you can use + + png_set_user_limits(png_ptr, width_max, height_max); + +to set your own limits, or use width_max = height_max = 0x7fffffffL +to allow all valid dimensions (libpng may reject some very large images +anyway because of potential buffer overflow conditions). + +You should put this statement after you create the PNG structure and +before calling png_read_info(), png_read_png(), or png_process_data(). + +When writing a PNG datastream, put this statement before calling +png_write_info() or png_write_png(). + +If you need to retrieve the limits that are being applied, use + + width_max = png_get_user_width_max(png_ptr); + height_max = png_get_user_height_max(png_ptr); + +The PNG specification sets no limit on the number of ancillary chunks +allowed in a PNG datastream. You can impose a limit on the total number +of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with + + png_set_chunk_cache_max(png_ptr, user_chunk_cache_max); + +where 0x7fffffffL means unlimited. You can retrieve this limit with + + chunk_cache_max = png_get_chunk_cache_max(png_ptr); + +You can also set a limit on the amount of memory that a compressed chunk +other than IDAT can occupy, with + + png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max); + +and you can retrieve the limit with + + chunk_malloc_max = png_get_chunk_malloc_max(png_ptr); + +Any chunks that would cause either of these limits to be exceeded will +be ignored. + +.SS Information about your system + +If you intend to display the PNG or to incorporate it in other image data you +need to tell libpng information about your display or drawing surface so that +libpng can convert the values in the image to match the display. + +From libpng-1.5.4 this information can be set before reading the PNG file +header. In earlier versions png_set_gamma() existed but behaved incorrectly if +called before the PNG file header had been read and png_set_alpha_mode() did not +exist. + +If you need to support versions prior to libpng-1.5.4 test the version number +as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures +described in the appropriate manual page. + +You give libpng the encoding expected by your system expressed as a 'gamma' +value. You can also specify a default encoding for the PNG file in +case the required information is missing from the file. By default libpng +assumes that the PNG data matches your system, to keep this default call: + + png_set_gamma(png_ptr, screen_gamma, output_gamma); + +or you can use the fixed point equivalent: + + png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma, + PNG_FP_1*output_gamma); + +If you don't know the gamma for your system it is probably 2.2 - a good +approximation to the IEC standard for display systems (sRGB). If images are +too contrasty or washed out you got the value wrong - check your system +documentation! + +Many systems permit the system gamma to be changed via a lookup table in the +display driver, a few systems, including older Macs, change the response by +default. As of 1.5.4 three special values are available to handle common +situations: + + PNG_DEFAULT_sRGB: Indicates that the system conforms to the + IEC 61966-2-1 standard. This matches almost + all systems. + PNG_GAMMA_MAC_18: Indicates that the system is an older + (pre Mac OS 10.6) Apple Macintosh system with + the default settings. + PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates + that the system expects data with no gamma + encoding. + +You would use the linear (unencoded) value if you need to process the pixel +values further because this avoids the need to decode and re-encode each +component value whenever arithmetic is performed. A lot of graphics software +uses linear values for this reason, often with higher precision component values +to preserve overall accuracy. + + +The output_gamma value expresses how to decode the output values, not how +they are encoded. The values used correspond to the normal numbers used to +describe the overall gamma of a computer display system; for example 2.2 for +an sRGB conformant system. The values are scaled by 100000 in the _fixed +version of the API (so 220000 for sRGB.) + +The inverse of the value is always used to provide a default for the PNG file +encoding if it has no gAMA chunk and if png_set_gamma() has not been called +to override the PNG gamma information. + +When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode +opaque pixels however pixels with lower alpha values are not encoded, +regardless of the output gamma setting. + +When the standard Porter Duff handling is requested with mode 1 the output +encoding is set to be linear and the output_gamma value is only relevant +as a default for input data that has no gamma information. The linear output +encoding will be overridden if png_set_gamma() is called - the results may be +highly unexpected! + +The following numbers are derived from the sRGB standard and the research +behind it. sRGB is defined to be approximated by a PNG gAMA chunk value of +0.45455 (1/2.2) for PNG. The value implicitly includes any viewing +correction required to take account of any differences in the color +environment of the original scene and the intended display environment; the +value expresses how to *decode* the image for display, not how the original +data was *encoded*. + +sRGB provides a peg for the PNG standard by defining a viewing environment. +sRGB itself, and earlier TV standards, actually use a more complex transform +(a linear portion then a gamma 2.4 power law) than PNG can express. (PNG is +limited to simple power laws.) By saying that an image for direct display on +an sRGB conformant system should be stored with a gAMA chunk value of 45455 +(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification +makes it possible to derive values for other display systems and +environments. + +The Mac value is deduced from the sRGB based on an assumption that the actual +extra viewing correction used in early Mac display systems was implemented as +a power 1.45 lookup table. + +Any system where a programmable lookup table is used or where the behavior of +the final display device characteristics can be changed requires system +specific code to obtain the current characteristic. However this can be +difficult and most PNG gamma correction only requires an approximate value. + +By default, if png_set_alpha_mode() is not called, libpng assumes that all +values are unencoded, linear, values and that the output device also has a +linear characteristic. This is only very rarely correct - it is invariably +better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the +default if you don't know what the right answer is! + +The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS +10.6) which used a correction table to implement a somewhat lower gamma on an +otherwise sRGB system. + +Both these values are reserved (not simple gamma values) in order to allow +more precise correction internally in the future. + +NOTE: the values can be passed to either the fixed or floating +point APIs, but the floating point API will also accept floating point +values. + +The second thing you may need to tell libpng about is how your system handles +alpha channel information. Some, but not all, PNG files contain an alpha +channel. To display these files correctly you need to compose the data onto a +suitable background, as described in the PNG specification. + +Libpng only supports composing onto a single color (using png_set_background; +see below). Otherwise you must do the composition yourself and, in this case, +you may need to call png_set_alpha_mode: + + #if PNG_LIBPNG_VER >= 10504 + png_set_alpha_mode(png_ptr, mode, screen_gamma); + #else + png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma); + #endif + +The screen_gamma value is the same as the argument to png_set_gamma; however, +how it affects the output depends on the mode. png_set_alpha_mode() sets the +file gamma default to 1/screen_gamma, so normally you don't need to call +png_set_gamma. If you need different defaults call png_set_gamma() before +png_set_alpha_mode() - if you call it after it will override the settings made +by png_set_alpha_mode(). + +The mode is as follows: + + PNG_ALPHA_PNG: The data is encoded according to the PNG +specification. Red, green and blue, or gray, components are +gamma encoded color values and are not premultiplied by the +alpha value. The alpha value is a linear measure of the +contribution of the pixel to the corresponding final output pixel. + +You should normally use this format if you intend to perform +color correction on the color values; most, maybe all, color +correction software has no handling for the alpha channel and, +anyway, the math to handle pre-multiplied component values is +unnecessarily complex. + +Before you do any arithmetic on the component values you need +to remove the gamma encoding and multiply out the alpha +channel. See the PNG specification for more detail. It is +important to note that when an image with an alpha channel is +scaled, linear encoded, pre-multiplied component values must +be used! + +The remaining modes assume you don't need to do any further color correction or +that if you do, your color correction software knows all about alpha (it +probably doesn't!). They 'associate' the alpha with the color information by +storing color channel values that have been scaled by the alpha. The +advantage is that the color channels can be resampled (the image can be +scaled) in this form. The disadvantage is that normal practice is to store +linear, not (gamma) encoded, values and this requires 16-bit channels for +still images rather than the 8-bit channels that are just about sufficient if +gamma encoding is used. In addition all non-transparent pixel values, +including completely opaque ones, must be gamma encoded to produce the final +image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes +described below (the latter being the two common names for associated alpha +color channels). Note that PNG files always contain non-associated color +channels; png_set_alpha_mode() with one of the modes causes the decoder to +convert the pixels to an associated form before returning them to your +application. + +Since it is not necessary to perform arithmetic on opaque color values so +long as they are not to be resampled and are in the final color space it is +possible to optimize the handling of alpha by storing the opaque pixels in +the PNG format (adjusted for the output color space) while storing partially +opaque pixels in the standard, linear, format. The accuracy required for +standard alpha composition is relatively low, because the pixels are +isolated, therefore typically the accuracy loss in storing 8-bit linear +values is acceptable. (This is not true if the alpha channel is used to +simulate transparency over large areas - use 16 bits or the PNG mode in +this case!) This is the 'OPTIMIZED' mode. For this mode a pixel is +treated as opaque only if the alpha value is equal to the maximum value. + + PNG_ALPHA_STANDARD: The data libpng produces is encoded in the +standard way assumed by most correctly written graphics software. +The gamma encoding will be removed by libpng and the +linear component values will be pre-multiplied by the +alpha channel. + +With this format the final image must be re-encoded to +match the display gamma before the image is displayed. +If your system doesn't do that, yet still seems to +perform arithmetic on the pixels without decoding them, +it is broken - check out the modes below. + +With PNG_ALPHA_STANDARD libpng always produces linear +component values, whatever screen_gamma you supply. The +screen_gamma value is, however, used as a default for +the file gamma if the PNG file has no gamma information. + +If you call png_set_gamma() after png_set_alpha_mode() you +will override the linear encoding. Instead the +pre-multiplied pixel values will be gamma encoded but +the alpha channel will still be linear. This may +actually match the requirements of some broken software, +but it is unlikely. + +While linear 8-bit data is often used it has +insufficient precision for any image with a reasonable +dynamic range. To avoid problems, and if your software +supports it, use png_set_expand_16() to force all +components to 16 bits. + + PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD +except that completely opaque pixels are gamma encoded according to +the screen_gamma value. Pixels with alpha less than 1.0 +will still have linear components. + +Use this format if you have control over your +compositing software and so don't do other arithmetic +(such as scaling) on the data you get from libpng. Your +compositing software can simply copy opaque pixels to +the output but still has linear values for the +non-opaque pixels. + +In normal compositing, where the alpha channel encodes +partial pixel coverage (as opposed to broad area +translucency), the inaccuracies of the 8-bit +representation of non-opaque pixels are irrelevant. + +You can also try this format if your software is broken; +it might look better. + + PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component +values, including the alpha channel are gamma encoded. This is +broken because, in practice, no implementation that uses this choice +correctly undoes the encoding before handling alpha composition. Use this +choice only if other serious errors in the software or hardware you use +mandate it. In most cases of broken software or hardware the bug in the +final display manifests as a subtle halo around composited parts of the +image. You may not even perceive this as a halo; the composited part of +the image may simply appear separate from the background, as though it had +been cut out of paper and pasted on afterward. + +If you don't have to deal with bugs in software or hardware, or if you can fix +them, there are three recommended ways of using png_set_alpha_mode(): + + png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG, + screen_gamma); + +You can do color correction on the result (libpng does not currently +support color correction internally). When you handle the alpha channel +you need to undo the gamma encoding and multiply out the alpha. + + png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD, + screen_gamma); + png_set_expand_16(png_ptr); + +If you are using the high level interface, don't call png_set_expand_16(); +instead pass PNG_TRANSFORM_EXPAND_16 to the interface. + +With this mode you can't do color correction, but you can do arithmetic, +including composition and scaling, on the data without further processing. + + png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED, + screen_gamma); + +You can avoid the expansion to 16-bit components with this mode, but you +lose the ability to scale the image or perform other linear arithmetic. +All you can do is compose the result onto a matching output. Since this +mode is libpng-specific you also need to write your own composition +software. + +The following are examples of calls to png_set_alpha_mode to achieve the +required overall gamma correction and, where necessary, alpha +premultiplication. + + png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); + +This is the default libpng handling of the alpha channel - it is not +pre-multiplied into the color components. In addition the call states +that the output is for a sRGB system and causes all PNG files without gAMA +chunks to be assumed to be encoded using sRGB. + + png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); + +In this case the output is assumed to be something like an sRGB conformant +display preceeded by a power-law lookup table of power 1.45. This is how +early Mac systems behaved. + + png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR); + +This is the classic Jim Blinn approach and will work in academic +environments where everything is done by the book. It has the shortcoming +of assuming that input PNG data with no gamma information is linear - this +is unlikely to be correct unless the PNG files where generated locally. +Most of the time the output precision will be so low as to show +significant banding in dark areas of the image. + + png_set_expand_16(pp); + png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB); + +This is a somewhat more realistic Jim Blinn inspired approach. PNG files +are assumed to have the sRGB encoding if not marked with a gamma value and +the output is always 16 bits per component. This permits accurate scaling +and processing of the data. If you know that your input PNG files were +generated locally you might need to replace PNG_DEFAULT_sRGB with the +correct value for your system. + + png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB); + +If you just need to composite the PNG image onto an existing background +and if you control the code that does this you can use the optimization +setting. In this case you just copy completely opaque pixels to the +output. For pixels that are not completely transparent (you just skip +those) you do the composition math using png_composite or png_composite_16 +below then encode the resultant 8-bit or 16-bit values to match the output +encoding. + + Other cases + +If neither the PNG nor the standard linear encoding work for you because +of the software or hardware you use then you have a big problem. The PNG +case will probably result in halos around the image. The linear encoding +will probably result in a washed out, too bright, image (it's actually too +contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably +substantially reduce the halos. Alternatively try: + + png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB); + +This option will also reduce the halos, but there will be slight dark +halos round the opaque parts of the image where the background is light. +In the OPTIMIZED mode the halos will be light halos where the background +is dark. Take your pick - the halos are unavoidable unless you can get +your hardware/software fixed! (The OPTIMIZED approach is slightly +faster.) + +When the default gamma of PNG files doesn't match the output gamma. +If you have PNG files with no gamma information png_set_alpha_mode allows +you to provide a default gamma, but it also sets the ouput gamma to the +matching value. If you know your PNG files have a gamma that doesn't +match the output you can take advantage of the fact that +png_set_alpha_mode always sets the output gamma but only sets the PNG +default if it is not already set: + + png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); + png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); + +The first call sets both the default and the output gamma values, the +second call overrides the output gamma without changing the default. This +is easier than achieving the same effect with png_set_gamma. You must use +PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will +fire if more than one call to png_set_alpha_mode and png_set_background is +made in the same read operation, however multiple calls with PNG_ALPHA_PNG +are ignored. + +If you don't need, or can't handle, the alpha channel you can call +png_set_background() to remove it by compositing against a fixed color. Don't +call png_set_strip_alpha() to do this - it will leave spurious pixel values in +transparent parts of this image. + + png_set_background(png_ptr, &background_color, + PNG_BACKGROUND_GAMMA_SCREEN, 0, 1); + +The background_color is an RGB or grayscale value according to the data format +libpng will produce for you. Because you don't yet know the format of the PNG +file, if you call png_set_background at this point you must arrange for the +format produced by libpng to always have 8-bit or 16-bit components and then +store the color as an 8-bit or 16-bit color as appropriate. The color contains +separate gray and RGB component values, so you can let libpng produce gray or +RGB output according to the input format, but low bit depth grayscale images +must always be converted to at least 8-bit format. (Even though low bit depth +grayscale images can't have an alpha channel they can have a transparent +color!) + +You set the transforms you need later, either as flags to the high level +interface or libpng API calls for the low level interface. For reference the +settings and API calls required are: + +8-bit values: + PNG_TRANSFORM_SCALE_16 | PNG_EXPAND + png_set_expand(png_ptr); png_set_scale_16(png_ptr); + + If you must get exactly the same inaccurate results + produced by default in versions prior to libpng-1.5.4, + use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr) + instead. + +16-bit values: + PNG_TRANSFORM_EXPAND_16 + png_set_expand_16(png_ptr); + +In either case palette image data will be expanded to RGB. If you just want +color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr) +to the list. + +Calling png_set_background before the PNG file header is read will not work +prior to libpng-1.5.4. Because the failure may result in unexpected warnings or +errors it is therefore much safer to call png_set_background after the head has +been read. Unfortunately this means that prior to libpng-1.5.4 it cannot be +used with the high level interface. + +.SS The high-level read interface + +At this point there are two ways to proceed; through the high-level +read interface, or through a sequence of low-level read operations. +You can use the high-level interface if (a) you are willing to read +the entire image into memory, and (b) the input transformations +you want to do are limited to the following set: + + PNG_TRANSFORM_IDENTITY No transformation + PNG_TRANSFORM_SCALE_16 Strip 16-bit samples to + 8-bit accurately + PNG_TRANSFORM_STRIP_16 Chop 16-bit samples to + 8-bit less accurately + PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel + PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit + samples to bytes + PNG_TRANSFORM_PACKSWAP Change order of packed + pixels to LSB first + PNG_TRANSFORM_EXPAND Perform set_expand() + PNG_TRANSFORM_INVERT_MONO Invert monochrome images + PNG_TRANSFORM_SHIFT Normalize pixels to the + sBIT depth + PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA + to BGRA + PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA + to AG + PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity + to transparency + PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples + PNG_TRANSFORM_GRAY_TO_RGB Expand grayscale samples + to RGB (or GA to RGBA) + PNG_TRANSFORM_EXPAND_16 Expand samples to 16 bits + +(This excludes setting a background color, doing gamma transformation, +quantizing, and setting filler.) If this is the case, simply do this: + + png_read_png(png_ptr, info_ptr, png_transforms, NULL) + +where png_transforms is an integer containing the bitwise OR of some +set of transformation flags. This call is equivalent to png_read_info(), +followed the set of transformations indicated by the transform mask, +then png_read_image(), and finally png_read_end(). + +(The final parameter of this call is not yet used. Someday it might point +to transformation parameters required by some future input transform.) + +You must use png_transforms and not call any png_set_transform() functions +when you use png_read_png(). + +After you have called png_read_png(), you can retrieve the image data +with + + row_pointers = png_get_rows(png_ptr, info_ptr); + +where row_pointers is an array of pointers to the pixel data for each row: + + png_bytep row_pointers[height]; + +If you know your image size and pixel size ahead of time, you can allocate +row_pointers prior to calling png_read_png() with + + if (height > PNG_UINT_32_MAX/(sizeof (png_byte))) + png_error (png_ptr, + "Image is too tall to process in memory"); + + if (width > PNG_UINT_32_MAX/pixel_size) + png_error (png_ptr, + "Image is too wide to process in memory"); + + row_pointers = png_malloc(png_ptr, + height*(sizeof (png_bytep))); + + for (int i=0; i<height, i++) + row_pointers[i]=NULL; /* security precaution */ + + for (int i=0; i<height, i++) + row_pointers[i]=png_malloc(png_ptr, + width*pixel_size); + + png_set_rows(png_ptr, info_ptr, &row_pointers); + +Alternatively you could allocate your image in one big block and define +row_pointers[i] to point into the proper places in your block. + +If you use png_set_rows(), the application is responsible for freeing +row_pointers (and row_pointers[i], if they were separately allocated). + +If you don't allocate row_pointers ahead of time, png_read_png() will +do it, and it'll be free'ed by libpng when you call png_destroy_*(). + +.SS The low-level read interface + +If you are going the low-level route, you are now ready to read all +the file information up to the actual image data. You do this with a +call to png_read_info(). + + png_read_info(png_ptr, info_ptr); + +This will process all chunks up to but not including the image data. + +This also copies some of the data from the PNG file into the decode structure +for use in later transformations. Important information copied in is: + +1) The PNG file gamma from the gAMA chunk. This overwrites the default value +provided by an earlier call to png_set_gamma or png_set_alpha_mode. + +2) Prior to libpng-1.5.4 the background color from a bKGd chunk. This +damages the information provided by an earlier call to png_set_background +resulting in unexpected behavior. Libpng-1.5.4 no longer does this. + +3) The number of significant bits in each component value. Libpng uses this to +optimize gamma handling by reducing the internal lookup table sizes. + +4) The transparent color information from a tRNS chunk. This can be modified by +a later call to png_set_tRNS. + +.SS Querying the info structure + +Functions are used to get the information from the info_ptr once it +has been read. Note that these fields may not be completely filled +in until png_read_end() has read the chunk data following the image. + + png_get_IHDR(png_ptr, info_ptr, &width, &height, + &bit_depth, &color_type, &interlace_type, + &compression_type, &filter_method); + + width - holds the width of the image + in pixels (up to 2^31). + + height - holds the height of the image + in pixels (up to 2^31). + + bit_depth - holds the bit depth of one of the + image channels. (valid values are + 1, 2, 4, 8, 16 and depend also on + the color_type. See also + significant bits (sBIT) below). + + color_type - describes which color/alpha channels + are present. + PNG_COLOR_TYPE_GRAY + (bit depths 1, 2, 4, 8, 16) + PNG_COLOR_TYPE_GRAY_ALPHA + (bit depths 8, 16) + PNG_COLOR_TYPE_PALETTE + (bit depths 1, 2, 4, 8) + PNG_COLOR_TYPE_RGB + (bit_depths 8, 16) + PNG_COLOR_TYPE_RGB_ALPHA + (bit_depths 8, 16) + + PNG_COLOR_MASK_PALETTE + PNG_COLOR_MASK_COLOR + PNG_COLOR_MASK_ALPHA + + interlace_type - (PNG_INTERLACE_NONE or + PNG_INTERLACE_ADAM7) + + compression_type - (must be PNG_COMPRESSION_TYPE_BASE + for PNG 1.0) + + filter_method - (must be PNG_FILTER_TYPE_BASE + for PNG 1.0, and can also be + PNG_INTRAPIXEL_DIFFERENCING if + the PNG datastream is embedded in + a MNG-1.0 datastream) + + Any or all of interlace_type, compression_type, or + filter_method can be NULL if you are + not interested in their values. + + Note that png_get_IHDR() returns 32-bit data into + the application's width and height variables. + This is an unsafe situation if these are 16-bit + variables. In such situations, the + png_get_image_width() and png_get_image_height() + functions described below are safer. + + width = png_get_image_width(png_ptr, + info_ptr); + + height = png_get_image_height(png_ptr, + info_ptr); + + bit_depth = png_get_bit_depth(png_ptr, + info_ptr); + + color_type = png_get_color_type(png_ptr, + info_ptr); + + interlace_type = png_get_interlace_type(png_ptr, + info_ptr); + + compression_type = png_get_compression_type(png_ptr, + info_ptr); + + filter_method = png_get_filter_type(png_ptr, + info_ptr); + + channels = png_get_channels(png_ptr, info_ptr); + + channels - number of channels of info for the + color type (valid values are 1 (GRAY, + PALETTE), 2 (GRAY_ALPHA), 3 (RGB), + 4 (RGB_ALPHA or RGB + filler byte)) + + rowbytes = png_get_rowbytes(png_ptr, info_ptr); + + rowbytes - number of bytes needed to hold a row + + signature = png_get_signature(png_ptr, info_ptr); + + signature - holds the signature read from the + file (if any). The data is kept in + the same offset it would be if the + whole signature were read (i.e. if an + application had already read in 4 + bytes of signature before starting + libpng, the remaining 4 bytes would + be in signature[4] through signature[7] + (see png_set_sig_bytes())). + +These are also important, but their validity depends on whether the chunk +has been read. The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and +png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the +data has been read, or zero if it is missing. The parameters to the +png_get_<chunk> are set directly if they are simple data types, or a +pointer into the info_ptr is returned for any complex types. + +The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks +is simply returned to give the application information about how the +image was encoded. Libpng itself only does transformations using the file +gamma when combining semitransparent pixels with the background color, and, +since libpng-1.6.0, when converting between 8-bit sRGB and 16-bit linear pixels +within the simplified API. Libpng also uses the file gamma when converting +RGB to gray, beginning with libpng-1.0.5, if the application calls +png_set_rgb_to_gray()). + + png_get_PLTE(png_ptr, info_ptr, &palette, + &num_palette); + + palette - the palette for the file + (array of png_color) + + num_palette - number of entries in the palette + + png_get_gAMA(png_ptr, info_ptr, &file_gamma); + png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma); + + file_gamma - the gamma at which the file is + written (PNG_INFO_gAMA) + + int_file_gamma - 100,000 times the gamma at which the + file is written + + png_get_cHRM(png_ptr, info_ptr, &white_x, &white_y, &red_x, + &red_y, &green_x, &green_y, &blue_x, &blue_y) + png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z, + &green_X, &green_Y, &green_Z, &blue_X, &blue_Y, + &blue_Z) + png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x, + &int_white_y, &int_red_x, &int_red_y, + &int_green_x, &int_green_y, &int_blue_x, + &int_blue_y) + png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y, + &int_red_Z, &int_green_X, &int_green_Y, + &int_green_Z, &int_blue_X, &int_blue_Y, + &int_blue_Z) + + {white,red,green,blue}_{x,y} + A color space encoding specified using the + chromaticities of the end points and the + white point. (PNG_INFO_cHRM) + + {red,green,blue}_{X,Y,Z} + A color space encoding specified using the + encoding end points - the CIE tristimulus + specification of the intended color of the red, + green and blue channels in the PNG RGB data. + The white point is simply the sum of the three + end points. (PNG_INFO_cHRM) + + png_get_sRGB(png_ptr, info_ptr, &srgb_intent); + + srgb_intent - the rendering intent (PNG_INFO_sRGB) + The presence of the sRGB chunk + means that the pixel data is in the + sRGB color space. This chunk also + implies specific values of gAMA and + cHRM. + + png_get_iCCP(png_ptr, info_ptr, &name, + &compression_type, &profile, &proflen); + + name - The profile name. + + compression_type - The compression type; always + PNG_COMPRESSION_TYPE_BASE for PNG 1.0. + You may give NULL to this argument to + ignore it. + + profile - International Color Consortium color + profile data. May contain NULs. + + proflen - length of profile data in bytes. + + png_get_sBIT(png_ptr, info_ptr, &sig_bit); + + sig_bit - the number of significant bits for + (PNG_INFO_sBIT) each of the gray, + red, green, and blue channels, + whichever are appropriate for the + given color type (png_color_16) + + png_get_tRNS(png_ptr, info_ptr, &trans_alpha, + &num_trans, &trans_color); + + trans_alpha - array of alpha (transparency) + entries for palette (PNG_INFO_tRNS) + + num_trans - number of transparent entries + (PNG_INFO_tRNS) + + trans_color - graylevel or color sample values of + the single transparent color for + non-paletted images (PNG_INFO_tRNS) + + png_get_hIST(png_ptr, info_ptr, &hist); + (PNG_INFO_hIST) + + hist - histogram of palette (array of + png_uint_16) + + png_get_tIME(png_ptr, info_ptr, &mod_time); + + mod_time - time image was last modified + (PNG_VALID_tIME) + + png_get_bKGD(png_ptr, info_ptr, &background); + + background - background color (of type + png_color_16p) (PNG_VALID_bKGD) + valid 16-bit red, green and blue + values, regardless of color_type + + num_comments = png_get_text(png_ptr, info_ptr, + &text_ptr, &num_text); + + num_comments - number of comments + + text_ptr - array of png_text holding image + comments + + text_ptr[i].compression - type of compression used + on "text" PNG_TEXT_COMPRESSION_NONE + PNG_TEXT_COMPRESSION_zTXt + PNG_ITXT_COMPRESSION_NONE + PNG_ITXT_COMPRESSION_zTXt + + text_ptr[i].key - keyword for comment. Must contain + 1-79 characters. + + text_ptr[i].text - text comments for current + keyword. Can be empty. + + text_ptr[i].text_length - length of text string, + after decompression, 0 for iTXt + + text_ptr[i].itxt_length - length of itxt string, + after decompression, 0 for tEXt/zTXt + + text_ptr[i].lang - language of comment (empty + string for unknown). + + text_ptr[i].lang_key - keyword in UTF-8 + (empty string for unknown). + + Note that the itxt_length, lang, and lang_key + members of the text_ptr structure only exist when the + library is built with iTXt chunk support. Prior to + libpng-1.4.0 the library was built by default without + iTXt support. Also note that when iTXt is supported, + they contain NULL pointers when the "compression" + field contains PNG_TEXT_COMPRESSION_NONE or + PNG_TEXT_COMPRESSION_zTXt. + + num_text - number of comments (same as + num_comments; you can put NULL here + to avoid the duplication) + + Note while png_set_text() will accept text, language, + and translated keywords that can be NULL pointers, the + structure returned by png_get_text will always contain + regular zero-terminated C strings. They might be + empty strings but they will never be NULL pointers. + + num_spalettes = png_get_sPLT(png_ptr, info_ptr, + &palette_ptr); + + num_spalettes - number of sPLT chunks read. + + palette_ptr - array of palette structures holding + contents of one or more sPLT chunks + read. + + png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y, + &unit_type); + + offset_x - positive offset from the left edge + of the screen (can be negative) + + offset_y - positive offset from the top edge + of the screen (can be negative) + + unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER + + png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y, + &unit_type); + + res_x - pixels/unit physical resolution in + x direction + + res_y - pixels/unit physical resolution in + x direction + + unit_type - PNG_RESOLUTION_UNKNOWN, + PNG_RESOLUTION_METER + + png_get_sCAL(png_ptr, info_ptr, &unit, &width, + &height) + + unit - physical scale units (an integer) + + width - width of a pixel in physical scale units + + height - height of a pixel in physical scale units + (width and height are doubles) + + png_get_sCAL_s(png_ptr, info_ptr, &unit, &width, + &height) + + unit - physical scale units (an integer) + + width - width of a pixel in physical scale units + (expressed as a string) + + height - height of a pixel in physical scale units + (width and height are strings like "2.54") + + num_unknown_chunks = png_get_unknown_chunks(png_ptr, + info_ptr, &unknowns) + + unknowns - array of png_unknown_chunk + structures holding unknown chunks + + unknowns[i].name - name of unknown chunk + + unknowns[i].data - data of unknown chunk + + unknowns[i].size - size of unknown chunk's data + + unknowns[i].location - position of chunk in file + + The value of "i" corresponds to the order in which the + chunks were read from the PNG file or inserted with the + png_set_unknown_chunks() function. + + The value of "location" is a bitwise "or" of + + PNG_HAVE_IHDR (0x01) + PNG_HAVE_PLTE (0x02) + PNG_AFTER_IDAT (0x08) + +The data from the pHYs chunk can be retrieved in several convenient +forms: + + res_x = png_get_x_pixels_per_meter(png_ptr, + info_ptr) + + res_y = png_get_y_pixels_per_meter(png_ptr, + info_ptr) + + res_x_and_y = png_get_pixels_per_meter(png_ptr, + info_ptr) + + res_x = png_get_x_pixels_per_inch(png_ptr, + info_ptr) + + res_y = png_get_y_pixels_per_inch(png_ptr, + info_ptr) + + res_x_and_y = png_get_pixels_per_inch(png_ptr, + info_ptr) + + aspect_ratio = png_get_pixel_aspect_ratio(png_ptr, + info_ptr) + + Each of these returns 0 [signifying "unknown"] if + the data is not present or if res_x is 0; + res_x_and_y is 0 if res_x != res_y + + Note that because of the way the resolutions are + stored internally, the inch conversions won't + come out to exactly even number. For example, + 72 dpi is stored as 0.28346 pixels/meter, and + when this is retrieved it is 71.9988 dpi, so + be sure to round the returned value appropriately + if you want to display a reasonable-looking result. + +The data from the oFFs chunk can be retrieved in several convenient +forms: + + x_offset = png_get_x_offset_microns(png_ptr, info_ptr); + + y_offset = png_get_y_offset_microns(png_ptr, info_ptr); + + x_offset = png_get_x_offset_inches(png_ptr, info_ptr); + + y_offset = png_get_y_offset_inches(png_ptr, info_ptr); + + Each of these returns 0 [signifying "unknown" if both + x and y are 0] if the data is not present or if the + chunk is present but the unit is the pixel. The + remark about inexact inch conversions applies here + as well, because a value in inches can't always be + converted to microns and back without some loss + of precision. + +For more information, see the +PNG specification for chunk contents. Be careful with trusting +rowbytes, as some of the transformations could increase the space +needed to hold a row (expand, filler, gray_to_rgb, etc.). +See png_read_update_info(), below. + +A quick word about text_ptr and num_text. PNG stores comments in +keyword/text pairs, one pair per chunk, with no limit on the number +of text chunks, and a 2^31 byte limit on their size. While there are +suggested keywords, there is no requirement to restrict the use to these +strings. It is strongly suggested that keywords and text be sensible +to humans (that's the point), so don't use abbreviations. Non-printing +symbols are not allowed. See the PNG specification for more details. +There is also no requirement to have text after the keyword. + +Keywords should be limited to 79 Latin-1 characters without leading or +trailing spaces, but non-consecutive spaces are allowed within the +keyword. It is possible to have the same keyword any number of times. +The text_ptr is an array of png_text structures, each holding a +pointer to a language string, a pointer to a keyword and a pointer to +a text string. The text string, language code, and translated +keyword may be empty or NULL pointers. The keyword/text +pairs are put into the array in the order that they are received. +However, some or all of the text chunks may be after the image, so, to +make sure you have read all the text chunks, don't mess with these +until after you read the stuff after the image. This will be +mentioned again below in the discussion that goes with png_read_end(). + +.SS Input transformations + +After you've read the header information, you can set up the library +to handle any special transformations of the image data. The various +ways to transform the data will be described in the order that they +should occur. This is important, as some of these change the color +type and/or bit depth of the data, and some others only work on +certain color types and bit depths. + +Transformations you request are ignored if they don't have any meaning for a +particular input data format. However some transformations can have an effect +as a result of a previous transformation. If you specify a contradictory set of +transformations, for example both adding and removing the alpha channel, you +cannot predict the final result. + +The color used for the transparency values should be supplied in the same +format/depth as the current image data. It is stored in the same format/depth +as the image data in a tRNS chunk, so this is what libpng expects for this data. + +The color used for the background value depends on the need_expand argument as +described below. + +Data will be decoded into the supplied row buffers packed into bytes +unless the library has been told to transform it into another format. +For example, 4 bit/pixel paletted or grayscale data will be returned +2 pixels/byte with the leftmost pixel in the high-order bits of the +byte, unless png_set_packing() is called. 8-bit RGB data will be stored +in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha() +is called to insert filler bytes, either before or after each RGB triplet. +16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant +byte of the color value first, unless png_set_scale_16() is called to +transform it to regular RGB RGB triplets, or png_set_filler() or +png_set_add alpha() is called to insert filler bytes, either before or +after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can +be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(), +or png_set_scale_16(). + +The following code transforms grayscale images of less than 8 to 8 bits, +changes paletted images to RGB, and adds a full alpha channel if there is +transparency information in a tRNS chunk. This is most useful on +grayscale images with bit depths of 2 or 4 or if there is a multiple-image +viewing application that wishes to treat all images in the same way. + + if (color_type == PNG_COLOR_TYPE_PALETTE) + png_set_palette_to_rgb(png_ptr); + + if (png_get_valid(png_ptr, info_ptr, + PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr); + + if (color_type == PNG_COLOR_TYPE_GRAY && + bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr); + +The first two functions are actually aliases for png_set_expand(), added +in libpng version 1.0.4, with the function names expanded to improve code +readability. In some future version they may actually do different +things. + +As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was +added. It expands the sample depth without changing tRNS to alpha. + +As of libpng version 1.5.2, png_set_expand_16() was added. It behaves as +png_set_expand(); however, the resultant channels have 16 bits rather than 8. +Use this when the output color or gray channels are made linear to avoid fairly +severe accuracy loss. + + if (bit_depth < 16) + png_set_expand_16(png_ptr); + +PNG can have files with 16 bits per channel. If you only can handle +8 bits per channel, this will strip the pixels down to 8-bit. + + if (bit_depth == 16) +#if PNG_LIBPNG_VER >= 10504 + png_set_scale_16(png_ptr); +#else + png_set_strip_16(png_ptr); +#endif + +(The more accurate "png_set_scale_16()" API became available in libpng version +1.5.4). + +If you need to process the alpha channel on the image separately from the image +data (for example if you convert it to a bitmap mask) it is possible to have +libpng strip the channel leaving just RGB or gray data: + + if (color_type & PNG_COLOR_MASK_ALPHA) + png_set_strip_alpha(png_ptr); + +If you strip the alpha channel you need to find some other way of dealing with +the information. If, instead, you want to convert the image to an opaque +version with no alpha channel use png_set_background; see below. + +As of libpng version 1.5.2, almost all useful expansions are supported, the +major ommissions are conversion of grayscale to indexed images (which can be +done trivially in the application) and conversion of indexed to grayscale (which +can be done by a trivial manipulation of the palette.) + +In the following table, the 01 means grayscale with depth<8, 31 means +indexed with depth<8, other numerals represent the color type, "T" means +the tRNS chunk is present, A means an alpha channel is present, and O +means tRNS or alpha is present but all pixels in the image are opaque. + + FROM 01 31 0 0T 0O 2 2T 2O 3 3T 3O 4A 4O 6A 6O + TO + 01 - [G] - - - - - - - - - - - - - + 31 [Q] Q [Q] [Q] [Q] Q Q Q Q Q Q [Q] [Q] Q Q + 0 1 G + . . G G G G G G B B GB GB + 0T lt Gt t + . Gt G G Gt G G Bt Bt GBt GBt + 0O lt Gt t . + Gt Gt G Gt Gt G Bt Bt GBt GBt + 2 C P C C C + . . C - - CB CB B B + 2T Ct - Ct C C t + t - - - CBt CBt Bt Bt + 2O Ct - Ct C C t t + - - - CBt CBt Bt Bt + 3 [Q] p [Q] [Q] [Q] Q Q Q + . . [Q] [Q] Q Q + 3T [Qt] p [Qt][Q] [Q] Qt Qt Qt t + t [Qt][Qt] Qt Qt + 3O [Qt] p [Qt][Q] [Q] Qt Qt Qt t t + [Qt][Qt] Qt Qt + 4A lA G A T T GA GT GT GA GT GT + BA G GBA + 4O lA GBA A T T GA GT GT GA GT GT BA + GBA G + 6A CA PA CA C C A T tT PA P P C CBA + BA + 6O CA PBA CA C C A tT T PA P P CBA C BA + + +Within the matrix, + "+" identifies entries where 'from' and 'to' are the same. + "-" means the transformation is not supported. + "." means nothing is necessary (a tRNS chunk can just be ignored). + "t" means the transformation is obtained by png_set_tRNS. + "A" means the transformation is obtained by png_set_add_alpha(). + "X" means the transformation is obtained by png_set_expand(). + "1" means the transformation is obtained by + png_set_expand_gray_1_2_4_to_8() (and by png_set_expand() + if there is no transparency in the original or the final + format). + "C" means the transformation is obtained by png_set_gray_to_rgb(). + "G" means the transformation is obtained by png_set_rgb_to_gray(). + "P" means the transformation is obtained by + png_set_expand_palette_to_rgb(). + "p" means the transformation is obtained by png_set_packing(). + "Q" means the transformation is obtained by png_set_quantize(). + "T" means the transformation is obtained by + png_set_tRNS_to_alpha(). + "B" means the transformation is obtained by + png_set_background(), or png_strip_alpha(). + +When an entry has multiple transforms listed all are required to cause the +right overall transformation. When two transforms are separated by a comma +either will do the job. When transforms are enclosed in [] the transform should +do the job but this is currently unimplemented - a different format will result +if the suggested transformations are used. + +In PNG files, the alpha channel in an image +is the level of opacity. If you need the alpha channel in an image to +be the level of transparency instead of opacity, you can invert the +alpha channel (or the tRNS chunk data) after it's read, so that 0 is +fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit +images) is fully transparent, with + + png_set_invert_alpha(png_ptr); + +PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as +they can, resulting in, for example, 8 pixels per byte for 1 bit +files. This code expands to 1 pixel per byte without changing the +values of the pixels: + + if (bit_depth < 8) + png_set_packing(png_ptr); + +PNG files have possible bit depths of 1, 2, 4, 8, and 16. All pixels +stored in a PNG image have been "scaled" or "shifted" up to the next +higher possible bit depth (e.g. from 5 bits/sample in the range [0,31] +to 8 bits/sample in the range [0, 255]). However, it is also possible +to convert the PNG pixel data back to the original bit depth of the +image. This call reduces the pixels back down to the original bit depth: + + png_color_8p sig_bit; + + if (png_get_sBIT(png_ptr, info_ptr, &sig_bit)) + png_set_shift(png_ptr, sig_bit); + +PNG files store 3-color pixels in red, green, blue order. This code +changes the storage of the pixels to blue, green, red: + + if (color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_RGB_ALPHA) + png_set_bgr(png_ptr); + +PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them +into 4 or 8 bytes for windowing systems that need them in this format: + + if (color_type == PNG_COLOR_TYPE_RGB) + png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE); + +where "filler" is the 8 or 16-bit number to fill with, and the location is +either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether +you want the filler before the RGB or after. This transformation +does not affect images that already have full alpha channels. To add an +opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which +will generate RGBA pixels. + +Note that png_set_filler() does not change the color type. If you want +to do that, you can add a true alpha channel with + + if (color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_GRAY) + png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER); + +where "filler" contains the alpha value to assign to each pixel. +This function was added in libpng-1.2.7. + +If you are reading an image with an alpha channel, and you need the +data as ARGB instead of the normal PNG format RGBA: + + if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) + png_set_swap_alpha(png_ptr); + +For some uses, you may want a grayscale image to be represented as +RGB. This code will do that conversion: + + if (color_type == PNG_COLOR_TYPE_GRAY || + color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + png_set_gray_to_rgb(png_ptr); + +Conversely, you can convert an RGB or RGBA image to grayscale or grayscale +with alpha. + + if (color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_RGB_ALPHA) + png_set_rgb_to_gray(png_ptr, error_action, + double red_weight, double green_weight); + + error_action = 1: silently do the conversion + + error_action = 2: issue a warning if the original + image has any pixel where + red != green or red != blue + + error_action = 3: issue an error and abort the + conversion if the original + image has any pixel where + red != green or red != blue + + red_weight: weight of red component + + green_weight: weight of green component + If either weight is negative, default + weights are used. + +In the corresponding fixed point API the red_weight and green_weight values are +simply scaled by 100,000: + + png_set_rgb_to_gray(png_ptr, error_action, + png_fixed_point red_weight, + png_fixed_point green_weight); + +If you have set error_action = 1 or 2, you can +later check whether the image really was gray, after processing +the image rows, with the png_get_rgb_to_gray_status(png_ptr) function. +It will return a png_byte that is zero if the image was gray or +1 if there were any non-gray pixels. Background and sBIT data +will be silently converted to grayscale, using the green channel +data for sBIT, regardless of the error_action setting. + +The default values come from the PNG file cHRM chunk if present; otherwise, the +defaults correspond to the ITU-R recommendation 709, and also the sRGB color +space, as recommended in the Charles Poynton's Colour FAQ, +<http://www.poynton.com/>, in section 9: + + <http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9> + + Y = 0.2126 * R + 0.7152 * G + 0.0722 * B + +Previous versions of this document, 1998 through 2002, recommended a slightly +different formula: + + Y = 0.212671 * R + 0.715160 * G + 0.072169 * B + +Libpng uses an integer approximation: + + Y = (6968 * R + 23434 * G + 2366 * B)/32768 + +The calculation is done in a linear colorspace, if the image gamma +can be determined. + +The png_set_background() function has been described already; it tells libpng to +composite images with alpha or simple transparency against the supplied +background color. For compatibility with versions of libpng earlier than +libpng-1.5.4 it is recommended that you call the function after reading the file +header, even if you don't want to use the color in a bKGD chunk, if one exists. + +If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid), +you may use this color, or supply another color more suitable for +the current display (e.g., the background color from a web page). You +need to tell libpng how the color is represented, both the format of the +component values in the color (the number of bits) and the gamma encoding of the +color. The function takes two arguments, background_gamma_mode and need_expand +to convey this information; however, only two combinations are likely to be +useful: + + png_color_16 my_background; + png_color_16p image_background; + + if (png_get_bKGD(png_ptr, info_ptr, &image_background)) + png_set_background(png_ptr, image_background, + PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1); + else + png_set_background(png_ptr, &my_background, + PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1); + +The second call was described above - my_background is in the format of the +final, display, output produced by libpng. Because you now know the format of +the PNG it is possible to avoid the need to choose either 8-bit or 16-bit +output and to retain palette images (the palette colors will be modified +appropriately and the tRNS chunk removed.) However, if you are doing this, +take great care not to ask for transformations without checking first that +they apply! + +In the first call the background color has the original bit depth and color type +of the PNG file. So, for palette images the color is supplied as a palette +index and for low bit greyscale images the color is a reduced bit value in +image_background->gray. + +If you didn't call png_set_gamma() before reading the file header, for example +if you need your code to remain compatible with older versions of libpng prior +to libpng-1.5.4, this is the place to call it. + +Do not call it if you called png_set_alpha_mode(); doing so will damage the +settings put in place by png_set_alpha_mode(). (If png_set_alpha_mode() is +supported then you can certainly do png_set_gamma() before reading the PNG +header.) + +This API unconditionally sets the screen and file gamma values, so it will +override the value in the PNG file unless it is called before the PNG file +reading starts. For this reason you must always call it with the PNG file +value when you call it in this position: + + if (png_get_gAMA(png_ptr, info_ptr, &file_gamma)) + png_set_gamma(png_ptr, screen_gamma, file_gamma); + + else + png_set_gamma(png_ptr, screen_gamma, 0.45455); + +If you need to reduce an RGB file to a paletted file, or if a paletted +file has more entries then will fit on your screen, png_set_quantize() +will do that. Note that this is a simple match quantization that merely +finds the closest color available. This should work fairly well with +optimized palettes, but fairly badly with linear color cubes. If you +pass a palette that is larger than maximum_colors, the file will +reduce the number of colors in the palette so it will fit into +maximum_colors. If there is a histogram, libpng will use it to make +more intelligent choices when reducing the palette. If there is no +histogram, it may not do as good a job. + + if (color_type & PNG_COLOR_MASK_COLOR) + { + if (png_get_valid(png_ptr, info_ptr, + PNG_INFO_PLTE)) + { + png_uint_16p histogram = NULL; + + png_get_hIST(png_ptr, info_ptr, + &histogram); + png_set_quantize(png_ptr, palette, num_palette, + max_screen_colors, histogram, 1); + } + + else + { + png_color std_color_cube[MAX_SCREEN_COLORS] = + { ... colors ... }; + + png_set_quantize(png_ptr, std_color_cube, + MAX_SCREEN_COLORS, MAX_SCREEN_COLORS, + NULL,0); + } + } + +PNG files describe monochrome as black being zero and white being one. +The following code will reverse this (make black be one and white be +zero): + + if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY) + png_set_invert_mono(png_ptr); + +This function can also be used to invert grayscale and gray-alpha images: + + if (color_type == PNG_COLOR_TYPE_GRAY || + color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + png_set_invert_mono(png_ptr); + +PNG files store 16-bit pixels in network byte order (big-endian, +ie. most significant bits first). This code changes the storage to the +other way (little-endian, i.e. least significant bits first, the +way PCs store them): + + if (bit_depth == 16) + png_set_swap(png_ptr); + +If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you +need to change the order the pixels are packed into bytes, you can use: + + if (bit_depth < 8) + png_set_packswap(png_ptr); + +Finally, you can write your own transformation function if none of +the existing ones meets your needs. This is done by setting a callback +with + + png_set_read_user_transform_fn(png_ptr, + read_transform_fn); + +You must supply the function + + void read_transform_fn(png_structp png_ptr, png_row_infop + row_info, png_bytep data) + +See pngtest.c for a working example. Your function will be called +after all of the other transformations have been processed. Take care with +interlaced images if you do the interlace yourself - the width of the row is the +width in 'row_info', not the overall image width. + +If supported, libpng provides two information routines that you can use to find +where you are in processing the image: + + png_get_current_pass_number(png_structp png_ptr); + png_get_current_row_number(png_structp png_ptr); + +Don't try using these outside a transform callback - firstly they are only +supported if user transforms are supported, secondly they may well return +unexpected results unless the row is actually being processed at the moment they +are called. + +With interlaced +images the value returned is the row in the input sub-image image. Use +PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to +find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass). + +The discussion of interlace handling above contains more information on how to +use these values. + +You can also set up a pointer to a user structure for use by your +callback function, and you can inform libpng that your transform +function will change the number of channels or bit depth with the +function + + png_set_user_transform_info(png_ptr, user_ptr, + user_depth, user_channels); + +The user's application, not libpng, is responsible for allocating and +freeing any memory required for the user structure. + +You can retrieve the pointer via the function +png_get_user_transform_ptr(). For example: + + voidp read_user_transform_ptr = + png_get_user_transform_ptr(png_ptr); + +The last thing to handle is interlacing; this is covered in detail below, +but you must call the function here if you want libpng to handle expansion +of the interlaced image. + + number_of_passes = png_set_interlace_handling(png_ptr); + +After setting the transformations, libpng can update your png_info +structure to reflect any transformations you've requested with this +call. + + png_read_update_info(png_ptr, info_ptr); + +This is most useful to update the info structure's rowbytes +field so you can use it to allocate your image memory. This function +will also update your palette with the correct screen_gamma and +background if these have been given with the calls above. You may +only call png_read_update_info() once with a particular info_ptr. + +After you call png_read_update_info(), you can allocate any +memory you need to hold the image. The row data is simply +raw byte data for all forms of images. As the actual allocation +varies among applications, no example will be given. If you +are allocating one large chunk, you will need to build an +array of pointers to each row, as it will be needed for some +of the functions below. + +Remember: Before you call png_read_update_info(), the png_get_*() +functions return the values corresponding to the original PNG image. +After you call png_read_update_info the values refer to the image +that libpng will output. Consequently you must call all the png_set_ +functions before you call png_read_update_info(). This is particularly +important for png_set_interlace_handling() - if you are going to call +png_read_update_info() you must call png_set_interlace_handling() before +it unless you want to receive interlaced output. + +.SS Reading image data + +After you've allocated memory, you can read the image data. +The simplest way to do this is in one function call. If you are +allocating enough memory to hold the whole image, you can just +call png_read_image() and libpng will read in all the image data +and put it in the memory area supplied. You will need to pass in +an array of pointers to each row. + +This function automatically handles interlacing, so you don't +need to call png_set_interlace_handling() (unless you call +png_read_update_info()) or call this function multiple times, or any +of that other stuff necessary with png_read_rows(). + + png_read_image(png_ptr, row_pointers); + +where row_pointers is: + + png_bytep row_pointers[height]; + +You can point to void or char or whatever you use for pixels. + +If you don't want to read in the whole image at once, you can +use png_read_rows() instead. If there is no interlacing (check +interlace_type == PNG_INTERLACE_NONE), this is simple: + + png_read_rows(png_ptr, row_pointers, NULL, + number_of_rows); + +where row_pointers is the same as in the png_read_image() call. + +If you are doing this just one row at a time, you can do this with +a single row_pointer instead of an array of row_pointers: + + png_bytep row_pointer = row; + png_read_row(png_ptr, row_pointer, NULL); + +If the file is interlaced (interlace_type != 0 in the IHDR chunk), things +get somewhat harder. The only current (PNG Specification version 1.2) +interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7); +a somewhat complicated 2D interlace scheme, known as Adam7, that +breaks down an image into seven smaller images of varying size, based +on an 8x8 grid. This number is defined (from libpng 1.5) as +PNG_INTERLACE_ADAM7_PASSES in png.h + +libpng can fill out those images or it can give them to you "as is". +It is almost always better to have libpng handle the interlacing for you. +If you want the images filled out, there are two ways to do that. The one +mentioned in the PNG specification is to expand each pixel to cover +those pixels that have not been read yet (the "rectangle" method). +This results in a blocky image for the first pass, which gradually +smooths out as more pixels are read. The other method is the "sparkle" +method, where pixels are drawn only in their final locations, with the +rest of the image remaining whatever colors they were initialized to +before the start of the read. The first method usually looks better, +but tends to be slower, as there are more pixels to put in the rows. + +If, as is likely, you want libpng to expand the images, call this before +calling png_start_read_image() or png_read_update_info(): + + if (interlace_type == PNG_INTERLACE_ADAM7) + number_of_passes + = png_set_interlace_handling(png_ptr); + +This will return the number of passes needed. Currently, this is seven, +but may change if another interlace type is added. This function can be +called even if the file is not interlaced, where it will return one pass. +You then need to read the whole image 'number_of_passes' times. Each time +will distribute the pixels from the current pass to the correct place in +the output image, so you need to supply the same rows to png_read_rows in +each pass. + +If you are not going to display the image after each pass, but are +going to wait until the entire image is read in, use the sparkle +effect. This effect is faster and the end result of either method +is exactly the same. If you are planning on displaying the image +after each pass, the "rectangle" effect is generally considered the +better looking one. + +If you only want the "sparkle" effect, just call png_read_rows() as +normal, with the third parameter NULL. Make sure you make pass over +the image number_of_passes times, and you don't change the data in the +rows between calls. You can change the locations of the data, just +not the data. Each pass only writes the pixels appropriate for that +pass, and assumes the data from previous passes is still valid. + + png_read_rows(png_ptr, row_pointers, NULL, + number_of_rows); + +If you only want the first effect (the rectangles), do the same as +before except pass the row buffer in the third parameter, and leave +the second parameter NULL. + + png_read_rows(png_ptr, NULL, row_pointers, + number_of_rows); + +If you don't want libpng to handle the interlacing details, just call +png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images. +Each of the images is a valid image by itself; however, you will almost +certainly need to distribute the pixels from each sub-image to the +correct place. This is where everything gets very tricky. + +If you want to retrieve the separate images you must pass the correct +number of rows to each successive call of png_read_rows(). The calculation +gets pretty complicated for small images, where some sub-images may +not even exist because either their width or height ends up zero. +libpng provides two macros to help you in 1.5 and later versions: + + png_uint_32 width = PNG_PASS_COLS(image_width, pass_number); + png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number); + +Respectively these tell you the width and height of the sub-image +corresponding to the numbered pass. 'pass' is in in the range 0 to 6 - +this can be confusing because the specification refers to the same passes +as 1 to 7! Be careful, you must check both the width and height before +calling png_read_rows() and not call it for that pass if either is zero. + +You can, of course, read each sub-image row by row. If you want to +produce optimal code to make a pixel-by-pixel transformation of an +interlaced image this is the best approach; read each row of each pass, +transform it, and write it out to a new interlaced image. + +If you want to de-interlace the image yourself libpng provides further +macros to help that tell you where to place the pixels in the output image. +Because the interlacing scheme is rectangular - sub-image pixels are always +arranged on a rectangular grid - all you need to know for each pass is the +starting column and row in the output image of the first pixel plus the +spacing between each pixel. As of libpng 1.5 there are four macros to +retrieve this information: + + png_uint_32 x = PNG_PASS_START_COL(pass); + png_uint_32 y = PNG_PASS_START_ROW(pass); + png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass); + png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass); + +These allow you to write the obvious loop: + + png_uint_32 input_y = 0; + png_uint_32 output_y = PNG_PASS_START_ROW(pass); + + while (output_y < output_image_height) + { + png_uint_32 input_x = 0; + png_uint_32 output_x = PNG_PASS_START_COL(pass); + + while (output_x < output_image_width) + { + image[output_y][output_x] = + subimage[pass][input_y][input_x++]; + + output_x += xStep; + } + + ++input_y; + output_y += yStep; + } + +Notice that the steps between successive output rows and columns are +returned as shifts. This is possible because the pixels in the subimages +are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original +image. In practice you may need to directly calculate the output coordinate +given an input coordinate. libpng provides two further macros for this +purpose: + + png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass); + png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass); + +Finally a pair of macros are provided to tell you if a particular image +row or column appears in a given pass: + + int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass); + int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass); + +Bear in mind that you will probably also need to check the width and height +of the pass in addition to the above to be sure the pass even exists! + +With any luck you are convinced by now that you don't want to do your own +interlace handling. In reality normally the only good reason for doing this +is if you are processing PNG files on a pixel-by-pixel basis and don't want +to load the whole file into memory when it is interlaced. + +libpng includes a test program, pngvalid, that illustrates reading and +writing of interlaced images. If you can't get interlacing to work in your +code and don't want to leave it to libpng (the recommended approach), see +how pngvalid.c does it. + +.SS Finishing a sequential read + +After you are finished reading the image through the +low-level interface, you can finish reading the file. + +If you want to use a different crc action for handling CRC errors in +chunks after the image data, you can call png_set_crc_action() +again at this point. + +If you are interested in comments or time, which may be stored either +before or after the image data, you should pass the separate png_info +struct if you want to keep the comments from before and after the image +separate. + + png_infop end_info = png_create_info_struct(png_ptr); + + if (!end_info) + { + png_destroy_read_struct(&png_ptr, &info_ptr, + (png_infopp)NULL); + return (ERROR); + } + + png_read_end(png_ptr, end_info); + +If you are not interested, you should still call png_read_end() +but you can pass NULL, avoiding the need to create an end_info structure. +If you do this, libpng will not process any chunks after IDAT other than +skipping over them and perhaps (depending on whether you have called +png_set_crc_action) checking their CRCs while looking for the IEND chunk. + + png_read_end(png_ptr, (png_infop)NULL); + +If you don't call png_read_end(), then your file pointer will be +left pointing to the first chunk after the last IDAT, which is probably +not what you want if you expect to read something beyond the end of +the PNG datastream. + +When you are done, you can free all memory allocated by libpng like this: + + png_destroy_read_struct(&png_ptr, &info_ptr, + &end_info); + +or, if you didn't create an end_info structure, + + png_destroy_read_struct(&png_ptr, &info_ptr, + (png_infopp)NULL); + +It is also possible to individually free the info_ptr members that +point to libpng-allocated storage with the following function: + + png_free_data(png_ptr, info_ptr, mask, seq) + + mask - identifies data to be freed, a mask + containing the bitwise OR of one or + more of + PNG_FREE_PLTE, PNG_FREE_TRNS, + PNG_FREE_HIST, PNG_FREE_ICCP, + PNG_FREE_PCAL, PNG_FREE_ROWS, + PNG_FREE_SCAL, PNG_FREE_SPLT, + PNG_FREE_TEXT, PNG_FREE_UNKN, + or simply PNG_FREE_ALL + + seq - sequence number of item to be freed + (\-1 for all items) + +This function may be safely called when the relevant storage has +already been freed, or has not yet been allocated, or was allocated +by the user and not by libpng, and will in those cases do nothing. +The "seq" parameter is ignored if only one item of the selected data +type, such as PLTE, is allowed. If "seq" is not \-1, and multiple items +are allowed for the data type identified in the mask, such as text or +sPLT, only the n'th item in the structure is freed, where n is "seq". + +The default behavior is only to free data that was allocated internally +by libpng. This can be changed, so that libpng will not free the data, +or so that it will free data that was allocated by the user with png_malloc() +or png_calloc() and passed in via a png_set_*() function, with + + png_data_freer(png_ptr, info_ptr, freer, mask) + + freer - one of + PNG_DESTROY_WILL_FREE_DATA + PNG_SET_WILL_FREE_DATA + PNG_USER_WILL_FREE_DATA + + mask - which data elements are affected + same choices as in png_free_data() + +This function only affects data that has already been allocated. +You can call this function after reading the PNG data but before calling +any png_set_*() functions, to control whether the user or the png_set_*() +function is responsible for freeing any existing data that might be present, +and again after the png_set_*() functions to control whether the user +or png_destroy_*() is supposed to free the data. When the user assumes +responsibility for libpng-allocated data, the application must use +png_free() to free it, and when the user transfers responsibility to libpng +for data that the user has allocated, the user must have used png_malloc() +or png_calloc() to allocate it. + +If you allocated your row_pointers in a single block, as suggested above in +the description of the high level read interface, you must not transfer +responsibility for freeing it to the png_set_rows or png_read_destroy function, +because they would also try to free the individual row_pointers[i]. + +If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword +separately, do not transfer responsibility for freeing text_ptr to libpng, +because when libpng fills a png_text structure it combines these members with +the key member, and png_free_data() will free only text_ptr.key. Similarly, +if you transfer responsibility for free'ing text_ptr from libpng to your +application, your application must not separately free those members. + +The png_free_data() function will turn off the "valid" flag for anything +it frees. If you need to turn the flag off for a chunk that was freed by +your application instead of by libpng, you can use + + png_set_invalid(png_ptr, info_ptr, mask); + + mask - identifies the chunks to be made invalid, + containing the bitwise OR of one or + more of + PNG_INFO_gAMA, PNG_INFO_sBIT, + PNG_INFO_cHRM, PNG_INFO_PLTE, + PNG_INFO_tRNS, PNG_INFO_bKGD, + PNG_INFO_hIST, PNG_INFO_pHYs, + PNG_INFO_oFFs, PNG_INFO_tIME, + PNG_INFO_pCAL, PNG_INFO_sRGB, + PNG_INFO_iCCP, PNG_INFO_sPLT, + PNG_INFO_sCAL, PNG_INFO_IDAT + +For a more compact example of reading a PNG image, see the file example.c. + +.SS Reading PNG files progressively + +The progressive reader is slightly different from the non-progressive +reader. Instead of calling png_read_info(), png_read_rows(), and +png_read_end(), you make one call to png_process_data(), which calls +callbacks when it has the info, a row, or the end of the image. You +set up these callbacks with png_set_progressive_read_fn(). You don't +have to worry about the input/output functions of libpng, as you are +giving the library the data directly in png_process_data(). I will +assume that you have read the section on reading PNG files above, +so I will only highlight the differences (although I will show +all of the code). + +png_structp png_ptr; +png_infop info_ptr; + + /* An example code fragment of how you would + initialize the progressive reader in your + application. */ + int + initialize_png_reader() + { + png_ptr = png_create_read_struct + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn); + + if (!png_ptr) + return (ERROR); + + info_ptr = png_create_info_struct(png_ptr); + + if (!info_ptr) + { + png_destroy_read_struct(&png_ptr, + (png_infopp)NULL, (png_infopp)NULL); + return (ERROR); + } + + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_read_struct(&png_ptr, &info_ptr, + (png_infopp)NULL); + return (ERROR); + } + + /* This one's new. You can provide functions + to be called when the header info is valid, + when each row is completed, and when the image + is finished. If you aren't using all functions, + you can specify NULL parameters. Even when all + three functions are NULL, you need to call + png_set_progressive_read_fn(). You can use + any struct as the user_ptr (cast to a void pointer + for the function call), and retrieve the pointer + from inside the callbacks using the function + + png_get_progressive_ptr(png_ptr); + + which will return a void pointer, which you have + to cast appropriately. + */ + png_set_progressive_read_fn(png_ptr, (void *)user_ptr, + info_callback, row_callback, end_callback); + + return 0; + } + + /* A code fragment that you call as you receive blocks + of data */ + int + process_data(png_bytep buffer, png_uint_32 length) + { + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_read_struct(&png_ptr, &info_ptr, + (png_infopp)NULL); + return (ERROR); + } + + /* This one's new also. Simply give it a chunk + of data from the file stream (in order, of + course). On machines with segmented memory + models machines, don't give it any more than + 64K. The library seems to run fine with sizes + of 4K. Although you can give it much less if + necessary (I assume you can give it chunks of + 1 byte, I haven't tried less then 256 bytes + yet). When this function returns, you may + want to display any rows that were generated + in the row callback if you don't already do + so there. + */ + png_process_data(png_ptr, info_ptr, buffer, length); + + /* At this point you can call png_process_data_skip if + you want to handle data the library will skip yourself; + it simply returns the number of bytes to skip (and stops + libpng skipping that number of bytes on the next + png_process_data call). + return 0; + } + + /* This function is called (as set by + png_set_progressive_read_fn() above) when enough data + has been supplied so all of the header has been + read. + */ + void + info_callback(png_structp png_ptr, png_infop info) + { + /* Do any setup here, including setting any of + the transformations mentioned in the Reading + PNG files section. For now, you _must_ call + either png_start_read_image() or + png_read_update_info() after all the + transformations are set (even if you don't set + any). You may start getting rows before + png_process_data() returns, so this is your + last chance to prepare for that. + + This is where you turn on interlace handling, + assuming you don't want to do it yourself. + + If you need to you can stop the processing of + your original input data at this point by calling + png_process_data_pause. This returns the number + of unprocessed bytes from the last png_process_data + call - it is up to you to ensure that the next call + sees these bytes again. If you don't want to bother + with this you can get libpng to cache the unread + bytes by setting the 'save' parameter (see png.h) but + then libpng will have to copy the data internally. + */ + } + + /* This function is called when each row of image + data is complete */ + void + row_callback(png_structp png_ptr, png_bytep new_row, + png_uint_32 row_num, int pass) + { + /* If the image is interlaced, and you turned + on the interlace handler, this function will + be called for every row in every pass. Some + of these rows will not be changed from the + previous pass. When the row is not changed, + the new_row variable will be NULL. The rows + and passes are called in order, so you don't + really need the row_num and pass, but I'm + supplying them because it may make your life + easier. + + If you did not turn on interlace handling then + the callback is called for each row of each + sub-image when the image is interlaced. In this + case 'row_num' is the row in the sub-image, not + the row in the output image as it is in all other + cases. + + For the non-NULL rows of interlaced images when + you have switched on libpng interlace handling, + you must call png_progressive_combine_row() + passing in the row and the old row. You can + call this function for NULL rows (it will just + return) and for non-interlaced images (it just + does the memcpy for you) if it will make the + code easier. Thus, you can just do this for + all cases if you switch on interlace handling; + */ + + png_progressive_combine_row(png_ptr, old_row, + new_row); + + /* where old_row is what was displayed + previously for the row. Note that the first + pass (pass == 0, really) will completely cover + the old row, so the rows do not have to be + initialized. After the first pass (and only + for interlaced images), you will have to pass + the current row, and the function will combine + the old row and the new row. + + You can also call png_process_data_pause in this + callback - see above. + */ + } + + void + end_callback(png_structp png_ptr, png_infop info) + { + /* This function is called after the whole image + has been read, including any chunks after the + image (up to and including the IEND). You + will usually have the same info chunk as you + had in the header, although some data may have + been added to the comments and time fields. + + Most people won't do much here, perhaps setting + a flag that marks the image as finished. + */ + } + + + +.SH IV. Writing + +Much of this is very similar to reading. However, everything of +importance is repeated here, so you won't have to constantly look +back up in the reading section to understand writing. + +.SS Setup + +You will want to do the I/O initialization before you get into libpng, +so if it doesn't work, you don't have anything to undo. If you are not +using the standard I/O functions, you will need to replace them with +custom writing functions. See the discussion under Customizing libpng. + + FILE *fp = fopen(file_name, "wb"); + + if (!fp) + return (ERROR); + +Next, png_struct and png_info need to be allocated and initialized. +As these can be both relatively large, you may not want to store these +on the stack, unless you have stack space to spare. Of course, you +will want to check if they return NULL. If you are also reading, +you won't want to name your read structure and your write structure +both "png_ptr"; you can call them anything you like, such as +"read_ptr" and "write_ptr". Look at pngtest.c, for example. + + png_structp png_ptr = png_create_write_struct + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn); + + if (!png_ptr) + return (ERROR); + + png_infop info_ptr = png_create_info_struct(png_ptr); + if (!info_ptr) + { + png_destroy_write_struct(&png_ptr, + (png_infopp)NULL); + return (ERROR); + } + +If you want to use your own memory allocation routines, +define PNG_USER_MEM_SUPPORTED and use +png_create_write_struct_2() instead of png_create_write_struct(): + + png_structp png_ptr = png_create_write_struct_2 + (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr, + user_error_fn, user_warning_fn, (png_voidp) + user_mem_ptr, user_malloc_fn, user_free_fn); + +After you have these structures, you will need to set up the +error handling. When libpng encounters an error, it expects to +longjmp() back to your routine. Therefore, you will need to call +setjmp() and pass the png_jmpbuf(png_ptr). If you +write the file from different routines, you will need to update +the png_jmpbuf(png_ptr) every time you enter a new routine that will +call a png_*() function. See your documentation of setjmp/longjmp +for your compiler for more information on setjmp/longjmp. See +the discussion on libpng error handling in the Customizing Libpng +section below for more information on the libpng error handling. + + if (setjmp(png_jmpbuf(png_ptr))) + { + png_destroy_write_struct(&png_ptr, &info_ptr); + fclose(fp); + return (ERROR); + } + ... + return; + +If you would rather avoid the complexity of setjmp/longjmp issues, +you can compile libpng with PNG_NO_SETJMP, in which case +errors will result in a call to PNG_ABORT() which defaults to abort(). + +You can #define PNG_ABORT() to a function that does something +more useful than abort(), as long as your function does not +return. + +Checking for invalid palette index on write was added at libpng +1.5.10. If a pixel contains an invalid (out-of-range) index libpng issues +a benign error. This is enabled by default because this condition is an +error according to the PNG specification, Clause 11.3.2, but the error can +be ignored in each png_ptr with + + png_set_check_for_invalid_index(png_ptr, 0); + +If the error is ignored, or if png_benign_error() treats it as a warning, +any invalid pixels are written as-is by the encoder, resulting in an +invalid PNG datastream as output. In this case the application is +responsible for ensuring that the pixel indexes are in range when it writes +a PLTE chunk with fewer entries than the bit depth would allow. + +Now you need to set up the output code. The default for libpng is to +use the C function fwrite(). If you use this, you will need to pass a +valid FILE * in the function png_init_io(). Be sure that the file is +opened in binary mode. Again, if you wish to handle writing data in +another way, see the discussion on libpng I/O handling in the Customizing +Libpng section below. + + png_init_io(png_ptr, fp); + +If you are embedding your PNG into a datastream such as MNG, and don't +want libpng to write the 8-byte signature, or if you have already +written the signature in your application, use + + png_set_sig_bytes(png_ptr, 8); + +to inform libpng that it should not write a signature. + +.SS Write callbacks + +At this point, you can set up a callback function that will be +called after each row has been written, which you can use to control +a progress meter or the like. It's demonstrated in pngtest.c. +You must supply a function + + void write_row_callback(png_structp png_ptr, png_uint_32 row, + int pass); + { + /* put your code here */ + } + +(You can give it another name that you like instead of "write_row_callback") + +To inform libpng about your function, use + + png_set_write_status_fn(png_ptr, write_row_callback); + +When this function is called the row has already been completely processed and +it has also been written out. The 'row' and 'pass' refer to the next row to be +handled. For the +non-interlaced case the row that was just handled is simply one less than the +passed in row number, and pass will always be 0. For the interlaced case the +same applies unless the row value is 0, in which case the row just handled was +the last one from one of the preceding passes. Because interlacing may skip a +pass you cannot be sure that the preceding pass is just 'pass\-1', if you really +need to know what the last pass is record (row,pass) from the callback and use +the last recorded value each time. + +As with the user transform you can find the output row using the +PNG_ROW_FROM_PASS_ROW macro. + +You now have the option of modifying how the compression library will +run. The following functions are mainly for testing, but may be useful +in some cases, like if you need to write PNG files extremely fast and +are willing to give up some compression, or if you want to get the +maximum possible compression at the expense of slower writing. If you +have no special needs in this area, let the library do what it wants by +not calling this function at all, as it has been tuned to deliver a good +speed/compression ratio. The second parameter to png_set_filter() is +the filter method, for which the only valid values are 0 (as of the +July 1999 PNG specification, version 1.2) or 64 (if you are writing +a PNG datastream that is to be embedded in a MNG datastream). The third +parameter is a flag that indicates which filter type(s) are to be tested +for each scanline. See the PNG specification for details on the specific +filter types. + + + /* turn on or off filtering, and/or choose + specific filters. You can use either a single + PNG_FILTER_VALUE_NAME or the bitwise OR of one + or more PNG_FILTER_NAME masks. + */ + png_set_filter(png_ptr, 0, + PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE | + PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB | + PNG_FILTER_UP | PNG_FILTER_VALUE_UP | + PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG | + PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH| + PNG_ALL_FILTERS); + +If an application wants to start and stop using particular filters during +compression, it should start out with all of the filters (to ensure that +the previous row of pixels will be stored in case it's needed later), +and then add and remove them after the start of compression. + +If you are writing a PNG datastream that is to be embedded in a MNG +datastream, the second parameter can be either 0 or 64. + +The png_set_compression_*() functions interface to the zlib compression +library, and should mostly be ignored unless you really know what you are +doing. The only generally useful call is png_set_compression_level() +which changes how much time zlib spends on trying to compress the image +data. See the Compression Library (zlib.h and algorithm.txt, distributed +with zlib) for details on the compression levels. + + #include zlib.h + + /* Set the zlib compression level */ + png_set_compression_level(png_ptr, + Z_BEST_COMPRESSION); + + /* Set other zlib parameters for compressing IDAT */ + png_set_compression_mem_level(png_ptr, 8); + png_set_compression_strategy(png_ptr, + Z_DEFAULT_STRATEGY); + png_set_compression_window_bits(png_ptr, 15); + png_set_compression_method(png_ptr, 8); + png_set_compression_buffer_size(png_ptr, 8192) + + /* Set zlib parameters for text compression + * If you don't call these, the parameters + * fall back on those defined for IDAT chunks + */ + png_set_text_compression_mem_level(png_ptr, 8); + png_set_text_compression_strategy(png_ptr, + Z_DEFAULT_STRATEGY); + png_set_text_compression_window_bits(png_ptr, 15); + png_set_text_compression_method(png_ptr, 8); + +.SS Setting the contents of info for output + +You now need to fill in the png_info structure with all the data you +wish to write before the actual image. Note that the only thing you +are allowed to write after the image is the text chunks and the time +chunk (as of PNG Specification 1.2, anyway). See png_write_end() and +the latest PNG specification for more information on that. If you +wish to write them before the image, fill them in now, and flag that +data as being valid. If you want to wait until after the data, don't +fill them until png_write_end(). For all the fields in png_info and +their data types, see png.h. For explanations of what the fields +contain, see the PNG specification. + +Some of the more important parts of the png_info are: + + png_set_IHDR(png_ptr, info_ptr, width, height, + bit_depth, color_type, interlace_type, + compression_type, filter_method) + + width - holds the width of the image + in pixels (up to 2^31). + + height - holds the height of the image + in pixels (up to 2^31). + + bit_depth - holds the bit depth of one of the + image channels. + (valid values are 1, 2, 4, 8, 16 + and depend also on the + color_type. See also significant + bits (sBIT) below). + + color_type - describes which color/alpha + channels are present. + PNG_COLOR_TYPE_GRAY + (bit depths 1, 2, 4, 8, 16) + PNG_COLOR_TYPE_GRAY_ALPHA + (bit depths 8, 16) + PNG_COLOR_TYPE_PALETTE + (bit depths 1, 2, 4, 8) + PNG_COLOR_TYPE_RGB + (bit_depths 8, 16) + PNG_COLOR_TYPE_RGB_ALPHA + (bit_depths 8, 16) + + PNG_COLOR_MASK_PALETTE + PNG_COLOR_MASK_COLOR + PNG_COLOR_MASK_ALPHA + + interlace_type - PNG_INTERLACE_NONE or + PNG_INTERLACE_ADAM7 + + compression_type - (must be + PNG_COMPRESSION_TYPE_DEFAULT) + + filter_method - (must be PNG_FILTER_TYPE_DEFAULT + or, if you are writing a PNG to + be embedded in a MNG datastream, + can also be + PNG_INTRAPIXEL_DIFFERENCING) + +If you call png_set_IHDR(), the call must appear before any of the +other png_set_*() functions, because they might require access to some of +the IHDR settings. The remaining png_set_*() functions can be called +in any order. + +If you wish, you can reset the compression_type, interlace_type, or +filter_method later by calling png_set_IHDR() again; if you do this, the +width, height, bit_depth, and color_type must be the same in each call. + + png_set_PLTE(png_ptr, info_ptr, palette, + num_palette); + + palette - the palette for the file + (array of png_color) + num_palette - number of entries in the palette + + png_set_gAMA(png_ptr, info_ptr, file_gamma); + png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma); + + file_gamma - the gamma at which the image was + created (PNG_INFO_gAMA) + + int_file_gamma - 100,000 times the gamma at which + the image was created + + png_set_cHRM(png_ptr, info_ptr, white_x, white_y, red_x, red_y, + green_x, green_y, blue_x, blue_y) + png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X, + green_Y, green_Z, blue_X, blue_Y, blue_Z) + png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y, + int_red_x, int_red_y, int_green_x, int_green_y, + int_blue_x, int_blue_y) + png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y, + int_red_Z, int_green_X, int_green_Y, int_green_Z, + int_blue_X, int_blue_Y, int_blue_Z) + + {white,red,green,blue}_{x,y} + A color space encoding specified using the chromaticities + of the end points and the white point. + + {red,green,blue}_{X,Y,Z} + A color space encoding specified using the encoding end + points - the CIE tristimulus specification of the intended + color of the red, green and blue channels in the PNG RGB + data. The white point is simply the sum of the three end + points. + + png_set_sRGB(png_ptr, info_ptr, srgb_intent); + + srgb_intent - the rendering intent + (PNG_INFO_sRGB) The presence of + the sRGB chunk means that the pixel + data is in the sRGB color space. + This chunk also implies specific + values of gAMA and cHRM. Rendering + intent is the CSS-1 property that + has been defined by the International + Color Consortium + (http://www.color.org). + It can be one of + PNG_sRGB_INTENT_SATURATION, + PNG_sRGB_INTENT_PERCEPTUAL, + PNG_sRGB_INTENT_ABSOLUTE, or + PNG_sRGB_INTENT_RELATIVE. + + + png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, + srgb_intent); + + srgb_intent - the rendering intent + (PNG_INFO_sRGB) The presence of the + sRGB chunk means that the pixel + data is in the sRGB color space. + This function also causes gAMA and + cHRM chunks with the specific values + that are consistent with sRGB to be + written. + + png_set_iCCP(png_ptr, info_ptr, name, compression_type, + profile, proflen); + + name - The profile name. + + compression_type - The compression type; always + PNG_COMPRESSION_TYPE_BASE for PNG 1.0. + You may give NULL to this argument to + ignore it. + + profile - International Color Consortium color + profile data. May contain NULs. + + proflen - length of profile data in bytes. + + png_set_sBIT(png_ptr, info_ptr, sig_bit); + + sig_bit - the number of significant bits for + (PNG_INFO_sBIT) each of the gray, red, + green, and blue channels, whichever are + appropriate for the given color type + (png_color_16) + + png_set_tRNS(png_ptr, info_ptr, trans_alpha, + num_trans, trans_color); + + trans_alpha - array of alpha (transparency) + entries for palette (PNG_INFO_tRNS) + + num_trans - number of transparent entries + (PNG_INFO_tRNS) + + trans_color - graylevel or color sample values + (in order red, green, blue) of the + single transparent color for + non-paletted images (PNG_INFO_tRNS) + + png_set_hIST(png_ptr, info_ptr, hist); + + hist - histogram of palette (array of + png_uint_16) (PNG_INFO_hIST) + + png_set_tIME(png_ptr, info_ptr, mod_time); + + mod_time - time image was last modified + (PNG_VALID_tIME) + + png_set_bKGD(png_ptr, info_ptr, background); + + background - background color (of type + png_color_16p) (PNG_VALID_bKGD) + + png_set_text(png_ptr, info_ptr, text_ptr, num_text); + + text_ptr - array of png_text holding image + comments + + text_ptr[i].compression - type of compression used + on "text" PNG_TEXT_COMPRESSION_NONE + PNG_TEXT_COMPRESSION_zTXt + PNG_ITXT_COMPRESSION_NONE + PNG_ITXT_COMPRESSION_zTXt + text_ptr[i].key - keyword for comment. Must contain + 1-79 characters. + text_ptr[i].text - text comments for current + keyword. Can be NULL or empty. + text_ptr[i].text_length - length of text string, + after decompression, 0 for iTXt + text_ptr[i].itxt_length - length of itxt string, + after decompression, 0 for tEXt/zTXt + text_ptr[i].lang - language of comment (NULL or + empty for unknown). + text_ptr[i].translated_keyword - keyword in UTF-8 (NULL + or empty for unknown). + + Note that the itxt_length, lang, and lang_key + members of the text_ptr structure only exist when the + library is built with iTXt chunk support. Prior to + libpng-1.4.0 the library was built by default without + iTXt support. Also note that when iTXt is supported, + they contain NULL pointers when the "compression" + field contains PNG_TEXT_COMPRESSION_NONE or + PNG_TEXT_COMPRESSION_zTXt. + + num_text - number of comments + + png_set_sPLT(png_ptr, info_ptr, &palette_ptr, + num_spalettes); + + palette_ptr - array of png_sPLT_struct structures + to be added to the list of palettes + in the info structure. + num_spalettes - number of palette structures to be + added. + + png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, + unit_type); + + offset_x - positive offset from the left + edge of the screen + + offset_y - positive offset from the top + edge of the screen + + unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER + + png_set_pHYs(png_ptr, info_ptr, res_x, res_y, + unit_type); + + res_x - pixels/unit physical resolution + in x direction + + res_y - pixels/unit physical resolution + in y direction + + unit_type - PNG_RESOLUTION_UNKNOWN, + PNG_RESOLUTION_METER + + png_set_sCAL(png_ptr, info_ptr, unit, width, height) + + unit - physical scale units (an integer) + + width - width of a pixel in physical scale units + + height - height of a pixel in physical scale units + (width and height are doubles) + + png_set_sCAL_s(png_ptr, info_ptr, unit, width, height) + + unit - physical scale units (an integer) + + width - width of a pixel in physical scale units + expressed as a string + + height - height of a pixel in physical scale units + (width and height are strings like "2.54") + + png_set_unknown_chunks(png_ptr, info_ptr, &unknowns, + num_unknowns) + + unknowns - array of png_unknown_chunk + structures holding unknown chunks + unknowns[i].name - name of unknown chunk + unknowns[i].data - data of unknown chunk + unknowns[i].size - size of unknown chunk's data + unknowns[i].location - position to write chunk in file + 0: do not write chunk + PNG_HAVE_IHDR: before PLTE + PNG_HAVE_PLTE: before IDAT + PNG_AFTER_IDAT: after IDAT + +The "location" member is set automatically according to +what part of the output file has already been written. +You can change its value after calling png_set_unknown_chunks() +as demonstrated in pngtest.c. Within each of the "locations", +the chunks are sequenced according to their position in the +structure (that is, the value of "i", which is the order in which +the chunk was either read from the input file or defined with +png_set_unknown_chunks). + +A quick word about text and num_text. text is an array of png_text +structures. num_text is the number of valid structures in the array. +Each png_text structure holds a language code, a keyword, a text value, +and a compression type. + +The compression types have the same valid numbers as the compression +types of the image data. Currently, the only valid number is zero. +However, you can store text either compressed or uncompressed, unlike +images, which always have to be compressed. So if you don't want the +text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE. +Because tEXt and zTXt chunks don't have a language field, if you +specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt +any language code or translated keyword will not be written out. + +Until text gets around a few hundred bytes, it is not worth compressing it. +After the text has been written out to the file, the compression type +is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR, +so that it isn't written out again at the end (in case you are calling +png_write_end() with the same struct). + +The keywords that are given in the PNG Specification are: + + Title Short (one line) title or + caption for image + + Author Name of image's creator + + Description Description of image (possibly long) + + Copyright Copyright notice + + Creation Time Time of original image creation + (usually RFC 1123 format, see below) + + Software Software used to create the image + + Disclaimer Legal disclaimer + + Warning Warning of nature of content + + Source Device used to create the image + + Comment Miscellaneous comment; conversion + from other image format + +The keyword-text pairs work like this. Keywords should be short +simple descriptions of what the comment is about. Some typical +keywords are found in the PNG specification, as is some recommendations +on keywords. You can repeat keywords in a file. You can even write +some text before the image and some after. For example, you may want +to put a description of the image before the image, but leave the +disclaimer until after, so viewers working over modem connections +don't have to wait for the disclaimer to go over the modem before +they start seeing the image. Finally, keywords should be full +words, not abbreviations. Keywords and text are in the ISO 8859-1 +(Latin-1) character set (a superset of regular ASCII) and can not +contain NUL characters, and should not contain control or other +unprintable characters. To make the comments widely readable, stick +with basic ASCII, and avoid machine specific character set extensions +like the IBM-PC character set. The keyword must be present, but +you can leave off the text string on non-compressed pairs. +Compressed pairs must have a text string, as only the text string +is compressed anyway, so the compression would be meaningless. + +PNG supports modification time via the png_time structure. Two +conversion routines are provided, png_convert_from_time_t() for +time_t and png_convert_from_struct_tm() for struct tm. The +time_t routine uses gmtime(). You don't have to use either of +these, but if you wish to fill in the png_time structure directly, +you should provide the time in universal time (GMT) if possible +instead of your local time. Note that the year number is the full +year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and +that months start with 1. + +If you want to store the time of the original image creation, you should +use a plain tEXt chunk with the "Creation Time" keyword. This is +necessary because the "creation time" of a PNG image is somewhat vague, +depending on whether you mean the PNG file, the time the image was +created in a non-PNG format, a still photo from which the image was +scanned, or possibly the subject matter itself. In order to facilitate +machine-readable dates, it is recommended that the "Creation Time" +tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"), +although this isn't a requirement. Unlike the tIME chunk, the +"Creation Time" tEXt chunk is not expected to be automatically changed +by the software. To facilitate the use of RFC 1123 dates, a function +png_convert_to_rfc1123_buffer(png_ptr, buffer, png_timep) is provided to +convert from PNG time to an RFC 1123 format string. The caller must provide +a writeable buffer of at least 29 bytes. + +.SS Writing unknown chunks + +You can use the png_set_unknown_chunks function to queue up private chunks +for writing. You give it a chunk name, location, raw data, and a size. You +also must use png_set_keep_unknown_chunks() to ensure that libpng will +handle them. That's all there is to it. The chunks will be written by the +next following png_write_info_before_PLTE, png_write_info, or png_write_end +function, depending upon the specified location. Any chunks previously +read into the info structure's unknown-chunk list will also be written out +in a sequence that satisfies the PNG specification's ordering rules. + +Here is an example of writing two private chunks, prVt and miNE: + + #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + /* Set unknown chunk data */ + png_unknown_chunk unk_chunk[2]; + strcpy((char *) unk_chunk[0].name, "prVt"; + unk_chunk[0].data = (unsigned char *) "PRIVATE DATA"; + unk_chunk[0].size = strlen(unk_chunk[0].data)+1; + unk_chunk[0].location = PNG_HAVE_IHDR; + strcpy((char *) unk_chunk[1].name, "miNE"; + unk_chunk[1].data = (unsigned char *) "MY CHUNK DATA"; + unk_chunk[1].size = strlen(unk_chunk[0].data)+1; + unk_chunk[1].location = PNG_AFTER_IDAT; + png_set_unknown_chunks(write_ptr, write_info_ptr, + unk_chunk, 2); + /* Needed because miNE is not safe-to-copy */ + png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS, + (png_bytep) "miNE", 1); + # if PNG_LIBPNG_VER < 10600 + /* Deal with unknown chunk location bug in 1.5.x and earlier */ + png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR); + png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT); + # endif + # if PNG_LIBPNG_VER < 10500 + /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0, + * one before IDAT and another after IDAT, so don't use it; only use + * PNG_HAVE_IHDR location. This call resets the location previously + * set by assignment and png_set_unknown_chunk_location() for chunk 1. + */ + png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR); + # endif + #endif + +.SS The high-level write interface + +At this point there are two ways to proceed; through the high-level +write interface, or through a sequence of low-level write operations. +You can use the high-level interface if your image data is present +in the info structure. All defined output +transformations are permitted, enabled by the following masks. + + PNG_TRANSFORM_IDENTITY No transformation + PNG_TRANSFORM_PACKING Pack 1, 2 and 4-bit samples + PNG_TRANSFORM_PACKSWAP Change order of packed + pixels to LSB first + PNG_TRANSFORM_INVERT_MONO Invert monochrome images + PNG_TRANSFORM_SHIFT Normalize pixels to the + sBIT depth + PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA + to BGRA + PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA + to AG + PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity + to transparency + PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples + PNG_TRANSFORM_STRIP_FILLER Strip out filler + bytes (deprecated). + PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading + filler bytes + PNG_TRANSFORM_STRIP_FILLER_AFTER Strip out trailing + filler bytes + +If you have valid image data in the info structure (you can use +png_set_rows() to put image data in the info structure), simply do this: + + png_write_png(png_ptr, info_ptr, png_transforms, NULL) + +where png_transforms is an integer containing the bitwise OR of some set of +transformation flags. This call is equivalent to png_write_info(), +followed the set of transformations indicated by the transform mask, +then png_write_image(), and finally png_write_end(). + +(The final parameter of this call is not yet used. Someday it might point +to transformation parameters required by some future output transform.) + +You must use png_transforms and not call any png_set_transform() functions +when you use png_write_png(). + +.SS The low-level write interface + +If you are going the low-level route instead, you are now ready to +write all the file information up to the actual image data. You do +this with a call to png_write_info(). + + png_write_info(png_ptr, info_ptr); + +Note that there is one transformation you may need to do before +png_write_info(). In PNG files, the alpha channel in an image is the +level of opacity. If your data is supplied as a level of transparency, +you can invert the alpha channel before you write it, so that 0 is +fully transparent and 255 (in 8-bit or paletted images) or 65535 +(in 16-bit images) is fully opaque, with + + png_set_invert_alpha(png_ptr); + +This must appear before png_write_info() instead of later with the +other transformations because in the case of paletted images the tRNS +chunk data has to be inverted before the tRNS chunk is written. If +your image is not a paletted image, the tRNS data (which in such cases +represents a single color to be rendered as transparent) won't need to +be changed, and you can safely do this transformation after your +png_write_info() call. + +If you need to write a private chunk that you want to appear before +the PLTE chunk when PLTE is present, you can write the PNG info in +two steps, and insert code to write your own chunk between them: + + png_write_info_before_PLTE(png_ptr, info_ptr); + png_set_unknown_chunks(png_ptr, info_ptr, ...); + png_write_info(png_ptr, info_ptr); + +After you've written the file information, you can set up the library +to handle any special transformations of the image data. The various +ways to transform the data will be described in the order that they +should occur. This is important, as some of these change the color +type and/or bit depth of the data, and some others only work on +certain color types and bit depths. Even though each transformation +checks to see if it has data that it can do something with, you should +make sure to only enable a transformation if it will be valid for the +data. For example, don't swap red and blue on grayscale data. + +PNG files store RGB pixels packed into 3 or 6 bytes. This code tells +the library to strip input data that has 4 or 8 bytes per pixel down +to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2 +bytes per pixel). + + png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE); + +where the 0 is unused, and the location is either PNG_FILLER_BEFORE or +PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel +is stored XRGB or RGBX. + +PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as +they can, resulting in, for example, 8 pixels per byte for 1 bit files. +If the data is supplied at 1 pixel per byte, use this code, which will +correctly pack the pixels into a single byte: + + png_set_packing(png_ptr); + +PNG files reduce possible bit depths to 1, 2, 4, 8, and 16. If your +data is of another bit depth, you can write an sBIT chunk into the +file so that decoders can recover the original data if desired. + + /* Set the true bit depth of the image data */ + if (color_type & PNG_COLOR_MASK_COLOR) + { + sig_bit.red = true_bit_depth; + sig_bit.green = true_bit_depth; + sig_bit.blue = true_bit_depth; + } + + else + { + sig_bit.gray = true_bit_depth; + } + + if (color_type & PNG_COLOR_MASK_ALPHA) + { + sig_bit.alpha = true_bit_depth; + } + + png_set_sBIT(png_ptr, info_ptr, &sig_bit); + +If the data is stored in the row buffer in a bit depth other than +one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG), +this will scale the values to appear to be the correct bit depth as +is required by PNG. + + png_set_shift(png_ptr, &sig_bit); + +PNG files store 16-bit pixels in network byte order (big-endian, +ie. most significant bits first). This code would be used if they are +supplied the other way (little-endian, i.e. least significant bits +first, the way PCs store them): + + if (bit_depth > 8) + png_set_swap(png_ptr); + +If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you +need to change the order the pixels are packed into bytes, you can use: + + if (bit_depth < 8) + png_set_packswap(png_ptr); + +PNG files store 3 color pixels in red, green, blue order. This code +would be used if they are supplied as blue, green, red: + + png_set_bgr(png_ptr); + +PNG files describe monochrome as black being zero and white being +one. This code would be used if the pixels are supplied with this reversed +(black being one and white being zero): + + png_set_invert_mono(png_ptr); + +Finally, you can write your own transformation function if none of +the existing ones meets your needs. This is done by setting a callback +with + + png_set_write_user_transform_fn(png_ptr, + write_transform_fn); + +You must supply the function + + void write_transform_fn(png_structp png_ptr, png_row_infop + row_info, png_bytep data) + +See pngtest.c for a working example. Your function will be called +before any of the other transformations are processed. If supported +libpng also supplies an information routine that may be called from +your callback: + + png_get_current_row_number(png_ptr); + png_get_current_pass_number(png_ptr); + +This returns the current row passed to the transform. With interlaced +images the value returned is the row in the input sub-image image. Use +PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to +find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass). + +The discussion of interlace handling above contains more information on how to +use these values. + +You can also set up a pointer to a user structure for use by your +callback function. + + png_set_user_transform_info(png_ptr, user_ptr, 0, 0); + +The user_channels and user_depth parameters of this function are ignored +when writing; you can set them to zero as shown. + +You can retrieve the pointer via the function png_get_user_transform_ptr(). +For example: + + voidp write_user_transform_ptr = + png_get_user_transform_ptr(png_ptr); + +It is possible to have libpng flush any pending output, either manually, +or automatically after a certain number of lines have been written. To +flush the output stream a single time call: + + png_write_flush(png_ptr); + +and to have libpng flush the output stream periodically after a certain +number of scanlines have been written, call: + + png_set_flush(png_ptr, nrows); + +Note that the distance between rows is from the last time png_write_flush() +was called, or the first row of the image if it has never been called. +So if you write 50 lines, and then png_set_flush 25, it will flush the +output on the next scanline, and every 25 lines thereafter, unless +png_write_flush() is called before 25 more lines have been written. +If nrows is too small (less than about 10 lines for a 640 pixel wide +RGB image) the image compression may decrease noticeably (although this +may be acceptable for real-time applications). Infrequent flushing will +only degrade the compression performance by a few percent over images +that do not use flushing. + +.SS Writing the image data + +That's it for the transformations. Now you can write the image data. +The simplest way to do this is in one function call. If you have the +whole image in memory, you can just call png_write_image() and libpng +will write the image. You will need to pass in an array of pointers to +each row. This function automatically handles interlacing, so you don't +need to call png_set_interlace_handling() or call this function multiple +times, or any of that other stuff necessary with png_write_rows(). + + png_write_image(png_ptr, row_pointers); + +where row_pointers is: + + png_byte *row_pointers[height]; + +You can point to void or char or whatever you use for pixels. + +If you don't want to write the whole image at once, you can +use png_write_rows() instead. If the file is not interlaced, +this is simple: + + png_write_rows(png_ptr, row_pointers, + number_of_rows); + +row_pointers is the same as in the png_write_image() call. + +If you are just writing one row at a time, you can do this with +a single row_pointer instead of an array of row_pointers: + + png_bytep row_pointer = row; + + png_write_row(png_ptr, row_pointer); + +When the file is interlaced, things can get a good deal more complicated. +The only currently (as of the PNG Specification version 1.2, dated July +1999) defined interlacing scheme for PNG files is the "Adam7" interlace +scheme, that breaks down an image into seven smaller images of varying +size. libpng will build these images for you, or you can do them +yourself. If you want to build them yourself, see the PNG specification +for details of which pixels to write when. + +If you don't want libpng to handle the interlacing details, just +use png_set_interlace_handling() and call png_write_rows() the +correct number of times to write all the sub-images +(png_set_interlace_handling() returns the number of sub-images.) + +If you want libpng to build the sub-images, call this before you start +writing any rows: + + number_of_passes = png_set_interlace_handling(png_ptr); + +This will return the number of passes needed. Currently, this is seven, +but may change if another interlace type is added. + +Then write the complete image number_of_passes times. + + png_write_rows(png_ptr, row_pointers, number_of_rows); + +Think carefully before you write an interlaced image. Typically code that +reads such images reads all the image data into memory, uncompressed, before +doing any processing. Only code that can display an image on the fly can +take advantage of the interlacing and even then the image has to be exactly +the correct size for the output device, because scaling an image requires +adjacent pixels and these are not available until all the passes have been +read. + +If you do write an interlaced image you will hardly ever need to handle +the interlacing yourself. Call png_set_interlace_handling() and use the +approach described above. + +The only time it is conceivable that you will really need to write an +interlaced image pass-by-pass is when you have read one pass by pass and +made some pixel-by-pixel transformation to it, as described in the read +code above. In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros +to determine the size of each sub-image in turn and simply write the rows +you obtained from the read code. + +.SS Finishing a sequential write + +After you are finished writing the image, you should finish writing +the file. If you are interested in writing comments or time, you should +pass an appropriately filled png_info pointer. If you are not interested, +you can pass NULL. + + png_write_end(png_ptr, info_ptr); + +When you are done, you can free all memory used by libpng like this: + + png_destroy_write_struct(&png_ptr, &info_ptr); + +It is also possible to individually free the info_ptr members that +point to libpng-allocated storage with the following function: + + png_free_data(png_ptr, info_ptr, mask, seq) + + mask - identifies data to be freed, a mask + containing the bitwise OR of one or + more of + PNG_FREE_PLTE, PNG_FREE_TRNS, + PNG_FREE_HIST, PNG_FREE_ICCP, + PNG_FREE_PCAL, PNG_FREE_ROWS, + PNG_FREE_SCAL, PNG_FREE_SPLT, + PNG_FREE_TEXT, PNG_FREE_UNKN, + or simply PNG_FREE_ALL + + seq - sequence number of item to be freed + (\-1 for all items) + +This function may be safely called when the relevant storage has +already been freed, or has not yet been allocated, or was allocated +by the user and not by libpng, and will in those cases do nothing. +The "seq" parameter is ignored if only one item of the selected data +type, such as PLTE, is allowed. If "seq" is not \-1, and multiple items +are allowed for the data type identified in the mask, such as text or +sPLT, only the n'th item in the structure is freed, where n is "seq". + +If you allocated data such as a palette that you passed in to libpng +with png_set_*, you must not free it until just before the call to +png_destroy_write_struct(). + +The default behavior is only to free data that was allocated internally +by libpng. This can be changed, so that libpng will not free the data, +or so that it will free data that was allocated by the user with png_malloc() +or png_calloc() and passed in via a png_set_*() function, with + + png_data_freer(png_ptr, info_ptr, freer, mask) + + freer - one of + PNG_DESTROY_WILL_FREE_DATA + PNG_SET_WILL_FREE_DATA + PNG_USER_WILL_FREE_DATA + + mask - which data elements are affected + same choices as in png_free_data() + +For example, to transfer responsibility for some data from a read structure +to a write structure, you could use + + png_data_freer(read_ptr, read_info_ptr, + PNG_USER_WILL_FREE_DATA, + PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST) + + png_data_freer(write_ptr, write_info_ptr, + PNG_DESTROY_WILL_FREE_DATA, + PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST) + +thereby briefly reassigning responsibility for freeing to the user but +immediately afterwards reassigning it once more to the write_destroy +function. Having done this, it would then be safe to destroy the read +structure and continue to use the PLTE, tRNS, and hIST data in the write +structure. + +This function only affects data that has already been allocated. +You can call this function before calling after the png_set_*() functions +to control whether the user or png_destroy_*() is supposed to free the data. +When the user assumes responsibility for libpng-allocated data, the +application must use +png_free() to free it, and when the user transfers responsibility to libpng +for data that the user has allocated, the user must have used png_malloc() +or png_calloc() to allocate it. + +If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword +separately, do not transfer responsibility for freeing text_ptr to libpng, +because when libpng fills a png_text structure it combines these members with +the key member, and png_free_data() will free only text_ptr.key. Similarly, +if you transfer responsibility for free'ing text_ptr from libpng to your +application, your application must not separately free those members. +For a more compact example of writing a PNG image, see the file example.c. + +.SH V. Simplified API + +The simplified API, which became available in libpng-1.6.0, hides the details +of both libpng and the PNG file format itself. +It allows PNG files to be read into a very limited number of +in-memory bitmap formats or to be written from the same formats. If these +formats do not accommodate your needs then you can, and should, use the more +sophisticated APIs above - these support a wide variety of in-memory formats +and a wide variety of sophisticated transformations to those formats as well +as a wide variety of APIs to manipulate ancilliary information. + +To read a PNG file using the simplified API: + + 1) Declare a 'png_image' structure (see below) on the + stack and memset() it to all zero. + + 2) Call the appropriate png_image_begin_read... function. + + 3) Set the png_image 'format' member to the required + format and allocate a buffer for the image. + + 4) Call png_image_finish_read to read the image into + your buffer. + +There are no restrictions on the format of the PNG input itself; all valid +color types, bit depths, and interlace methods are acceptable, and the +input image is transformed as necessary to the requested in-memory format +during the png_image_finish_read() step. + +To write a PNG file using the simplified API: + + 1) Declare a 'png_image' structure on the stack and memset() + it to all zero. + + 2) Initialize the members of the structure that describe the + image, setting the 'format' member to the format of the + image in memory. + + 3) Call the appropriate png_image_write... function with a + pointer to the image to write the PNG data. + +png_image is a structure that describes the in-memory format of an image +when it is being read or define the in-memory format of an image that you +need to write. The "png_image" structure contains the following members: + + png_uint_32 version Set to PNG_IMAGE_VERSION + png_uint_32 width Image width in pixels (columns) + png_uint_32 height Image height in pixels (rows) + png_uint_32 format Image format as defined below + png_uint_32 flags A bit mask containing informational flags + png_controlp opaque Initialize to NULL, free with png_image_free + png_uint_32 colormap_entries; Number of entries in the color-map + png_uint_32 warning_or_error; + char message[64]; + +In the event of an error or warning the following field warning_or_error +field will be set to a non-zero value and the 'message' field will contain +a '\0' terminated string with the libpng error or warning message. If both +warnings and an error were encountered, only the error is recorded. If there +are multiple warnings, only the first one is recorded. + +The upper 30 bits of this value are reserved; the low two bits contain +a two bit code such that a value more than 1 indicates a failure in the API +just called: + + 0 - no warning or error + 1 - warning + 2 - error + 3 - error preceded by warning + +The pixels (samples) of the image have one to four channels whose components +have original values in the range 0 to 1.0: + + 1: A single gray or luminance channel (G). + 2: A gray/luminance channel and an alpha channel (GA). + 3: Three red, green, blue color channels (RGB). + 4: Three color channels and an alpha channel (RGBA). + +The channels are encoded in one of two ways: + + a) As a small integer, value 0..255, contained in a single byte. For the +alpha channel the original value is simply value/255. For the color or +luminance channels the value is encoded according to the sRGB specification +and matches the 8-bit format expected by typical display devices. + +The color/gray channels are not scaled (pre-multiplied) by the alpha +channel and are suitable for passing to color management software. + + b) As a value in the range 0..65535, contained in a 2-byte integer, in +the native byte order of the platform on which the application is running. +All channels can be converted to the original value by dividing by 65535; all +channels are linear. Color channels use the RGB encoding (RGB end-points) of +the sRGB specification. This encoding is identified by the +PNG_FORMAT_FLAG_LINEAR flag below. + +When an alpha channel is present it is expected to denote pixel coverage +of the color or luminance channels and is returned as an associated alpha +channel: the color/gray channels are scaled (pre-multiplied) by the alpha +value. + +When a color-mapped image is used as a result of calling +png_image_read_colormap or png_image_write_colormap the channels are encoded +in the color-map and the descriptions above apply to the color-map entries. +The image data is encoded as small integers, value 0..255, that index the +entries in the color-map. One integer (one byte) is stored for each pixel. + +PNG_FORMAT_* + +The #defines to be used in png_image::format. Each #define identifies a +particular layout of channel data and, if present, alpha values. There are +separate defines for each of the two channel encodings. + +A format is built up using single bit flag values. Not all combinations are +valid: use the bit flag values below for testing a format returned by the +read APIs, but set formats from the derived values. + +When reading or writing color-mapped images the format should be set to the +format of the entries in the color-map then png_image_{read,write}_colormap +called to read or write the color-map and set the format correctly for the +image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly! + +NOTE: libpng can be built with particular features disabled, if you see +compiler errors because the definition of one of the following flags has been +compiled out it is because libpng does not have the required support. It is +possible, however, for the libpng configuration to enable the format on just +read or just write; in that case you may see an error at run time. You can +guard against this by checking for the definition of: + + PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED + + PNG_FORMAT_FLAG_ALPHA 0x01 format with an alpha channel + PNG_FORMAT_FLAG_COLOR 0x02 color format: otherwise grayscale + PNG_FORMAT_FLAG_LINEAR 0x04 png_uint_16 channels else png_byte + PNG_FORMAT_FLAG_COLORMAP 0x08 libpng use only + PNG_FORMAT_FLAG_BGR 0x10 BGR colors, else order is RGB + PNG_FORMAT_FLAG_AFIRST 0x20 alpha channel comes first + +Supported formats are as follows. Future versions of libpng may support more +formats; for compatibility with older versions simply check if the format +macro is defined using #ifdef. These defines describe the in-memory layout +of the components of the pixels of the image. + +First the single byte formats: + + PNG_FORMAT_GRAY 0 + PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA + PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST) + PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR + PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR) + PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA) + PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST) + PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA) + PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST) + +Then the linear 2-byte formats. When naming these "Y" is used to +indicate a luminance (gray) channel. The component order within the pixel +is always the same - there is no provision for swapping the order of the +components in the linear format. The components are 16-bit integers in +the native byte order for your platform, and there is no provision for +swapping the bytes to a different endian condition. + + PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR + PNG_FORMAT_LINEAR_Y_ALPHA + (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA) + PNG_FORMAT_LINEAR_RGB + (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR) + PNG_FORMAT_LINEAR_RGB_ALPHA + (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR| + PNG_FORMAT_FLAG_ALPHA) + +Color-mapped formats are obtained by calling png_image_{read,write}_colormap, +as appropriate after setting png_image::format to the format of the color-map +to be read or written. Applications may check the value of +PNG_FORMAT_FLAG_COLORMAP to see if they have called the colormap API. The +format of the color-map may be extracted using the following macro. + + PNG_FORMAT_OF_COLORMAP(fmt) ((fmt) & ~PNG_FORMAT_FLAG_COLORMAP) + +PNG_IMAGE macros + +These are convenience macros to derive information from a png_image +structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the +actual image sample values - either the entries in the color-map or the +pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values +for the pixels and will always return 1 after a call to +png_image_{read,write}_colormap. The remaining macros return information +about the rows in the image and the complete image. + +NOTE: All the macros that take a png_image::format parameter are compile time +constants if the format parameter is, itself, a constant. Therefore these +macros can be used in array declarations and case labels where required. +Similarly the macros are also pre-processor constants (sizeof is not used) so +they can be used in #if tests. + +First the information about the samples. + + PNG_IMAGE_SAMPLE_CHANNELS(fmt) + Returns the total number of channels in a given format: 1..4 + + PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt) + Returns the size in bytes of a single component of a pixel or color-map + entry (as appropriate) in the image. + + PNG_IMAGE_SAMPLE_SIZE(fmt) + This is the size of the sample data for one sample. If the image is + color-mapped it is the size of one color-map entry (and image pixels are + one byte in size), otherwise it is the size of one image pixel. + + PNG_IMAGE_COLORMAP_SIZE(fmt) + The size of the color-map required by the format; this is the size of the + color-map buffer passed to the png_image_{read,write}_colormap APIs, it is + a fixed number determined by the format so can easily be allocated on the + stack if necessary. + +#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\ + (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256) + /* The maximum size of the color-map required by the format expressed in a + * count of components. This can be used to compile-time allocate a + * color-map: + * + * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)]; + * + * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)]; + * + * Alternatively, use the PNG_IMAGE_COLORMAP_SIZE macro below to use the + * information from one of the png_image_begin_read_ APIs and dynamically + * allocate the required memory. + */ + + +Corresponding information about the pixels + + PNG_IMAGE_PIXEL_(test,fmt) + + PNG_IMAGE_PIXEL_CHANNELS(fmt) + The number of separate channels (components) in a pixel; 1 for a + color-mapped image. + + PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\ + The size, in bytes, of each component in a pixel; 1 for a color-mapped + image. + + PNG_IMAGE_PIXEL_SIZE(fmt) + The size, in bytes, of a complete pixel; 1 for a color-mapped image. + +Information about the whole row, or whole image + + PNG_IMAGE_ROW_STRIDE(image) + Returns the total number of components in a single row of the image; this + is the minimum 'row stride', the minimum count of components between each + row. For a color-mapped image this is the minimum number of bytes in a + row. + + If you need the stride measured in bytes, row_stride_bytes is + PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt) + plus any padding bytes that your application might need, for example + to start the next row on a 4-byte boundary. + + PNG_IMAGE_BUFFER_SIZE(image, row_stride) + Returns the size, in bytes, of an image buffer given a png_image and a row + stride - the number of components to leave space for in each row. This + macro takes care of multiplying row_stride by PNG_IMAGE_PIXEL_COMONENT_SIZE + when the image has 2-byte components. + + PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01 + This indicates the the RGB values of the in-memory bitmap do not + correspond to the red, green and blue end-points defined by sRGB. + + PNG_IMAGE_FLAG_COLORMAP == 0x02 + The PNG is color-mapped. If this flag is set png_image_read_colormap + can be used without further loss of image information. If it is not set + png_image_read_colormap will cause significant loss if the image has any + +READ APIs + + The png_image passed to the read APIs must have been initialized by setting + the png_controlp field 'opaque' to NULL (or, better, memset the whole thing.) + + int png_image_begin_read_from_file( png_imagep image, + const char *file_name) + + The named file is opened for read and the image header + is filled in from the PNG header in the file. + + int png_image_begin_read_from_stdio (png_imagep image, + FILE* file) + + The PNG header is read from the stdio FILE object. + + int png_image_begin_read_from_memory(png_imagep image, + png_const_voidp memory, png_size_t size) + + The PNG header is read from the given memory buffer. + + int png_image_finish_read(png_imagep image, + png_colorp background, void *buffer, + png_int_32 row_stride, void *colormap)); + + Finish reading the image into the supplied buffer and + clean up the png_image structure. + + row_stride is the step, in png_byte or png_uint_16 units + as appropriate, between adjacent rows. A positive stride + indicates that the top-most row is first in the buffer - + the normal top-down arrangement. A negative stride + indicates that the bottom-most row is first in the buffer. + + background need only be supplied if an alpha channel must + be removed from a png_byte format and the removal is to be + done by compositing on a solid color; otherwise it may be + NULL and any composition will be done directly onto the + buffer. The value is an sRGB color to use for the + background, for grayscale output the green channel is used. + + For linear output removing the alpha channel is always done + by compositing on black. + + void png_image_free(png_imagep image) + + Free any data allocated by libpng in image->opaque, + setting the pointer to NULL. May be called at any time + after the structure is initialized. + +When the simplified API needs to convert between sRGB and linear colorspaces, +the actual sRGB transfer curve defined in the sRGB specification (see the +article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2 +approximation used elsewhere in libpng. + +WRITE APIS + +For write you must initialize a png_image structure to describe the image to +be written: + + version: must be set to PNG_IMAGE_VERSION + opaque: must be initialized to NULL + width: image width in pixels + height: image height in rows + format: the format of the data you wish to write + flags: set to 0 unless one of the defined flags applies; set + PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images + where the RGB values do not correspond to the colors in sRGB. + colormap_entries: set to the number of entries in the color-map (0 to 256) + + int png_image_write_to_file, (png_imagep image, + const char *file, int convert_to_8bit, const void *buffer, + png_int_32 row_stride, const void *colormap)); + + Write the image to the named file. + + int png_image_write_to_stdio(png_imagep image, FILE *file, + int convert_to_8_bit, const void *buffer, + png_int_32 row_stride, const void *colormap) + + Write the image to the given (FILE*). + +With all write APIs if image is in one of the linear formats with +(png_uint_16) data then setting convert_to_8_bit will cause the output to be +a (png_byte) PNG gamma encoded according to the sRGB specification, otherwise +a 16-bit linear encoded PNG file is written. + +With all APIs row_stride is handled as in the read APIs - it is the spacing +from one row to the next in component sized units (float) and if negative +indicates a bottom-up row layout in the buffer. + +Note that the write API does not support interlacing, sub-8-bit pixels, +and indexed (paletted) images. + +.SH VI. Modifying/Customizing libpng + +There are two issues here. The first is changing how libpng does +standard things like memory allocation, input/output, and error handling. +The second deals with more complicated things like adding new chunks, +adding new transformations, and generally changing how libpng works. +Both of those are compile-time issues; that is, they are generally +determined at the time the code is written, and there is rarely a need +to provide the user with a means of changing them. + +Memory allocation, input/output, and error handling + +All of the memory allocation, input/output, and error handling in libpng +goes through callbacks that are user-settable. The default routines are +in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively. To change +these functions, call the appropriate png_set_*_fn() function. + +Memory allocation is done through the functions png_malloc(), png_calloc(), +and png_free(). The png_malloc() and png_free() functions currently just +call the standard C functions and png_calloc() calls png_malloc() and then +clears the newly allocated memory to zero; note that png_calloc(png_ptr, size) +is not the same as the calloc(number, size) function provided by stdlib.h. +There is limited support for certain systems with segmented memory +architectures and the types of pointers declared by png.h match this; you +will have to use appropriate pointers in your application. If you prefer +to use a different method of allocating and freeing data, you can use +png_create_read_struct_2() or png_create_write_struct_2() to register your +own functions as described above. These functions also provide a void +pointer that can be retrieved via + + mem_ptr=png_get_mem_ptr(png_ptr); + +Your replacement memory functions must have prototypes as follows: + + png_voidp malloc_fn(png_structp png_ptr, + png_alloc_size_t size); + + void free_fn(png_structp png_ptr, png_voidp ptr); + +Your malloc_fn() must return NULL in case of failure. The png_malloc() +function will normally call png_error() if it receives a NULL from the +system memory allocator or from your replacement malloc_fn(). + +Your free_fn() will never be called with a NULL ptr, since libpng's +png_free() checks for NULL before calling free_fn(). + +Input/Output in libpng is done through png_read() and png_write(), +which currently just call fread() and fwrite(). The FILE * is stored in +png_struct and is initialized via png_init_io(). If you wish to change +the method of I/O, the library supplies callbacks that you can set +through the function png_set_read_fn() and png_set_write_fn() at run +time, instead of calling the png_init_io() function. These functions +also provide a void pointer that can be retrieved via the function +png_get_io_ptr(). For example: + + png_set_read_fn(png_structp read_ptr, + voidp read_io_ptr, png_rw_ptr read_data_fn) + + png_set_write_fn(png_structp write_ptr, + voidp write_io_ptr, png_rw_ptr write_data_fn, + png_flush_ptr output_flush_fn); + + voidp read_io_ptr = png_get_io_ptr(read_ptr); + voidp write_io_ptr = png_get_io_ptr(write_ptr); + +The replacement I/O functions must have prototypes as follows: + + void user_read_data(png_structp png_ptr, + png_bytep data, png_size_t length); + + void user_write_data(png_structp png_ptr, + png_bytep data, png_size_t length); + + void user_flush_data(png_structp png_ptr); + +The user_read_data() function is responsible for detecting and +handling end-of-data errors. + +Supplying NULL for the read, write, or flush functions sets them back +to using the default C stream functions, which expect the io_ptr to +point to a standard *FILE structure. It is probably a mistake +to use NULL for one of write_data_fn and output_flush_fn but not both +of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined. +It is an error to read from a write stream, and vice versa. + +Error handling in libpng is done through png_error() and png_warning(). +Errors handled through png_error() are fatal, meaning that png_error() +should never return to its caller. Currently, this is handled via +setjmp() and longjmp() (unless you have compiled libpng with +PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()), +but you could change this to do things like exit() if you should wish, +as long as your function does not return. + +On non-fatal errors, png_warning() is called +to print a warning message, and then control returns to the calling code. +By default png_error() and png_warning() print a message on stderr via +fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined +(because you don't want the messages) or PNG_NO_STDIO defined (because +fprintf() isn't available). If you wish to change the behavior of the error +functions, you will need to set up your own message callbacks. These +functions are normally supplied at the time that the png_struct is created. +It is also possible to redirect errors and warnings to your own replacement +functions after png_create_*_struct() has been called by calling: + + png_set_error_fn(png_structp png_ptr, + png_voidp error_ptr, png_error_ptr error_fn, + png_error_ptr warning_fn); + + png_voidp error_ptr = png_get_error_ptr(png_ptr); + +If NULL is supplied for either error_fn or warning_fn, then the libpng +default function will be used, calling fprintf() and/or longjmp() if a +problem is encountered. The replacement error functions should have +parameters as follows: + + void user_error_fn(png_structp png_ptr, + png_const_charp error_msg); + + void user_warning_fn(png_structp png_ptr, + png_const_charp warning_msg); + +The motivation behind using setjmp() and longjmp() is the C++ throw and +catch exception handling methods. This makes the code much easier to write, +as there is no need to check every return code of every function call. +However, there are some uncertainties about the status of local variables +after a longjmp, so the user may want to be careful about doing anything +after setjmp returns non-zero besides returning itself. Consult your +compiler documentation for more details. For an alternative approach, you +may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net), +which is illustrated in pngvalid.c and in contrib/visupng. + +Beginning in libpng-1.4.0, the png_set_benign_errors() API became available. +You can use this to handle certain errors (normally handled as errors) +as warnings. + + png_set_benign_errors (png_ptr, int allowed); + + allowed: 0: treat png_benign_error() as an error. + 1: treat png_benign_error() as a warning. + +As of libpng-1.6.0, the default condition is to treat benign errors as +warnings while reading and as errors while writing. + +.SS Custom chunks + +If you need to read or write custom chunks, you may need to get deeper +into the libpng code. The library now has mechanisms for storing +and writing chunks of unknown type; you can even declare callbacks +for custom chunks. However, this may not be good enough if the +library code itself needs to know about interactions between your +chunk and existing `intrinsic' chunks. + +If you need to write a new intrinsic chunk, first read the PNG +specification. Acquire a first level of understanding of how it works. +Pay particular attention to the sections that describe chunk names, +and look at how other chunks were designed, so you can do things +similarly. Second, check out the sections of libpng that read and +write chunks. Try to find a chunk that is similar to yours and use +it as a template. More details can be found in the comments inside +the code. It is best to handle private or unknown chunks in a generic method, +via callback functions, instead of by modifying libpng functions. This +is illustrated in pngtest.c, which uses a callback function to handle a +private "vpAg" chunk and the new "sTER" chunk, which are both unknown to +libpng. + +If you wish to write your own transformation for the data, look through +the part of the code that does the transformations, and check out some of +the simpler ones to get an idea of how they work. Try to find a similar +transformation to the one you want to add and copy off of it. More details +can be found in the comments inside the code itself. + +.SS Configuring for gui/windowing platforms: + +You will need to write new error and warning functions that use the GUI +interface, as described previously, and set them to be the error and +warning functions at the time that png_create_*_struct() is called, +in order to have them available during the structure initialization. +They can be changed later via png_set_error_fn(). On some compilers, +you may also have to change the memory allocators (png_malloc, etc.). + +.SS Configuring zlib: + +There are special functions to configure the compression. Perhaps the +most useful one changes the compression level, which currently uses +input compression values in the range 0 - 9. The library normally +uses the default compression level (Z_DEFAULT_COMPRESSION = 6). Tests +have shown that for a large majority of images, compression values in +the range 3-6 compress nearly as well as higher levels, and do so much +faster. For online applications it may be desirable to have maximum speed +(Z_BEST_SPEED = 1). With versions of zlib after v0.99, you can also +specify no compression (Z_NO_COMPRESSION = 0), but this would create +files larger than just storing the raw bitmap. You can specify the +compression level by calling: + + #include zlib.h + png_set_compression_level(png_ptr, level); + +Another useful one is to reduce the memory level used by the library. +The memory level defaults to 8, but it can be lowered if you are +short on memory (running DOS, for example, where you only have 640K). +Note that the memory level does have an effect on compression; among +other things, lower levels will result in sections of incompressible +data being emitted in smaller stored blocks, with a correspondingly +larger relative overhead of up to 15% in the worst case. + + #include zlib.h + png_set_compression_mem_level(png_ptr, level); + +The other functions are for configuring zlib. They are not recommended +for normal use and may result in writing an invalid PNG file. See +zlib.h for more information on what these mean. + + #include zlib.h + png_set_compression_strategy(png_ptr, + strategy); + + png_set_compression_window_bits(png_ptr, + window_bits); + + png_set_compression_method(png_ptr, method); + +This controls the size of the IDAT chunks (default 8192): + + png_set_compression_buffer_size(png_ptr, size); + +As of libpng version 1.5.4, additional APIs became +available to set these separately for non-IDAT +compressed chunks such as zTXt, iTXt, and iCCP: + + #include zlib.h + #if PNG_LIBPNG_VER >= 10504 + png_set_text_compression_level(png_ptr, level); + + png_set_text_compression_mem_level(png_ptr, level); + + png_set_text_compression_strategy(png_ptr, + strategy); + + png_set_text_compression_window_bits(png_ptr, + window_bits); + + png_set_text_compression_method(png_ptr, method); + #endif + +.SS Controlling row filtering + +If you want to control whether libpng uses filtering or not, which +filters are used, and how it goes about picking row filters, you +can call one of these functions. The selection and configuration +of row filters can have a significant impact on the size and +encoding speed and a somewhat lesser impact on the decoding speed +of an image. Filtering is enabled by default for RGB and grayscale +images (with and without alpha), but not for paletted images nor +for any images with bit depths less than 8 bits/pixel. + +The 'method' parameter sets the main filtering method, which is +currently only '0' in the PNG 1.2 specification. The 'filters' +parameter sets which filter(s), if any, should be used for each +scanline. Possible values are PNG_ALL_FILTERS and PNG_NO_FILTERS +to turn filtering on and off, respectively. + +Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB, +PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise +ORed together with '|' to specify one or more filters to use. +These filters are described in more detail in the PNG specification. +If you intend to change the filter type during the course of writing +the image, you should start with flags set for all of the filters +you intend to use so that libpng can initialize its internal +structures appropriately for all of the filter types. (Note that this +means the first row must always be adaptively filtered, because libpng +currently does not allocate the filter buffers until png_write_row() +is called for the first time.) + + filters = PNG_FILTER_NONE | PNG_FILTER_SUB + PNG_FILTER_UP | PNG_FILTER_AVG | + PNG_FILTER_PAETH | PNG_ALL_FILTERS; + + png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, + filters); + The second parameter can also be + PNG_INTRAPIXEL_DIFFERENCING if you are + writing a PNG to be embedded in a MNG + datastream. This parameter must be the + same as the value of filter_method used + in png_set_IHDR(). + +It is also possible to influence how libpng chooses from among the +available filters. This is done in one or both of two ways - by +telling it how important it is to keep the same filter for successive +rows, and by telling it the relative computational costs of the filters. + + double weights[3] = {1.5, 1.3, 1.1}, + costs[PNG_FILTER_VALUE_LAST] = + {1.0, 1.3, 1.3, 1.5, 1.7}; + + png_set_filter_heuristics(png_ptr, + PNG_FILTER_HEURISTIC_WEIGHTED, 3, + weights, costs); + +The weights are multiplying factors that indicate to libpng that the +row filter should be the same for successive rows unless another row filter +is that many times better than the previous filter. In the above example, +if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a +"sum of absolute differences" 1.5 x 1.3 times higher than other filters +and still be chosen, while the NONE filter could have a sum 1.1 times +higher than other filters and still be chosen. Unspecified weights are +taken to be 1.0, and the specified weights should probably be declining +like those above in order to emphasize recent filters over older filters. + +The filter costs specify for each filter type a relative decoding cost +to be considered when selecting row filters. This means that filters +with higher costs are less likely to be chosen over filters with lower +costs, unless their "sum of absolute differences" is that much smaller. +The costs do not necessarily reflect the exact computational speeds of +the various filters, since this would unduly influence the final image +size. + +Note that the numbers above were invented purely for this example and +are given only to help explain the function usage. Little testing has +been done to find optimum values for either the costs or the weights. + +.SS Requesting debug printout + +The macro definition PNG_DEBUG can be used to request debugging +printout. Set it to an integer value in the range 0 to 3. Higher +numbers result in increasing amounts of debugging information. The +information is printed to the "stderr" file, unless another file +name is specified in the PNG_DEBUG_FILE macro definition. + +When PNG_DEBUG > 0, the following functions (macros) become available: + + png_debug(level, message) + png_debug1(level, message, p1) + png_debug2(level, message, p1, p2) + +in which "level" is compared to PNG_DEBUG to decide whether to print +the message, "message" is the formatted string to be printed, +and p1 and p2 are parameters that are to be embedded in the string +according to printf-style formatting directives. For example, + + png_debug1(2, "foo=%d", foo); + +is expanded to + + if (PNG_DEBUG > 2) + fprintf(PNG_DEBUG_FILE, "foo=%d\en", foo); + +When PNG_DEBUG is defined but is zero, the macros aren't defined, but you +can still use PNG_DEBUG to control your own debugging: + + #ifdef PNG_DEBUG + fprintf(stderr, ... + #endif + +When PNG_DEBUG = 1, the macros are defined, but only png_debug statements +having level = 0 will be printed. There aren't any such statements in +this version of libpng, but if you insert some they will be printed. + +.SH VII. MNG support + +The MNG specification (available at http://www.libpng.org/pub/mng) allows +certain extensions to PNG for PNG images that are embedded in MNG datastreams. +Libpng can support some of these extensions. To enable them, use the +png_permit_mng_features() function: + + feature_set = png_permit_mng_features(png_ptr, mask) + + mask is a png_uint_32 containing the bitwise OR of the + features you want to enable. These include + PNG_FLAG_MNG_EMPTY_PLTE + PNG_FLAG_MNG_FILTER_64 + PNG_ALL_MNG_FEATURES + + feature_set is a png_uint_32 that is the bitwise AND of + your mask with the set of MNG features that is + supported by the version of libpng that you are using. + +It is an error to use this function when reading or writing a standalone +PNG file with the PNG 8-byte signature. The PNG datastream must be wrapped +in a MNG datastream. As a minimum, it must have the MNG 8-byte signature +and the MHDR and MEND chunks. Libpng does not provide support for these +or any other MNG chunks; your application must provide its own support for +them. You may wish to consider using libmng (available at +http://www.libmng.com) instead. + +.SH VIII. Changes to Libpng from version 0.88 + +It should be noted that versions of libpng later than 0.96 are not +distributed by the original libpng author, Guy Schalnat, nor by +Andreas Dilger, who had taken over from Guy during 1996 and 1997, and +distributed versions 0.89 through 0.96, but rather by another member +of the original PNG Group, Glenn Randers-Pehrson. Guy and Andreas are +still alive and well, but they have moved on to other things. + +The old libpng functions png_read_init(), png_write_init(), +png_info_init(), png_read_destroy(), and png_write_destroy() have been +moved to PNG_INTERNAL in version 0.95 to discourage their use. These +functions will be removed from libpng version 1.4.0. + +The preferred method of creating and initializing the libpng structures is +via the png_create_read_struct(), png_create_write_struct(), and +png_create_info_struct() because they isolate the size of the structures +from the application, allow version error checking, and also allow the +use of custom error handling routines during the initialization, which +the old functions do not. The functions png_read_destroy() and +png_write_destroy() do not actually free the memory that libpng +allocated for these structs, but just reset the data structures, so they +can be used instead of png_destroy_read_struct() and +png_destroy_write_struct() if you feel there is too much system overhead +allocating and freeing the png_struct for each image read. + +Setting the error callbacks via png_set_message_fn() before +png_read_init() as was suggested in libpng-0.88 is no longer supported +because this caused applications that do not use custom error functions +to fail if the png_ptr was not initialized to zero. It is still possible +to set the error callbacks AFTER png_read_init(), or to change them with +png_set_error_fn(), which is essentially the same function, but with a new +name to force compilation errors with applications that try to use the old +method. + +Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6; +however, iTXt support was not enabled by default. + +Starting with version 1.0.7, you can find out which version of the library +you are using at run-time: + + png_uint_32 libpng_vn = png_access_version_number(); + +The number libpng_vn is constructed from the major version, minor +version with leading zero, and release number with leading zero, +(e.g., libpng_vn for version 1.0.7 is 10007). + +Note that this function does not take a png_ptr, so you can call it +before you've created one. + +You can also check which version of png.h you used when compiling your +application: + + png_uint_32 application_vn = PNG_LIBPNG_VER; + +.SH IX. Changes to Libpng from version 1.0.x to 1.2.x + +Support for user memory management was enabled by default. To +accomplish this, the functions png_create_read_struct_2(), +png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(), +png_malloc_default(), and png_free_default() were added. + +Support for the iTXt chunk has been enabled by default as of +version 1.2.41. + +Support for certain MNG features was enabled. + +Support for numbered error messages was added. However, we never got +around to actually numbering the error messages. The function +png_set_strip_error_numbers() was added (Note: the prototype for this +function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE +builds of libpng-1.2.15. It was restored in libpng-1.2.36). + +The png_malloc_warn() function was added at libpng-1.2.3. This issues +a png_warning and returns NULL instead of aborting when it fails to +acquire the requested memory allocation. + +Support for setting user limits on image width and height was enabled +by default. The functions png_set_user_limits(), png_get_user_width_max(), +and png_get_user_height_max() were added at libpng-1.2.6. + +The png_set_add_alpha() function was added at libpng-1.2.7. + +The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9. +Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the +tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is +deprecated. + +A number of macro definitions in support of runtime selection of +assembler code features (especially Intel MMX code support) were +added at libpng-1.2.0: + + PNG_ASM_FLAG_MMX_SUPPORT_COMPILED + PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU + PNG_ASM_FLAG_MMX_READ_COMBINE_ROW + PNG_ASM_FLAG_MMX_READ_INTERLACE + PNG_ASM_FLAG_MMX_READ_FILTER_SUB + PNG_ASM_FLAG_MMX_READ_FILTER_UP + PNG_ASM_FLAG_MMX_READ_FILTER_AVG + PNG_ASM_FLAG_MMX_READ_FILTER_PAETH + PNG_ASM_FLAGS_INITIALIZED + PNG_MMX_READ_FLAGS + PNG_MMX_FLAGS + PNG_MMX_WRITE_FLAGS + PNG_MMX_FLAGS + +We added the following functions in support of runtime +selection of assembler code features: + + png_get_mmx_flagmask() + png_set_mmx_thresholds() + png_get_asm_flags() + png_get_mmx_bitdepth_threshold() + png_get_mmx_rowbytes_threshold() + png_set_asm_flags() + +We replaced all of these functions with simple stubs in libpng-1.2.20, +when the Intel assembler code was removed due to a licensing issue. + +These macros are deprecated: + + PNG_READ_TRANSFORMS_NOT_SUPPORTED + PNG_PROGRESSIVE_READ_NOT_SUPPORTED + PNG_NO_SEQUENTIAL_READ_SUPPORTED + PNG_WRITE_TRANSFORMS_NOT_SUPPORTED + PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED + PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED + +They have been replaced, respectively, by: + + PNG_NO_READ_TRANSFORMS + PNG_NO_PROGRESSIVE_READ + PNG_NO_SEQUENTIAL_READ + PNG_NO_WRITE_TRANSFORMS + PNG_NO_READ_ANCILLARY_CHUNKS + PNG_NO_WRITE_ANCILLARY_CHUNKS + +PNG_MAX_UINT was replaced with PNG_UINT_31_MAX. It has been +deprecated since libpng-1.0.16 and libpng-1.2.6. + +The function + png_check_sig(sig, num) +was replaced with + !png_sig_cmp(sig, 0, num) +It has been deprecated since libpng-0.90. + +The function + png_set_gray_1_2_4_to_8() +which also expands tRNS to alpha was replaced with + png_set_expand_gray_1_2_4_to_8() +which does not. It has been deprecated since libpng-1.0.18 and 1.2.9. + +.SH X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x + +Private libpng prototypes and macro definitions were moved from +png.h and pngconf.h into a new pngpriv.h header file. + +Functions png_set_benign_errors(), png_benign_error(), and +png_chunk_benign_error() were added. + +Support for setting the maximum amount of memory that the application +will allocate for reading chunks was added, as a security measure. +The functions png_set_chunk_cache_max() and png_get_chunk_cache_max() +were added to the library. + +We implemented support for I/O states by adding png_ptr member io_state +and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c + +We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level +input transforms. + +Checking for and reporting of errors in the IHDR chunk is more thorough. + +Support for global arrays was removed, to improve thread safety. + +Some obsolete/deprecated macros and functions have been removed. + +Typecasted NULL definitions such as + #define png_voidp_NULL (png_voidp)NULL +were eliminated. If you used these in your application, just use +NULL instead. + +The png_struct and info_struct members "trans" and "trans_values" were +changed to "trans_alpha" and "trans_color", respectively. + +The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles +were removed. + +The PNG_1_0_X and PNG_1_2_X macros were eliminated. + +The PNG_LEGACY_SUPPORTED macro was eliminated. + +Many WIN32_WCE #ifdefs were removed. + +The functions png_read_init(info_ptr), png_write_init(info_ptr), +png_info_init(info_ptr), png_read_destroy(), and png_write_destroy() +have been removed. They have been deprecated since libpng-0.95. + +The png_permit_empty_plte() was removed. It has been deprecated +since libpng-1.0.9. Use png_permit_mng_features() instead. + +We removed the obsolete stub functions png_get_mmx_flagmask(), +png_set_mmx_thresholds(), png_get_asm_flags(), +png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(), +png_set_asm_flags(), and png_mmx_supported() + +We removed the obsolete png_check_sig(), png_memcpy_check(), and +png_memset_check() functions. Instead use !png_sig_cmp(), memcpy(), +and memset(), respectively. + +The function png_set_gray_1_2_4_to_8() was removed. It has been +deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with +png_set_expand_gray_1_2_4_to_8() because the former function also +expanded any tRNS chunk to an alpha channel. + +Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32 +were added and are used by default instead of the corresponding +functions. Unfortunately, +from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the +function) incorrectly returned a value of type png_uint_32. + +We changed the prototype for png_malloc() from + png_malloc(png_structp png_ptr, png_uint_32 size) +to + png_malloc(png_structp png_ptr, png_alloc_size_t size) + +This also applies to the prototype for the user replacement malloc_fn(). + +The png_calloc() function was added and is used in place of +of "png_malloc(); memset();" except in the case in png_read_png() +where the array consists of pointers; in this case a "for" loop is used +after the png_malloc() to set the pointers to NULL, to give robust. +behavior in case the application runs out of memory part-way through +the process. + +We changed the prototypes of png_get_compression_buffer_size() and +png_set_compression_buffer_size() to work with png_size_t instead of +png_uint_32. + +Support for numbered error messages was removed by default, since we +never got around to actually numbering the error messages. The function +png_set_strip_error_numbers() was removed from the library by default. + +The png_zalloc() and png_zfree() functions are no longer exported. +The png_zalloc() function no longer zeroes out the memory that it +allocates. Applications that called png_zalloc(png_ptr, number, size) +can call png_calloc(png_ptr, number*size) instead, and can call +png_free() instead of png_zfree(). + +Support for dithering was disabled by default in libpng-1.4.0, because +it has not been well tested and doesn't actually "dither". +The code was not +removed, however, and could be enabled by building libpng with +PNG_READ_DITHER_SUPPORTED defined. In libpng-1.4.2, this support +was re-enabled, but the function was renamed png_set_quantize() to +reflect more accurately what it actually does. At the same time, +the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to +PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED +was renamed to PNG_READ_QUANTIZE_SUPPORTED. + +We removed the trailing '.' from the warning and error messages. + +.SH XI. Changes to Libpng from version 1.4.x to 1.5.x + +From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the +function) incorrectly returned a value of type png_uint_32. +The incorrect macro was removed from libpng-1.4.5. + +Checking for invalid palette index on write was added at libpng +1.5.10. If a pixel contains an invalid (out-of-range) index libpng issues +a benign error. This is enabled by default because this condition is an +error according to the PNG specification, Clause 11.3.2, but the error can +be ignored in each png_ptr with + + png_set_check_for_invalid_index(png_ptr, allowed); + + allowed - one of + 0: disable benign error (accept the + invalid data without warning). + 1: enable benign error (treat the + invalid data as an error or a + warning). + +If the error is ignored, or if png_benign_error() treats it as a warning, +any invalid pixels are decoded as opaque black by the decoder and written +as-is by the encoder. + +Retrieving the maximum palette index found was added at libpng-1.5.15. +This statement must appear after png_read_png() or png_read_image() while +reading, and after png_write_png() or png_write_image() while writing. + + int max_palette = png_get_palette_max(png_ptr, info_ptr); + +This will return the maximum palette index found in the image, or "\-1" if +the palette was not checked, or "0" if no palette was found. Note that this +does not account for any palette index used by ancillary chunks such as the +bKGD chunk; you must check those separately to determine the maximum +palette index actually used. + +There are no substantial API changes between the non-deprecated parts of +the 1.4.5 API and the 1.5.0 API; however, the ability to directly access +members of the main libpng control structures, png_struct and png_info, +deprecated in earlier versions of libpng, has been completely removed from +libpng 1.5. + +We no longer include zlib.h in png.h. The include statement has been moved +to pngstruct.h, where it is not accessible by applications. Applications that +need access to information in zlib.h will need to add the '#include "zlib.h"' +directive. It does not matter whether this is placed prior to or after +the '"#include png.h"' directive. + +The png_sprintf(), png_strcpy(), and png_strncpy() macros are no longer used +and were removed. + +We moved the png_strlen(), png_memcpy(), png_memset(), and png_memcmp() +macros into a private header file (pngpriv.h) that is not accessible to +applications. + +In png_get_iCCP, the type of "profile" was changed from png_charpp +to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep. + +There are changes of form in png.h, including new and changed macros to +declare parts of the API. Some API functions with arguments that are +pointers to data not modified within the function have been corrected to +declare these arguments with PNG_CONST. + +Much of the internal use of C macros to control the library build has also +changed and some of this is visible in the exported header files, in +particular the use of macros to control data and API elements visible +during application compilation may require significant revision to +application code. (It is extremely rare for an application to do this.) + +Any program that compiled against libpng 1.4 and did not use deprecated +features or access internal library structures should compile and work +against libpng 1.5, except for the change in the prototype for +png_get_iCCP() and png_set_iCCP() API functions mentioned above. + +libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of +interlaced images. The macros return the number of rows and columns in +each pass and information that can be used to de-interlace and (if +absolutely necessary) interlace an image. + +libpng 1.5.0 adds an API png_longjmp(png_ptr, value). This API calls +the application-provided png_longjmp_ptr on the internal, but application +initialized, longjmp buffer. It is provided as a convenience to avoid +the need to use the png_jmpbuf macro, which had the unnecessary side +effect of resetting the internal png_longjmp_ptr value. + +libpng 1.5.0 includes a complete fixed point API. By default this is +present along with the corresponding floating point API. In general the +fixed point API is faster and smaller than the floating point one because +the PNG file format used fixed point, not floating point. This applies +even if the library uses floating point in internal calculations. A new +macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library +uses floating point arithmetic (the default) or fixed point arithmetic +internally for performance critical calculations such as gamma correction. +In some cases, the gamma calculations may produce slightly different +results. This has changed the results in png_rgb_to_gray and in alpha +composition (png_set_background for example). This applies even if the +original image was already linear (gamma == 1.0) and, therefore, it is +not necessary to linearize the image. This is because libpng has *not* +been changed to optimize that case correctly, yet. + +Fixed point support for the sCAL chunk comes with an important caveat; +the sCAL specification uses a decimal encoding of floating point values +and the accuracy of PNG fixed point values is insufficient for +representation of these values. Consequently a "string" API +(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading +arbitrary sCAL chunks in the absence of either the floating point API or +internal floating point calculations. Starting with libpng-1.5.0, both +of these functions are present when PNG_sCAL_SUPPORTED is defined. Prior +to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED +being defined and PNG_FLOATING_POINT_SUPPORTED not being defined. + +Applications no longer need to include the optional distribution header +file pngusr.h or define the corresponding macros during application +build in order to see the correct variant of the libpng API. From 1.5.0 +application code can check for the corresponding _SUPPORTED macro: + +#ifdef PNG_INCH_CONVERSIONS_SUPPORTED + /* code that uses the inch conversion APIs. */ +#endif + +This macro will only be defined if the inch conversion functions have been +compiled into libpng. The full set of macros, and whether or not support +has been compiled in, are available in the header file pnglibconf.h. +This header file is specific to the libpng build. Notice that prior to +1.5.0 the _SUPPORTED macros would always have the default definition unless +reset by pngusr.h or by explicit settings on the compiler command line. +These settings may produce compiler warnings or errors in 1.5.0 because +of macro redefinition. + +Applications can now choose whether to use these macros or to call the +corresponding function by defining PNG_USE_READ_MACROS or +PNG_NO_USE_READ_MACROS before including png.h. Notice that this is +only supported from 1.5.0; defining PNG_NO_USE_READ_MACROS prior to 1.5.0 +will lead to a link failure. + +Prior to libpng-1.5.4, the zlib compressor used the same set of parameters +when compressing the IDAT data and textual data such as zTXt and iCCP. +In libpng-1.5.4 we reinitialized the zlib stream for each type of data. +We added five png_set_text_*() functions for setting the parameters to +use with textual data. + +Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED +option was off by default, and slightly inaccurate scaling occurred. +This option can no longer be turned off, and the choice of accurate +or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8() +API for accurate scaling or the old png_set_strip_16_to_8() API for simple +chopping. In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED +macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8 +macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two +png_set_*_16_to_8() functions separately. + +Prior to libpng-1.5.4, the png_set_user_limits() function could only be +used to reduce the width and height limits from the value of +PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said +that it could be used to override them. Now this function will reduce or +increase the limits. + +Starting in libpng-1.5.10, the user limits can be set en masse with the +configuration option PNG_SAFE_LIMITS_SUPPORTED. If this option is enabled, +a set of "safe" limits is applied in pngpriv.h. These can be overridden by +application calls to png_set_user_limits(), png_set_user_chunk_cache_max(), +and/or png_set_user_malloc_max() that increase or decrease the limits. Also, +in libpng-1.5.10 the default width and height limits were increased +from 1,000,000 to 0x7ffffff (i.e., made unlimited). Therefore, the +limits are now + default safe + png_user_width_max 0x7fffffff 1,000,000 + png_user_height_max 0x7fffffff 1,000,000 + png_user_chunk_cache_max 0 (unlimited) 128 + png_user_chunk_malloc_max 0 (unlimited) 8,000,000 + +The png_set_option() function (and the "options" member of the png struct) was +added to libpng-1.5.15. + +The library now supports a complete fixed point implementation and can +thus be used on systems that have no floating point support or very +limited or slow support. Previously gamma correction, an essential part +of complete PNG support, required reasonably fast floating point. + +As part of this the choice of internal implementation has been made +independent of the choice of fixed versus floating point APIs and all the +missing fixed point APIs have been implemented. + +The exact mechanism used to control attributes of API functions has +changed, as described in the INSTALL file. + +A new test program, pngvalid, is provided in addition to pngtest. +pngvalid validates the arithmetic accuracy of the gamma correction +calculations and includes a number of validations of the file format. +A subset of the full range of tests is run when "make check" is done +(in the 'configure' build.) pngvalid also allows total allocated memory +usage to be evaluated and performs additional memory overwrite validation. + +Many changes to individual feature macros have been made. The following +are the changes most likely to be noticed by library builders who +configure libpng: + +1) All feature macros now have consistent naming: + +#define PNG_NO_feature turns the feature off +#define PNG_feature_SUPPORTED turns the feature on + +pnglibconf.h contains one line for each feature macro which is either: + +#define PNG_feature_SUPPORTED + +if the feature is supported or: + +/*#undef PNG_feature_SUPPORTED*/ + +if it is not. Library code consistently checks for the 'SUPPORTED' macro. +It does not, and libpng applications should not, check for the 'NO' macro +which will not normally be defined even if the feature is not supported. +The 'NO' macros are only used internally for setting or not setting the +corresponding 'SUPPORTED' macros. + +Compatibility with the old names is provided as follows: + +PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED + +And the following definitions disable the corresponding feature: + +PNG_SETJMP_NOT_SUPPORTED disables SETJMP +PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS +PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV +PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS +PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS +PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS + +Library builders should remove use of the above, inconsistent, names. + +2) Warning and error message formatting was previously conditional on +the STDIO feature. The library has been changed to use the +CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled +the library no longer uses the printf(3) functions, even though the +default read/write implementations use (FILE) style stdio.h functions. + +3) Three feature macros now control the fixed/floating point decisions: + +PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs + +PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in +practice these are normally required internally anyway (because the PNG +file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT +merely stops the function from being exported. + +PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating +point implementation or the fixed point one. Typically the fixed point +implementation is larger and slower than the floating point implementation +on a system that supports floating point; however, it may be faster on a +system which lacks floating point hardware and therefore uses a software +emulation. + +4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED. This allows the +functions to read and write ints to be disabled independently of +PNG_USE_READ_MACROS, which allows libpng to be built with the functions +even though the default is to use the macros - this allows applications +to choose at app buildtime whether or not to use macros (previously +impossible because the functions weren't in the default build.) + +.SH XII. Changes to Libpng from version 1.5.x to 1.6.x + +A "simplified API" has been added (see documentation in png.h and a simple +example in contrib/examples/pngtopng.c). The new publicly visible API +includes the following: + + macros: + PNG_FORMAT_* + PNG_IMAGE_* + structures: + png_control + png_image + read functions + png_image_begin_read_from_file() + png_image_begin_read_from_stdio() + png_image_begin_read_from_memory() + png_image_finish_read() + png_image_free() + write functions + png_image_write_to_file() + png_image_write_to_stdio() + +Starting with libpng-1.6.0, you can configure libpng to prefix all exported +symbols, using the PNG_PREFIX macro. + +We no longer include string.h in png.h. The include statement has been moved +to pngpriv.h, where it is not accessible by applications. Applications that +need access to information in string.h must add an '#include <string.h>' +directive. It does not matter whether this is placed prior to or after +the '#include "png.h"' directive. + +The following API are now DEPRECATED: + png_info_init_3() + png_convert_to_rfc1123() which has been replaced + with png_convert_to_rfc1123_buffer() + png_malloc_default() + png_free_default() + png_reset_zstream() + +The following have been removed: + png_get_io_chunk_name(), which has been replaced + with png_get_io_chunk_type(). The new + function returns a 32-bit integer instead of + a string. + The png_sizeof(), png_strlen(), png_memcpy(), png_memcmp(), and + png_memset() macros are no longer used in the libpng sources and + have been removed. These had already been made invisible to applications + (i.e., defined in the private pngpriv.h header file) since libpng-1.5.0. + +The signatures of many exported functions were changed, such that + png_structp became png_structrp or png_const_structrp + png_infop became png_inforp or png_const_inforp +where "rp" indicates a "restricted pointer". + +Error detection in some chunks has improved; in particular the iCCP chunk +reader now does pretty complete validation of the basic format. Some bad +profiles that were previously accepted are now accepted with a warning or +rejected, depending upon the png_set_benign_errors() setting, in particular the +very old broken Microsoft/HP 3144-byte sRGB profile. Starting with +libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by +means of + + #ifdef PNG_SKIP_sRGB_CHECK_PROFILE + png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE, + PNG_OPTION_ON); + #endif + +It's not a good idea to do this if you are using the "simplified API", +which needs to be able to recognize an sRGB profile conveyed via the iCCP +chunk. + +The PNG spec requirement that only grayscale profiles may appear in images +with color type 0 or 4 and that even if the image only contains gray pixels, +only RGB profiles may appear in images with color type 2, 3, or 6, is now +enforced. The sRGB chunk is allowed to appear in images with any color type +and is interpreted by libpng to convey a one-tracer-curve profile or a +three-tracer-curve profile as appropriate. + +Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained +an empty language field or an empty translated keyword. Both of these +are allowed by the PNG specification, so these warnings are no longer issued. + +The library now issues an error if the application attempts to set a +transform after it calls png_read_update_info() or if it attempts to call +both png_read_update_info() and png_start_read_image() or to call either +of them more than once. + +The default condition for benign_errors is now to treat benign errors as +warnings while reading and as errors while writing. + +The library now issues a warning if both background processing and RGB to +gray are used when gamma correction happens. As with previous versions of +the library the results are numerically very incorrect in this case. + +There are some minor arithmetic changes in some transforms such as +png_set_background(), that might be detected by certain regression tests. + +Unknown chunk handling has been improved internally, without any API change. +This adds more correct option control of the unknown handling, corrects +a pre-existing bug where the per-chunk 'keep' setting is ignored, and makes +it possible to skip IDAT chunks in the sequential reader. + +The machine-generated configure files are no longer included in branches +libpng16 and later of the GIT repository. They continue to be included +in the tarball releases, however. + +Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT +stream to set the size of the sliding window for reading instead of using the +default 32-kbyte sliding window size. It was discovered that there are +hundreds of PNG files in the wild that have incorrect CMF bytes that caused +zlib to issue the "invalid distance too far back" error and reject the file. +Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions, +provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes +and using a 32-kbyte sliding window), by using + + png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW, + PNG_OPTION_ON); + +and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while +optimizing the CMF bytes in its IDAT chunk correctly. + +Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong +length, which resulted in PNG files that cannot be read beyond the bad iTXt +chunk. This error was fixed in libpng-1.6.3, and a tool (called +contrib/tools/png-fix-itxt) has been added to the libpng distribution. + +.SH XIII. Detecting libpng + +The png_get_io_ptr() function has been present since libpng-0.88, has never +changed, and is unaffected by conditional compilation macros. It is the +best choice for use in configure scripts for detecting the presence of any +libpng version since 0.88. In an autoconf "configure.in" you could use + + AC_CHECK_LIB(png, png_get_io_ptr, ... + +.SH XV. Source code repository + +Since about February 2009, version 1.2.34, libpng has been under "git" source +control. The git repository was built from old libpng-x.y.z.tar.gz files +going back to version 0.70. You can access the git repository (read only) +at + + git://git.code.sf.net/p/libpng/code + +or you can browse it with a web browser by selecting the "code" button at + + https://sourceforge.net/projects/libpng + +Patches can be sent to glennrp at users.sourceforge.net or to +png-mng-implement at lists.sourceforge.net or you can upload them to +the libpng bug tracker at + + http://libpng.sourceforge.net + +We also accept patches built from the tar or zip distributions, and +simple verbal discriptions of bug fixes, reported either to the +SourceForge bug tracker, to the png-mng-implement at lists.sf.net +mailing list, or directly to glennrp. + +.SH XV. Coding style + +Our coding style is similar to the "Allman" style +(See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly +braces on separate lines: + + if (condition) + { + action; + } + + else if (another condition) + { + another action; + } + +The braces can be omitted from simple one-line actions: + + if (condition) + return (0); + +We use 3-space indentation, except for continued statements which +are usually indented the same as the first line of the statement +plus four more spaces. + +For macro definitions we use 2-space indentation, always leaving the "#" +in the first column. + + #ifndef PNG_NO_FEATURE + # ifndef PNG_FEATURE_SUPPORTED + # define PNG_FEATURE_SUPPORTED + # endif + #endif + +Comments appear with the leading "/*" at the same indentation as +the statement that follows the comment: + + /* Single-line comment */ + statement; + + /* This is a multiple-line + * comment. + */ + statement; + +Very short comments can be placed after the end of the statement +to which they pertain: + + statement; /* comment */ + +We don't use C++ style ("//") comments. We have, however, +used them in the past in some now-abandoned MMX assembler +code. + +Functions and their curly braces are not indented, and +exported functions are marked with PNGAPI: + + /* This is a public function that is visible to + * application programmers. It does thus-and-so. + */ + void PNGAPI + png_exported_function(png_ptr, png_info, foo) + { + body; + } + +The return type and decorations are placed on a separate line +ahead of the function name, as illustrated above. + +The prototypes for all exported functions appear in png.h, +above the comment that says + + /* Maintainer: Put new public prototypes here ... */ + +We mark all non-exported functions with "/* PRIVATE */"": + + void /* PRIVATE */ + png_non_exported_function(png_ptr, png_info, foo) + { + body; + } + +The prototypes for non-exported functions (except for those in +pngtest) appear in +pngpriv.h +above the comment that says + + /* Maintainer: Put new private prototypes here ^ */ + +We put a space after the "sizeof" operator and we omit the +optional parentheses around its argument when the argument +is an expression, not a type name, and we always enclose the +sizeof operator, with its argument, in parentheses: + + (sizeof (png_uint_32)) + (sizeof array) + +Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as +though it were a function. + +To avoid polluting the global namespace, the names of all exported +functions and variables begin with "png_", and all publicly visible C +preprocessor macros begin with "PNG". We request that applications that +use libpng *not* begin any of their own symbols with either of these strings. + +We put a space after each comma and after each semicolon +in "for" statements, and we put spaces before and after each +C binary operator and after "for" or "while", and before +"?". We don't put a space between a typecast and the expression +being cast, nor do we put one between a function name and the +left parenthesis that follows it: + + for (i = 2; i > 0; \-\-i) + y[i] = a(x) + (int)b; + +We prefer #ifdef and #ifndef to #if defined() and #if !defined() +when there is only one macro being tested. We always use parentheses +with "defined". + +We prefer to express integers that are used as bit masks in hex format, +with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100). + +We prefer to use underscores in variable names rather than camelCase, except +for a few type names that we inherit from zlib.h. + +We prefer "if (something != 0)" and "if (something == 0)" +over "if (something)" and if "(!something)", respectively. + +We do not use the TAB character for indentation in the C sources. + +Lines do not exceed 80 characters. + +Other rules can be inferred by inspecting the libpng source. + +.SH XVI. Y2K Compliance in libpng + +June 12, 2014 + +Since the PNG Development group is an ad-hoc body, we can't make +an official declaration. + +This is your unofficial assurance that libpng from version 0.71 and +upward through 1.6.12 are Y2K compliant. It is my belief that earlier +versions were also Y2K compliant. + +Libpng only has two year fields. One is a 2-byte unsigned integer +that will hold years up to 65535. The other, which is deprecated, +holds the date in text format, and will hold years up to 9999. + +The integer is + "png_uint_16 year" in png_time_struct. + +The string is + "char time_buffer[29]" in png_struct. This is no longer used +in libpng-1.6.x and will be removed from libpng-1.7.0. + +There are seven time-related functions: + + png_convert_to_rfc_1123() in png.c + (formerly png_convert_to_rfc_1152() in error) + png_convert_from_struct_tm() in pngwrite.c, called + in pngwrite.c + png_convert_from_time_t() in pngwrite.c + png_get_tIME() in pngget.c + png_handle_tIME() in pngrutil.c, called in pngread.c + png_set_tIME() in pngset.c + png_write_tIME() in pngwutil.c, called in pngwrite.c + +All appear to handle dates properly in a Y2K environment. The +png_convert_from_time_t() function calls gmtime() to convert from system +clock time, which returns (year - 1900), which we properly convert to +the full 4-digit year. There is a possibility that applications using +libpng are not passing 4-digit years into the png_convert_to_rfc_1123() +function, or that they are incorrectly passing only a 2-digit year +instead of "year - 1900" into the png_convert_from_struct_tm() function, +but this is not under our control. The libpng documentation has always +stated that it works with 4-digit years, and the APIs have been +documented as such. + +The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned +integer to hold the year, and can hold years as large as 65535. + +zlib, upon which libpng depends, is also Y2K compliant. It contains +no date-related code. + + + Glenn Randers-Pehrson + libpng maintainer + PNG Development Group + +.SH NOTE + +Note about libpng version numbers: + +Due to various miscommunications, unforeseen code incompatibilities +and occasional factors outside the authors' control, version numbering +on the library has not always been consistent and straightforward. +The following table summarizes matters since version 0.89c, which was +the first widely used release: + + source png.h png.h shared-lib + version string int version + ------- ------ ----- ---------- + 0.89c ("beta 3") 0.89 89 1.0.89 + 0.90 ("beta 4") 0.90 90 0.90 + 0.95 ("beta 5") 0.95 95 0.95 + 0.96 ("beta 6") 0.96 96 0.96 + 0.97b ("beta 7") 1.00.97 97 1.0.1 + 0.97c 0.97 97 2.0.97 + 0.98 0.98 98 2.0.98 + 0.99 0.99 98 2.0.99 + 0.99a-m 0.99 99 2.0.99 + 1.00 1.00 100 2.1.0 + 1.0.0 1.0.0 100 2.1.0 + 1.0.0 (from here on, the 100 2.1.0 + 1.0.1 png.h string is 10001 2.1.0 + 1.0.1a-e identical to the 10002 from here on, the + 1.0.2 source version) 10002 shared library is 2.V + 1.0.2a-b 10003 where V is the source + 1.0.1 10001 code version except as + 1.0.1a-e 10002 2.1.0.1a-e noted. + 1.0.2 10002 2.1.0.2 + 1.0.2a-b 10003 2.1.0.2a-b + 1.0.3 10003 2.1.0.3 + 1.0.3a-d 10004 2.1.0.3a-d + 1.0.4 10004 2.1.0.4 + 1.0.4a-f 10005 2.1.0.4a-f + 1.0.5 (+ 2 patches) 10005 2.1.0.5 + 1.0.5a-d 10006 2.1.0.5a-d + 1.0.5e-r 10100 2.1.0.5e-r + 1.0.5s-v 10006 2.1.0.5s-v + 1.0.6 (+ 3 patches) 10006 2.1.0.6 + 1.0.6d-g 10007 2.1.0.6d-g + 1.0.6h 10007 10.6h + 1.0.6i 10007 10.6i + 1.0.6j 10007 2.1.0.6j + 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 + 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 + 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 + 1.0.7 1 10007 2.1.0.7 + 1.0.8beta1-4 1 10008 2.1.0.8beta1-4 + 1.0.8rc1 1 10008 2.1.0.8rc1 + 1.0.8 1 10008 2.1.0.8 + 1.0.9beta1-6 1 10009 2.1.0.9beta1-6 + 1.0.9rc1 1 10009 2.1.0.9rc1 + 1.0.9beta7-10 1 10009 2.1.0.9beta7-10 + 1.0.9rc2 1 10009 2.1.0.9rc2 + 1.0.9 1 10009 2.1.0.9 + 1.0.10beta1 1 10010 2.1.0.10beta1 + 1.0.10rc1 1 10010 2.1.0.10rc1 + 1.0.10 1 10010 2.1.0.10 + 1.0.11beta1-3 1 10011 2.1.0.11beta1-3 + 1.0.11rc1 1 10011 2.1.0.11rc1 + 1.0.11 1 10011 2.1.0.11 + 1.0.12beta1-2 2 10012 2.1.0.12beta1-2 + 1.0.12rc1 2 10012 2.1.0.12rc1 + 1.0.12 2 10012 2.1.0.12 + 1.1.0a-f - 10100 2.1.1.0a-f abandoned + 1.2.0beta1-2 2 10200 2.1.2.0beta1-2 + 1.2.0beta3-5 3 10200 3.1.2.0beta3-5 + 1.2.0rc1 3 10200 3.1.2.0rc1 + 1.2.0 3 10200 3.1.2.0 + 1.2.1beta-4 3 10201 3.1.2.1beta1-4 + 1.2.1rc1-2 3 10201 3.1.2.1rc1-2 + 1.2.1 3 10201 3.1.2.1 + 1.2.2beta1-6 12 10202 12.so.0.1.2.2beta1-6 + 1.0.13beta1 10 10013 10.so.0.1.0.13beta1 + 1.0.13rc1 10 10013 10.so.0.1.0.13rc1 + 1.2.2rc1 12 10202 12.so.0.1.2.2rc1 + 1.0.13 10 10013 10.so.0.1.0.13 + 1.2.2 12 10202 12.so.0.1.2.2 + 1.2.3rc1-6 12 10203 12.so.0.1.2.3rc1-6 + 1.2.3 12 10203 12.so.0.1.2.3 + 1.2.4beta1-3 13 10204 12.so.0.1.2.4beta1-3 + 1.2.4rc1 13 10204 12.so.0.1.2.4rc1 + 1.0.14 10 10014 10.so.0.1.0.14 + 1.2.4 13 10204 12.so.0.1.2.4 + 1.2.5beta1-2 13 10205 12.so.0.1.2.5beta1-2 + 1.0.15rc1 10 10015 10.so.0.1.0.15rc1 + 1.0.15 10 10015 10.so.0.1.0.15 + 1.2.5 13 10205 12.so.0.1.2.5 + 1.2.6beta1-4 13 10206 12.so.0.1.2.6beta1-4 + 1.2.6rc1-5 13 10206 12.so.0.1.2.6rc1-5 + 1.0.16 10 10016 10.so.0.1.0.16 + 1.2.6 13 10206 12.so.0.1.2.6 + 1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2 + 1.0.17rc1 10 10017 12.so.0.1.0.17rc1 + 1.2.7rc1 13 10207 12.so.0.1.2.7rc1 + 1.0.17 10 10017 12.so.0.1.0.17 + 1.2.7 13 10207 12.so.0.1.2.7 + 1.2.8beta1-5 13 10208 12.so.0.1.2.8beta1-5 + 1.0.18rc1-5 10 10018 12.so.0.1.0.18rc1-5 + 1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5 + 1.0.18 10 10018 12.so.0.1.0.18 + 1.2.8 13 10208 12.so.0.1.2.8 + 1.2.9beta1-3 13 10209 12.so.0.1.2.9beta1-3 + 1.2.9beta4-11 13 10209 12.so.0.9[.0] + 1.2.9rc1 13 10209 12.so.0.9[.0] + 1.2.9 13 10209 12.so.0.9[.0] + 1.2.10beta1-7 13 10210 12.so.0.10[.0] + 1.2.10rc1-2 13 10210 12.so.0.10[.0] + 1.2.10 13 10210 12.so.0.10[.0] + 1.4.0beta1-6 14 10400 14.so.0.0[.0] + 1.2.11beta1-4 13 10210 12.so.0.11[.0] + 1.4.0beta7-8 14 10400 14.so.0.0[.0] + 1.2.11 13 10211 12.so.0.11[.0] + 1.2.12 13 10212 12.so.0.12[.0] + 1.4.0beta9-14 14 10400 14.so.0.0[.0] + 1.2.13 13 10213 12.so.0.13[.0] + 1.4.0beta15-36 14 10400 14.so.0.0[.0] + 1.4.0beta37-87 14 10400 14.so.14.0[.0] + 1.4.0rc01 14 10400 14.so.14.0[.0] + 1.4.0beta88-109 14 10400 14.so.14.0[.0] + 1.4.0rc02-08 14 10400 14.so.14.0[.0] + 1.4.0 14 10400 14.so.14.0[.0] + 1.4.1beta01-03 14 10401 14.so.14.1[.0] + 1.4.1rc01 14 10401 14.so.14.1[.0] + 1.4.1beta04-12 14 10401 14.so.14.1[.0] + 1.4.1 14 10401 14.so.14.1[.0] + 1.4.2 14 10402 14.so.14.2[.0] + 1.4.3 14 10403 14.so.14.3[.0] + 1.4.4 14 10404 14.so.14.4[.0] + 1.5.0beta01-58 15 10500 15.so.15.0[.0] + 1.5.0rc01-07 15 10500 15.so.15.0[.0] + 1.5.0 15 10500 15.so.15.0[.0] + 1.5.1beta01-11 15 10501 15.so.15.1[.0] + 1.5.1rc01-02 15 10501 15.so.15.1[.0] + 1.5.1 15 10501 15.so.15.1[.0] + 1.5.2beta01-03 15 10502 15.so.15.2[.0] + 1.5.2rc01-03 15 10502 15.so.15.2[.0] + 1.5.2 15 10502 15.so.15.2[.0] + 1.5.3beta01-10 15 10503 15.so.15.3[.0] + 1.5.3rc01-02 15 10503 15.so.15.3[.0] + 1.5.3beta11 15 10503 15.so.15.3[.0] + 1.5.3 [omitted] + 1.5.4beta01-08 15 10504 15.so.15.4[.0] + 1.5.4rc01 15 10504 15.so.15.4[.0] + 1.5.4 15 10504 15.so.15.4[.0] + 1.5.5beta01-08 15 10505 15.so.15.5[.0] + 1.5.5rc01 15 10505 15.so.15.5[.0] + 1.5.5 15 10505 15.so.15.5[.0] + 1.5.6beta01-07 15 10506 15.so.15.6[.0] + 1.5.6rc01-03 15 10506 15.so.15.6[.0] + 1.5.6 15 10506 15.so.15.6[.0] + 1.5.7beta01-05 15 10507 15.so.15.7[.0] + 1.5.7rc01-03 15 10507 15.so.15.7[.0] + 1.5.7 15 10507 15.so.15.7[.0] + 1.6.0beta01-40 16 10600 16.so.16.0[.0] + 1.6.0rc01-08 16 10600 16.so.16.0[.0] + 1.6.0 16 10600 16.so.16.0[.0] + 1.6.1beta01-09 16 10601 16.so.16.1[.0] + 1.6.1rc01 16 10601 16.so.16.1[.0] + 1.6.1 16 10601 16.so.16.1[.0] + 1.6.2beta01 16 10602 16.so.16.2[.0] + 1.6.2rc01-06 16 10602 16.so.16.2[.0] + 1.6.2 16 10602 16.so.16.2[.0] + 1.6.3beta01-11 16 10603 16.so.16.3[.0] + 1.6.3rc01 16 10603 16.so.16.3[.0] + 1.6.3 16 10603 16.so.16.3[.0] + 1.6.4beta01-02 16 10604 16.so.16.4[.0] + 1.6.4rc01 16 10604 16.so.16.4[.0] + 1.6.4 16 10604 16.so.16.4[.0] + 1.6.5 16 10605 16.so.16.5[.0] + 1.6.6 16 10606 16.so.16.6[.0] + 1.6.7beta01-04 16 10607 16.so.16.7[.0] + 1.6.7rc01-02 16 10607 16.so.16.7[.0] + 1.6.7 16 10607 16.so.16.7[.0] + 1.6.8beta01-02 16 10608 16.so.16.8[.0] + 1.6.8rc01-02 16 10608 16.so.16.8[.0] + 1.6.8 16 10608 16.so.16.8[.0] + 1.6.9beta01-04 16 10609 16.so.16.9[.0] + 1.6.9rc01-02 16 10609 16.so.16.9[.0] + 1.6.9 16 10609 16.so.16.9[.0] + 1.6.10beta01-03 16 10610 16.so.16.10[.0] + 1.6.10rc01-03 16 10610 16.so.16.10[.0] + 1.6.10 16 10610 16.so.16.10[.0] + 1.6.11beta01-06 16 10611 16.so.16.11[.0] + 1.6.11rc01-02 16 10611 16.so.16.11[.0] + 1.6.11 16 10611 16.so.16.11[.0] + 1.6.12rc01 16 10612 16.so.16.12[.0] + 1.6.12 16 10612 16.so.16.12[.0] + +Henceforth the source version will match the shared-library minor +and patch numbers; the shared-library major version number will be +used for changes in backward compatibility, as it is intended. The +PNG_PNGLIB_VER macro, which is not used within libpng but is available +for applications, is an unsigned integer of the form xyyzz corresponding +to the source version x.y.z (leading zeros in y and z). Beta versions +were given the previous public release number plus a letter, until +version 1.0.6j; from then on they were given the upcoming public +release number plus "betaNN" or "rcN". + +.SH "SEE ALSO" +.BR "png"(5), " libpngpf"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5) + +.LP +.IR libpng : +.IP +http://libpng.sourceforge.net (follow the [DOWNLOAD] link) +http://www.libpng.org/pub/png + +.LP +.IR zlib : +.IP +(generally) at the same location as +.I libpng +or at +.br +ftp://ftp.info-zip.org/pub/infozip/zlib + +.LP +.IR PNG specification: RFC 2083 +.IP +(generally) at the same location as +.I libpng +or at +.br +ftp://ds.internic.net/rfc/rfc2083.txt +.br +or (as a W3C Recommendation) at +.br +http://www.w3.org/TR/REC-png.html + +.LP +In the case of any inconsistency between the PNG specification +and this library, the specification takes precedence. + +.SH AUTHORS +This man page: Glenn Randers-Pehrson +<glennrp at users.sourceforge.net> + +The contributing authors would like to thank all those who helped +with testing, bug fixes, and patience. This wouldn't have been +possible without all of you. + +Thanks to Frank J. T. Wojcik for helping with the documentation. + +Libpng version 1.6.12 - June 12, 2014: +Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc. +Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net). + +Supported by the PNG development group +.br +png-mng-implement at lists.sf.net +(subscription required; visit +png-mng-implement at lists.sourceforge.net (subscription required; visit +https://lists.sourceforge.net/lists/listinfo/png-mng-implement +to subscribe). + +.SH COPYRIGHT NOTICE, DISCLAIMER, and LICENSE: + +(This copy of the libpng notices is provided for your convenience. In case of +any discrepancy between this copy and the notices in the file png.h that is +included in the libpng distribution, the latter shall prevail.) + +If you modify libpng you may insert additional notices immediately following +this sentence. + +This code is released under the libpng license. + +libpng versions 1.2.6, August 15, 2004, through 1.6.12, June 12, 2014, are +Copyright (c) 2004,2006-2014 Glenn Randers-Pehrson, and are +distributed according to the same disclaimer and license as libpng-1.2.5 +with the following individual added to the list of Contributing Authors + + Cosmin Truta + +libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are +Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are +distributed according to the same disclaimer and license as libpng-1.0.6 +with the following individuals added to the list of Contributing Authors + + Simon-Pierre Cadieux + Eric S. Raymond + Gilles Vollant + +and with the following additions to the disclaimer: + + There is no warranty against interference with your + enjoyment of the library or against infringement. + There is no warranty that our efforts or the library + will fulfill any of your particular purposes or needs. + This library is provided with all faults, and the entire + risk of satisfactory quality, performance, accuracy, and + effort is with the user. + +libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are +Copyright (c) 1998, 1999 Glenn Randers-Pehrson +Distributed according to the same disclaimer and license as libpng-0.96, +with the following individuals added to the list of Contributing Authors: + + Tom Lane + Glenn Randers-Pehrson + Willem van Schaik + +libpng versions 0.89, June 1996, through 0.96, May 1997, are +Copyright (c) 1996, 1997 Andreas Dilger +Distributed according to the same disclaimer and license as libpng-0.88, +with the following individuals added to the list of Contributing Authors: + + John Bowler + Kevin Bracey + Sam Bushell + Magnus Holmgren + Greg Roelofs + Tom Tanner + +libpng versions 0.5, May 1995, through 0.88, January 1996, are +Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc. + +For the purposes of this copyright and license, "Contributing Authors" +is defined as the following set of individuals: + + Andreas Dilger + Dave Martindale + Guy Eric Schalnat + Paul Schmidt + Tim Wegner + +The PNG Reference Library is supplied "AS IS". The Contributing Authors +and Group 42, Inc. disclaim all warranties, expressed or implied, +including, without limitation, the warranties of merchantability and of +fitness for any purpose. The Contributing Authors and Group 42, Inc. +assume no liability for direct, indirect, incidental, special, exemplary, +or consequential damages, which may result from the use of the PNG +Reference Library, even if advised of the possibility of such damage. + +Permission is hereby granted to use, copy, modify, and distribute this +source code, or portions hereof, for any purpose, without fee, subject +to the following restrictions: + +1. The origin of this source code must not be misrepresented. + +2. Altered versions must be plainly marked as such and + must not be misrepresented as being the original source. + +3. This Copyright notice may not be removed or altered from + any source or altered source distribution. + +The Contributing Authors and Group 42, Inc. specifically permit, without +fee, and encourage the use of this source code as a component to +supporting the PNG file format in commercial products. If you use this +source code in a product, acknowledgment is not required but would be +appreciated. + + +A "png_get_copyright" function is available, for convenient use in "about" +boxes and the like: + + printf("%s",png_get_copyright(NULL)); + +Also, the PNG logo (in PNG format, of course) is supplied in the +files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31). + +Libpng is OSI Certified Open Source Software. OSI Certified Open Source is a +certification mark of the Open Source Initiative. + +Glenn Randers-Pehrson +glennrp at users.sourceforge.net +June 12, 2014 + +.\" end of man page + diff --git a/png/libpng.pc.in b/png/libpng.pc.in new file mode 100755 index 0000000..3e7e2c5 --- /dev/null +++ b/png/libpng.pc.in @@ -0,0 +1,11 @@ +prefix=@prefix@ +exec_prefix=@exec_prefix@ +libdir=@libdir@ +includedir=@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ + +Name: libpng +Description: Loads and saves PNG files +Version: @PNGLIB_VERSION@ +Libs: -L${libdir} -lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ +Libs.private: @LIBS@ +Cflags: -I${includedir} diff --git a/png/libpngpf.3 b/png/libpngpf.3 new file mode 100755 index 0000000..6ac6285 --- /dev/null +++ b/png/libpngpf.3 @@ -0,0 +1,18 @@ +.TH LIBPNGPF 3 "June 12, 2014" +.SH NAME +libpng \- Portable Network Graphics (PNG) Reference Library 1.6.12 +(private functions) +.SH SYNOPSIS +\fB#include \fI"pngpriv.h" + +\fBAs of libpng version \fP\fI1.5.1\fP\fB, this section is no longer \fP\fImaintained\fP\fB, now that the private function prototypes are hidden in pngpriv.h and not accessible to applications. Look in pngpriv.h for the prototypes and a short description of each \fIfunction. + +.SH DESCRIPTION +The functions previously listed here are used privately by libpng and are not +available for use by applications. They are not "exported" to applications +using shared libraries. + +.SH SEE ALSO +.BR "png"(5), " libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5) +.SH AUTHOR +Glenn Randers-Pehrson diff --git a/png/png.5 b/png/png.5 new file mode 100755 index 0000000..8f329fd --- /dev/null +++ b/png/png.5 @@ -0,0 +1,74 @@ +.TH PNG 5 "June 12, 2014" +.SH NAME +png \- Portable Network Graphics (PNG) format +.SH DESCRIPTION +PNG (Portable Network Graphics) is an extensible file format for the +lossless, portable, well-compressed storage of raster images. PNG provides +a patent-free replacement for GIF and can also replace many +common uses of TIFF. Indexed-color, grayscale, and truecolor images are +supported, plus an optional alpha channel. Sample depths range from +1 to 16 bits. +.br + +PNG is designed to work well in online viewing applications, such as the +World Wide Web, so it is fully streamable with a progressive display +option. PNG is robust, providing both full file integrity checking and +fast, simple detection of common transmission errors. Also, PNG can store +gamma and chromaticity data for improved color matching on heterogeneous +platforms. + +.SH "SEE ALSO" +.BR "libpng"(3), " libpngpf"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5) +.LP +PNG specification (second edition), November 2003: +.IP +.br + <http://www.w3.org/TR/2003/REC-PNG-20031110/ +PNG 1.2 specification, July 1999: +.IP +.br +http://www.libpng.org/pub/png +.LP +PNG 1.0 specification, October 1996: +.IP +.br +RFC 2083 +.IP +.br +ftp://ds.internic.net/rfc/rfc2083.txt +.br +or (as a W3C Recommendation) at +.br +http://www.w3.org/TR/REC-png.html +.SH AUTHORS +This man page: Glenn Randers-Pehrson +.LP +Portable Network Graphics (PNG) Specification (Second Edition) +Information technology - Computer graphics and image processing - +Portable Network Graphics (PNG): Functional specification. +ISO/IEC 15948:2003 (E) (November 10, 2003): David Duce and others. +.LP +Portable Network Graphics (PNG) Specification Version 1.2 (July 8, 1999): +Glenn Randers-Pehrson and others (png-list). +.LP +Portable Network Graphics (PNG) Specification Version 1.0 (October 1, 1996): +Thomas Boutell and others (png-list). +.LP + + +.SH COPYRIGHT NOTICE +.LP +This man page is Copyright (c) 1998-2006 Glenn Randers-Pehrson. See png.h +for conditions of use and distribution. +.LP +The PNG Specification (Second Edition) is +Copyright (c) 2003 W3C. (MIT, ERCIM, Keio), All Rights Reserved. +.LP +The PNG-1.2 specification is copyright (c) 1999 Glenn Randers-Pehrson. +See the specification for conditions of use and distribution. +.LP +The PNG-1.0 specification is copyright (c) 1996 Massachusetts Institute of +Technology. See the specification for conditions of use and distribution. +.LP +.\" end of man page + diff --git a/png/png.c b/png/png.c new file mode 100755 index 0000000..f813e0a --- /dev/null +++ b/png/png.c @@ -0,0 +1,4385 @@ + +/* png.c - location for general purpose libpng functions + * + * Last changed in libpng 1.6.12 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +#include "pngpriv.h" + +/* Generate a compiler error if there is an old png.h in the search path. */ +typedef png_libpng_version_1_6_12 Your_png_h_is_not_version_1_6_12; + +/* Tells libpng that we have already handled the first "num_bytes" bytes + * of the PNG file signature. If the PNG data is embedded into another + * stream we can set num_bytes = 8 so that libpng will not attempt to read + * or write any of the magic bytes before it starts on the IHDR. + */ + +#ifdef PNG_READ_SUPPORTED +void PNGAPI +png_set_sig_bytes(png_structrp png_ptr, int num_bytes) +{ + png_debug(1, "in png_set_sig_bytes"); + + if (png_ptr == NULL) + return; + + if (num_bytes > 8) + png_error(png_ptr, "Too many bytes for PNG signature"); + + png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes); +} + +/* Checks whether the supplied bytes match the PNG signature. We allow + * checking less than the full 8-byte signature so that those apps that + * already read the first few bytes of a file to determine the file type + * can simply check the remaining bytes for extra assurance. Returns + * an integer less than, equal to, or greater than zero if sig is found, + * respectively, to be less than, to match, or be greater than the correct + * PNG signature (this is the same behavior as strcmp, memcmp, etc). + */ +int PNGAPI +png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check) +{ + png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; + + if (num_to_check > 8) + num_to_check = 8; + + else if (num_to_check < 1) + return (-1); + + if (start > 7) + return (-1); + + if (start + num_to_check > 8) + num_to_check = 8 - start; + + return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check))); +} + +#endif /* PNG_READ_SUPPORTED */ + +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) +/* Function to allocate memory for zlib */ +PNG_FUNCTION(voidpf /* PRIVATE */, +png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED) +{ + png_alloc_size_t num_bytes = size; + + if (png_ptr == NULL) + return NULL; + + if (items >= (~(png_alloc_size_t)0)/size) + { + png_warning (png_voidcast(png_structrp, png_ptr), + "Potential overflow in png_zalloc()"); + return NULL; + } + + num_bytes *= items; + return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes); +} + +/* Function to free memory for zlib */ +void /* PRIVATE */ +png_zfree(voidpf png_ptr, voidpf ptr) +{ + png_free(png_voidcast(png_const_structrp,png_ptr), ptr); +} + +/* Reset the CRC variable to 32 bits of 1's. Care must be taken + * in case CRC is > 32 bits to leave the top bits 0. + */ +void /* PRIVATE */ +png_reset_crc(png_structrp png_ptr) +{ + /* The cast is safe because the crc is a 32 bit value. */ + png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0); +} + +/* Calculate the CRC over a section of data. We can only pass as + * much data to this routine as the largest single buffer size. We + * also check that this data will actually be used before going to the + * trouble of calculating it. + */ +void /* PRIVATE */ +png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length) +{ + int need_crc = 1; + + if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)) + { + if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == + (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) + need_crc = 0; + } + + else /* critical */ + { + if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) + need_crc = 0; + } + + /* 'uLong' is defined in zlib.h as unsigned long; this means that on some + * systems it is a 64 bit value. crc32, however, returns 32 bits so the + * following cast is safe. 'uInt' may be no more than 16 bits, so it is + * necessary to perform a loop here. + */ + if (need_crc && length > 0) + { + uLong crc = png_ptr->crc; /* Should never issue a warning */ + + do + { + uInt safe_length = (uInt)length; + if (safe_length == 0) + safe_length = (uInt)-1; /* evil, but safe */ + + crc = crc32(crc, ptr, safe_length); + + /* The following should never issue compiler warnings; if they do the + * target system has characteristics that will probably violate other + * assumptions within the libpng code. + */ + ptr += safe_length; + length -= safe_length; + } + while (length > 0); + + /* And the following is always safe because the crc is only 32 bits. */ + png_ptr->crc = (png_uint_32)crc; + } +} + +/* Check a user supplied version number, called from both read and write + * functions that create a png_struct. + */ +int +png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver) +{ + if (user_png_ver != NULL) + { + int i = 0; + + do + { + if (user_png_ver[i] != png_libpng_ver[i]) + png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; + } while (png_libpng_ver[i++]); + } + + else + png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH; + + if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) + { + /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so + * we must recompile any applications that use any older library version. + * For versions after libpng 1.0, we will be compatible, so we need + * only check the first and third digits (note that when we reach version + * 1.10 we will need to check the fourth symbol, namely user_png_ver[3]). + */ + if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] || + (user_png_ver[0] == '1' && (user_png_ver[2] != png_libpng_ver[2] || + user_png_ver[3] != png_libpng_ver[3])) || + (user_png_ver[0] == '0' && user_png_ver[2] < '9')) + { +#ifdef PNG_WARNINGS_SUPPORTED + size_t pos = 0; + char m[128]; + + pos = png_safecat(m, (sizeof m), pos, + "Application built with libpng-"); + pos = png_safecat(m, (sizeof m), pos, user_png_ver); + pos = png_safecat(m, (sizeof m), pos, " but running with "); + pos = png_safecat(m, (sizeof m), pos, png_libpng_ver); + PNG_UNUSED(pos) + + png_warning(png_ptr, m); +#endif + +#ifdef PNG_ERROR_NUMBERS_SUPPORTED + png_ptr->flags = 0; +#endif + + return 0; + } + } + + /* Success return. */ + return 1; +} + +/* Generic function to create a png_struct for either read or write - this + * contains the common initialization. + */ +PNG_FUNCTION(png_structp /* PRIVATE */, +png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr, + png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr, + png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED) +{ + png_struct create_struct; +# ifdef PNG_SETJMP_SUPPORTED + jmp_buf create_jmp_buf; +# endif + + /* This temporary stack-allocated structure is used to provide a place to + * build enough context to allow the user provided memory allocator (if any) + * to be called. + */ + memset(&create_struct, 0, (sizeof create_struct)); + + /* Added at libpng-1.2.6 */ +# ifdef PNG_USER_LIMITS_SUPPORTED + create_struct.user_width_max = PNG_USER_WIDTH_MAX; + create_struct.user_height_max = PNG_USER_HEIGHT_MAX; + +# ifdef PNG_USER_CHUNK_CACHE_MAX + /* Added at libpng-1.2.43 and 1.4.0 */ + create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX; +# endif + +# ifdef PNG_USER_CHUNK_MALLOC_MAX + /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists + * in png_struct regardless. + */ + create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX; +# endif +# endif + + /* The following two API calls simply set fields in png_struct, so it is safe + * to do them now even though error handling is not yet set up. + */ +# ifdef PNG_USER_MEM_SUPPORTED + png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn); +# else + PNG_UNUSED(mem_ptr) + PNG_UNUSED(malloc_fn) + PNG_UNUSED(free_fn) +# endif + + /* (*error_fn) can return control to the caller after the error_ptr is set, + * this will result in a memory leak unless the error_fn does something + * extremely sophisticated. The design lacks merit but is implicit in the + * API. + */ + png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn); + +# ifdef PNG_SETJMP_SUPPORTED + if (!setjmp(create_jmp_buf)) + { + /* Temporarily fake out the longjmp information until we have + * successfully completed this function. This only works if we have + * setjmp() support compiled in, but it is safe - this stuff should + * never happen. + */ + create_struct.jmp_buf_ptr = &create_jmp_buf; + create_struct.jmp_buf_size = 0; /*stack allocation*/ + create_struct.longjmp_fn = longjmp; +# else + { +# endif + /* Call the general version checker (shared with read and write code): + */ + if (png_user_version_check(&create_struct, user_png_ver)) + { + png_structrp png_ptr = png_voidcast(png_structrp, + png_malloc_warn(&create_struct, (sizeof *png_ptr))); + + if (png_ptr != NULL) + { + /* png_ptr->zstream holds a back-pointer to the png_struct, so + * this can only be done now: + */ + create_struct.zstream.zalloc = png_zalloc; + create_struct.zstream.zfree = png_zfree; + create_struct.zstream.opaque = png_ptr; + +# ifdef PNG_SETJMP_SUPPORTED + /* Eliminate the local error handling: */ + create_struct.jmp_buf_ptr = NULL; + create_struct.jmp_buf_size = 0; + create_struct.longjmp_fn = 0; +# endif + + *png_ptr = create_struct; + + /* This is the successful return point */ + return png_ptr; + } + } + } + + /* A longjmp because of a bug in the application storage allocator or a + * simple failure to allocate the png_struct. + */ + return NULL; +} + +/* Allocate the memory for an info_struct for the application. */ +PNG_FUNCTION(png_infop,PNGAPI +png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED) +{ + png_inforp info_ptr; + + png_debug(1, "in png_create_info_struct"); + + if (png_ptr == NULL) + return NULL; + + /* Use the internal API that does not (or at least should not) error out, so + * that this call always returns ok. The application typically sets up the + * error handling *after* creating the info_struct because this is the way it + * has always been done in 'example.c'. + */ + info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr, + (sizeof *info_ptr))); + + if (info_ptr != NULL) + memset(info_ptr, 0, (sizeof *info_ptr)); + + return info_ptr; +} + +/* This function frees the memory associated with a single info struct. + * Normally, one would use either png_destroy_read_struct() or + * png_destroy_write_struct() to free an info struct, but this may be + * useful for some applications. From libpng 1.6.0 this function is also used + * internally to implement the png_info release part of the 'struct' destroy + * APIs. This ensures that all possible approaches free the same data (all of + * it). + */ +void PNGAPI +png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr) +{ + png_inforp info_ptr = NULL; + + png_debug(1, "in png_destroy_info_struct"); + + if (png_ptr == NULL) + return; + + if (info_ptr_ptr != NULL) + info_ptr = *info_ptr_ptr; + + if (info_ptr != NULL) + { + /* Do this first in case of an error below; if the app implements its own + * memory management this can lead to png_free calling png_error, which + * will abort this routine and return control to the app error handler. + * An infinite loop may result if it then tries to free the same info + * ptr. + */ + *info_ptr_ptr = NULL; + + png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1); + memset(info_ptr, 0, (sizeof *info_ptr)); + png_free(png_ptr, info_ptr); + } +} + +/* Initialize the info structure. This is now an internal function (0.89) + * and applications using it are urged to use png_create_info_struct() + * instead. Use deprecated in 1.6.0, internal use removed (used internally it + * is just a memset). + * + * NOTE: it is almost inconceivable that this API is used because it bypasses + * the user-memory mechanism and the user error handling/warning mechanisms in + * those cases where it does anything other than a memset. + */ +PNG_FUNCTION(void,PNGAPI +png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size), + PNG_DEPRECATED) +{ + png_inforp info_ptr = *ptr_ptr; + + png_debug(1, "in png_info_init_3"); + + if (info_ptr == NULL) + return; + + if ((sizeof (png_info)) > png_info_struct_size) + { + *ptr_ptr = NULL; + /* The following line is why this API should not be used: */ + free(info_ptr); + info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL, + (sizeof *info_ptr))); + *ptr_ptr = info_ptr; + } + + /* Set everything to 0 */ + memset(info_ptr, 0, (sizeof *info_ptr)); +} + +/* The following API is not called internally */ +void PNGAPI +png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr, + int freer, png_uint_32 mask) +{ + png_debug(1, "in png_data_freer"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + if (freer == PNG_DESTROY_WILL_FREE_DATA) + info_ptr->free_me |= mask; + + else if (freer == PNG_USER_WILL_FREE_DATA) + info_ptr->free_me &= ~mask; + + else + png_error(png_ptr, "Unknown freer parameter in png_data_freer"); +} + +void PNGAPI +png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask, + int num) +{ + png_debug(1, "in png_free_data"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + +#ifdef PNG_TEXT_SUPPORTED + /* Free text item num or (if num == -1) all text items */ + if ((mask & PNG_FREE_TEXT) & info_ptr->free_me) + { + if (num != -1) + { + if (info_ptr->text && info_ptr->text[num].key) + { + png_free(png_ptr, info_ptr->text[num].key); + info_ptr->text[num].key = NULL; + } + } + + else + { + int i; + for (i = 0; i < info_ptr->num_text; i++) + png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i); + png_free(png_ptr, info_ptr->text); + info_ptr->text = NULL; + info_ptr->num_text=0; + } + } +#endif + +#ifdef PNG_tRNS_SUPPORTED + /* Free any tRNS entry */ + if ((mask & PNG_FREE_TRNS) & info_ptr->free_me) + { + png_free(png_ptr, info_ptr->trans_alpha); + info_ptr->trans_alpha = NULL; + info_ptr->valid &= ~PNG_INFO_tRNS; + } +#endif + +#ifdef PNG_sCAL_SUPPORTED + /* Free any sCAL entry */ + if ((mask & PNG_FREE_SCAL) & info_ptr->free_me) + { + png_free(png_ptr, info_ptr->scal_s_width); + png_free(png_ptr, info_ptr->scal_s_height); + info_ptr->scal_s_width = NULL; + info_ptr->scal_s_height = NULL; + info_ptr->valid &= ~PNG_INFO_sCAL; + } +#endif + +#ifdef PNG_pCAL_SUPPORTED + /* Free any pCAL entry */ + if ((mask & PNG_FREE_PCAL) & info_ptr->free_me) + { + png_free(png_ptr, info_ptr->pcal_purpose); + png_free(png_ptr, info_ptr->pcal_units); + info_ptr->pcal_purpose = NULL; + info_ptr->pcal_units = NULL; + if (info_ptr->pcal_params != NULL) + { + unsigned int i; + for (i = 0; i < info_ptr->pcal_nparams; i++) + { + png_free(png_ptr, info_ptr->pcal_params[i]); + info_ptr->pcal_params[i] = NULL; + } + png_free(png_ptr, info_ptr->pcal_params); + info_ptr->pcal_params = NULL; + } + info_ptr->valid &= ~PNG_INFO_pCAL; + } +#endif + +#ifdef PNG_iCCP_SUPPORTED + /* Free any profile entry */ + if ((mask & PNG_FREE_ICCP) & info_ptr->free_me) + { + png_free(png_ptr, info_ptr->iccp_name); + png_free(png_ptr, info_ptr->iccp_profile); + info_ptr->iccp_name = NULL; + info_ptr->iccp_profile = NULL; + info_ptr->valid &= ~PNG_INFO_iCCP; + } +#endif + +#ifdef PNG_sPLT_SUPPORTED + /* Free a given sPLT entry, or (if num == -1) all sPLT entries */ + if ((mask & PNG_FREE_SPLT) & info_ptr->free_me) + { + if (num != -1) + { + if (info_ptr->splt_palettes) + { + png_free(png_ptr, info_ptr->splt_palettes[num].name); + png_free(png_ptr, info_ptr->splt_palettes[num].entries); + info_ptr->splt_palettes[num].name = NULL; + info_ptr->splt_palettes[num].entries = NULL; + } + } + + else + { + if (info_ptr->splt_palettes_num) + { + int i; + for (i = 0; i < info_ptr->splt_palettes_num; i++) + png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, (int)i); + + png_free(png_ptr, info_ptr->splt_palettes); + info_ptr->splt_palettes = NULL; + info_ptr->splt_palettes_num = 0; + } + info_ptr->valid &= ~PNG_INFO_sPLT; + } + } +#endif + +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED + if ((mask & PNG_FREE_UNKN) & info_ptr->free_me) + { + if (num != -1) + { + if (info_ptr->unknown_chunks) + { + png_free(png_ptr, info_ptr->unknown_chunks[num].data); + info_ptr->unknown_chunks[num].data = NULL; + } + } + + else + { + int i; + + if (info_ptr->unknown_chunks_num) + { + for (i = 0; i < info_ptr->unknown_chunks_num; i++) + png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, (int)i); + + png_free(png_ptr, info_ptr->unknown_chunks); + info_ptr->unknown_chunks = NULL; + info_ptr->unknown_chunks_num = 0; + } + } + } +#endif + +#ifdef PNG_hIST_SUPPORTED + /* Free any hIST entry */ + if ((mask & PNG_FREE_HIST) & info_ptr->free_me) + { + png_free(png_ptr, info_ptr->hist); + info_ptr->hist = NULL; + info_ptr->valid &= ~PNG_INFO_hIST; + } +#endif + + /* Free any PLTE entry that was internally allocated */ + if ((mask & PNG_FREE_PLTE) & info_ptr->free_me) + { + png_free(png_ptr, info_ptr->palette); + info_ptr->palette = NULL; + info_ptr->valid &= ~PNG_INFO_PLTE; + info_ptr->num_palette = 0; + } + +#ifdef PNG_INFO_IMAGE_SUPPORTED + /* Free any image bits attached to the info structure */ + if ((mask & PNG_FREE_ROWS) & info_ptr->free_me) + { + if (info_ptr->row_pointers) + { + png_uint_32 row; + for (row = 0; row < info_ptr->height; row++) + { + png_free(png_ptr, info_ptr->row_pointers[row]); + info_ptr->row_pointers[row] = NULL; + } + png_free(png_ptr, info_ptr->row_pointers); + info_ptr->row_pointers = NULL; + } + info_ptr->valid &= ~PNG_INFO_IDAT; + } +#endif + + if (num != -1) + mask &= ~PNG_FREE_MUL; + + info_ptr->free_me &= ~mask; +} +#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ + +/* This function returns a pointer to the io_ptr associated with the user + * functions. The application should free any memory associated with this + * pointer before png_write_destroy() or png_read_destroy() are called. + */ +png_voidp PNGAPI +png_get_io_ptr(png_const_structrp png_ptr) +{ + if (png_ptr == NULL) + return (NULL); + + return (png_ptr->io_ptr); +} + +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) +# ifdef PNG_STDIO_SUPPORTED +/* Initialize the default input/output functions for the PNG file. If you + * use your own read or write routines, you can call either png_set_read_fn() + * or png_set_write_fn() instead of png_init_io(). If you have defined + * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a + * function of your own because "FILE *" isn't necessarily available. + */ +void PNGAPI +png_init_io(png_structrp png_ptr, png_FILE_p fp) +{ + png_debug(1, "in png_init_io"); + + if (png_ptr == NULL) + return; + + png_ptr->io_ptr = (png_voidp)fp; +} +# endif + +#ifdef PNG_SAVE_INT_32_SUPPORTED +/* The png_save_int_32 function assumes integers are stored in two's + * complement format. If this isn't the case, then this routine needs to + * be modified to write data in two's complement format. Note that, + * the following works correctly even if png_int_32 has more than 32 bits + * (compare the more complex code required on read for sign extension.) + */ +void PNGAPI +png_save_int_32(png_bytep buf, png_int_32 i) +{ + buf[0] = (png_byte)((i >> 24) & 0xff); + buf[1] = (png_byte)((i >> 16) & 0xff); + buf[2] = (png_byte)((i >> 8) & 0xff); + buf[3] = (png_byte)(i & 0xff); +} +#endif + +# ifdef PNG_TIME_RFC1123_SUPPORTED +/* Convert the supplied time into an RFC 1123 string suitable for use in + * a "Creation Time" or other text-based time string. + */ +int PNGAPI +png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime) +{ + static PNG_CONST char short_months[12][4] = + {"Jan", "Feb", "Mar", "Apr", "May", "Jun", + "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}; + + if (out == NULL) + return 0; + + if (ptime->year > 9999 /* RFC1123 limitation */ || + ptime->month == 0 || ptime->month > 12 || + ptime->day == 0 || ptime->day > 31 || + ptime->hour > 23 || ptime->minute > 59 || + ptime->second > 60) + return 0; + + { + size_t pos = 0; + char number_buf[5]; /* enough for a four-digit year */ + +# define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string)) +# define APPEND_NUMBER(format, value)\ + APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value))) +# define APPEND(ch) if (pos < 28) out[pos++] = (ch) + + APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day); + APPEND(' '); + APPEND_STRING(short_months[(ptime->month - 1)]); + APPEND(' '); + APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year); + APPEND(' '); + APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour); + APPEND(':'); + APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute); + APPEND(':'); + APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second); + APPEND_STRING(" +0000"); /* This reliably terminates the buffer */ + +# undef APPEND +# undef APPEND_NUMBER +# undef APPEND_STRING + } + + return 1; +} + +# if PNG_LIBPNG_VER < 10700 +/* To do: remove the following from libpng-1.7 */ +/* Original API that uses a private buffer in png_struct. + * Deprecated because it causes png_struct to carry a spurious temporary + * buffer (png_struct::time_buffer), better to have the caller pass this in. + */ +png_const_charp PNGAPI +png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime) +{ + if (png_ptr != NULL) + { + /* The only failure above if png_ptr != NULL is from an invalid ptime */ + if (!png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime)) + png_warning(png_ptr, "Ignoring invalid time value"); + + else + return png_ptr->time_buffer; + } + + return NULL; +} +# endif +# endif /* PNG_TIME_RFC1123_SUPPORTED */ + +#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ + +png_const_charp PNGAPI +png_get_copyright(png_const_structrp png_ptr) +{ + PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ +#ifdef PNG_STRING_COPYRIGHT + return PNG_STRING_COPYRIGHT +#else +# ifdef __STDC__ + return PNG_STRING_NEWLINE \ + "libpng version 1.6.12 - June 12, 2014" PNG_STRING_NEWLINE \ + "Copyright (c) 1998-2014 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \ + "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \ + "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \ + PNG_STRING_NEWLINE; +# else + return "libpng version 1.6.12 - June 12, 2014\ + Copyright (c) 1998-2014 Glenn Randers-Pehrson\ + Copyright (c) 1996-1997 Andreas Dilger\ + Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc."; +# endif +#endif +} + +/* The following return the library version as a short string in the + * format 1.0.0 through 99.99.99zz. To get the version of *.h files + * used with your application, print out PNG_LIBPNG_VER_STRING, which + * is defined in png.h. + * Note: now there is no difference between png_get_libpng_ver() and + * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard, + * it is guaranteed that png.c uses the correct version of png.h. + */ +png_const_charp PNGAPI +png_get_libpng_ver(png_const_structrp png_ptr) +{ + /* Version of *.c files used when building libpng */ + return png_get_header_ver(png_ptr); +} + +png_const_charp PNGAPI +png_get_header_ver(png_const_structrp png_ptr) +{ + /* Version of *.h files used when building libpng */ + PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ + return PNG_LIBPNG_VER_STRING; +} + +png_const_charp PNGAPI +png_get_header_version(png_const_structrp png_ptr) +{ + /* Returns longer string containing both version and date */ + PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */ +#ifdef __STDC__ + return PNG_HEADER_VERSION_STRING +# ifndef PNG_READ_SUPPORTED + " (NO READ SUPPORT)" +# endif + PNG_STRING_NEWLINE; +#else + return PNG_HEADER_VERSION_STRING; +#endif +} + +#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED +/* NOTE: this routine is not used internally! */ +/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth + * large of png_color. This lets grayscale images be treated as + * paletted. Most useful for gamma correction and simplification + * of code. This API is not used internally. + */ +void PNGAPI +png_build_grayscale_palette(int bit_depth, png_colorp palette) +{ + int num_palette; + int color_inc; + int i; + int v; + + png_debug(1, "in png_do_build_grayscale_palette"); + + if (palette == NULL) + return; + + switch (bit_depth) + { + case 1: + num_palette = 2; + color_inc = 0xff; + break; + + case 2: + num_palette = 4; + color_inc = 0x55; + break; + + case 4: + num_palette = 16; + color_inc = 0x11; + break; + + case 8: + num_palette = 256; + color_inc = 1; + break; + + default: + num_palette = 0; + color_inc = 0; + break; + } + + for (i = 0, v = 0; i < num_palette; i++, v += color_inc) + { + palette[i].red = (png_byte)v; + palette[i].green = (png_byte)v; + palette[i].blue = (png_byte)v; + } +} +#endif + +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED +int PNGAPI +png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name) +{ + /* Check chunk_name and return "keep" value if it's on the list, else 0 */ + png_const_bytep p, p_end; + + if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0) + return PNG_HANDLE_CHUNK_AS_DEFAULT; + + p_end = png_ptr->chunk_list; + p = p_end + png_ptr->num_chunk_list*5; /* beyond end */ + + /* The code is the fifth byte after each four byte string. Historically this + * code was always searched from the end of the list, this is no longer + * necessary because the 'set' routine handles duplicate entries correcty. + */ + do /* num_chunk_list > 0, so at least one */ + { + p -= 5; + + if (!memcmp(chunk_name, p, 4)) + return p[4]; + } + while (p > p_end); + + /* This means that known chunks should be processed and unknown chunks should + * be handled according to the value of png_ptr->unknown_default; this can be + * confusing because, as a result, there are two levels of defaulting for + * unknown chunks. + */ + return PNG_HANDLE_CHUNK_AS_DEFAULT; +} + +#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\ + defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED) +int /* PRIVATE */ +png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name) +{ + png_byte chunk_string[5]; + + PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name); + return png_handle_as_unknown(png_ptr, chunk_string); +} +#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */ +#endif /* SET_UNKNOWN_CHUNKS */ + +#ifdef PNG_READ_SUPPORTED +/* This function, added to libpng-1.0.6g, is untested. */ +int PNGAPI +png_reset_zstream(png_structrp png_ptr) +{ + if (png_ptr == NULL) + return Z_STREAM_ERROR; + + /* WARNING: this resets the window bits to the maximum! */ + return (inflateReset(&png_ptr->zstream)); +} +#endif /* PNG_READ_SUPPORTED */ + +/* This function was added to libpng-1.0.7 */ +png_uint_32 PNGAPI +png_access_version_number(void) +{ + /* Version of *.c files used when building libpng */ + return((png_uint_32)PNG_LIBPNG_VER); +} + + + +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) +/* Ensure that png_ptr->zstream.msg holds some appropriate error message string. + * If it doesn't 'ret' is used to set it to something appropriate, even in cases + * like Z_OK or Z_STREAM_END where the error code is apparently a success code. + */ +void /* PRIVATE */ +png_zstream_error(png_structrp png_ptr, int ret) +{ + /* Translate 'ret' into an appropriate error string, priority is given to the + * one in zstream if set. This always returns a string, even in cases like + * Z_OK or Z_STREAM_END where the error code is a success code. + */ + if (png_ptr->zstream.msg == NULL) switch (ret) + { + default: + case Z_OK: + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code"); + break; + + case Z_STREAM_END: + /* Normal exit */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream"); + break; + + case Z_NEED_DICT: + /* This means the deflate stream did not have a dictionary; this + * indicates a bogus PNG. + */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary"); + break; + + case Z_ERRNO: + /* gz APIs only: should not happen */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error"); + break; + + case Z_STREAM_ERROR: + /* internal libpng error */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib"); + break; + + case Z_DATA_ERROR: + png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream"); + break; + + case Z_MEM_ERROR: + png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory"); + break; + + case Z_BUF_ERROR: + /* End of input or output; not a problem if the caller is doing + * incremental read or write. + */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated"); + break; + + case Z_VERSION_ERROR: + png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version"); + break; + + case PNG_UNEXPECTED_ZLIB_RETURN: + /* Compile errors here mean that zlib now uses the value co-opted in + * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above + * and change pngpriv.h. Note that this message is "... return", + * whereas the default/Z_OK one is "... return code". + */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return"); + break; + } +} + +/* png_convert_size: a PNGAPI but no longer in png.h, so deleted + * at libpng 1.5.5! + */ + +/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */ +#ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */ +static int +png_colorspace_check_gamma(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_fixed_point gAMA, int from) + /* This is called to check a new gamma value against an existing one. The + * routine returns false if the new gamma value should not be written. + * + * 'from' says where the new gamma value comes from: + * + * 0: the new gamma value is the libpng estimate for an ICC profile + * 1: the new gamma value comes from a gAMA chunk + * 2: the new gamma value comes from an sRGB chunk + */ +{ + png_fixed_point gtest; + + if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 && + (!png_muldiv(>est, colorspace->gamma, PNG_FP_1, gAMA) || + png_gamma_significant(gtest))) + { + /* Either this is an sRGB image, in which case the calculated gamma + * approximation should match, or this is an image with a profile and the + * value libpng calculates for the gamma of the profile does not match the + * value recorded in the file. The former, sRGB, case is an error, the + * latter is just a warning. + */ + if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2) + { + png_chunk_report(png_ptr, "gamma value does not match sRGB", + PNG_CHUNK_ERROR); + /* Do not overwrite an sRGB value */ + return from == 2; + } + + else /* sRGB tag not involved */ + { + png_chunk_report(png_ptr, "gamma value does not match libpng estimate", + PNG_CHUNK_WARNING); + return from == 1; + } + } + + return 1; +} + +void /* PRIVATE */ +png_colorspace_set_gamma(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_fixed_point gAMA) +{ + /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't + * occur. Since the fixed point representation is assymetrical it is + * possible for 1/gamma to overflow the limit of 21474 and this means the + * gamma value must be at least 5/100000 and hence at most 20000.0. For + * safety the limits here are a little narrower. The values are 0.00016 to + * 6250.0, which are truly ridiculous gamma values (and will produce + * displays that are all black or all white.) + * + * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk + * handling code, which only required the value to be >0. + */ + png_const_charp errmsg; + + if (gAMA < 16 || gAMA > 625000000) + errmsg = "gamma value out of range"; + +# ifdef PNG_READ_gAMA_SUPPORTED + /* Allow the application to set the gamma value more than once */ + else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && + (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0) + errmsg = "duplicate"; +# endif + + /* Do nothing if the colorspace is already invalid */ + else if (colorspace->flags & PNG_COLORSPACE_INVALID) + return; + + else + { + if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA, 1/*from gAMA*/)) + { + /* Store this gamma value. */ + colorspace->gamma = gAMA; + colorspace->flags |= + (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA); + } + + /* At present if the check_gamma test fails the gamma of the colorspace is + * not updated however the colorspace is not invalidated. This + * corresponds to the case where the existing gamma comes from an sRGB + * chunk or profile. An error message has already been output. + */ + return; + } + + /* Error exit - errmsg has been set. */ + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR); +} + +void /* PRIVATE */ +png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr) +{ + if (info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) + { + /* Everything is invalid */ + info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB| + PNG_INFO_iCCP); + +# ifdef PNG_COLORSPACE_SUPPORTED + /* Clean up the iCCP profile now if it won't be used. */ + png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/); +# else + PNG_UNUSED(png_ptr) +# endif + } + + else + { +# ifdef PNG_COLORSPACE_SUPPORTED + /* Leave the INFO_iCCP flag set if the pngset.c code has already set + * it; this allows a PNG to contain a profile which matches sRGB and + * yet still have that profile retrievable by the application. + */ + if (info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) + info_ptr->valid |= PNG_INFO_sRGB; + + else + info_ptr->valid &= ~PNG_INFO_sRGB; + + if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) + info_ptr->valid |= PNG_INFO_cHRM; + + else + info_ptr->valid &= ~PNG_INFO_cHRM; +# endif + + if (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) + info_ptr->valid |= PNG_INFO_gAMA; + + else + info_ptr->valid &= ~PNG_INFO_gAMA; + } +} + +#ifdef PNG_READ_SUPPORTED +void /* PRIVATE */ +png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr) +{ + if (info_ptr == NULL) /* reduce code size; check here not in the caller */ + return; + + info_ptr->colorspace = png_ptr->colorspace; + png_colorspace_sync_info(png_ptr, info_ptr); +} +#endif +#endif + +#ifdef PNG_COLORSPACE_SUPPORTED +/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for + * cHRM, as opposed to using chromaticities. These internal APIs return + * non-zero on a parameter error. The X, Y and Z values are required to be + * positive and less than 1.0. + */ +static int +png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ) +{ + png_int_32 d, dwhite, whiteX, whiteY; + + d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z; + if (!png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d)) return 1; + if (!png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d)) return 1; + dwhite = d; + whiteX = XYZ->red_X; + whiteY = XYZ->red_Y; + + d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z; + if (!png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d)) return 1; + if (!png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d)) return 1; + dwhite += d; + whiteX += XYZ->green_X; + whiteY += XYZ->green_Y; + + d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z; + if (!png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d)) return 1; + if (!png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d)) return 1; + dwhite += d; + whiteX += XYZ->blue_X; + whiteY += XYZ->blue_Y; + + /* The reference white is simply the sum of the end-point (X,Y,Z) vectors, + * thus: + */ + if (!png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite)) return 1; + if (!png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite)) return 1; + + return 0; +} + +static int +png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy) +{ + png_fixed_point red_inverse, green_inverse, blue_scale; + png_fixed_point left, right, denominator; + + /* Check xy and, implicitly, z. Note that wide gamut color spaces typically + * have end points with 0 tristimulus values (these are impossible end + * points, but they are used to cover the possible colors.) + */ + if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1; + if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1; + if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1; + if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1; + if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1; + if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1; + if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1; + if (xy->whitey < 0 || xy->whitey > PNG_FP_1-xy->whitex) return 1; + + /* The reverse calculation is more difficult because the original tristimulus + * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8 + * derived values were recorded in the cHRM chunk; + * (red,green,blue,white)x(x,y). This loses one degree of freedom and + * therefore an arbitrary ninth value has to be introduced to undo the + * original transformations. + * + * Think of the original end-points as points in (X,Y,Z) space. The + * chromaticity values (c) have the property: + * + * C + * c = --------- + * X + Y + Z + * + * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the + * three chromaticity values (x,y,z) for each end-point obey the + * relationship: + * + * x + y + z = 1 + * + * This describes the plane in (X,Y,Z) space that intersects each axis at the + * value 1.0; call this the chromaticity plane. Thus the chromaticity + * calculation has scaled each end-point so that it is on the x+y+z=1 plane + * and chromaticity is the intersection of the vector from the origin to the + * (X,Y,Z) value with the chromaticity plane. + * + * To fully invert the chromaticity calculation we would need the three + * end-point scale factors, (red-scale, green-scale, blue-scale), but these + * were not recorded. Instead we calculated the reference white (X,Y,Z) and + * recorded the chromaticity of this. The reference white (X,Y,Z) would have + * given all three of the scale factors since: + * + * color-C = color-c * color-scale + * white-C = red-C + green-C + blue-C + * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale + * + * But cHRM records only white-x and white-y, so we have lost the white scale + * factor: + * + * white-C = white-c*white-scale + * + * To handle this the inverse transformation makes an arbitrary assumption + * about white-scale: + * + * Assume: white-Y = 1.0 + * Hence: white-scale = 1/white-y + * Or: red-Y + green-Y + blue-Y = 1.0 + * + * Notice the last statement of the assumption gives an equation in three of + * the nine values we want to calculate. 8 more equations come from the + * above routine as summarised at the top above (the chromaticity + * calculation): + * + * Given: color-x = color-X / (color-X + color-Y + color-Z) + * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0 + * + * This is 9 simultaneous equations in the 9 variables "color-C" and can be + * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix + * determinants, however this is not as bad as it seems because only 28 of + * the total of 90 terms in the various matrices are non-zero. Nevertheless + * Cramer's rule is notoriously numerically unstable because the determinant + * calculation involves the difference of large, but similar, numbers. It is + * difficult to be sure that the calculation is stable for real world values + * and it is certain that it becomes unstable where the end points are close + * together. + * + * So this code uses the perhaps slightly less optimal but more + * understandable and totally obvious approach of calculating color-scale. + * + * This algorithm depends on the precision in white-scale and that is + * (1/white-y), so we can immediately see that as white-y approaches 0 the + * accuracy inherent in the cHRM chunk drops off substantially. + * + * libpng arithmetic: a simple invertion of the above equations + * ------------------------------------------------------------ + * + * white_scale = 1/white-y + * white-X = white-x * white-scale + * white-Y = 1.0 + * white-Z = (1 - white-x - white-y) * white_scale + * + * white-C = red-C + green-C + blue-C + * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale + * + * This gives us three equations in (red-scale,green-scale,blue-scale) where + * all the coefficients are now known: + * + * red-x*red-scale + green-x*green-scale + blue-x*blue-scale + * = white-x/white-y + * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1 + * red-z*red-scale + green-z*green-scale + blue-z*blue-scale + * = (1 - white-x - white-y)/white-y + * + * In the last equation color-z is (1 - color-x - color-y) so we can add all + * three equations together to get an alternative third: + * + * red-scale + green-scale + blue-scale = 1/white-y = white-scale + * + * So now we have a Cramer's rule solution where the determinants are just + * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve + * multiplication of three coefficients so we can't guarantee to avoid + * overflow in the libpng fixed point representation. Using Cramer's rule in + * floating point is probably a good choice here, but it's not an option for + * fixed point. Instead proceed to simplify the first two equations by + * eliminating what is likely to be the largest value, blue-scale: + * + * blue-scale = white-scale - red-scale - green-scale + * + * Hence: + * + * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale = + * (white-x - blue-x)*white-scale + * + * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale = + * 1 - blue-y*white-scale + * + * And now we can trivially solve for (red-scale,green-scale): + * + * green-scale = + * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale + * ----------------------------------------------------------- + * green-x - blue-x + * + * red-scale = + * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale + * --------------------------------------------------------- + * red-y - blue-y + * + * Hence: + * + * red-scale = + * ( (green-x - blue-x) * (white-y - blue-y) - + * (green-y - blue-y) * (white-x - blue-x) ) / white-y + * ------------------------------------------------------------------------- + * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x) + * + * green-scale = + * ( (red-y - blue-y) * (white-x - blue-x) - + * (red-x - blue-x) * (white-y - blue-y) ) / white-y + * ------------------------------------------------------------------------- + * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x) + * + * Accuracy: + * The input values have 5 decimal digits of accuracy. The values are all in + * the range 0 < value < 1, so simple products are in the same range but may + * need up to 10 decimal digits to preserve the original precision and avoid + * underflow. Because we are using a 32-bit signed representation we cannot + * match this; the best is a little over 9 decimal digits, less than 10. + * + * The approach used here is to preserve the maximum precision within the + * signed representation. Because the red-scale calculation above uses the + * difference between two products of values that must be in the range -1..+1 + * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The + * factor is irrelevant in the calculation because it is applied to both + * numerator and denominator. + * + * Note that the values of the differences of the products of the + * chromaticities in the above equations tend to be small, for example for + * the sRGB chromaticities they are: + * + * red numerator: -0.04751 + * green numerator: -0.08788 + * denominator: -0.2241 (without white-y multiplication) + * + * The resultant Y coefficients from the chromaticities of some widely used + * color space definitions are (to 15 decimal places): + * + * sRGB + * 0.212639005871510 0.715168678767756 0.072192315360734 + * Kodak ProPhoto + * 0.288071128229293 0.711843217810102 0.000085653960605 + * Adobe RGB + * 0.297344975250536 0.627363566255466 0.075291458493998 + * Adobe Wide Gamut RGB + * 0.258728243040113 0.724682314948566 0.016589442011321 + */ + /* By the argument, above overflow should be impossible here. The return + * value of 2 indicates an internal error to the caller. + */ + if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7)) + return 2; + if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7)) + return 2; + denominator = left - right; + + /* Now find the red numerator. */ + if (!png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7)) + return 2; + if (!png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7)) + return 2; + + /* Overflow is possible here and it indicates an extreme set of PNG cHRM + * chunk values. This calculation actually returns the reciprocal of the + * scale value because this allows us to delay the multiplication of white-y + * into the denominator, which tends to produce a small number. + */ + if (!png_muldiv(&red_inverse, xy->whitey, denominator, left-right) || + red_inverse <= xy->whitey /* r+g+b scales = white scale */) + return 1; + + /* Similarly for green_inverse: */ + if (!png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7)) + return 2; + if (!png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7)) + return 2; + if (!png_muldiv(&green_inverse, xy->whitey, denominator, left-right) || + green_inverse <= xy->whitey) + return 1; + + /* And the blue scale, the checks above guarantee this can't overflow but it + * can still produce 0 for extreme cHRM values. + */ + blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) - + png_reciprocal(green_inverse); + if (blue_scale <= 0) return 1; + + + /* And fill in the png_XYZ: */ + if (!png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse)) return 1; + if (!png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse)) return 1; + if (!png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1, + red_inverse)) + return 1; + + if (!png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse)) + return 1; + if (!png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse)) + return 1; + if (!png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1, + green_inverse)) + return 1; + + if (!png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1)) return 1; + if (!png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1)) return 1; + if (!png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale, + PNG_FP_1)) + return 1; + + return 0; /*success*/ +} + +static int +png_XYZ_normalize(png_XYZ *XYZ) +{ + png_int_32 Y; + + if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 || + XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 || + XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0) + return 1; + + /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1. + * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore + * relying on addition of two positive values producing a negative one is not + * safe. + */ + Y = XYZ->red_Y; + if (0x7fffffff - Y < XYZ->green_X) return 1; + Y += XYZ->green_Y; + if (0x7fffffff - Y < XYZ->blue_X) return 1; + Y += XYZ->blue_Y; + + if (Y != PNG_FP_1) + { + if (!png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y)) return 1; + + if (!png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y)) return 1; + + if (!png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y)) return 1; + if (!png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y)) return 1; + } + + return 0; +} + +static int +png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta) +{ + /* Allow an error of +/-0.01 (absolute value) on each chromaticity */ + return !(PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) || + PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) || + PNG_OUT_OF_RANGE(xy1->redx, xy2->redx, delta) || + PNG_OUT_OF_RANGE(xy1->redy, xy2->redy, delta) || + PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) || + PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) || + PNG_OUT_OF_RANGE(xy1->bluex, xy2->bluex, delta) || + PNG_OUT_OF_RANGE(xy1->bluey, xy2->bluey, delta)); +} + +/* Added in libpng-1.6.0, a different check for the validity of a set of cHRM + * chunk chromaticities. Earlier checks used to simply look for the overflow + * condition (where the determinant of the matrix to solve for XYZ ends up zero + * because the chromaticity values are not all distinct.) Despite this it is + * theoretically possible to produce chromaticities that are apparently valid + * but that rapidly degrade to invalid, potentially crashing, sets because of + * arithmetic inaccuracies when calculations are performed on them. The new + * check is to round-trip xy -> XYZ -> xy and then check that the result is + * within a small percentage of the original. + */ +static int +png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy) +{ + int result; + png_xy xy_test; + + /* As a side-effect this routine also returns the XYZ endpoints. */ + result = png_XYZ_from_xy(XYZ, xy); + if (result != 0) return result; + + result = png_xy_from_XYZ(&xy_test, XYZ); + if (result != 0) return result; + + if (png_colorspace_endpoints_match(xy, &xy_test, + 5/*actually, the math is pretty accurate*/)) + return 0; + + /* Too much slip */ + return 1; +} + +/* This is the check going the other way. The XYZ is modified to normalize it + * (another side-effect) and the xy chromaticities are returned. + */ +static int +png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ) +{ + int result; + png_XYZ XYZtemp; + + result = png_XYZ_normalize(XYZ); + if (result != 0) return result; + + result = png_xy_from_XYZ(xy, XYZ); + if (result != 0) return result; + + XYZtemp = *XYZ; + return png_colorspace_check_xy(&XYZtemp, xy); +} + +/* Used to check for an endpoint match against sRGB */ +static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */ +{ + /* color x y */ + /* red */ 64000, 33000, + /* green */ 30000, 60000, + /* blue */ 15000, 6000, + /* white */ 31270, 32900 +}; + +static int +png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr, + png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ, + int preferred) +{ + if (colorspace->flags & PNG_COLORSPACE_INVALID) + return 0; + + /* The consistency check is performed on the chromaticities; this factors out + * variations because of the normalization (or not) of the end point Y + * values. + */ + if (preferred < 2 && (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS)) + { + /* The end points must be reasonably close to any we already have. The + * following allows an error of up to +/-.001 + */ + if (!png_colorspace_endpoints_match(xy, &colorspace->end_points_xy, 100)) + { + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_benign_error(png_ptr, "inconsistent chromaticities"); + return 0; /* failed */ + } + + /* Only overwrite with preferred values */ + if (preferred == 0) + return 1; /* ok, but no change */ + } + + colorspace->end_points_xy = *xy; + colorspace->end_points_XYZ = *XYZ; + colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS; + + /* The end points are normally quoted to two decimal digits, so allow +/-0.01 + * on this test. + */ + if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000)) + colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB; + + else + colorspace->flags &= PNG_COLORSPACE_CANCEL( + PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB); + + return 2; /* ok and changed */ +} + +int /* PRIVATE */ +png_colorspace_set_chromaticities(png_const_structrp png_ptr, + png_colorspacerp colorspace, const png_xy *xy, int preferred) +{ + /* We must check the end points to ensure they are reasonable - in the past + * color management systems have crashed as a result of getting bogus + * colorant values, while this isn't the fault of libpng it is the + * responsibility of libpng because PNG carries the bomb and libpng is in a + * position to protect against it. + */ + png_XYZ XYZ; + + switch (png_colorspace_check_xy(&XYZ, xy)) + { + case 0: /* success */ + return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ, + preferred); + + case 1: + /* We can't invert the chromaticities so we can't produce value XYZ + * values. Likely as not a color management system will fail too. + */ + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_benign_error(png_ptr, "invalid chromaticities"); + break; + + default: + /* libpng is broken; this should be a warning but if it happens we + * want error reports so for the moment it is an error. + */ + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_error(png_ptr, "internal error checking chromaticities"); + break; + } + + return 0; /* failed */ +} + +int /* PRIVATE */ +png_colorspace_set_endpoints(png_const_structrp png_ptr, + png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred) +{ + png_XYZ XYZ = *XYZ_in; + png_xy xy; + + switch (png_colorspace_check_XYZ(&xy, &XYZ)) + { + case 0: + return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ, + preferred); + + case 1: + /* End points are invalid. */ + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_benign_error(png_ptr, "invalid end points"); + break; + + default: + colorspace->flags |= PNG_COLORSPACE_INVALID; + png_error(png_ptr, "internal error checking chromaticities"); + break; + } + + return 0; /* failed */ +} + +#if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED) +/* Error message generation */ +static char +png_icc_tag_char(png_uint_32 byte) +{ + byte &= 0xff; + if (byte >= 32 && byte <= 126) + return (char)byte; + else + return '?'; +} + +static void +png_icc_tag_name(char *name, png_uint_32 tag) +{ + name[0] = '\''; + name[1] = png_icc_tag_char(tag >> 24); + name[2] = png_icc_tag_char(tag >> 16); + name[3] = png_icc_tag_char(tag >> 8); + name[4] = png_icc_tag_char(tag ); + name[5] = '\''; +} + +static int +is_ICC_signature_char(png_alloc_size_t it) +{ + return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) || + (it >= 97 && it <= 122); +} + +static int +is_ICC_signature(png_alloc_size_t it) +{ + return is_ICC_signature_char(it >> 24) /* checks all the top bits */ && + is_ICC_signature_char((it >> 16) & 0xff) && + is_ICC_signature_char((it >> 8) & 0xff) && + is_ICC_signature_char(it & 0xff); +} + +static int +png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_alloc_size_t value, png_const_charp reason) +{ + size_t pos; + char message[196]; /* see below for calculation */ + + if (colorspace != NULL) + colorspace->flags |= PNG_COLORSPACE_INVALID; + + pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */ + pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */ + pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */ + if (is_ICC_signature(value)) + { + /* So 'value' is at most 4 bytes and the following cast is safe */ + png_icc_tag_name(message+pos, (png_uint_32)value); + pos += 6; /* total +8; less than the else clause */ + message[pos++] = ':'; + message[pos++] = ' '; + } +# ifdef PNG_WARNINGS_SUPPORTED + else + { + char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/ + + pos = png_safecat(message, (sizeof message), pos, + png_format_number(number, number+(sizeof number), + PNG_NUMBER_FORMAT_x, value)); + pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/ + } +# endif + /* The 'reason' is an arbitrary message, allow +79 maximum 195 */ + pos = png_safecat(message, (sizeof message), pos, reason); + PNG_UNUSED(pos) + + /* This is recoverable, but make it unconditionally an app_error on write to + * avoid writing invalid ICC profiles into PNG files. (I.e. we handle them + * on read, with a warning, but on write unless the app turns off + * application errors the PNG won't be written.) + */ + png_chunk_report(png_ptr, message, + (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR); + + return 0; +} +#endif /* sRGB || iCCP */ + +#ifdef PNG_sRGB_SUPPORTED +int /* PRIVATE */ +png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace, + int intent) +{ + /* sRGB sets known gamma, end points and (from the chunk) intent. */ + /* IMPORTANT: these are not necessarily the values found in an ICC profile + * because ICC profiles store values adapted to a D50 environment; it is + * expected that the ICC profile mediaWhitePointTag will be D50, see the + * checks and code elsewhere to understand this better. + * + * These XYZ values, which are accurate to 5dp, produce rgb to gray + * coefficients of (6968,23435,2366), which are reduced (because they add up + * to 32769 not 32768) to (6968,23434,2366). These are the values that + * libpng has traditionally used (and are the best values given the 15bit + * algorithm used by the rgb to gray code.) + */ + static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */ + { + /* color X Y Z */ + /* red */ 41239, 21264, 1933, + /* green */ 35758, 71517, 11919, + /* blue */ 18048, 7219, 95053 + }; + + /* Do nothing if the colorspace is already invalidated. */ + if (colorspace->flags & PNG_COLORSPACE_INVALID) + return 0; + + /* Check the intent, then check for existing settings. It is valid for the + * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must + * be consistent with the correct values. If, however, this function is + * called below because an iCCP chunk matches sRGB then it is quite + * conceivable that an older app recorded incorrect gAMA and cHRM because of + * an incorrect calculation based on the values in the profile - this does + * *not* invalidate the profile (though it still produces an error, which can + * be ignored.) + */ + if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST) + return png_icc_profile_error(png_ptr, colorspace, "sRGB", + (unsigned)intent, "invalid sRGB rendering intent"); + + if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 && + colorspace->rendering_intent != intent) + return png_icc_profile_error(png_ptr, colorspace, "sRGB", + (unsigned)intent, "inconsistent rendering intents"); + + if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0) + { + png_benign_error(png_ptr, "duplicate sRGB information ignored"); + return 0; + } + + /* If the standard sRGB cHRM chunk does not match the one from the PNG file + * warn but overwrite the value with the correct one. + */ + if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 && + !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy, + 100)) + png_chunk_report(png_ptr, "cHRM chunk does not match sRGB", + PNG_CHUNK_ERROR); + + /* This check is just done for the error reporting - the routine always + * returns true when the 'from' argument corresponds to sRGB (2). + */ + (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE, + 2/*from sRGB*/); + + /* intent: bugs in GCC force 'int' to be used as the parameter type. */ + colorspace->rendering_intent = (png_uint_16)intent; + colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT; + + /* endpoints */ + colorspace->end_points_xy = sRGB_xy; + colorspace->end_points_XYZ = sRGB_XYZ; + colorspace->flags |= + (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB); + + /* gamma */ + colorspace->gamma = PNG_GAMMA_sRGB_INVERSE; + colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA; + + /* Finally record that we have an sRGB profile */ + colorspace->flags |= + (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB); + + return 1; /* set */ +} +#endif /* sRGB */ + +#ifdef PNG_iCCP_SUPPORTED +/* Encoded value of D50 as an ICC XYZNumber. From the ICC 2010 spec the value + * is XYZ(0.9642,1.0,0.8249), which scales to: + * + * (63189.8112, 65536, 54060.6464) + */ +static const png_byte D50_nCIEXYZ[12] = + { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d }; + +int /* PRIVATE */ +png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_uint_32 profile_length) +{ + if (profile_length < 132) + return png_icc_profile_error(png_ptr, colorspace, name, profile_length, + "too short"); + + return 1; +} + +int /* PRIVATE */ +png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_uint_32 profile_length, + png_const_bytep profile/* first 132 bytes only */, int color_type) +{ + png_uint_32 temp; + + /* Length check; this cannot be ignored in this code because profile_length + * is used later to check the tag table, so even if the profile seems over + * long profile_length from the caller must be correct. The caller can fix + * this up on read or write by just passing in the profile header length. + */ + temp = png_get_uint_32(profile); + if (temp != profile_length) + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "length does not match profile"); + + temp = (png_uint_32) (*(profile+8)); + if (temp > 3 && (profile_length & 3)) + return png_icc_profile_error(png_ptr, colorspace, name, profile_length, + "invalid length"); + + temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */ + if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */ + profile_length < 132+12*temp) /* truncated tag table */ + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "tag count too large"); + + /* The 'intent' must be valid or we can't store it, ICC limits the intent to + * 16 bits. + */ + temp = png_get_uint_32(profile+64); + if (temp >= 0xffff) /* The ICC limit */ + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "invalid rendering intent"); + + /* This is just a warning because the profile may be valid in future + * versions. + */ + if (temp >= PNG_sRGB_INTENT_LAST) + (void)png_icc_profile_error(png_ptr, NULL, name, temp, + "intent outside defined range"); + + /* At this point the tag table can't be checked because it hasn't necessarily + * been loaded; however, various header fields can be checked. These checks + * are for values permitted by the PNG spec in an ICC profile; the PNG spec + * restricts the profiles that can be passed in an iCCP chunk (they must be + * appropriate to processing PNG data!) + */ + + /* Data checks (could be skipped). These checks must be independent of the + * version number; however, the version number doesn't accomodate changes in + * the header fields (just the known tags and the interpretation of the + * data.) + */ + temp = png_get_uint_32(profile+36); /* signature 'ascp' */ + if (temp != 0x61637370) + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "invalid signature"); + + /* Currently the PCS illuminant/adopted white point (the computational + * white point) are required to be D50, + * however the profile contains a record of the illuminant so perhaps ICC + * expects to be able to change this in the future (despite the rationale in + * the introduction for using a fixed PCS adopted white.) Consequently the + * following is just a warning. + */ + if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0) + (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/, + "PCS illuminant is not D50"); + + /* The PNG spec requires this: + * "If the iCCP chunk is present, the image samples conform to the colour + * space represented by the embedded ICC profile as defined by the + * International Color Consortium [ICC]. The colour space of the ICC profile + * shall be an RGB colour space for colour images (PNG colour types 2, 3, and + * 6), or a greyscale colour space for greyscale images (PNG colour types 0 + * and 4)." + * + * This checking code ensures the embedded profile (on either read or write) + * conforms to the specification requirements. Notice that an ICC 'gray' + * color-space profile contains the information to transform the monochrome + * data to XYZ or L*a*b (according to which PCS the profile uses) and this + * should be used in preference to the standard libpng K channel replication + * into R, G and B channels. + * + * Previously it was suggested that an RGB profile on grayscale data could be + * handled. However it it is clear that using an RGB profile in this context + * must be an error - there is no specification of what it means. Thus it is + * almost certainly more correct to ignore the profile. + */ + temp = png_get_uint_32(profile+16); /* data colour space field */ + switch (temp) + { + case 0x52474220: /* 'RGB ' */ + if (!(color_type & PNG_COLOR_MASK_COLOR)) + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "RGB color space not permitted on grayscale PNG"); + break; + + case 0x47524159: /* 'GRAY' */ + if (color_type & PNG_COLOR_MASK_COLOR) + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "Gray color space not permitted on RGB PNG"); + break; + + default: + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "invalid ICC profile color space"); + } + + /* It is up to the application to check that the profile class matches the + * application requirements; the spec provides no guidance, but it's pretty + * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer + * ('prtr') or 'spac' (for generic color spaces). Issue a warning in these + * cases. Issue an error for device link or abstract profiles - these don't + * contain the records necessary to transform the color-space to anything + * other than the target device (and not even that for an abstract profile). + * Profiles of these classes may not be embedded in images. + */ + temp = png_get_uint_32(profile+12); /* profile/device class */ + switch (temp) + { + case 0x73636E72: /* 'scnr' */ + case 0x6D6E7472: /* 'mntr' */ + case 0x70727472: /* 'prtr' */ + case 0x73706163: /* 'spac' */ + /* All supported */ + break; + + case 0x61627374: /* 'abst' */ + /* May not be embedded in an image */ + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "invalid embedded Abstract ICC profile"); + + case 0x6C696E6B: /* 'link' */ + /* DeviceLink profiles cannot be interpreted in a non-device specific + * fashion, if an app uses the AToB0Tag in the profile the results are + * undefined unless the result is sent to the intended device, + * therefore a DeviceLink profile should not be found embedded in a + * PNG. + */ + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "unexpected DeviceLink ICC profile class"); + + case 0x6E6D636C: /* 'nmcl' */ + /* A NamedColor profile is also device specific, however it doesn't + * contain an AToB0 tag that is open to misinterpretation. Almost + * certainly it will fail the tests below. + */ + (void)png_icc_profile_error(png_ptr, NULL, name, temp, + "unexpected NamedColor ICC profile class"); + break; + + default: + /* To allow for future enhancements to the profile accept unrecognized + * profile classes with a warning, these then hit the test below on the + * tag content to ensure they are backward compatible with one of the + * understood profiles. + */ + (void)png_icc_profile_error(png_ptr, NULL, name, temp, + "unrecognized ICC profile class"); + break; + } + + /* For any profile other than a device link one the PCS must be encoded + * either in XYZ or Lab. + */ + temp = png_get_uint_32(profile+20); + switch (temp) + { + case 0x58595A20: /* 'XYZ ' */ + case 0x4C616220: /* 'Lab ' */ + break; + + default: + return png_icc_profile_error(png_ptr, colorspace, name, temp, + "unexpected ICC PCS encoding"); + } + + return 1; +} + +int /* PRIVATE */ +png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_uint_32 profile_length, + png_const_bytep profile /* header plus whole tag table */) +{ + png_uint_32 tag_count = png_get_uint_32(profile+128); + png_uint_32 itag; + png_const_bytep tag = profile+132; /* The first tag */ + + /* First scan all the tags in the table and add bits to the icc_info value + * (temporarily in 'tags'). + */ + for (itag=0; itag < tag_count; ++itag, tag += 12) + { + png_uint_32 tag_id = png_get_uint_32(tag+0); + png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */ + png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */ + + /* The ICC specification does not exclude zero length tags, therefore the + * start might actually be anywhere if there is no data, but this would be + * a clear abuse of the intent of the standard so the start is checked for + * being in range. All defined tag types have an 8 byte header - a 4 byte + * type signature then 0. + */ + if ((tag_start & 3) != 0) + { + /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is + * only a warning here because libpng does not care about the + * alignment. + */ + (void)png_icc_profile_error(png_ptr, NULL, name, tag_id, + "ICC profile tag start not a multiple of 4"); + } + + /* This is a hard error; potentially it can cause read outside the + * profile. + */ + if (tag_start > profile_length || tag_length > profile_length - tag_start) + return png_icc_profile_error(png_ptr, colorspace, name, tag_id, + "ICC profile tag outside profile"); + } + + return 1; /* success, maybe with warnings */ +} + +#if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0 +/* Information about the known ICC sRGB profiles */ +static const struct +{ + png_uint_32 adler, crc, length; + png_uint_32 md5[4]; + png_byte have_md5; + png_byte is_broken; + png_uint_16 intent; + +# define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0) +# define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\ + { adler, crc, length, md5, broke, intent }, + +} png_sRGB_checks[] = +{ + /* This data comes from contrib/tools/checksum-icc run on downloads of + * all four ICC sRGB profiles from www.color.org. + */ + /* adler32, crc32, MD5[4], intent, date, length, file-name */ + PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9, + PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0, + "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc") + + /* ICC sRGB v2 perceptual no black-compensation: */ + PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21, + PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0, + "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc") + + PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae, + PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0, + "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc") + + /* ICC sRGB v4 perceptual */ + PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812, + PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0, + "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc") + + /* The following profiles have no known MD5 checksum. If there is a match + * on the (empty) MD5 the other fields are used to attempt a match and + * a warning is produced. The first two of these profiles have a 'cprt' tag + * which suggests that they were also made by Hewlett Packard. + */ + PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce, + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0, + "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc") + + /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not + * match the D50 PCS illuminant in the header (it is in fact the D65 values, + * so the white point is recorded as the un-adapted value.) The profiles + * below only differ in one byte - the intent - and are basically the same as + * the previous profile except for the mediaWhitePointTag error and a missing + * chromaticAdaptationTag. + */ + PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552, + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/, + "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual") + + PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d, + PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/, + "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative") +}; + +static int +png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr, + png_const_bytep profile, uLong adler) +{ + /* The quick check is to verify just the MD5 signature and trust the + * rest of the data. Because the profile has already been verified for + * correctness this is safe. png_colorspace_set_sRGB will check the 'intent' + * field too, so if the profile has been edited with an intent not defined + * by sRGB (but maybe defined by a later ICC specification) the read of + * the profile will fail at that point. + */ + + png_uint_32 length = 0; + png_uint_32 intent = 0x10000; /* invalid */ +#if PNG_sRGB_PROFILE_CHECKS > 1 + uLong crc = 0; /* the value for 0 length data */ +#endif + unsigned int i; + + /* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */ + if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) == + PNG_OPTION_ON) + return 0; + + for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i) + { + if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] && + png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] && + png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] && + png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3]) + { + /* This may be one of the old HP profiles without an MD5, in that + * case we can only use the length and Adler32 (note that these + * are not used by default if there is an MD5!) + */ +# if PNG_sRGB_PROFILE_CHECKS == 0 + if (png_sRGB_checks[i].have_md5) + return 1+png_sRGB_checks[i].is_broken; +# endif + + /* Profile is unsigned or more checks have been configured in. */ + if (length == 0) + { + length = png_get_uint_32(profile); + intent = png_get_uint_32(profile+64); + } + + /* Length *and* intent must match */ + if (length == png_sRGB_checks[i].length && + intent == png_sRGB_checks[i].intent) + { + /* Now calculate the adler32 if not done already. */ + if (adler == 0) + { + adler = adler32(0, NULL, 0); + adler = adler32(adler, profile, length); + } + + if (adler == png_sRGB_checks[i].adler) + { + /* These basic checks suggest that the data has not been + * modified, but if the check level is more than 1 perform + * our own crc32 checksum on the data. + */ +# if PNG_sRGB_PROFILE_CHECKS > 1 + if (crc == 0) + { + crc = crc32(0, NULL, 0); + crc = crc32(crc, profile, length); + } + + /* So this check must pass for the 'return' below to happen. + */ + if (crc == png_sRGB_checks[i].crc) +# endif + { + if (png_sRGB_checks[i].is_broken) + { + /* These profiles are known to have bad data that may cause + * problems if they are used, therefore attempt to + * discourage their use, skip the 'have_md5' warning below, + * which is made irrelevant by this error. + */ + png_chunk_report(png_ptr, "known incorrect sRGB profile", + PNG_CHUNK_ERROR); + } + + /* Warn that this being done; this isn't even an error since + * the profile is perfectly valid, but it would be nice if + * people used the up-to-date ones. + */ + else if (!png_sRGB_checks[i].have_md5) + { + png_chunk_report(png_ptr, + "out-of-date sRGB profile with no signature", + PNG_CHUNK_WARNING); + } + + return 1+png_sRGB_checks[i].is_broken; + } + } + +# if PNG_sRGB_PROFILE_CHECKS > 0 + /* The signature matched, but the profile had been changed in some + * way. This probably indicates a data error or uninformed hacking. + * Fall through to "no match". + */ + png_chunk_report(png_ptr, + "Not recognizing known sRGB profile that has been edited", + PNG_CHUNK_WARNING); + break; +# endif + } + } + } + + return 0; /* no match */ +} +#endif + +#ifdef PNG_sRGB_SUPPORTED +void /* PRIVATE */ +png_icc_set_sRGB(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_const_bytep profile, uLong adler) +{ + /* Is this profile one of the known ICC sRGB profiles? If it is, just set + * the sRGB information. + */ +#if PNG_sRGB_PROFILE_CHECKS >= 0 + if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler)) +#endif + (void)png_colorspace_set_sRGB(png_ptr, colorspace, + (int)/*already checked*/png_get_uint_32(profile+64)); +} +#endif /* PNG_READ_sRGB_SUPPORTED */ + +int /* PRIVATE */ +png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_charp name, png_uint_32 profile_length, png_const_bytep profile, + int color_type) +{ + if (colorspace->flags & PNG_COLORSPACE_INVALID) + return 0; + + if (png_icc_check_length(png_ptr, colorspace, name, profile_length) && + png_icc_check_header(png_ptr, colorspace, name, profile_length, profile, + color_type) && + png_icc_check_tag_table(png_ptr, colorspace, name, profile_length, + profile)) + { +# ifdef PNG_sRGB_SUPPORTED + /* If no sRGB support, don't try storing sRGB information */ + png_icc_set_sRGB(png_ptr, colorspace, profile, 0); +# endif + return 1; + } + + /* Failure case */ + return 0; +} +#endif /* iCCP */ + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +void /* PRIVATE */ +png_colorspace_set_rgb_coefficients(png_structrp png_ptr) +{ + /* Set the rgb_to_gray coefficients from the colorspace. */ + if (!png_ptr->rgb_to_gray_coefficients_set && + (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0) + { + /* png_set_background has not been called, get the coefficients from the Y + * values of the colorspace colorants. + */ + png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y; + png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y; + png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y; + png_fixed_point total = r+g+b; + + if (total > 0 && + r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 && + g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 && + b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 && + r+g+b <= 32769) + { + /* We allow 0 coefficients here. r+g+b may be 32769 if two or + * all of the coefficients were rounded up. Handle this by + * reducing the *largest* coefficient by 1; this matches the + * approach used for the default coefficients in pngrtran.c + */ + int add = 0; + + if (r+g+b > 32768) + add = -1; + else if (r+g+b < 32768) + add = 1; + + if (add != 0) + { + if (g >= r && g >= b) + g += add; + else if (r >= g && r >= b) + r += add; + else + b += add; + } + + /* Check for an internal error. */ + if (r+g+b != 32768) + png_error(png_ptr, + "internal error handling cHRM coefficients"); + + else + { + png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r; + png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g; + } + } + + /* This is a png_error at present even though it could be ignored - + * it should never happen, but it is important that if it does, the + * bug is fixed. + */ + else + png_error(png_ptr, "internal error handling cHRM->XYZ"); + } +} +#endif + +#endif /* COLORSPACE */ + +void /* PRIVATE */ +png_check_IHDR(png_const_structrp png_ptr, + png_uint_32 width, png_uint_32 height, int bit_depth, + int color_type, int interlace_type, int compression_type, + int filter_type) +{ + int error = 0; + + /* Check for width and height valid values */ + if (width == 0) + { + png_warning(png_ptr, "Image width is zero in IHDR"); + error = 1; + } + else if (width > PNG_UINT_31_MAX) + { + png_warning(png_ptr, "Invalid image width in IHDR"); + error = 1; + } + else + { +# ifdef PNG_SET_USER_LIMITS_SUPPORTED + if (width > png_ptr->user_width_max) +# else + if (width > PNG_USER_WIDTH_MAX) +# endif + { + png_warning(png_ptr, "Image width exceeds user limit in IHDR"); + error = 1; + } + } + + if (height == 0) + { + png_warning(png_ptr, "Image height is zero in IHDR"); + error = 1; + } + else if (height > PNG_UINT_31_MAX) + { + png_warning(png_ptr, "Invalid image height in IHDR"); + error = 1; + } + else + { +# ifdef PNG_SET_USER_LIMITS_SUPPORTED + if (height > png_ptr->user_height_max) +# else + if (height > PNG_USER_HEIGHT_MAX) +# endif + { + png_warning(png_ptr, "Image height exceeds user limit in IHDR"); + error = 1; + } + } + + /* Check other values */ + if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 && + bit_depth != 8 && bit_depth != 16) + { + png_warning(png_ptr, "Invalid bit depth in IHDR"); + error = 1; + } + + if (color_type < 0 || color_type == 1 || + color_type == 5 || color_type > 6) + { + png_warning(png_ptr, "Invalid color type in IHDR"); + error = 1; + } + + if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) || + ((color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_GRAY_ALPHA || + color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8)) + { + png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR"); + error = 1; + } + + if (interlace_type >= PNG_INTERLACE_LAST) + { + png_warning(png_ptr, "Unknown interlace method in IHDR"); + error = 1; + } + + if (compression_type != PNG_COMPRESSION_TYPE_BASE) + { + png_warning(png_ptr, "Unknown compression method in IHDR"); + error = 1; + } + +# ifdef PNG_MNG_FEATURES_SUPPORTED + /* Accept filter_method 64 (intrapixel differencing) only if + * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and + * 2. Libpng did not read a PNG signature (this filter_method is only + * used in PNG datastreams that are embedded in MNG datastreams) and + * 3. The application called png_permit_mng_features with a mask that + * included PNG_FLAG_MNG_FILTER_64 and + * 4. The filter_method is 64 and + * 5. The color_type is RGB or RGBA + */ + if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) && + png_ptr->mng_features_permitted) + png_warning(png_ptr, "MNG features are not allowed in a PNG datastream"); + + if (filter_type != PNG_FILTER_TYPE_BASE) + { + if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && + (filter_type == PNG_INTRAPIXEL_DIFFERENCING) && + ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && + (color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_RGB_ALPHA))) + { + png_warning(png_ptr, "Unknown filter method in IHDR"); + error = 1; + } + + if (png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) + { + png_warning(png_ptr, "Invalid filter method in IHDR"); + error = 1; + } + } + +# else + if (filter_type != PNG_FILTER_TYPE_BASE) + { + png_warning(png_ptr, "Unknown filter method in IHDR"); + error = 1; + } +# endif + + if (error == 1) + png_error(png_ptr, "Invalid IHDR data"); +} + +#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED) +/* ASCII to fp functions */ +/* Check an ASCII formated floating point value, see the more detailed + * comments in pngpriv.h + */ +/* The following is used internally to preserve the sticky flags */ +#define png_fp_add(state, flags) ((state) |= (flags)) +#define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY)) + +int /* PRIVATE */ +png_check_fp_number(png_const_charp string, png_size_t size, int *statep, + png_size_tp whereami) +{ + int state = *statep; + png_size_t i = *whereami; + + while (i < size) + { + int type; + /* First find the type of the next character */ + switch (string[i]) + { + case 43: type = PNG_FP_SAW_SIGN; break; + case 45: type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break; + case 46: type = PNG_FP_SAW_DOT; break; + case 48: type = PNG_FP_SAW_DIGIT; break; + case 49: case 50: case 51: case 52: + case 53: case 54: case 55: case 56: + case 57: type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break; + case 69: + case 101: type = PNG_FP_SAW_E; break; + default: goto PNG_FP_End; + } + + /* Now deal with this type according to the current + * state, the type is arranged to not overlap the + * bits of the PNG_FP_STATE. + */ + switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY)) + { + case PNG_FP_INTEGER + PNG_FP_SAW_SIGN: + if (state & PNG_FP_SAW_ANY) + goto PNG_FP_End; /* not a part of the number */ + + png_fp_add(state, type); + break; + + case PNG_FP_INTEGER + PNG_FP_SAW_DOT: + /* Ok as trailer, ok as lead of fraction. */ + if (state & PNG_FP_SAW_DOT) /* two dots */ + goto PNG_FP_End; + + else if (state & PNG_FP_SAW_DIGIT) /* trailing dot? */ + png_fp_add(state, type); + + else + png_fp_set(state, PNG_FP_FRACTION | type); + + break; + + case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT: + if (state & PNG_FP_SAW_DOT) /* delayed fraction */ + png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT); + + png_fp_add(state, type | PNG_FP_WAS_VALID); + + break; + + case PNG_FP_INTEGER + PNG_FP_SAW_E: + if ((state & PNG_FP_SAW_DIGIT) == 0) + goto PNG_FP_End; + + png_fp_set(state, PNG_FP_EXPONENT); + + break; + + /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN: + goto PNG_FP_End; ** no sign in fraction */ + + /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT: + goto PNG_FP_End; ** Because SAW_DOT is always set */ + + case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT: + png_fp_add(state, type | PNG_FP_WAS_VALID); + break; + + case PNG_FP_FRACTION + PNG_FP_SAW_E: + /* This is correct because the trailing '.' on an + * integer is handled above - so we can only get here + * with the sequence ".E" (with no preceding digits). + */ + if ((state & PNG_FP_SAW_DIGIT) == 0) + goto PNG_FP_End; + + png_fp_set(state, PNG_FP_EXPONENT); + + break; + + case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN: + if (state & PNG_FP_SAW_ANY) + goto PNG_FP_End; /* not a part of the number */ + + png_fp_add(state, PNG_FP_SAW_SIGN); + + break; + + /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT: + goto PNG_FP_End; */ + + case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT: + png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID); + + break; + + /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E: + goto PNG_FP_End; */ + + default: goto PNG_FP_End; /* I.e. break 2 */ + } + + /* The character seems ok, continue. */ + ++i; + } + +PNG_FP_End: + /* Here at the end, update the state and return the correct + * return code. + */ + *statep = state; + *whereami = i; + + return (state & PNG_FP_SAW_DIGIT) != 0; +} + + +/* The same but for a complete string. */ +int +png_check_fp_string(png_const_charp string, png_size_t size) +{ + int state=0; + png_size_t char_index=0; + + if (png_check_fp_number(string, size, &state, &char_index) && + (char_index == size || string[char_index] == 0)) + return state /* must be non-zero - see above */; + + return 0; /* i.e. fail */ +} +#endif /* pCAL or sCAL */ + +#ifdef PNG_sCAL_SUPPORTED +# ifdef PNG_FLOATING_POINT_SUPPORTED +/* Utility used below - a simple accurate power of ten from an integral + * exponent. + */ +static double +png_pow10(int power) +{ + int recip = 0; + double d = 1; + + /* Handle negative exponent with a reciprocal at the end because + * 10 is exact whereas .1 is inexact in base 2 + */ + if (power < 0) + { + if (power < DBL_MIN_10_EXP) return 0; + recip = 1, power = -power; + } + + if (power > 0) + { + /* Decompose power bitwise. */ + double mult = 10; + do + { + if (power & 1) d *= mult; + mult *= mult; + power >>= 1; + } + while (power > 0); + + if (recip != 0) d = 1/d; + } + /* else power is 0 and d is 1 */ + + return d; +} + +/* Function to format a floating point value in ASCII with a given + * precision. + */ +void /* PRIVATE */ +png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size, + double fp, unsigned int precision) +{ + /* We use standard functions from math.h, but not printf because + * that would require stdio. The caller must supply a buffer of + * sufficient size or we will png_error. The tests on size and + * the space in ascii[] consumed are indicated below. + */ + if (precision < 1) + precision = DBL_DIG; + + /* Enforce the limit of the implementation precision too. */ + if (precision > DBL_DIG+1) + precision = DBL_DIG+1; + + /* Basic sanity checks */ + if (size >= precision+5) /* See the requirements below. */ + { + if (fp < 0) + { + fp = -fp; + *ascii++ = 45; /* '-' PLUS 1 TOTAL 1 */ + --size; + } + + if (fp >= DBL_MIN && fp <= DBL_MAX) + { + int exp_b10; /* A base 10 exponent */ + double base; /* 10^exp_b10 */ + + /* First extract a base 10 exponent of the number, + * the calculation below rounds down when converting + * from base 2 to base 10 (multiply by log10(2) - + * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to + * be increased. Note that the arithmetic shift + * performs a floor() unlike C arithmetic - using a + * C multiply would break the following for negative + * exponents. + */ + (void)frexp(fp, &exp_b10); /* exponent to base 2 */ + + exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */ + + /* Avoid underflow here. */ + base = png_pow10(exp_b10); /* May underflow */ + + while (base < DBL_MIN || base < fp) + { + /* And this may overflow. */ + double test = png_pow10(exp_b10+1); + + if (test <= DBL_MAX) + ++exp_b10, base = test; + + else + break; + } + + /* Normalize fp and correct exp_b10, after this fp is in the + * range [.1,1) and exp_b10 is both the exponent and the digit + * *before* which the decimal point should be inserted + * (starting with 0 for the first digit). Note that this + * works even if 10^exp_b10 is out of range because of the + * test on DBL_MAX above. + */ + fp /= base; + while (fp >= 1) fp /= 10, ++exp_b10; + + /* Because of the code above fp may, at this point, be + * less than .1, this is ok because the code below can + * handle the leading zeros this generates, so no attempt + * is made to correct that here. + */ + + { + int czero, clead, cdigits; + char exponent[10]; + + /* Allow up to two leading zeros - this will not lengthen + * the number compared to using E-n. + */ + if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */ + { + czero = -exp_b10; /* PLUS 2 digits: TOTAL 3 */ + exp_b10 = 0; /* Dot added below before first output. */ + } + else + czero = 0; /* No zeros to add */ + + /* Generate the digit list, stripping trailing zeros and + * inserting a '.' before a digit if the exponent is 0. + */ + clead = czero; /* Count of leading zeros */ + cdigits = 0; /* Count of digits in list. */ + + do + { + double d; + + fp *= 10; + /* Use modf here, not floor and subtract, so that + * the separation is done in one step. At the end + * of the loop don't break the number into parts so + * that the final digit is rounded. + */ + if (cdigits+czero-clead+1 < (int)precision) + fp = modf(fp, &d); + + else + { + d = floor(fp + .5); + + if (d > 9) + { + /* Rounding up to 10, handle that here. */ + if (czero > 0) + { + --czero, d = 1; + if (cdigits == 0) --clead; + } + else + { + while (cdigits > 0 && d > 9) + { + int ch = *--ascii; + + if (exp_b10 != (-1)) + ++exp_b10; + + else if (ch == 46) + { + ch = *--ascii, ++size; + /* Advance exp_b10 to '1', so that the + * decimal point happens after the + * previous digit. + */ + exp_b10 = 1; + } + + --cdigits; + d = ch - 47; /* I.e. 1+(ch-48) */ + } + + /* Did we reach the beginning? If so adjust the + * exponent but take into account the leading + * decimal point. + */ + if (d > 9) /* cdigits == 0 */ + { + if (exp_b10 == (-1)) + { + /* Leading decimal point (plus zeros?), if + * we lose the decimal point here it must + * be reentered below. + */ + int ch = *--ascii; + + if (ch == 46) + ++size, exp_b10 = 1; + + /* Else lost a leading zero, so 'exp_b10' is + * still ok at (-1) + */ + } + else + ++exp_b10; + + /* In all cases we output a '1' */ + d = 1; + } + } + } + fp = 0; /* Guarantees termination below. */ + } + + if (d == 0) + { + ++czero; + if (cdigits == 0) ++clead; + } + else + { + /* Included embedded zeros in the digit count. */ + cdigits += czero - clead; + clead = 0; + + while (czero > 0) + { + /* exp_b10 == (-1) means we just output the decimal + * place - after the DP don't adjust 'exp_b10' any + * more! + */ + if (exp_b10 != (-1)) + { + if (exp_b10 == 0) *ascii++ = 46, --size; + /* PLUS 1: TOTAL 4 */ + --exp_b10; + } + *ascii++ = 48, --czero; + } + + if (exp_b10 != (-1)) + { + if (exp_b10 == 0) *ascii++ = 46, --size; /* counted + above */ + --exp_b10; + } + *ascii++ = (char)(48 + (int)d), ++cdigits; + } + } + while (cdigits+czero-clead < (int)precision && fp > DBL_MIN); + + /* The total output count (max) is now 4+precision */ + + /* Check for an exponent, if we don't need one we are + * done and just need to terminate the string. At + * this point exp_b10==(-1) is effectively if flag - it got + * to '-1' because of the decrement after outputing + * the decimal point above (the exponent required is + * *not* -1!) + */ + if (exp_b10 >= (-1) && exp_b10 <= 2) + { + /* The following only happens if we didn't output the + * leading zeros above for negative exponent, so this + * doest add to the digit requirement. Note that the + * two zeros here can only be output if the two leading + * zeros were *not* output, so this doesn't increase + * the output count. + */ + while (--exp_b10 >= 0) *ascii++ = 48; + + *ascii = 0; + + /* Total buffer requirement (including the '\0') is + * 5+precision - see check at the start. + */ + return; + } + + /* Here if an exponent is required, adjust size for + * the digits we output but did not count. The total + * digit output here so far is at most 1+precision - no + * decimal point and no leading or trailing zeros have + * been output. + */ + size -= cdigits; + + *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */ + + /* The following use of an unsigned temporary avoids ambiguities in + * the signed arithmetic on exp_b10 and permits GCC at least to do + * better optimization. + */ + { + unsigned int uexp_b10; + + if (exp_b10 < 0) + { + *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */ + uexp_b10 = -exp_b10; + } + + else + uexp_b10 = exp_b10; + + cdigits = 0; + + while (uexp_b10 > 0) + { + exponent[cdigits++] = (char)(48 + uexp_b10 % 10); + uexp_b10 /= 10; + } + } + + /* Need another size check here for the exponent digits, so + * this need not be considered above. + */ + if ((int)size > cdigits) + { + while (cdigits > 0) *ascii++ = exponent[--cdigits]; + + *ascii = 0; + + return; + } + } + } + else if (!(fp >= DBL_MIN)) + { + *ascii++ = 48; /* '0' */ + *ascii = 0; + return; + } + else + { + *ascii++ = 105; /* 'i' */ + *ascii++ = 110; /* 'n' */ + *ascii++ = 102; /* 'f' */ + *ascii = 0; + return; + } + } + + /* Here on buffer too small. */ + png_error(png_ptr, "ASCII conversion buffer too small"); +} + +# endif /* FLOATING_POINT */ + +# ifdef PNG_FIXED_POINT_SUPPORTED +/* Function to format a fixed point value in ASCII. + */ +void /* PRIVATE */ +png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii, + png_size_t size, png_fixed_point fp) +{ + /* Require space for 10 decimal digits, a decimal point, a minus sign and a + * trailing \0, 13 characters: + */ + if (size > 12) + { + png_uint_32 num; + + /* Avoid overflow here on the minimum integer. */ + if (fp < 0) + *ascii++ = 45, --size, num = -fp; + else + num = fp; + + if (num <= 0x80000000) /* else overflowed */ + { + unsigned int ndigits = 0, first = 16 /* flag value */; + char digits[10]; + + while (num) + { + /* Split the low digit off num: */ + unsigned int tmp = num/10; + num -= tmp*10; + digits[ndigits++] = (char)(48 + num); + /* Record the first non-zero digit, note that this is a number + * starting at 1, it's not actually the array index. + */ + if (first == 16 && num > 0) + first = ndigits; + num = tmp; + } + + if (ndigits > 0) + { + while (ndigits > 5) *ascii++ = digits[--ndigits]; + /* The remaining digits are fractional digits, ndigits is '5' or + * smaller at this point. It is certainly not zero. Check for a + * non-zero fractional digit: + */ + if (first <= 5) + { + unsigned int i; + *ascii++ = 46; /* decimal point */ + /* ndigits may be <5 for small numbers, output leading zeros + * then ndigits digits to first: + */ + i = 5; + while (ndigits < i) *ascii++ = 48, --i; + while (ndigits >= first) *ascii++ = digits[--ndigits]; + /* Don't output the trailing zeros! */ + } + } + else + *ascii++ = 48; + + /* And null terminate the string: */ + *ascii = 0; + return; + } + } + + /* Here on buffer too small. */ + png_error(png_ptr, "ASCII conversion buffer too small"); +} +# endif /* FIXED_POINT */ +#endif /* READ_SCAL */ + +#if defined(PNG_FLOATING_POINT_SUPPORTED) && \ + !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \ + (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \ + defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \ + (defined(PNG_sCAL_SUPPORTED) && \ + defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)) +png_fixed_point +png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text) +{ + double r = floor(100000 * fp + .5); + + if (r > 2147483647. || r < -2147483648.) + png_fixed_error(png_ptr, text); + +# ifndef PNG_ERROR_TEXT_SUPPORTED + PNG_UNUSED(text) +# endif + + return (png_fixed_point)r; +} +#endif + +#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_COLORSPACE_SUPPORTED) ||\ + defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED) +/* muldiv functions */ +/* This API takes signed arguments and rounds the result to the nearest + * integer (or, for a fixed point number - the standard argument - to + * the nearest .00001). Overflow and divide by zero are signalled in + * the result, a boolean - true on success, false on overflow. + */ +int +png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times, + png_int_32 divisor) +{ + /* Return a * times / divisor, rounded. */ + if (divisor != 0) + { + if (a == 0 || times == 0) + { + *res = 0; + return 1; + } + else + { +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED + double r = a; + r *= times; + r /= divisor; + r = floor(r+.5); + + /* A png_fixed_point is a 32-bit integer. */ + if (r <= 2147483647. && r >= -2147483648.) + { + *res = (png_fixed_point)r; + return 1; + } +#else + int negative = 0; + png_uint_32 A, T, D; + png_uint_32 s16, s32, s00; + + if (a < 0) + negative = 1, A = -a; + else + A = a; + + if (times < 0) + negative = !negative, T = -times; + else + T = times; + + if (divisor < 0) + negative = !negative, D = -divisor; + else + D = divisor; + + /* Following can't overflow because the arguments only + * have 31 bits each, however the result may be 32 bits. + */ + s16 = (A >> 16) * (T & 0xffff) + + (A & 0xffff) * (T >> 16); + /* Can't overflow because the a*times bit is only 30 + * bits at most. + */ + s32 = (A >> 16) * (T >> 16) + (s16 >> 16); + s00 = (A & 0xffff) * (T & 0xffff); + + s16 = (s16 & 0xffff) << 16; + s00 += s16; + + if (s00 < s16) + ++s32; /* carry */ + + if (s32 < D) /* else overflow */ + { + /* s32.s00 is now the 64-bit product, do a standard + * division, we know that s32 < D, so the maximum + * required shift is 31. + */ + int bitshift = 32; + png_fixed_point result = 0; /* NOTE: signed */ + + while (--bitshift >= 0) + { + png_uint_32 d32, d00; + + if (bitshift > 0) + d32 = D >> (32-bitshift), d00 = D << bitshift; + + else + d32 = 0, d00 = D; + + if (s32 > d32) + { + if (s00 < d00) --s32; /* carry */ + s32 -= d32, s00 -= d00, result += 1<<bitshift; + } + + else + if (s32 == d32 && s00 >= d00) + s32 = 0, s00 -= d00, result += 1<<bitshift; + } + + /* Handle the rounding. */ + if (s00 >= (D >> 1)) + ++result; + + if (negative != 0) + result = -result; + + /* Check for overflow. */ + if ((negative && result <= 0) || (!negative && result >= 0)) + { + *res = result; + return 1; + } + } +#endif + } + } + + return 0; +} +#endif /* READ_GAMMA || INCH_CONVERSIONS */ + +#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED) +/* The following is for when the caller doesn't much care about the + * result. + */ +png_fixed_point +png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times, + png_int_32 divisor) +{ + png_fixed_point result; + + if (png_muldiv(&result, a, times, divisor)) + return result; + + png_warning(png_ptr, "fixed point overflow ignored"); + return 0; +} +#endif + +#ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */ +/* Calculate a reciprocal, return 0 on div-by-zero or overflow. */ +png_fixed_point +png_reciprocal(png_fixed_point a) +{ +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED + double r = floor(1E10/a+.5); + + if (r <= 2147483647. && r >= -2147483648.) + return (png_fixed_point)r; +#else + png_fixed_point res; + + if (png_muldiv(&res, 100000, 100000, a)) + return res; +#endif + + return 0; /* error/overflow */ +} + +/* This is the shared test on whether a gamma value is 'significant' - whether + * it is worth doing gamma correction. + */ +int /* PRIVATE */ +png_gamma_significant(png_fixed_point gamma_val) +{ + return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED || + gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED; +} +#endif + +#ifdef PNG_READ_GAMMA_SUPPORTED +# ifdef PNG_16BIT_SUPPORTED +/* A local convenience routine. */ +static png_fixed_point +png_product2(png_fixed_point a, png_fixed_point b) +{ + /* The required result is 1/a * 1/b; the following preserves accuracy. */ +# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED + double r = a * 1E-5; + r *= b; + r = floor(r+.5); + + if (r <= 2147483647. && r >= -2147483648.) + return (png_fixed_point)r; +# else + png_fixed_point res; + + if (png_muldiv(&res, a, b, 100000)) + return res; +# endif + + return 0; /* overflow */ +} +# endif /* 16BIT */ + +/* The inverse of the above. */ +png_fixed_point +png_reciprocal2(png_fixed_point a, png_fixed_point b) +{ + /* The required result is 1/a * 1/b; the following preserves accuracy. */ +#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED + double r = 1E15/a; + r /= b; + r = floor(r+.5); + + if (r <= 2147483647. && r >= -2147483648.) + return (png_fixed_point)r; +#else + /* This may overflow because the range of png_fixed_point isn't symmetric, + * but this API is only used for the product of file and screen gamma so it + * doesn't matter that the smallest number it can produce is 1/21474, not + * 1/100000 + */ + png_fixed_point res = png_product2(a, b); + + if (res != 0) + return png_reciprocal(res); +#endif + + return 0; /* overflow */ +} +#endif /* READ_GAMMA */ + +#ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */ +#ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED +/* Fixed point gamma. + * + * The code to calculate the tables used below can be found in the shell script + * contrib/tools/intgamma.sh + * + * To calculate gamma this code implements fast log() and exp() calls using only + * fixed point arithmetic. This code has sufficient precision for either 8-bit + * or 16-bit sample values. + * + * The tables used here were calculated using simple 'bc' programs, but C double + * precision floating point arithmetic would work fine. + * + * 8-bit log table + * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to + * 255, so it's the base 2 logarithm of a normalized 8-bit floating point + * mantissa. The numbers are 32-bit fractions. + */ +static const png_uint_32 +png_8bit_l2[128] = +{ + 4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U, + 3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U, + 3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U, + 3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U, + 3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U, + 2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U, + 2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U, + 2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U, + 2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U, + 2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U, + 1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U, + 1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U, + 1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U, + 1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U, + 1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U, + 971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U, + 803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U, + 639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U, + 479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U, + 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U, + 172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U, + 24347096U, 0U + +#if 0 + /* The following are the values for 16-bit tables - these work fine for the + * 8-bit conversions but produce very slightly larger errors in the 16-bit + * log (about 1.2 as opposed to 0.7 absolute error in the final value). To + * use these all the shifts below must be adjusted appropriately. + */ + 65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054, + 57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803, + 50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068, + 43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782, + 37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887, + 31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339, + 25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098, + 20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132, + 15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415, + 10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523, + 6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495, + 1119, 744, 372 +#endif +}; + +static png_int_32 +png_log8bit(unsigned int x) +{ + unsigned int lg2 = 0; + /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log, + * because the log is actually negate that means adding 1. The final + * returned value thus has the range 0 (for 255 input) to 7.994 (for 1 + * input), return -1 for the overflow (log 0) case, - so the result is + * always at most 19 bits. + */ + if ((x &= 0xff) == 0) + return -1; + + if ((x & 0xf0) == 0) + lg2 = 4, x <<= 4; + + if ((x & 0xc0) == 0) + lg2 += 2, x <<= 2; + + if ((x & 0x80) == 0) + lg2 += 1, x <<= 1; + + /* result is at most 19 bits, so this cast is safe: */ + return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16)); +} + +/* The above gives exact (to 16 binary places) log2 values for 8-bit images, + * for 16-bit images we use the most significant 8 bits of the 16-bit value to + * get an approximation then multiply the approximation by a correction factor + * determined by the remaining up to 8 bits. This requires an additional step + * in the 16-bit case. + * + * We want log2(value/65535), we have log2(v'/255), where: + * + * value = v' * 256 + v'' + * = v' * f + * + * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128 + * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less + * than 258. The final factor also needs to correct for the fact that our 8-bit + * value is scaled by 255, whereas the 16-bit values must be scaled by 65535. + * + * This gives a final formula using a calculated value 'x' which is value/v' and + * scaling by 65536 to match the above table: + * + * log2(x/257) * 65536 + * + * Since these numbers are so close to '1' we can use simple linear + * interpolation between the two end values 256/257 (result -368.61) and 258/257 + * (result 367.179). The values used below are scaled by a further 64 to give + * 16-bit precision in the interpolation: + * + * Start (256): -23591 + * Zero (257): 0 + * End (258): 23499 + */ +static png_int_32 +png_log16bit(png_uint_32 x) +{ + unsigned int lg2 = 0; + + /* As above, but now the input has 16 bits. */ + if ((x &= 0xffff) == 0) + return -1; + + if ((x & 0xff00) == 0) + lg2 = 8, x <<= 8; + + if ((x & 0xf000) == 0) + lg2 += 4, x <<= 4; + + if ((x & 0xc000) == 0) + lg2 += 2, x <<= 2; + + if ((x & 0x8000) == 0) + lg2 += 1, x <<= 1; + + /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional + * value. + */ + lg2 <<= 28; + lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4; + + /* Now we need to interpolate the factor, this requires a division by the top + * 8 bits. Do this with maximum precision. + */ + x = ((x << 16) + (x >> 9)) / (x >> 8); + + /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24, + * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly + * 16 bits to interpolate to get the low bits of the result. Round the + * answer. Note that the end point values are scaled by 64 to retain overall + * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust + * the overall scaling by 6-12. Round at every step. + */ + x -= 1U << 24; + + if (x <= 65536U) /* <= '257' */ + lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12); + + else + lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12); + + /* Safe, because the result can't have more than 20 bits: */ + return (png_int_32)((lg2 + 2048) >> 12); +} + +/* The 'exp()' case must invert the above, taking a 20-bit fixed point + * logarithmic value and returning a 16 or 8-bit number as appropriate. In + * each case only the low 16 bits are relevant - the fraction - since the + * integer bits (the top 4) simply determine a shift. + * + * The worst case is the 16-bit distinction between 65535 and 65534, this + * requires perhaps spurious accuracty in the decoding of the logarithm to + * distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance + * of getting this accuracy in practice. + * + * To deal with this the following exp() function works out the exponent of the + * frational part of the logarithm by using an accurate 32-bit value from the + * top four fractional bits then multiplying in the remaining bits. + */ +static const png_uint_32 +png_32bit_exp[16] = +{ + /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */ + 4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U, + 3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U, + 2553802834U, 2445529972U, 2341847524U, 2242560872U +}; + +/* Adjustment table; provided to explain the numbers in the code below. */ +#if 0 +for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"} + 11 44937.64284865548751208448 + 10 45180.98734845585101160448 + 9 45303.31936980687359311872 + 8 45364.65110595323018870784 + 7 45395.35850361789624614912 + 6 45410.72259715102037508096 + 5 45418.40724413220722311168 + 4 45422.25021786898173001728 + 3 45424.17186732298419044352 + 2 45425.13273269940811464704 + 1 45425.61317555035558641664 + 0 45425.85339951654943850496 +#endif + +static png_uint_32 +png_exp(png_fixed_point x) +{ + if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */ + { + /* Obtain a 4-bit approximation */ + png_uint_32 e = png_32bit_exp[(x >> 12) & 0xf]; + + /* Incorporate the low 12 bits - these decrease the returned value by + * multiplying by a number less than 1 if the bit is set. The multiplier + * is determined by the above table and the shift. Notice that the values + * converge on 45426 and this is used to allow linear interpolation of the + * low bits. + */ + if (x & 0x800) + e -= (((e >> 16) * 44938U) + 16U) >> 5; + + if (x & 0x400) + e -= (((e >> 16) * 45181U) + 32U) >> 6; + + if (x & 0x200) + e -= (((e >> 16) * 45303U) + 64U) >> 7; + + if (x & 0x100) + e -= (((e >> 16) * 45365U) + 128U) >> 8; + + if (x & 0x080) + e -= (((e >> 16) * 45395U) + 256U) >> 9; + + if (x & 0x040) + e -= (((e >> 16) * 45410U) + 512U) >> 10; + + /* And handle the low 6 bits in a single block. */ + e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9; + + /* Handle the upper bits of x. */ + e >>= x >> 16; + return e; + } + + /* Check for overflow */ + if (x <= 0) + return png_32bit_exp[0]; + + /* Else underflow */ + return 0; +} + +static png_byte +png_exp8bit(png_fixed_point lg2) +{ + /* Get a 32-bit value: */ + png_uint_32 x = png_exp(lg2); + + /* Convert the 32-bit value to 0..255 by multiplying by 256-1, note that the + * second, rounding, step can't overflow because of the first, subtraction, + * step. + */ + x -= x >> 8; + return (png_byte)((x + 0x7fffffU) >> 24); +} + +#ifdef PNG_16BIT_SUPPORTED +static png_uint_16 +png_exp16bit(png_fixed_point lg2) +{ + /* Get a 32-bit value: */ + png_uint_32 x = png_exp(lg2); + + /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */ + x -= x >> 16; + return (png_uint_16)((x + 32767U) >> 16); +} +#endif /* 16BIT */ +#endif /* FLOATING_ARITHMETIC */ + +png_byte +png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val) +{ + if (value > 0 && value < 255) + { +# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED + double r = floor(255*pow(value/255.,gamma_val*.00001)+.5); + return (png_byte)r; +# else + png_int_32 lg2 = png_log8bit(value); + png_fixed_point res; + + if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1)) + return png_exp8bit(res); + + /* Overflow. */ + value = 0; +# endif + } + + return (png_byte)value; +} + +#ifdef PNG_16BIT_SUPPORTED +png_uint_16 +png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val) +{ + if (value > 0 && value < 65535) + { +# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED + double r = floor(65535*pow(value/65535.,gamma_val*.00001)+.5); + return (png_uint_16)r; +# else + png_int_32 lg2 = png_log16bit(value); + png_fixed_point res; + + if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1)) + return png_exp16bit(res); + + /* Overflow. */ + value = 0; +# endif + } + + return (png_uint_16)value; +} +#endif /* 16BIT */ + +/* This does the right thing based on the bit_depth field of the + * png_struct, interpreting values as 8-bit or 16-bit. While the result + * is nominally a 16-bit value if bit depth is 8 then the result is + * 8-bit (as are the arguments.) + */ +png_uint_16 /* PRIVATE */ +png_gamma_correct(png_structrp png_ptr, unsigned int value, + png_fixed_point gamma_val) +{ + if (png_ptr->bit_depth == 8) + return png_gamma_8bit_correct(value, gamma_val); + +#ifdef PNG_16BIT_SUPPORTED + else + return png_gamma_16bit_correct(value, gamma_val); +#else + /* should not reach this */ + return 0; +#endif /* 16BIT */ +} + +#ifdef PNG_16BIT_SUPPORTED +/* Internal function to build a single 16-bit table - the table consists of + * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount + * to shift the input values right (or 16-number_of_signifiant_bits). + * + * The caller is responsible for ensuring that the table gets cleaned up on + * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument + * should be somewhere that will be cleaned. + */ +static void +png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable, + PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val) +{ + /* Various values derived from 'shift': */ + PNG_CONST unsigned int num = 1U << (8U - shift); + PNG_CONST unsigned int max = (1U << (16U - shift))-1U; + PNG_CONST unsigned int max_by_2 = 1U << (15U-shift); + unsigned int i; + + png_uint_16pp table = *ptable = + (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p))); + + for (i = 0; i < num; i++) + { + png_uint_16p sub_table = table[i] = + (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16))); + + /* The 'threshold' test is repeated here because it can arise for one of + * the 16-bit tables even if the others don't hit it. + */ + if (png_gamma_significant(gamma_val)) + { + /* The old code would overflow at the end and this would cause the + * 'pow' function to return a result >1, resulting in an + * arithmetic error. This code follows the spec exactly; ig is + * the recovered input sample, it always has 8-16 bits. + * + * We want input * 65535/max, rounded, the arithmetic fits in 32 + * bits (unsigned) so long as max <= 32767. + */ + unsigned int j; + for (j = 0; j < 256; j++) + { + png_uint_32 ig = (j << (8-shift)) + i; +# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED + /* Inline the 'max' scaling operation: */ + double d = floor(65535*pow(ig/(double)max, gamma_val*.00001)+.5); + sub_table[j] = (png_uint_16)d; +# else + if (shift != 0) + ig = (ig * 65535U + max_by_2)/max; + + sub_table[j] = png_gamma_16bit_correct(ig, gamma_val); +# endif + } + } + else + { + /* We must still build a table, but do it the fast way. */ + unsigned int j; + + for (j = 0; j < 256; j++) + { + png_uint_32 ig = (j << (8-shift)) + i; + + if (shift != 0) + ig = (ig * 65535U + max_by_2)/max; + + sub_table[j] = (png_uint_16)ig; + } + } + } +} + +/* NOTE: this function expects the *inverse* of the overall gamma transformation + * required. + */ +static void +png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable, + PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val) +{ + PNG_CONST unsigned int num = 1U << (8U - shift); + PNG_CONST unsigned int max = (1U << (16U - shift))-1U; + unsigned int i; + png_uint_32 last; + + png_uint_16pp table = *ptable = + (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p))); + + /* 'num' is the number of tables and also the number of low bits of low + * bits of the input 16-bit value used to select a table. Each table is + * itself index by the high 8 bits of the value. + */ + for (i = 0; i < num; i++) + table[i] = (png_uint_16p)png_malloc(png_ptr, + 256 * (sizeof (png_uint_16))); + + /* 'gamma_val' is set to the reciprocal of the value calculated above, so + * pow(out,g) is an *input* value. 'last' is the last input value set. + * + * In the loop 'i' is used to find output values. Since the output is + * 8-bit there are only 256 possible values. The tables are set up to + * select the closest possible output value for each input by finding + * the input value at the boundary between each pair of output values + * and filling the table up to that boundary with the lower output + * value. + * + * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit + * values the code below uses a 16-bit value in i; the values start at + * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last + * entries are filled with 255). Start i at 128 and fill all 'last' + * table entries <= 'max' + */ + last = 0; + for (i = 0; i < 255; ++i) /* 8-bit output value */ + { + /* Find the corresponding maximum input value */ + png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */ + + /* Find the boundary value in 16 bits: */ + png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val); + + /* Adjust (round) to (16-shift) bits: */ + bound = (bound * max + 32768U)/65535U + 1U; + + while (last < bound) + { + table[last & (0xffU >> shift)][last >> (8U - shift)] = out; + last++; + } + } + + /* And fill in the final entries. */ + while (last < (num << 8)) + { + table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U; + last++; + } +} +#endif /* 16BIT */ + +/* Build a single 8-bit table: same as the 16-bit case but much simpler (and + * typically much faster). Note that libpng currently does no sBIT processing + * (apparently contrary to the spec) so a 256 entry table is always generated. + */ +static void +png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable, + PNG_CONST png_fixed_point gamma_val) +{ + unsigned int i; + png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256); + + if (png_gamma_significant(gamma_val)) for (i=0; i<256; i++) + table[i] = png_gamma_8bit_correct(i, gamma_val); + + else for (i=0; i<256; ++i) + table[i] = (png_byte)i; +} + +/* Used from png_read_destroy and below to release the memory used by the gamma + * tables. + */ +void /* PRIVATE */ +png_destroy_gamma_table(png_structrp png_ptr) +{ + png_free(png_ptr, png_ptr->gamma_table); + png_ptr->gamma_table = NULL; + +#ifdef PNG_16BIT_SUPPORTED + if (png_ptr->gamma_16_table != NULL) + { + int i; + int istop = (1 << (8 - png_ptr->gamma_shift)); + for (i = 0; i < istop; i++) + { + png_free(png_ptr, png_ptr->gamma_16_table[i]); + } + png_free(png_ptr, png_ptr->gamma_16_table); + png_ptr->gamma_16_table = NULL; + } +#endif /* 16BIT */ + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) + png_free(png_ptr, png_ptr->gamma_from_1); + png_ptr->gamma_from_1 = NULL; + png_free(png_ptr, png_ptr->gamma_to_1); + png_ptr->gamma_to_1 = NULL; + +#ifdef PNG_16BIT_SUPPORTED + if (png_ptr->gamma_16_from_1 != NULL) + { + int i; + int istop = (1 << (8 - png_ptr->gamma_shift)); + for (i = 0; i < istop; i++) + { + png_free(png_ptr, png_ptr->gamma_16_from_1[i]); + } + png_free(png_ptr, png_ptr->gamma_16_from_1); + png_ptr->gamma_16_from_1 = NULL; + } + if (png_ptr->gamma_16_to_1 != NULL) + { + int i; + int istop = (1 << (8 - png_ptr->gamma_shift)); + for (i = 0; i < istop; i++) + { + png_free(png_ptr, png_ptr->gamma_16_to_1[i]); + } + png_free(png_ptr, png_ptr->gamma_16_to_1); + png_ptr->gamma_16_to_1 = NULL; + } +#endif /* 16BIT */ +#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ +} + +/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit + * tables, we don't make a full table if we are reducing to 8-bit in + * the future. Note also how the gamma_16 tables are segmented so that + * we don't need to allocate > 64K chunks for a full 16-bit table. + */ +void /* PRIVATE */ +png_build_gamma_table(png_structrp png_ptr, int bit_depth) +{ + png_debug(1, "in png_build_gamma_table"); + + /* Remove any existing table; this copes with multiple calls to + * png_read_update_info. The warning is because building the gamma tables + * multiple times is a performance hit - it's harmless but the ability to call + * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible + * to warn if the app introduces such a hit. + */ + if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL) + { + png_warning(png_ptr, "gamma table being rebuilt"); + png_destroy_gamma_table(png_ptr); + } + + if (bit_depth <= 8) + { + png_build_8bit_table(png_ptr, &png_ptr->gamma_table, + png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma, + png_ptr->screen_gamma) : PNG_FP_1); + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) + if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) + { + png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1, + png_reciprocal(png_ptr->colorspace.gamma)); + + png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1, + png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) : + png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */); + } +#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ + } +#ifdef PNG_16BIT_SUPPORTED + else + { + png_byte shift, sig_bit; + + if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) + { + sig_bit = png_ptr->sig_bit.red; + + if (png_ptr->sig_bit.green > sig_bit) + sig_bit = png_ptr->sig_bit.green; + + if (png_ptr->sig_bit.blue > sig_bit) + sig_bit = png_ptr->sig_bit.blue; + } + else + sig_bit = png_ptr->sig_bit.gray; + + /* 16-bit gamma code uses this equation: + * + * ov = table[(iv & 0xff) >> gamma_shift][iv >> 8] + * + * Where 'iv' is the input color value and 'ov' is the output value - + * pow(iv, gamma). + * + * Thus the gamma table consists of up to 256 256 entry tables. The table + * is selected by the (8-gamma_shift) most significant of the low 8 bits of + * the color value then indexed by the upper 8 bits: + * + * table[low bits][high 8 bits] + * + * So the table 'n' corresponds to all those 'iv' of: + * + * <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1> + * + */ + if (sig_bit > 0 && sig_bit < 16U) + shift = (png_byte)(16U - sig_bit); /* shift == insignificant bits */ + + else + shift = 0; /* keep all 16 bits */ + + if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) + { + /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively + * the significant bits in the *input* when the output will + * eventually be 8 bits. By default it is 11. + */ + if (shift < (16U - PNG_MAX_GAMMA_8)) + shift = (16U - PNG_MAX_GAMMA_8); + } + + if (shift > 8U) + shift = 8U; /* Guarantees at least one table! */ + + png_ptr->gamma_shift = shift; + + /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now + * PNG_COMPOSE). This effectively smashed the background calculation for + * 16-bit output because the 8-bit table assumes the result will be reduced + * to 8 bits. + */ + if (png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) + png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift, + png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma, + png_ptr->screen_gamma) : PNG_FP_1); + + else + png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift, + png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma, + png_ptr->screen_gamma) : PNG_FP_1); + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) + if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) + { + png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift, + png_reciprocal(png_ptr->colorspace.gamma)); + + /* Notice that the '16 from 1' table should be full precision, however + * the lookup on this table still uses gamma_shift, so it can't be. + * TODO: fix this. + */ + png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift, + png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) : + png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */); + } +#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ + } +#endif /* 16BIT */ +} +#endif /* READ_GAMMA */ + +/* HARDWARE OR SOFTWARE OPTION SUPPORT */ +#ifdef PNG_SET_OPTION_SUPPORTED +int PNGAPI +png_set_option(png_structrp png_ptr, int option, int onoff) +{ + if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT && + (option & 1) == 0) + { + int mask = 3 << option; + int setting = (2 + (onoff != 0)) << option; + int current = png_ptr->options; + + png_ptr->options = (png_byte)((current & ~mask) | setting); + + return (current & mask) >> option; + } + + return PNG_OPTION_INVALID; +} +#endif + +/* sRGB support */ +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ + defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) +/* sRGB conversion tables; these are machine generated with the code in + * contrib/tools/makesRGB.c. The actual sRGB transfer curve defined in the + * specification (see the article at http://en.wikipedia.org/wiki/SRGB) + * is used, not the gamma=1/2.2 approximation use elsewhere in libpng. + * The sRGB to linear table is exact (to the nearest 16 bit linear fraction). + * The inverse (linear to sRGB) table has accuracies as follows: + * + * For all possible (255*65535+1) input values: + * + * error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact + * + * For the input values corresponding to the 65536 16-bit values: + * + * error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact + * + * In all cases the inexact readings are off by one. + */ + +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED +/* The convert-to-sRGB table is only currently required for read. */ +const png_uint_16 png_sRGB_table[256] = +{ + 0,20,40,60,80,99,119,139, + 159,179,199,219,241,264,288,313, + 340,367,396,427,458,491,526,562, + 599,637,677,718,761,805,851,898, + 947,997,1048,1101,1156,1212,1270,1330, + 1391,1453,1517,1583,1651,1720,1790,1863, + 1937,2013,2090,2170,2250,2333,2418,2504, + 2592,2681,2773,2866,2961,3058,3157,3258, + 3360,3464,3570,3678,3788,3900,4014,4129, + 4247,4366,4488,4611,4736,4864,4993,5124, + 5257,5392,5530,5669,5810,5953,6099,6246, + 6395,6547,6700,6856,7014,7174,7335,7500, + 7666,7834,8004,8177,8352,8528,8708,8889, + 9072,9258,9445,9635,9828,10022,10219,10417, + 10619,10822,11028,11235,11446,11658,11873,12090, + 12309,12530,12754,12980,13209,13440,13673,13909, + 14146,14387,14629,14874,15122,15371,15623,15878, + 16135,16394,16656,16920,17187,17456,17727,18001, + 18277,18556,18837,19121,19407,19696,19987,20281, + 20577,20876,21177,21481,21787,22096,22407,22721, + 23038,23357,23678,24002,24329,24658,24990,25325, + 25662,26001,26344,26688,27036,27386,27739,28094, + 28452,28813,29176,29542,29911,30282,30656,31033, + 31412,31794,32179,32567,32957,33350,33745,34143, + 34544,34948,35355,35764,36176,36591,37008,37429, + 37852,38278,38706,39138,39572,40009,40449,40891, + 41337,41785,42236,42690,43147,43606,44069,44534, + 45002,45473,45947,46423,46903,47385,47871,48359, + 48850,49344,49841,50341,50844,51349,51858,52369, + 52884,53401,53921,54445,54971,55500,56032,56567, + 57105,57646,58190,58737,59287,59840,60396,60955, + 61517,62082,62650,63221,63795,64372,64952,65535 +}; + +#endif /* simplified read only */ + +/* The base/delta tables are required for both read and write (but currently + * only the simplified versions.) + */ +const png_uint_16 png_sRGB_base[512] = +{ + 128,1782,3383,4644,5675,6564,7357,8074, + 8732,9346,9921,10463,10977,11466,11935,12384, + 12816,13233,13634,14024,14402,14769,15125,15473, + 15812,16142,16466,16781,17090,17393,17690,17981, + 18266,18546,18822,19093,19359,19621,19879,20133, + 20383,20630,20873,21113,21349,21583,21813,22041, + 22265,22487,22707,22923,23138,23350,23559,23767, + 23972,24175,24376,24575,24772,24967,25160,25352, + 25542,25730,25916,26101,26284,26465,26645,26823, + 27000,27176,27350,27523,27695,27865,28034,28201, + 28368,28533,28697,28860,29021,29182,29341,29500, + 29657,29813,29969,30123,30276,30429,30580,30730, + 30880,31028,31176,31323,31469,31614,31758,31902, + 32045,32186,32327,32468,32607,32746,32884,33021, + 33158,33294,33429,33564,33697,33831,33963,34095, + 34226,34357,34486,34616,34744,34873,35000,35127, + 35253,35379,35504,35629,35753,35876,35999,36122, + 36244,36365,36486,36606,36726,36845,36964,37083, + 37201,37318,37435,37551,37668,37783,37898,38013, + 38127,38241,38354,38467,38580,38692,38803,38915, + 39026,39136,39246,39356,39465,39574,39682,39790, + 39898,40005,40112,40219,40325,40431,40537,40642, + 40747,40851,40955,41059,41163,41266,41369,41471, + 41573,41675,41777,41878,41979,42079,42179,42279, + 42379,42478,42577,42676,42775,42873,42971,43068, + 43165,43262,43359,43456,43552,43648,43743,43839, + 43934,44028,44123,44217,44311,44405,44499,44592, + 44685,44778,44870,44962,45054,45146,45238,45329, + 45420,45511,45601,45692,45782,45872,45961,46051, + 46140,46229,46318,46406,46494,46583,46670,46758, + 46846,46933,47020,47107,47193,47280,47366,47452, + 47538,47623,47709,47794,47879,47964,48048,48133, + 48217,48301,48385,48468,48552,48635,48718,48801, + 48884,48966,49048,49131,49213,49294,49376,49458, + 49539,49620,49701,49782,49862,49943,50023,50103, + 50183,50263,50342,50422,50501,50580,50659,50738, + 50816,50895,50973,51051,51129,51207,51285,51362, + 51439,51517,51594,51671,51747,51824,51900,51977, + 52053,52129,52205,52280,52356,52432,52507,52582, + 52657,52732,52807,52881,52956,53030,53104,53178, + 53252,53326,53400,53473,53546,53620,53693,53766, + 53839,53911,53984,54056,54129,54201,54273,54345, + 54417,54489,54560,54632,54703,54774,54845,54916, + 54987,55058,55129,55199,55269,55340,55410,55480, + 55550,55620,55689,55759,55828,55898,55967,56036, + 56105,56174,56243,56311,56380,56448,56517,56585, + 56653,56721,56789,56857,56924,56992,57059,57127, + 57194,57261,57328,57395,57462,57529,57595,57662, + 57728,57795,57861,57927,57993,58059,58125,58191, + 58256,58322,58387,58453,58518,58583,58648,58713, + 58778,58843,58908,58972,59037,59101,59165,59230, + 59294,59358,59422,59486,59549,59613,59677,59740, + 59804,59867,59930,59993,60056,60119,60182,60245, + 60308,60370,60433,60495,60558,60620,60682,60744, + 60806,60868,60930,60992,61054,61115,61177,61238, + 61300,61361,61422,61483,61544,61605,61666,61727, + 61788,61848,61909,61969,62030,62090,62150,62211, + 62271,62331,62391,62450,62510,62570,62630,62689, + 62749,62808,62867,62927,62986,63045,63104,63163, + 63222,63281,63340,63398,63457,63515,63574,63632, + 63691,63749,63807,63865,63923,63981,64039,64097, + 64155,64212,64270,64328,64385,64443,64500,64557, + 64614,64672,64729,64786,64843,64900,64956,65013, + 65070,65126,65183,65239,65296,65352,65409,65465 +}; + +const png_byte png_sRGB_delta[512] = +{ + 207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54, + 52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36, + 35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28, + 28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24, + 23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21, + 21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19, + 19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17, + 17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16, + 16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15, + 15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14, + 14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13, + 13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12, + 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12, + 12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11, + 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11, + 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11, + 11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, + 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, + 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10, + 10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, + 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, + 9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8, + 8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, + 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 +}; +#endif /* SIMPLIFIED READ/WRITE sRGB support */ + +/* SIMPLIFIED READ/WRITE SUPPORT */ +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ + defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) +static int +png_image_free_function(png_voidp argument) +{ + png_imagep image = png_voidcast(png_imagep, argument); + png_controlp cp = image->opaque; + png_control c; + + /* Double check that we have a png_ptr - it should be impossible to get here + * without one. + */ + if (cp->png_ptr == NULL) + return 0; + + /* First free any data held in the control structure. */ +# ifdef PNG_STDIO_SUPPORTED + if (cp->owned_file) + { + FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr); + cp->owned_file = 0; + + /* Ignore errors here. */ + if (fp != NULL) + { + cp->png_ptr->io_ptr = NULL; + (void)fclose(fp); + } + } +# endif + + /* Copy the control structure so that the original, allocated, version can be + * safely freed. Notice that a png_error here stops the remainder of the + * cleanup, but this is probably fine because that would indicate bad memory + * problems anyway. + */ + c = *cp; + image->opaque = &c; + png_free(c.png_ptr, cp); + + /* Then the structures, calling the correct API. */ + if (c.for_write) + { +# ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED + png_destroy_write_struct(&c.png_ptr, &c.info_ptr); +# else + png_error(c.png_ptr, "simplified write not supported"); +# endif + } + else + { +# ifdef PNG_SIMPLIFIED_READ_SUPPORTED + png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL); +# else + png_error(c.png_ptr, "simplified read not supported"); +# endif + } + + /* Success. */ + return 1; +} + +void PNGAPI +png_image_free(png_imagep image) +{ + /* Safely call the real function, but only if doing so is safe at this point + * (if not inside an error handling context). Otherwise assume + * png_safe_execute will call this API after the return. + */ + if (image != NULL && image->opaque != NULL && + image->opaque->error_buf == NULL) + { + /* Ignore errors here: */ + (void)png_safe_execute(image, png_image_free_function, image); + image->opaque = NULL; + } +} + +int /* PRIVATE */ +png_image_error(png_imagep image, png_const_charp error_message) +{ + /* Utility to log an error. */ + png_safecat(image->message, (sizeof image->message), 0, error_message); + image->warning_or_error |= PNG_IMAGE_ERROR; + png_image_free(image); + return 0; +} + +#endif /* SIMPLIFIED READ/WRITE */ +#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */ diff --git a/png/png.h b/png/png.h new file mode 100755 index 0000000..75e8736 --- /dev/null +++ b/png/png.h @@ -0,0 +1,3268 @@ + +/* png.h - header file for PNG reference library + * + * libpng version 1.6.12 - June 12, 2014 + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license (See LICENSE, below) + * + * Authors and maintainers: + * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat + * libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger + * libpng versions 0.97, January 1998, through 1.6.12 - June 12, 2014: Glenn + * See also "Contributing Authors", below. + * + * Note about libpng version numbers: + * + * Due to various miscommunications, unforeseen code incompatibilities + * and occasional factors outside the authors' control, version numbering + * on the library has not always been consistent and straightforward. + * The following table summarizes matters since version 0.89c, which was + * the first widely used release: + * + * source png.h png.h shared-lib + * version string int version + * ------- ------ ----- ---------- + * 0.89c "1.0 beta 3" 0.89 89 1.0.89 + * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90] + * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95] + * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96] + * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97] + * 0.97c 0.97 97 2.0.97 + * 0.98 0.98 98 2.0.98 + * 0.99 0.99 98 2.0.99 + * 0.99a-m 0.99 99 2.0.99 + * 1.00 1.00 100 2.1.0 [100 should be 10000] + * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000] + * 1.0.1 png.h string is 10001 2.1.0 + * 1.0.1a-e identical to the 10002 from here on, the shared library + * 1.0.2 source version) 10002 is 2.V where V is the source code + * 1.0.2a-b 10003 version, except as noted. + * 1.0.3 10003 + * 1.0.3a-d 10004 + * 1.0.4 10004 + * 1.0.4a-f 10005 + * 1.0.5 (+ 2 patches) 10005 + * 1.0.5a-d 10006 + * 1.0.5e-r 10100 (not source compatible) + * 1.0.5s-v 10006 (not binary compatible) + * 1.0.6 (+ 3 patches) 10006 (still binary incompatible) + * 1.0.6d-f 10007 (still binary incompatible) + * 1.0.6g 10007 + * 1.0.6h 10007 10.6h (testing xy.z so-numbering) + * 1.0.6i 10007 10.6i + * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0) + * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible) + * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible) + * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible) + * 1.0.7 1 10007 (still compatible) + * 1.0.8beta1-4 1 10008 2.1.0.8beta1-4 + * 1.0.8rc1 1 10008 2.1.0.8rc1 + * 1.0.8 1 10008 2.1.0.8 + * 1.0.9beta1-6 1 10009 2.1.0.9beta1-6 + * 1.0.9rc1 1 10009 2.1.0.9rc1 + * 1.0.9beta7-10 1 10009 2.1.0.9beta7-10 + * 1.0.9rc2 1 10009 2.1.0.9rc2 + * 1.0.9 1 10009 2.1.0.9 + * 1.0.10beta1 1 10010 2.1.0.10beta1 + * 1.0.10rc1 1 10010 2.1.0.10rc1 + * 1.0.10 1 10010 2.1.0.10 + * 1.0.11beta1-3 1 10011 2.1.0.11beta1-3 + * 1.0.11rc1 1 10011 2.1.0.11rc1 + * 1.0.11 1 10011 2.1.0.11 + * 1.0.12beta1-2 2 10012 2.1.0.12beta1-2 + * 1.0.12rc1 2 10012 2.1.0.12rc1 + * 1.0.12 2 10012 2.1.0.12 + * 1.1.0a-f - 10100 2.1.1.0a-f (branch abandoned) + * 1.2.0beta1-2 2 10200 2.1.2.0beta1-2 + * 1.2.0beta3-5 3 10200 3.1.2.0beta3-5 + * 1.2.0rc1 3 10200 3.1.2.0rc1 + * 1.2.0 3 10200 3.1.2.0 + * 1.2.1beta1-4 3 10201 3.1.2.1beta1-4 + * 1.2.1rc1-2 3 10201 3.1.2.1rc1-2 + * 1.2.1 3 10201 3.1.2.1 + * 1.2.2beta1-6 12 10202 12.so.0.1.2.2beta1-6 + * 1.0.13beta1 10 10013 10.so.0.1.0.13beta1 + * 1.0.13rc1 10 10013 10.so.0.1.0.13rc1 + * 1.2.2rc1 12 10202 12.so.0.1.2.2rc1 + * 1.0.13 10 10013 10.so.0.1.0.13 + * 1.2.2 12 10202 12.so.0.1.2.2 + * 1.2.3rc1-6 12 10203 12.so.0.1.2.3rc1-6 + * 1.2.3 12 10203 12.so.0.1.2.3 + * 1.2.4beta1-3 13 10204 12.so.0.1.2.4beta1-3 + * 1.0.14rc1 13 10014 10.so.0.1.0.14rc1 + * 1.2.4rc1 13 10204 12.so.0.1.2.4rc1 + * 1.0.14 10 10014 10.so.0.1.0.14 + * 1.2.4 13 10204 12.so.0.1.2.4 + * 1.2.5beta1-2 13 10205 12.so.0.1.2.5beta1-2 + * 1.0.15rc1-3 10 10015 10.so.0.1.0.15rc1-3 + * 1.2.5rc1-3 13 10205 12.so.0.1.2.5rc1-3 + * 1.0.15 10 10015 10.so.0.1.0.15 + * 1.2.5 13 10205 12.so.0.1.2.5 + * 1.2.6beta1-4 13 10206 12.so.0.1.2.6beta1-4 + * 1.0.16 10 10016 10.so.0.1.0.16 + * 1.2.6 13 10206 12.so.0.1.2.6 + * 1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2 + * 1.0.17rc1 10 10017 12.so.0.1.0.17rc1 + * 1.2.7rc1 13 10207 12.so.0.1.2.7rc1 + * 1.0.17 10 10017 12.so.0.1.0.17 + * 1.2.7 13 10207 12.so.0.1.2.7 + * 1.2.8beta1-5 13 10208 12.so.0.1.2.8beta1-5 + * 1.0.18rc1-5 10 10018 12.so.0.1.0.18rc1-5 + * 1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5 + * 1.0.18 10 10018 12.so.0.1.0.18 + * 1.2.8 13 10208 12.so.0.1.2.8 + * 1.2.9beta1-3 13 10209 12.so.0.1.2.9beta1-3 + * 1.2.9beta4-11 13 10209 12.so.0.9[.0] + * 1.2.9rc1 13 10209 12.so.0.9[.0] + * 1.2.9 13 10209 12.so.0.9[.0] + * 1.2.10beta1-7 13 10210 12.so.0.10[.0] + * 1.2.10rc1-2 13 10210 12.so.0.10[.0] + * 1.2.10 13 10210 12.so.0.10[.0] + * 1.4.0beta1-5 14 10400 14.so.0.0[.0] + * 1.2.11beta1-4 13 10211 12.so.0.11[.0] + * 1.4.0beta7-8 14 10400 14.so.0.0[.0] + * 1.2.11 13 10211 12.so.0.11[.0] + * 1.2.12 13 10212 12.so.0.12[.0] + * 1.4.0beta9-14 14 10400 14.so.0.0[.0] + * 1.2.13 13 10213 12.so.0.13[.0] + * 1.4.0beta15-36 14 10400 14.so.0.0[.0] + * 1.4.0beta37-87 14 10400 14.so.14.0[.0] + * 1.4.0rc01 14 10400 14.so.14.0[.0] + * 1.4.0beta88-109 14 10400 14.so.14.0[.0] + * 1.4.0rc02-08 14 10400 14.so.14.0[.0] + * 1.4.0 14 10400 14.so.14.0[.0] + * 1.4.1beta01-03 14 10401 14.so.14.1[.0] + * 1.4.1rc01 14 10401 14.so.14.1[.0] + * 1.4.1beta04-12 14 10401 14.so.14.1[.0] + * 1.4.1 14 10401 14.so.14.1[.0] + * 1.4.2 14 10402 14.so.14.2[.0] + * 1.4.3 14 10403 14.so.14.3[.0] + * 1.4.4 14 10404 14.so.14.4[.0] + * 1.5.0beta01-58 15 10500 15.so.15.0[.0] + * 1.5.0rc01-07 15 10500 15.so.15.0[.0] + * 1.5.0 15 10500 15.so.15.0[.0] + * 1.5.1beta01-11 15 10501 15.so.15.1[.0] + * 1.5.1rc01-02 15 10501 15.so.15.1[.0] + * 1.5.1 15 10501 15.so.15.1[.0] + * 1.5.2beta01-03 15 10502 15.so.15.2[.0] + * 1.5.2rc01-03 15 10502 15.so.15.2[.0] + * 1.5.2 15 10502 15.so.15.2[.0] + * 1.5.3beta01-10 15 10503 15.so.15.3[.0] + * 1.5.3rc01-02 15 10503 15.so.15.3[.0] + * 1.5.3beta11 15 10503 15.so.15.3[.0] + * 1.5.3 [omitted] + * 1.5.4beta01-08 15 10504 15.so.15.4[.0] + * 1.5.4rc01 15 10504 15.so.15.4[.0] + * 1.5.4 15 10504 15.so.15.4[.0] + * 1.5.5beta01-08 15 10505 15.so.15.5[.0] + * 1.5.5rc01 15 10505 15.so.15.5[.0] + * 1.5.5 15 10505 15.so.15.5[.0] + * 1.5.6beta01-07 15 10506 15.so.15.6[.0] + * 1.5.6rc01-03 15 10506 15.so.15.6[.0] + * 1.5.6 15 10506 15.so.15.6[.0] + * 1.5.7beta01-05 15 10507 15.so.15.7[.0] + * 1.5.7rc01-03 15 10507 15.so.15.7[.0] + * 1.5.7 15 10507 15.so.15.7[.0] + * 1.6.0beta01-40 16 10600 16.so.16.0[.0] + * 1.6.0rc01-08 16 10600 16.so.16.0[.0] + * 1.6.0 16 10600 16.so.16.0[.0] + * 1.6.1beta01-09 16 10601 16.so.16.1[.0] + * 1.6.1rc01 16 10601 16.so.16.1[.0] + * 1.6.1 16 10601 16.so.16.1[.0] + * 1.6.2beta01 16 10602 16.so.16.2[.0] + * 1.6.2rc01-06 16 10602 16.so.16.2[.0] + * 1.6.2 16 10602 16.so.16.2[.0] + * 1.6.3beta01-11 16 10603 16.so.16.3[.0] + * 1.6.3rc01 16 10603 16.so.16.3[.0] + * 1.6.3 16 10603 16.so.16.3[.0] + * 1.6.4beta01-02 16 10604 16.so.16.4[.0] + * 1.6.4rc01 16 10604 16.so.16.4[.0] + * 1.6.4 16 10604 16.so.16.4[.0] + * 1.6.5 16 10605 16.so.16.5[.0] + * 1.6.6 16 10606 16.so.16.6[.0] + * 1.6.7beta01-04 16 10607 16.so.16.7[.0] + * 1.6.7rc01-03 16 10607 16.so.16.7[.0] + * 1.6.7 16 10607 16.so.16.7[.0] + * 1.6.8beta01-02 16 10608 16.so.16.8[.0] + * 1.6.8rc01-02 16 10608 16.so.16.8[.0] + * 1.6.8 16 10608 16.so.16.8[.0] + * 1.6.9beta01-04 16 10609 16.so.16.9[.0] + * 1.6.9rc01-02 16 10609 16.so.16.9[.0] + * 1.6.9 16 10609 16.so.16.9[.0] + * 1.6.10beta01-03 16 10610 16.so.16.10[.0] + * 1.6.10rc01-03 16 10610 16.so.16.10[.0] + * 1.6.10 16 10610 16.so.16.10[.0] + * 1.6.11beta01-06 16 10611 16.so.16.11[.0] + * 1.6.11rc01-02 16 10611 16.so.16.11[.0] + * 1.6.11 16 10611 16.so.16.11[.0] + * 1.6.12rc01-03 16 10612 16.so.16.12[.0] + * 1.6.12 16 10612 16.so.16.12[.0] + * + * Henceforth the source version will match the shared-library major + * and minor numbers; the shared-library major version number will be + * used for changes in backward compatibility, as it is intended. The + * PNG_LIBPNG_VER macro, which is not used within libpng but is available + * for applications, is an unsigned integer of the form xyyzz corresponding + * to the source version x.y.z (leading zeros in y and z). Beta versions + * were given the previous public release number plus a letter, until + * version 1.0.6j; from then on they were given the upcoming public + * release number plus "betaNN" or "rcNN". + * + * Binary incompatibility exists only when applications make direct access + * to the info_ptr or png_ptr members through png.h, and the compiled + * application is loaded with a different version of the library. + * + * DLLNUM will change each time there are forward or backward changes + * in binary compatibility (e.g., when a new feature is added). + * + * See libpng-manual.txt or libpng.3 for more information. The PNG + * specification is available as a W3C Recommendation and as an ISO + * Specification, <http://www.w3.org/TR/2003/REC-PNG-20031110/ + */ + +/* + * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE: + * + * If you modify libpng you may insert additional notices immediately following + * this sentence. + * + * This code is released under the libpng license. + * + * libpng versions 1.2.6, August 15, 2004, through 1.6.12, June 12, 2014, are + * Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are + * distributed according to the same disclaimer and license as libpng-1.2.5 + * with the following individual added to the list of Contributing Authors: + * + * Cosmin Truta + * + * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are + * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are + * distributed according to the same disclaimer and license as libpng-1.0.6 + * with the following individuals added to the list of Contributing Authors: + * + * Simon-Pierre Cadieux + * Eric S. Raymond + * Gilles Vollant + * + * and with the following additions to the disclaimer: + * + * There is no warranty against interference with your enjoyment of the + * library or against infringement. There is no warranty that our + * efforts or the library will fulfill any of your particular purposes + * or needs. This library is provided with all faults, and the entire + * risk of satisfactory quality, performance, accuracy, and effort is with + * the user. + * + * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are + * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are + * distributed according to the same disclaimer and license as libpng-0.96, + * with the following individuals added to the list of Contributing Authors: + * + * Tom Lane + * Glenn Randers-Pehrson + * Willem van Schaik + * + * libpng versions 0.89, June 1996, through 0.96, May 1997, are + * Copyright (c) 1996, 1997 Andreas Dilger + * Distributed according to the same disclaimer and license as libpng-0.88, + * with the following individuals added to the list of Contributing Authors: + * + * John Bowler + * Kevin Bracey + * Sam Bushell + * Magnus Holmgren + * Greg Roelofs + * Tom Tanner + * + * libpng versions 0.5, May 1995, through 0.88, January 1996, are + * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc. + * + * For the purposes of this copyright and license, "Contributing Authors" + * is defined as the following set of individuals: + * + * Andreas Dilger + * Dave Martindale + * Guy Eric Schalnat + * Paul Schmidt + * Tim Wegner + * + * The PNG Reference Library is supplied "AS IS". The Contributing Authors + * and Group 42, Inc. disclaim all warranties, expressed or implied, + * including, without limitation, the warranties of merchantability and of + * fitness for any purpose. The Contributing Authors and Group 42, Inc. + * assume no liability for direct, indirect, incidental, special, exemplary, + * or consequential damages, which may result from the use of the PNG + * Reference Library, even if advised of the possibility of such damage. + * + * Permission is hereby granted to use, copy, modify, and distribute this + * source code, or portions hereof, for any purpose, without fee, subject + * to the following restrictions: + * + * 1. The origin of this source code must not be misrepresented. + * + * 2. Altered versions must be plainly marked as such and must not + * be misrepresented as being the original source. + * + * 3. This Copyright notice may not be removed or altered from + * any source or altered source distribution. + * + * The Contributing Authors and Group 42, Inc. specifically permit, without + * fee, and encourage the use of this source code as a component to + * supporting the PNG file format in commercial products. If you use this + * source code in a product, acknowledgment is not required but would be + * appreciated. + */ + +/* + * A "png_get_copyright" function is available, for convenient use in "about" + * boxes and the like: + * + * printf("%s", png_get_copyright(NULL)); + * + * Also, the PNG logo (in PNG format, of course) is supplied in the + * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31). + */ + +/* + * Libpng is OSI Certified Open Source Software. OSI Certified is a + * certification mark of the Open Source Initiative. + */ + +/* + * The contributing authors would like to thank all those who helped + * with testing, bug fixes, and patience. This wouldn't have been + * possible without all of you. + * + * Thanks to Frank J. T. Wojcik for helping with the documentation. + */ + +/* + * Y2K compliance in libpng: + * ========================= + * + * June 12, 2014 + * + * Since the PNG Development group is an ad-hoc body, we can't make + * an official declaration. + * + * This is your unofficial assurance that libpng from version 0.71 and + * upward through 1.6.12 are Y2K compliant. It is my belief that + * earlier versions were also Y2K compliant. + * + * Libpng only has two year fields. One is a 2-byte unsigned integer + * that will hold years up to 65535. The other, which is deprecated, + * holds the date in text format, and will hold years up to 9999. + * + * The integer is + * "png_uint_16 year" in png_time_struct. + * + * The string is + * "char time_buffer[29]" in png_struct. This is no longer used + * in libpng-1.6.x and will be removed from libpng-1.7.0. + * + * There are seven time-related functions: + * png.c: png_convert_to_rfc_1123_buffer() in png.c + * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and + * png_convert_to_rfc_1152() in error prior to libpng-0.98) + * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c + * png_convert_from_time_t() in pngwrite.c + * png_get_tIME() in pngget.c + * png_handle_tIME() in pngrutil.c, called in pngread.c + * png_set_tIME() in pngset.c + * png_write_tIME() in pngwutil.c, called in pngwrite.c + * + * All handle dates properly in a Y2K environment. The + * png_convert_from_time_t() function calls gmtime() to convert from system + * clock time, which returns (year - 1900), which we properly convert to + * the full 4-digit year. There is a possibility that libpng applications + * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer() + * function, or that they are incorrectly passing only a 2-digit year + * instead of "year - 1900" into the png_convert_from_struct_tm() function, + * but this is not under our control. The libpng documentation has always + * stated that it works with 4-digit years, and the APIs have been + * documented as such. + * + * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned + * integer to hold the year, and can hold years as large as 65535. + * + * zlib, upon which libpng depends, is also Y2K compliant. It contains + * no date-related code. + * + * Glenn Randers-Pehrson + * libpng maintainer + * PNG Development Group + */ + +#ifndef PNG_H +#define PNG_H + +/* This is not the place to learn how to use libpng. The file libpng-manual.txt + * describes how to use libpng, and the file example.c summarizes it + * with some code on which to build. This file is useful for looking + * at the actual function definitions and structure components. If that + * file has been stripped from your copy of libpng, you can find it at + * <http://www.libpng.org/pub/png/libpng-manual.txt> + * + * If you just need to read a PNG file and don't want to read the documentation + * skip to the end of this file and read the section entitled 'simplified API'. + */ + +/* Version information for png.h - this should match the version in png.c */ +#define PNG_LIBPNG_VER_STRING "1.6.12" +#define PNG_HEADER_VERSION_STRING \ + " libpng version 1.6.12 - June 12, 2014\n" + +#define PNG_LIBPNG_VER_SONUM 16 +#define PNG_LIBPNG_VER_DLLNUM 16 + +/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */ +#define PNG_LIBPNG_VER_MAJOR 1 +#define PNG_LIBPNG_VER_MINOR 6 +#define PNG_LIBPNG_VER_RELEASE 12 + +/* This should match the numeric part of the final component of + * PNG_LIBPNG_VER_STRING, omitting any leading zero: + */ + +#define PNG_LIBPNG_VER_BUILD 0 + +/* Release Status */ +#define PNG_LIBPNG_BUILD_ALPHA 1 +#define PNG_LIBPNG_BUILD_BETA 2 +#define PNG_LIBPNG_BUILD_RC 3 +#define PNG_LIBPNG_BUILD_STABLE 4 +#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7 + +/* Release-Specific Flags */ +#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with + PNG_LIBPNG_BUILD_STABLE only */ +#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with + PNG_LIBPNG_BUILD_SPECIAL */ +#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with + PNG_LIBPNG_BUILD_PRIVATE */ + +#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE + +/* Careful here. At one time, Guy wanted to use 082, but that would be octal. + * We must not include leading zeros. + * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only + * version 1.0.0 was mis-numbered 100 instead of 10000). From + * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release + */ +#define PNG_LIBPNG_VER 10612 /* 1.6.12 */ + +/* Library configuration: these options cannot be changed after + * the library has been built. + */ +#ifndef PNGLCONF_H + /* If pnglibconf.h is missing, you can + * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h + */ +# include "pnglibconf.h" +#endif + +#ifndef PNG_VERSION_INFO_ONLY + /* Machine specific configuration. */ +# include "pngconf.h" +#endif + +/* + * Added at libpng-1.2.8 + * + * Ref MSDN: Private as priority over Special + * VS_FF_PRIVATEBUILD File *was not* built using standard release + * procedures. If this value is given, the StringFileInfo block must + * contain a PrivateBuild string. + * + * VS_FF_SPECIALBUILD File *was* built by the original company using + * standard release procedures but is a variation of the standard + * file of the same version number. If this value is given, the + * StringFileInfo block must contain a SpecialBuild string. + */ + +#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */ +# define PNG_LIBPNG_BUILD_TYPE \ + (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE) +#else +# ifdef PNG_LIBPNG_SPECIALBUILD +# define PNG_LIBPNG_BUILD_TYPE \ + (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL) +# else +# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE) +# endif +#endif + +#ifndef PNG_VERSION_INFO_ONLY + +/* Inhibit C++ name-mangling for libpng functions but not for system calls. */ +#ifdef __cplusplus +extern "C" { +#endif /* __cplusplus */ + +/* Version information for C files, stored in png.c. This had better match + * the version above. + */ +#define png_libpng_ver png_get_header_ver(NULL) + +/* This file is arranged in several sections: + * + * 1. Any configuration options that can be specified by for the application + * code when it is built. (Build time configuration is in pnglibconf.h) + * 2. Type definitions (base types are defined in pngconf.h), structure + * definitions. + * 3. Exported library functions. + * 4. Simplified API. + * + * The library source code has additional files (principally pngpriv.h) that + * allow configuration of the library. + */ +/* Section 1: run time configuration + * See pnglibconf.h for build time configuration + * + * Run time configuration allows the application to choose between + * implementations of certain arithmetic APIs. The default is set + * at build time and recorded in pnglibconf.h, but it is safe to + * override these (and only these) settings. Note that this won't + * change what the library does, only application code, and the + * settings can (and probably should) be made on a per-file basis + * by setting the #defines before including png.h + * + * Use macros to read integers from PNG data or use the exported + * functions? + * PNG_USE_READ_MACROS: use the macros (see below) Note that + * the macros evaluate their argument multiple times. + * PNG_NO_USE_READ_MACROS: call the relevant library function. + * + * Use the alternative algorithm for compositing alpha samples that + * does not use division? + * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division' + * algorithm. + * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm. + * + * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is + * false? + * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error + * APIs to png_warning. + * Otherwise the calls are mapped to png_error. + */ + +/* Section 2: type definitions, including structures and compile time + * constants. + * See pngconf.h for base types that vary by machine/system + */ + +/* This triggers a compiler error in png.c, if png.c and png.h + * do not agree upon the version number. + */ +typedef char* png_libpng_version_1_6_12; + +/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info. + * + * png_struct is the cache of information used while reading or writing a single + * PNG file. One of these is always required, although the simplified API + * (below) hides the creation and destruction of it. + */ +typedef struct png_struct_def png_struct; +typedef const png_struct * png_const_structp; +typedef png_struct * png_structp; +typedef png_struct * * png_structpp; + +/* png_info contains information read from or to be written to a PNG file. One + * or more of these must exist while reading or creating a PNG file. The + * information is not used by libpng during read but is used to control what + * gets written when a PNG file is created. "png_get_" function calls read + * information during read and "png_set_" functions calls write information + * when creating a PNG. + * been moved into a separate header file that is not accessible to + * applications. Read libpng-manual.txt or libpng.3 for more info. + */ +typedef struct png_info_def png_info; +typedef png_info * png_infop; +typedef const png_info * png_const_infop; +typedef png_info * * png_infopp; + +/* Types with names ending 'p' are pointer types. The corresponding types with + * names ending 'rp' are identical pointer types except that the pointer is + * marked 'restrict', which means that it is the only pointer to the object + * passed to the function. Applications should not use the 'restrict' types; + * it is always valid to pass 'p' to a pointer with a function argument of the + * corresponding 'rp' type. Different compilers have different rules with + * regard to type matching in the presence of 'restrict'. For backward + * compatibility libpng callbacks never have 'restrict' in their parameters and, + * consequentially, writing portable application code is extremely difficult if + * an attempt is made to use 'restrict'. + */ +typedef png_struct * PNG_RESTRICT png_structrp; +typedef const png_struct * PNG_RESTRICT png_const_structrp; +typedef png_info * PNG_RESTRICT png_inforp; +typedef const png_info * PNG_RESTRICT png_const_inforp; + +/* Three color definitions. The order of the red, green, and blue, (and the + * exact size) is not important, although the size of the fields need to + * be png_byte or png_uint_16 (as defined below). + */ +typedef struct png_color_struct +{ + png_byte red; + png_byte green; + png_byte blue; +} png_color; +typedef png_color * png_colorp; +typedef const png_color * png_const_colorp; +typedef png_color * * png_colorpp; + +typedef struct png_color_16_struct +{ + png_byte index; /* used for palette files */ + png_uint_16 red; /* for use in red green blue files */ + png_uint_16 green; + png_uint_16 blue; + png_uint_16 gray; /* for use in grayscale files */ +} png_color_16; +typedef png_color_16 * png_color_16p; +typedef const png_color_16 * png_const_color_16p; +typedef png_color_16 * * png_color_16pp; + +typedef struct png_color_8_struct +{ + png_byte red; /* for use in red green blue files */ + png_byte green; + png_byte blue; + png_byte gray; /* for use in grayscale files */ + png_byte alpha; /* for alpha channel files */ +} png_color_8; +typedef png_color_8 * png_color_8p; +typedef const png_color_8 * png_const_color_8p; +typedef png_color_8 * * png_color_8pp; + +/* + * The following two structures are used for the in-core representation + * of sPLT chunks. + */ +typedef struct png_sPLT_entry_struct +{ + png_uint_16 red; + png_uint_16 green; + png_uint_16 blue; + png_uint_16 alpha; + png_uint_16 frequency; +} png_sPLT_entry; +typedef png_sPLT_entry * png_sPLT_entryp; +typedef const png_sPLT_entry * png_const_sPLT_entryp; +typedef png_sPLT_entry * * png_sPLT_entrypp; + +/* When the depth of the sPLT palette is 8 bits, the color and alpha samples + * occupy the LSB of their respective members, and the MSB of each member + * is zero-filled. The frequency member always occupies the full 16 bits. + */ + +typedef struct png_sPLT_struct +{ + png_charp name; /* palette name */ + png_byte depth; /* depth of palette samples */ + png_sPLT_entryp entries; /* palette entries */ + png_int_32 nentries; /* number of palette entries */ +} png_sPLT_t; +typedef png_sPLT_t * png_sPLT_tp; +typedef const png_sPLT_t * png_const_sPLT_tp; +typedef png_sPLT_t * * png_sPLT_tpp; + +#ifdef PNG_TEXT_SUPPORTED +/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file, + * and whether that contents is compressed or not. The "key" field + * points to a regular zero-terminated C string. The "text" fields can be a + * regular C string, an empty string, or a NULL pointer. + * However, the structure returned by png_get_text() will always contain + * the "text" field as a regular zero-terminated C string (possibly + * empty), never a NULL pointer, so it can be safely used in printf() and + * other string-handling functions. Note that the "itxt_length", "lang", and + * "lang_key" members of the structure only exist when the library is built + * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by + * default without iTXt support. Also note that when iTXt *is* supported, + * the "lang" and "lang_key" fields contain NULL pointers when the + * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or + * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the + * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag" + * which is always 0 or 1, or its "compression method" which is always 0. + */ +typedef struct png_text_struct +{ + int compression; /* compression value: + -1: tEXt, none + 0: zTXt, deflate + 1: iTXt, none + 2: iTXt, deflate */ + png_charp key; /* keyword, 1-79 character description of "text" */ + png_charp text; /* comment, may be an empty string (ie "") + or a NULL pointer */ + png_size_t text_length; /* length of the text string */ + png_size_t itxt_length; /* length of the itxt string */ + png_charp lang; /* language code, 0-79 characters + or a NULL pointer */ + png_charp lang_key; /* keyword translated UTF-8 string, 0 or more + chars or a NULL pointer */ +} png_text; +typedef png_text * png_textp; +typedef const png_text * png_const_textp; +typedef png_text * * png_textpp; +#endif + +/* Supported compression types for text in PNG files (tEXt, and zTXt). + * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */ +#define PNG_TEXT_COMPRESSION_NONE_WR -3 +#define PNG_TEXT_COMPRESSION_zTXt_WR -2 +#define PNG_TEXT_COMPRESSION_NONE -1 +#define PNG_TEXT_COMPRESSION_zTXt 0 +#define PNG_ITXT_COMPRESSION_NONE 1 +#define PNG_ITXT_COMPRESSION_zTXt 2 +#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */ + +/* png_time is a way to hold the time in an machine independent way. + * Two conversions are provided, both from time_t and struct tm. There + * is no portable way to convert to either of these structures, as far + * as I know. If you know of a portable way, send it to me. As a side + * note - PNG has always been Year 2000 compliant! + */ +typedef struct png_time_struct +{ + png_uint_16 year; /* full year, as in, 1995 */ + png_byte month; /* month of year, 1 - 12 */ + png_byte day; /* day of month, 1 - 31 */ + png_byte hour; /* hour of day, 0 - 23 */ + png_byte minute; /* minute of hour, 0 - 59 */ + png_byte second; /* second of minute, 0 - 60 (for leap seconds) */ +} png_time; +typedef png_time * png_timep; +typedef const png_time * png_const_timep; +typedef png_time * * png_timepp; + +#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\ + defined(PNG_USER_CHUNKS_SUPPORTED) +/* png_unknown_chunk is a structure to hold queued chunks for which there is + * no specific support. The idea is that we can use this to queue + * up private chunks for output even though the library doesn't actually + * know about their semantics. + * + * The data in the structure is set by libpng on read and used on write. + */ +typedef struct png_unknown_chunk_t +{ + png_byte name[5]; /* Textual chunk name with '\0' terminator */ + png_byte *data; /* Data, should not be modified on read! */ + png_size_t size; + + /* On write 'location' must be set using the flag values listed below. + * Notice that on read it is set by libpng however the values stored have + * more bits set than are listed below. Always treat the value as a + * bitmask. On write set only one bit - setting multiple bits may cause the + * chunk to be written in multiple places. + */ + png_byte location; /* mode of operation at read time */ +} +png_unknown_chunk; + +typedef png_unknown_chunk * png_unknown_chunkp; +typedef const png_unknown_chunk * png_const_unknown_chunkp; +typedef png_unknown_chunk * * png_unknown_chunkpp; +#endif + +/* Flag values for the unknown chunk location byte. */ +#define PNG_HAVE_IHDR 0x01 +#define PNG_HAVE_PLTE 0x02 +#define PNG_AFTER_IDAT 0x08 + +/* Maximum positive integer used in PNG is (2^31)-1 */ +#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL) +#define PNG_UINT_32_MAX ((png_uint_32)(-1)) +#define PNG_SIZE_MAX ((png_size_t)(-1)) + +/* These are constants for fixed point values encoded in the + * PNG specification manner (x100000) + */ +#define PNG_FP_1 100000 +#define PNG_FP_HALF 50000 +#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL) +#define PNG_FP_MIN (-PNG_FP_MAX) + +/* These describe the color_type field in png_info. */ +/* color type masks */ +#define PNG_COLOR_MASK_PALETTE 1 +#define PNG_COLOR_MASK_COLOR 2 +#define PNG_COLOR_MASK_ALPHA 4 + +/* color types. Note that not all combinations are legal */ +#define PNG_COLOR_TYPE_GRAY 0 +#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE) +#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR) +#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA) +#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA) +/* aliases */ +#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA +#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA + +/* This is for compression type. PNG 1.0-1.2 only define the single type. */ +#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */ +#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE + +/* This is for filter type. PNG 1.0-1.2 only define the single type. */ +#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */ +#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */ +#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE + +/* These are for the interlacing type. These values should NOT be changed. */ +#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */ +#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */ +#define PNG_INTERLACE_LAST 2 /* Not a valid value */ + +/* These are for the oFFs chunk. These values should NOT be changed. */ +#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */ +#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */ +#define PNG_OFFSET_LAST 2 /* Not a valid value */ + +/* These are for the pCAL chunk. These values should NOT be changed. */ +#define PNG_EQUATION_LINEAR 0 /* Linear transformation */ +#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */ +#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */ +#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */ +#define PNG_EQUATION_LAST 4 /* Not a valid value */ + +/* These are for the sCAL chunk. These values should NOT be changed. */ +#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */ +#define PNG_SCALE_METER 1 /* meters per pixel */ +#define PNG_SCALE_RADIAN 2 /* radians per pixel */ +#define PNG_SCALE_LAST 3 /* Not a valid value */ + +/* These are for the pHYs chunk. These values should NOT be changed. */ +#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */ +#define PNG_RESOLUTION_METER 1 /* pixels/meter */ +#define PNG_RESOLUTION_LAST 2 /* Not a valid value */ + +/* These are for the sRGB chunk. These values should NOT be changed. */ +#define PNG_sRGB_INTENT_PERCEPTUAL 0 +#define PNG_sRGB_INTENT_RELATIVE 1 +#define PNG_sRGB_INTENT_SATURATION 2 +#define PNG_sRGB_INTENT_ABSOLUTE 3 +#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */ + +/* This is for text chunks */ +#define PNG_KEYWORD_MAX_LENGTH 79 + +/* Maximum number of entries in PLTE/sPLT/tRNS arrays */ +#define PNG_MAX_PALETTE_LENGTH 256 + +/* These determine if an ancillary chunk's data has been successfully read + * from the PNG header, or if the application has filled in the corresponding + * data in the info_struct to be written into the output file. The values + * of the PNG_INFO_<chunk> defines should NOT be changed. + */ +#define PNG_INFO_gAMA 0x0001 +#define PNG_INFO_sBIT 0x0002 +#define PNG_INFO_cHRM 0x0004 +#define PNG_INFO_PLTE 0x0008 +#define PNG_INFO_tRNS 0x0010 +#define PNG_INFO_bKGD 0x0020 +#define PNG_INFO_hIST 0x0040 +#define PNG_INFO_pHYs 0x0080 +#define PNG_INFO_oFFs 0x0100 +#define PNG_INFO_tIME 0x0200 +#define PNG_INFO_pCAL 0x0400 +#define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */ +#define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */ +#define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */ +#define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */ +#define PNG_INFO_IDAT 0x8000 /* ESR, 1.0.6 */ + +/* This is used for the transformation routines, as some of them + * change these values for the row. It also should enable using + * the routines for other purposes. + */ +typedef struct png_row_info_struct +{ + png_uint_32 width; /* width of row */ + png_size_t rowbytes; /* number of bytes in row */ + png_byte color_type; /* color type of row */ + png_byte bit_depth; /* bit depth of row */ + png_byte channels; /* number of channels (1, 2, 3, or 4) */ + png_byte pixel_depth; /* bits per pixel (depth * channels) */ +} png_row_info; + +typedef png_row_info * png_row_infop; +typedef png_row_info * * png_row_infopp; + +/* These are the function types for the I/O functions and for the functions + * that allow the user to override the default I/O functions with his or her + * own. The png_error_ptr type should match that of user-supplied warning + * and error functions, while the png_rw_ptr type should match that of the + * user read/write data functions. Note that the 'write' function must not + * modify the buffer it is passed. The 'read' function, on the other hand, is + * expected to return the read data in the buffer. + */ +typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp)); +typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t)); +typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp)); +typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32, + int)); +typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32, + int)); + +#ifdef PNG_PROGRESSIVE_READ_SUPPORTED +typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop)); +typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop)); + +/* The following callback receives png_uint_32 row_number, int pass for the + * png_bytep data of the row. When transforming an interlaced image the + * row number is the row number within the sub-image of the interlace pass, so + * the value will increase to the height of the sub-image (not the full image) + * then reset to 0 for the next pass. + * + * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to + * find the output pixel (x,y) given an interlaced sub-image pixel + * (row,col,pass). (See below for these macros.) + */ +typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep, + png_uint_32, int)); +#endif + +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ + defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) +typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop, + png_bytep)); +#endif + +#ifdef PNG_USER_CHUNKS_SUPPORTED +typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp, + png_unknown_chunkp)); +#endif +#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED +/* not used anywhere */ +/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */ +#endif + +#ifdef PNG_SETJMP_SUPPORTED +/* This must match the function definition in <setjmp.h>, and the application + * must include this before png.h to obtain the definition of jmp_buf. The + * function is required to be PNG_NORETURN, but this is not checked. If the + * function does return the application will crash via an abort() or similar + * system level call. + * + * If you get a warning here while building the library you may need to make + * changes to ensure that pnglibconf.h records the calling convention used by + * your compiler. This may be very difficult - try using a different compiler + * to build the library! + */ +PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef); +#endif + +/* Transform masks for the high-level interface */ +#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */ +#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */ +#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */ +#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */ +#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */ +#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */ +#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */ +#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */ +#define PNG_TRANSFORM_BGR 0x0080 /* read and write */ +#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */ +#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */ +#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */ +#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */ +/* Added to libpng-1.2.34 */ +#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER +#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */ +/* Added to libpng-1.4.0 */ +#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */ +/* Added to libpng-1.5.4 */ +#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */ +#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */ + +/* Flags for MNG supported features */ +#define PNG_FLAG_MNG_EMPTY_PLTE 0x01 +#define PNG_FLAG_MNG_FILTER_64 0x04 +#define PNG_ALL_MNG_FEATURES 0x05 + +/* NOTE: prior to 1.5 these functions had no 'API' style declaration, + * this allowed the zlib default functions to be used on Windows + * platforms. In 1.5 the zlib default malloc (which just calls malloc and + * ignores the first argument) should be completely compatible with the + * following. + */ +typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp, + png_alloc_size_t)); +typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp)); + +/* Section 3: exported functions + * Here are the function definitions most commonly used. This is not + * the place to find out how to use libpng. See libpng-manual.txt for the + * full explanation, see example.c for the summary. This just provides + * a simple one line description of the use of each function. + * + * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in + * pngconf.h and in the *.dfn files in the scripts directory. + * + * PNG_EXPORT(ordinal, type, name, (args)); + * + * ordinal: ordinal that is used while building + * *.def files. The ordinal value is only + * relevant when preprocessing png.h with + * the *.dfn files for building symbol table + * entries, and are removed by pngconf.h. + * type: return type of the function + * name: function name + * args: function arguments, with types + * + * When we wish to append attributes to a function prototype we use + * the PNG_EXPORTA() macro instead. + * + * PNG_EXPORTA(ordinal, type, name, (args), attributes); + * + * ordinal, type, name, and args: same as in PNG_EXPORT(). + * attributes: function attributes + */ + +/* Returns the version number of the library */ +PNG_EXPORT(1, png_uint_32, png_access_version_number, (void)); + +/* Tell lib we have already handled the first <num_bytes> magic bytes. + * Handling more than 8 bytes from the beginning of the file is an error. + */ +PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes)); + +/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a + * PNG file. Returns zero if the supplied bytes match the 8-byte PNG + * signature, and non-zero otherwise. Having num_to_check == 0 or + * start > 7 will always fail (ie return non-zero). + */ +PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start, + png_size_t num_to_check)); + +/* Simple signature checking function. This is the same as calling + * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n). + */ +#define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n)) + +/* Allocate and initialize png_ptr struct for reading, and any other memory. */ +PNG_EXPORTA(4, png_structp, png_create_read_struct, + (png_const_charp user_png_ver, png_voidp error_ptr, + png_error_ptr error_fn, png_error_ptr warn_fn), + PNG_ALLOCATED); + +/* Allocate and initialize png_ptr struct for writing, and any other memory */ +PNG_EXPORTA(5, png_structp, png_create_write_struct, + (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn, + png_error_ptr warn_fn), + PNG_ALLOCATED); + +PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size, + (png_const_structrp png_ptr)); + +PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr, + png_size_t size)); + +/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp + * match up. + */ +#ifdef PNG_SETJMP_SUPPORTED +/* This function returns the jmp_buf built in to *png_ptr. It must be + * supplied with an appropriate 'longjmp' function to use on that jmp_buf + * unless the default error function is overridden in which case NULL is + * acceptable. The size of the jmp_buf is checked against the actual size + * allocated by the library - the call will return NULL on a mismatch + * indicating an ABI mismatch. + */ +PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr, + png_longjmp_ptr longjmp_fn, size_t jmp_buf_size)); +# define png_jmpbuf(png_ptr) \ + (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf)))) +#else +# define png_jmpbuf(png_ptr) \ + (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP) +#endif +/* This function should be used by libpng applications in place of + * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it + * will use it; otherwise it will call PNG_ABORT(). This function was + * added in libpng-1.5.0. + */ +PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val), + PNG_NORETURN); + +#ifdef PNG_READ_SUPPORTED +/* Reset the compression stream */ +PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED); +#endif + +/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */ +#ifdef PNG_USER_MEM_SUPPORTED +PNG_EXPORTA(11, png_structp, png_create_read_struct_2, + (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn, + png_error_ptr warn_fn, + png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn), + PNG_ALLOCATED); +PNG_EXPORTA(12, png_structp, png_create_write_struct_2, + (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn, + png_error_ptr warn_fn, + png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn), + PNG_ALLOCATED); +#endif + +/* Write the PNG file signature. */ +PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr)); + +/* Write a PNG chunk - size, type, (optional) data, CRC. */ +PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep + chunk_name, png_const_bytep data, png_size_t length)); + +/* Write the start of a PNG chunk - length and chunk name. */ +PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr, + png_const_bytep chunk_name, png_uint_32 length)); + +/* Write the data of a PNG chunk started with png_write_chunk_start(). */ +PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr, + png_const_bytep data, png_size_t length)); + +/* Finish a chunk started with png_write_chunk_start() (includes CRC). */ +PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr)); + +/* Allocate and initialize the info structure */ +PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr), + PNG_ALLOCATED); + +/* DEPRECATED: this function allowed init structures to be created using the + * default allocation method (typically malloc). Use is deprecated in 1.6.0 and + * the API will be removed in the future. + */ +PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr, + png_size_t png_info_struct_size), PNG_DEPRECATED); + +/* Writes all the PNG information before the image. */ +PNG_EXPORT(20, void, png_write_info_before_PLTE, + (png_structrp png_ptr, png_const_inforp info_ptr)); +PNG_EXPORT(21, void, png_write_info, + (png_structrp png_ptr, png_const_inforp info_ptr)); + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read the information before the actual image data. */ +PNG_EXPORT(22, void, png_read_info, + (png_structrp png_ptr, png_inforp info_ptr)); +#endif + +#ifdef PNG_TIME_RFC1123_SUPPORTED + /* Convert to a US string format: there is no localization support in this + * routine. The original implementation used a 29 character buffer in + * png_struct, this will be removed in future versions. + */ +#if PNG_LIBPNG_VER < 10700 +/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */ +PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr, + png_const_timep ptime),PNG_DEPRECATED); +#endif +PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29], + png_const_timep ptime)); +#endif + +#ifdef PNG_CONVERT_tIME_SUPPORTED +/* Convert from a struct tm to png_time */ +PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime, + const struct tm * ttime)); + +/* Convert from time_t to png_time. Uses gmtime() */ +PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime)); +#endif /* PNG_CONVERT_tIME_SUPPORTED */ + +#ifdef PNG_READ_EXPAND_SUPPORTED +/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */ +PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr)); +PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr)); +PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr)); +PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr)); +#endif + +#ifdef PNG_READ_EXPAND_16_SUPPORTED +/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion + * of a tRNS chunk if present. + */ +PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr)); +#endif + +#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) +/* Use blue, green, red order for pixels. */ +PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr)); +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED +/* Expand the grayscale to 24-bit RGB if necessary. */ +PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr)); +#endif + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +/* Reduce RGB to grayscale. */ +#define PNG_ERROR_ACTION_NONE 1 +#define PNG_ERROR_ACTION_WARN 2 +#define PNG_ERROR_ACTION_ERROR 3 +#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/ + +PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr, + int error_action, double red, double green)) +PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr, + int error_action, png_fixed_point red, png_fixed_point green)) + +PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp + png_ptr)); +#endif + +#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED +PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth, + png_colorp palette)); +#endif + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED +/* How the alpha channel is interpreted - this affects how the color channels + * of a PNG file are returned to the calling application when an alpha channel, + * or a tRNS chunk in a palette file, is present. + * + * This has no effect on the way pixels are written into a PNG output + * datastream. The color samples in a PNG datastream are never premultiplied + * with the alpha samples. + * + * The default is to return data according to the PNG specification: the alpha + * channel is a linear measure of the contribution of the pixel to the + * corresponding composited pixel, and the color channels are unassociated + * (not premultiplied). The gamma encoded color channels must be scaled + * according to the contribution and to do this it is necessary to undo + * the encoding, scale the color values, perform the composition and reencode + * the values. This is the 'PNG' mode. + * + * The alternative is to 'associate' the alpha with the color information by + * storing color channel values that have been scaled by the alpha. + * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes + * (the latter being the two common names for associated alpha color channels). + * + * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha + * value is equal to the maximum value. + * + * The final choice is to gamma encode the alpha channel as well. This is + * broken because, in practice, no implementation that uses this choice + * correctly undoes the encoding before handling alpha composition. Use this + * choice only if other serious errors in the software or hardware you use + * mandate it; the typical serious error is for dark halos to appear around + * opaque areas of the composited PNG image because of arithmetic overflow. + * + * The API function png_set_alpha_mode specifies which of these choices to use + * with an enumerated 'mode' value and the gamma of the required output: + */ +#define PNG_ALPHA_PNG 0 /* according to the PNG standard */ +#define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */ +#define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */ +#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */ +#define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */ +#define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */ + +PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode, + double output_gamma)) +PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr, + int mode, png_fixed_point output_gamma)) +#endif + +#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED) +/* The output_gamma value is a screen gamma in libpng terminology: it expresses + * how to decode the output values, not how they are encoded. + */ +#define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */ +#define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */ +#define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */ +#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */ +#endif + +/* The following are examples of calls to png_set_alpha_mode to achieve the + * required overall gamma correction and, where necessary, alpha + * premultiplication. + * + * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); + * This is the default libpng handling of the alpha channel - it is not + * pre-multiplied into the color components. In addition the call states + * that the output is for a sRGB system and causes all PNG files without gAMA + * chunks to be assumed to be encoded using sRGB. + * + * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); + * In this case the output is assumed to be something like an sRGB conformant + * display preceeded by a power-law lookup table of power 1.45. This is how + * early Mac systems behaved. + * + * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR); + * This is the classic Jim Blinn approach and will work in academic + * environments where everything is done by the book. It has the shortcoming + * of assuming that input PNG data with no gamma information is linear - this + * is unlikely to be correct unless the PNG files where generated locally. + * Most of the time the output precision will be so low as to show + * significant banding in dark areas of the image. + * + * png_set_expand_16(pp); + * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB); + * This is a somewhat more realistic Jim Blinn inspired approach. PNG files + * are assumed to have the sRGB encoding if not marked with a gamma value and + * the output is always 16 bits per component. This permits accurate scaling + * and processing of the data. If you know that your input PNG files were + * generated locally you might need to replace PNG_DEFAULT_sRGB with the + * correct value for your system. + * + * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB); + * If you just need to composite the PNG image onto an existing background + * and if you control the code that does this you can use the optimization + * setting. In this case you just copy completely opaque pixels to the + * output. For pixels that are not completely transparent (you just skip + * those) you do the composition math using png_composite or png_composite_16 + * below then encode the resultant 8-bit or 16-bit values to match the output + * encoding. + * + * Other cases + * If neither the PNG nor the standard linear encoding work for you because + * of the software or hardware you use then you have a big problem. The PNG + * case will probably result in halos around the image. The linear encoding + * will probably result in a washed out, too bright, image (it's actually too + * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably + * substantially reduce the halos. Alternatively try: + * + * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB); + * This option will also reduce the halos, but there will be slight dark + * halos round the opaque parts of the image where the background is light. + * In the OPTIMIZED mode the halos will be light halos where the background + * is dark. Take your pick - the halos are unavoidable unless you can get + * your hardware/software fixed! (The OPTIMIZED approach is slightly + * faster.) + * + * When the default gamma of PNG files doesn't match the output gamma. + * If you have PNG files with no gamma information png_set_alpha_mode allows + * you to provide a default gamma, but it also sets the ouput gamma to the + * matching value. If you know your PNG files have a gamma that doesn't + * match the output you can take advantage of the fact that + * png_set_alpha_mode always sets the output gamma but only sets the PNG + * default if it is not already set: + * + * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB); + * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC); + * The first call sets both the default and the output gamma values, the + * second call overrides the output gamma without changing the default. This + * is easier than achieving the same effect with png_set_gamma. You must use + * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will + * fire if more than one call to png_set_alpha_mode and png_set_background is + * made in the same read operation, however multiple calls with PNG_ALPHA_PNG + * are ignored. + */ + +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED +PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr)); +#endif + +#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ + defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) +PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr)); +#endif + +#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ + defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) +PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr)); +#endif + +#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) +/* Add a filler byte to 8-bit Gray or 24-bit RGB images. */ +PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler, + int flags)); +/* The values of the PNG_FILLER_ defines should NOT be changed */ +# define PNG_FILLER_BEFORE 0 +# define PNG_FILLER_AFTER 1 +/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */ +PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr, + png_uint_32 filler, int flags)); +#endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */ + +#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) +/* Swap bytes in 16-bit depth files. */ +PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr)); +#endif + +#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) +/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */ +PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr)); +#endif + +#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \ + defined(PNG_WRITE_PACKSWAP_SUPPORTED) +/* Swap packing order of pixels in bytes. */ +PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr)); +#endif + +#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) +/* Converts files to legal bit depths. */ +PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p + true_bits)); +#endif + +#if defined(PNG_READ_INTERLACING_SUPPORTED) || \ + defined(PNG_WRITE_INTERLACING_SUPPORTED) +/* Have the code handle the interlacing. Returns the number of passes. + * MUST be called before png_read_update_info or png_start_read_image, + * otherwise it will not have the desired effect. Note that it is still + * necessary to call png_read_row or png_read_rows png_get_image_height + * times for each pass. +*/ +PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr)); +#endif + +#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) +/* Invert monochrome files */ +PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr)); +#endif + +#ifdef PNG_READ_BACKGROUND_SUPPORTED +/* Handle alpha and tRNS by replacing with a background color. Prior to + * libpng-1.5.4 this API must not be called before the PNG file header has been + * read. Doing so will result in unexpected behavior and possible warnings or + * errors if the PNG file contains a bKGD chunk. + */ +PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr, + png_const_color_16p background_color, int background_gamma_code, + int need_expand, double background_gamma)) +PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr, + png_const_color_16p background_color, int background_gamma_code, + int need_expand, png_fixed_point background_gamma)) +#endif +#ifdef PNG_READ_BACKGROUND_SUPPORTED +# define PNG_BACKGROUND_GAMMA_UNKNOWN 0 +# define PNG_BACKGROUND_GAMMA_SCREEN 1 +# define PNG_BACKGROUND_GAMMA_FILE 2 +# define PNG_BACKGROUND_GAMMA_UNIQUE 3 +#endif + +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED +/* Scale a 16-bit depth file down to 8-bit, accurately. */ +PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr)); +#endif + +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED +#define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */ +/* Strip the second byte of information from a 16-bit depth file. */ +PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr)); +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED +/* Turn on quantizing, and reduce the palette to the number of colors + * available. + */ +PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr, + png_colorp palette, int num_palette, int maximum_colors, + png_const_uint_16p histogram, int full_quantize)); +#endif + +#ifdef PNG_READ_GAMMA_SUPPORTED +/* The threshold on gamma processing is configurable but hard-wired into the + * library. The following is the floating point variant. + */ +#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001) + +/* Handle gamma correction. Screen_gamma=(display_exponent). + * NOTE: this API simply sets the screen and file gamma values. It will + * therefore override the value for gamma in a PNG file if it is called after + * the file header has been read - use with care - call before reading the PNG + * file for best results! + * + * These routines accept the same gamma values as png_set_alpha_mode (described + * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either + * API (floating point or fixed.) Notice, however, that the 'file_gamma' value + * is the inverse of a 'screen gamma' value. + */ +PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr, + double screen_gamma, double override_file_gamma)) +PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr, + png_fixed_point screen_gamma, png_fixed_point override_file_gamma)) +#endif + +#ifdef PNG_WRITE_FLUSH_SUPPORTED +/* Set how many lines between output flushes - 0 for no flushing */ +PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows)); +/* Flush the current PNG output buffer */ +PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr)); +#endif + +/* Optional update palette with requested transformations */ +PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr)); + +/* Optional call to update the users info structure */ +PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr, + png_inforp info_ptr)); + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read one or more rows of image data. */ +PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row, + png_bytepp display_row, png_uint_32 num_rows)); +#endif + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read a row of data. */ +PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row, + png_bytep display_row)); +#endif + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read the whole image into memory at once. */ +PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image)); +#endif + +/* Write a row of image data */ +PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr, + png_const_bytep row)); + +/* Write a few rows of image data: (*row) is not written; however, the type + * is declared as writeable to maintain compatibility with previous versions + * of libpng and to allow the 'display_row' array from read_rows to be passed + * unchanged to write_rows. + */ +PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row, + png_uint_32 num_rows)); + +/* Write the image data */ +PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image)); + +/* Write the end of the PNG file. */ +PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr, + png_inforp info_ptr)); + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read the end of the PNG file. */ +PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr)); +#endif + +/* Free any memory associated with the png_info_struct */ +PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr, + png_infopp info_ptr_ptr)); + +/* Free any memory associated with the png_struct and the png_info_structs */ +PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr, + png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr)); + +/* Free any memory associated with the png_struct and the png_info_structs */ +PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr, + png_infopp info_ptr_ptr)); + +/* Set the libpng method of handling chunk CRC errors */ +PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action, + int ancil_action)); + +/* Values for png_set_crc_action() say how to handle CRC errors in + * ancillary and critical chunks, and whether to use the data contained + * therein. Note that it is impossible to "discard" data in a critical + * chunk. For versions prior to 0.90, the action was always error/quit, + * whereas in version 0.90 and later, the action for CRC errors in ancillary + * chunks is warn/discard. These values should NOT be changed. + * + * value action:critical action:ancillary + */ +#define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */ +#define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */ +#define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */ +#define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */ +#define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */ +#define PNG_CRC_NO_CHANGE 5 /* use current value use current value */ + +/* These functions give the user control over the scan-line filtering in + * libpng and the compression methods used by zlib. These functions are + * mainly useful for testing, as the defaults should work with most users. + * Those users who are tight on memory or want faster performance at the + * expense of compression can modify them. See the compression library + * header file (zlib.h) for an explination of the compression functions. + */ + +/* Set the filtering method(s) used by libpng. Currently, the only valid + * value for "method" is 0. + */ +PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method, + int filters)); + +/* Flags for png_set_filter() to say which filters to use. The flags + * are chosen so that they don't conflict with real filter types + * below, in case they are supplied instead of the #defined constants. + * These values should NOT be changed. + */ +#define PNG_NO_FILTERS 0x00 +#define PNG_FILTER_NONE 0x08 +#define PNG_FILTER_SUB 0x10 +#define PNG_FILTER_UP 0x20 +#define PNG_FILTER_AVG 0x40 +#define PNG_FILTER_PAETH 0x80 +#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \ + PNG_FILTER_AVG | PNG_FILTER_PAETH) + +/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now. + * These defines should NOT be changed. + */ +#define PNG_FILTER_VALUE_NONE 0 +#define PNG_FILTER_VALUE_SUB 1 +#define PNG_FILTER_VALUE_UP 2 +#define PNG_FILTER_VALUE_AVG 3 +#define PNG_FILTER_VALUE_PAETH 4 +#define PNG_FILTER_VALUE_LAST 5 + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */ +/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_ + * defines, either the default (minimum-sum-of-absolute-differences), or + * the experimental method (weighted-minimum-sum-of-absolute-differences). + * + * Weights are factors >= 1.0, indicating how important it is to keep the + * filter type consistent between rows. Larger numbers mean the current + * filter is that many times as likely to be the same as the "num_weights" + * previous filters. This is cumulative for each previous row with a weight. + * There needs to be "num_weights" values in "filter_weights", or it can be + * NULL if the weights aren't being specified. Weights have no influence on + * the selection of the first row filter. Well chosen weights can (in theory) + * improve the compression for a given image. + * + * Costs are factors >= 1.0 indicating the relative decoding costs of a + * filter type. Higher costs indicate more decoding expense, and are + * therefore less likely to be selected over a filter with lower computational + * costs. There needs to be a value in "filter_costs" for each valid filter + * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't + * setting the costs. Costs try to improve the speed of decompression without + * unduly increasing the compressed image size. + * + * A negative weight or cost indicates the default value is to be used, and + * values in the range [0.0, 1.0) indicate the value is to remain unchanged. + * The default values for both weights and costs are currently 1.0, but may + * change if good general weighting/cost heuristics can be found. If both + * the weights and costs are set to 1.0, this degenerates the WEIGHTED method + * to the UNWEIGHTED method, but with added encoding time/computation. + */ +PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr, + int heuristic_method, int num_weights, png_const_doublep filter_weights, + png_const_doublep filter_costs)) +PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed, + (png_structrp png_ptr, int heuristic_method, int num_weights, + png_const_fixed_point_p filter_weights, + png_const_fixed_point_p filter_costs)) +#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */ + +/* Heuristic used for row filter selection. These defines should NOT be + * changed. + */ +#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */ +#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */ +#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */ +#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */ + +#ifdef PNG_WRITE_SUPPORTED +/* Set the library compression level. Currently, valid values range from + * 0 - 9, corresponding directly to the zlib compression levels 0 - 9 + * (0 - no compression, 9 - "maximal" compression). Note that tests have + * shown that zlib compression levels 3-6 usually perform as well as level 9 + * for PNG images, and do considerably fewer caclulations. In the future, + * these values may not correspond directly to the zlib compression levels. + */ +PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr, + int level)); + +PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr, + int mem_level)); + +PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr, + int strategy)); + +/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a + * smaller value of window_bits if it can do so safely. + */ +PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr, + int window_bits)); + +PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr, + int method)); +#endif + +#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED +/* Also set zlib parameters for compressing non-IDAT chunks */ +PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr, + int level)); + +PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr, + int mem_level)); + +PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr, + int strategy)); + +/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a + * smaller value of window_bits if it can do so safely. + */ +PNG_EXPORT(225, void, png_set_text_compression_window_bits, + (png_structrp png_ptr, int window_bits)); + +PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr, + int method)); +#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */ + +/* These next functions are called for input/output, memory, and error + * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c, + * and call standard C I/O routines such as fread(), fwrite(), and + * fprintf(). These functions can be made to use other I/O routines + * at run time for those applications that need to handle I/O in a + * different manner by calling png_set_???_fn(). See libpng-manual.txt for + * more information. + */ + +#ifdef PNG_STDIO_SUPPORTED +/* Initialize the input/output for the PNG file to the default functions. */ +PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp)); +#endif + +/* Replace the (error and abort), and warning functions with user + * supplied functions. If no messages are to be printed you must still + * write and use replacement functions. The replacement error_fn should + * still do a longjmp to the last setjmp location if you are using this + * method of error handling. If error_fn or warning_fn is NULL, the + * default function will be used. + */ + +PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr, + png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn)); + +/* Return the user pointer associated with the error functions */ +PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr)); + +/* Replace the default data output functions with a user supplied one(s). + * If buffered output is not used, then output_flush_fn can be set to NULL. + * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time + * output_flush_fn will be ignored (and thus can be NULL). + * It is probably a mistake to use NULL for output_flush_fn if + * write_data_fn is not also NULL unless you have built libpng with + * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's + * default flush function, which uses the standard *FILE structure, will + * be used. + */ +PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr, + png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)); + +/* Replace the default data input function with a user supplied one. */ +PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr, + png_rw_ptr read_data_fn)); + +/* Return the user pointer associated with the I/O functions */ +PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr)); + +PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr, + png_read_status_ptr read_row_fn)); + +PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr, + png_write_status_ptr write_row_fn)); + +#ifdef PNG_USER_MEM_SUPPORTED +/* Replace the default memory allocation functions with user supplied one(s). */ +PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr, + png_malloc_ptr malloc_fn, png_free_ptr free_fn)); +/* Return the user pointer associated with the memory functions */ +PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr)); +#endif + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED +PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr, + png_user_transform_ptr read_user_transform_fn)); +#endif + +#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED +PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr, + png_user_transform_ptr write_user_transform_fn)); +#endif + +#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED +PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr, + png_voidp user_transform_ptr, int user_transform_depth, + int user_transform_channels)); +/* Return the user pointer associated with the user transform functions */ +PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr, + (png_const_structrp png_ptr)); +#endif + +#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED +/* Return information about the row currently being processed. Note that these + * APIs do not fail but will return unexpected results if called outside a user + * transform callback. Also note that when transforming an interlaced image the + * row number is the row number within the sub-image of the interlace pass, so + * the value will increase to the height of the sub-image (not the full image) + * then reset to 0 for the next pass. + * + * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to + * find the output pixel (x,y) given an interlaced sub-image pixel + * (row,col,pass). (See below for these macros.) + */ +PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp)); +PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp)); +#endif + +#ifdef PNG_READ_USER_CHUNKS_SUPPORTED +/* This callback is called only for *unknown* chunks. If + * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known + * chunks to be treated as unknown, however in this case the callback must do + * any processing required by the chunk (e.g. by calling the appropriate + * png_set_ APIs.) + * + * There is no write support - on write, by default, all the chunks in the + * 'unknown' list are written in the specified position. + * + * The integer return from the callback function is interpreted thus: + * + * negative: An error occured, png_chunk_error will be called. + * zero: The chunk was not handled, the chunk will be saved. A critical + * chunk will cause an error at this point unless it is to be saved. + * positive: The chunk was handled, libpng will ignore/discard it. + * + * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about + * how this behavior will change in libpng 1.7 + */ +PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr, + png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn)); +#endif + +#ifdef PNG_USER_CHUNKS_SUPPORTED +PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr)); +#endif + +#ifdef PNG_PROGRESSIVE_READ_SUPPORTED +/* Sets the function callbacks for the push reader, and a pointer to a + * user-defined structure available to the callback functions. + */ +PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr, + png_voidp progressive_ptr, png_progressive_info_ptr info_fn, + png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn)); + +/* Returns the user pointer associated with the push read functions */ +PNG_EXPORT(91, png_voidp, png_get_progressive_ptr, + (png_const_structrp png_ptr)); + +/* Function to be called when data becomes available */ +PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr, + png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size)); + +/* A function which may be called *only* within png_process_data to stop the + * processing of any more data. The function returns the number of bytes + * remaining, excluding any that libpng has cached internally. A subsequent + * call to png_process_data must supply these bytes again. If the argument + * 'save' is set to true the routine will first save all the pending data and + * will always return 0. + */ +PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save)); + +/* A function which may be called *only* outside (after) a call to + * png_process_data. It returns the number of bytes of data to skip in the + * input. Normally it will return 0, but if it returns a non-zero value the + * application must skip than number of bytes of input data and pass the + * following data to the next call to png_process_data. + */ +PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp)); + +/* Function that combines rows. 'new_row' is a flag that should come from + * the callback and be non-NULL if anything needs to be done; the library + * stores its own version of the new data internally and ignores the passed + * in value. + */ +PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr, + png_bytep old_row, png_const_bytep new_row)); +#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ + +PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr, + png_alloc_size_t size), PNG_ALLOCATED); +/* Added at libpng version 1.4.0 */ +PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr, + png_alloc_size_t size), PNG_ALLOCATED); + +/* Added at libpng version 1.2.4 */ +PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr, + png_alloc_size_t size), PNG_ALLOCATED); + +/* Frees a pointer allocated by png_malloc() */ +PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr)); + +/* Free data that was allocated internally */ +PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr, + png_inforp info_ptr, png_uint_32 free_me, int num)); + +/* Reassign responsibility for freeing existing data, whether allocated + * by libpng or by the application; this works on the png_info structure passed + * in, it does not change the state for other png_info structures. + * + * It is unlikely that this function works correctly as of 1.6.0 and using it + * may result either in memory leaks or double free of allocated data. + */ +PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr, + png_inforp info_ptr, int freer, png_uint_32 mask)); + +/* Assignments for png_data_freer */ +#define PNG_DESTROY_WILL_FREE_DATA 1 +#define PNG_SET_WILL_FREE_DATA 1 +#define PNG_USER_WILL_FREE_DATA 2 +/* Flags for png_ptr->free_me and info_ptr->free_me */ +#define PNG_FREE_HIST 0x0008 +#define PNG_FREE_ICCP 0x0010 +#define PNG_FREE_SPLT 0x0020 +#define PNG_FREE_ROWS 0x0040 +#define PNG_FREE_PCAL 0x0080 +#define PNG_FREE_SCAL 0x0100 +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED +# define PNG_FREE_UNKN 0x0200 +#endif +/* PNG_FREE_LIST 0x0400 removed in 1.6.0 because it is ignored */ +#define PNG_FREE_PLTE 0x1000 +#define PNG_FREE_TRNS 0x2000 +#define PNG_FREE_TEXT 0x4000 +#define PNG_FREE_ALL 0x7fff +#define PNG_FREE_MUL 0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */ + +#ifdef PNG_USER_MEM_SUPPORTED +PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr, + png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED); +PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr, + png_voidp ptr), PNG_DEPRECATED); +#endif + +#ifdef PNG_ERROR_TEXT_SUPPORTED +/* Fatal error in PNG image of libpng - can't continue */ +PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr, + png_const_charp error_message), PNG_NORETURN); + +/* The same, but the chunk name is prepended to the error string. */ +PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr, + png_const_charp error_message), PNG_NORETURN); + +#else +/* Fatal error in PNG image of libpng - can't continue */ +PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN); +# define png_error(s1,s2) png_err(s1) +# define png_chunk_error(s1,s2) png_err(s1) +#endif + +#ifdef PNG_WARNINGS_SUPPORTED +/* Non-fatal error in libpng. Can continue, but may have a problem. */ +PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr, + png_const_charp warning_message)); + +/* Non-fatal error in libpng, chunk name is prepended to message. */ +PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr, + png_const_charp warning_message)); +#else +# define png_warning(s1,s2) ((void)(s1)) +# define png_chunk_warning(s1,s2) ((void)(s1)) +#endif + +#ifdef PNG_BENIGN_ERRORS_SUPPORTED +/* Benign error in libpng. Can continue, but may have a problem. + * User can choose whether to handle as a fatal error or as a warning. */ +PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr, + png_const_charp warning_message)); + +#ifdef PNG_READ_SUPPORTED +/* Same, chunk name is prepended to message (only during read) */ +PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr, + png_const_charp warning_message)); +#endif + +PNG_EXPORT(109, void, png_set_benign_errors, + (png_structrp png_ptr, int allowed)); +#else +# ifdef PNG_ALLOW_BENIGN_ERRORS +# define png_benign_error png_warning +# define png_chunk_benign_error png_chunk_warning +# else +# define png_benign_error png_error +# define png_chunk_benign_error png_chunk_error +# endif +#endif + +/* The png_set_<chunk> functions are for storing values in the png_info_struct. + * Similarly, the png_get_<chunk> calls are used to read values from the + * png_info_struct, either storing the parameters in the passed variables, or + * setting pointers into the png_info_struct where the data is stored. The + * png_get_<chunk> functions return a non-zero value if the data was available + * in info_ptr, or return zero and do not change any of the parameters if the + * data was not available. + * + * These functions should be used instead of directly accessing png_info + * to avoid problems with future changes in the size and internal layout of + * png_info_struct. + */ +/* Returns "flag" if chunk data is valid in info_ptr. */ +PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr, + png_const_inforp info_ptr, png_uint_32 flag)); + +/* Returns number of bytes needed to hold a transformed row. */ +PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +#ifdef PNG_INFO_IMAGE_SUPPORTED +/* Returns row_pointers, which is an array of pointers to scanlines that was + * returned from png_read_png(). + */ +PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +/* Set row_pointers, which is an array of pointers to scanlines for use + * by png_write_png(). + */ +PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr, + png_inforp info_ptr, png_bytepp row_pointers)); +#endif + +/* Returns number of color channels in image. */ +PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +#ifdef PNG_EASY_ACCESS_SUPPORTED +/* Returns image width in pixels. */ +PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +/* Returns image height in pixels. */ +PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +/* Returns image bit_depth. */ +PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +/* Returns image color_type. */ +PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +/* Returns image filter_type. */ +PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +/* Returns image interlace_type. */ +PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +/* Returns image compression_type. */ +PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); + +/* Returns image resolution in pixels per meter, from pHYs chunk data. */ +PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); +PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); +PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); + +/* Returns pixel aspect ratio, computed from pHYs chunk data. */ +PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio, + (png_const_structrp png_ptr, png_const_inforp info_ptr)) +PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed, + (png_const_structrp png_ptr, png_const_inforp info_ptr)) + +/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */ +PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); +PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); +PNG_EXPORT(128, png_int_32, png_get_x_offset_microns, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); +PNG_EXPORT(129, png_int_32, png_get_y_offset_microns, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); + +#endif /* PNG_EASY_ACCESS_SUPPORTED */ + +#ifdef PNG_READ_SUPPORTED +/* Returns pointer to signature string read from PNG header */ +PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr, + png_const_inforp info_ptr)); +#endif + +#ifdef PNG_bKGD_SUPPORTED +PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr, + png_inforp info_ptr, png_color_16p *background)); +#endif + +#ifdef PNG_bKGD_SUPPORTED +PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_color_16p background)); +#endif + +#ifdef PNG_cHRM_SUPPORTED +PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr, + png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x, + double *red_y, double *green_x, double *green_y, double *blue_x, + double *blue_y)) +PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr, + png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z, + double *green_X, double *green_Y, double *green_Z, double *blue_X, + double *blue_Y, double *blue_Z)) +PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed, + (png_const_structrp png_ptr, png_const_inforp info_ptr, + png_fixed_point *int_white_x, png_fixed_point *int_white_y, + png_fixed_point *int_red_x, png_fixed_point *int_red_y, + png_fixed_point *int_green_x, png_fixed_point *int_green_y, + png_fixed_point *int_blue_x, png_fixed_point *int_blue_y)) +PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed, + (png_const_structrp png_ptr, png_const_inforp info_ptr, + png_fixed_point *int_red_X, png_fixed_point *int_red_Y, + png_fixed_point *int_red_Z, png_fixed_point *int_green_X, + png_fixed_point *int_green_Y, png_fixed_point *int_green_Z, + png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y, + png_fixed_point *int_blue_Z)) +#endif + +#ifdef PNG_cHRM_SUPPORTED +PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr, + png_inforp info_ptr, + double white_x, double white_y, double red_x, double red_y, double green_x, + double green_y, double blue_x, double blue_y)) +PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr, + png_inforp info_ptr, double red_X, double red_Y, double red_Z, + double green_X, double green_Y, double green_Z, double blue_X, + double blue_Y, double blue_Z)) +PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr, + png_inforp info_ptr, png_fixed_point int_white_x, + png_fixed_point int_white_y, png_fixed_point int_red_x, + png_fixed_point int_red_y, png_fixed_point int_green_x, + png_fixed_point int_green_y, png_fixed_point int_blue_x, + png_fixed_point int_blue_y)) +PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr, + png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y, + png_fixed_point int_red_Z, png_fixed_point int_green_X, + png_fixed_point int_green_Y, png_fixed_point int_green_Z, + png_fixed_point int_blue_X, png_fixed_point int_blue_Y, + png_fixed_point int_blue_Z)) +#endif + +#ifdef PNG_gAMA_SUPPORTED +PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr, + png_const_inforp info_ptr, double *file_gamma)) +PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed, + (png_const_structrp png_ptr, png_const_inforp info_ptr, + png_fixed_point *int_file_gamma)) +#endif + +#ifdef PNG_gAMA_SUPPORTED +PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr, + png_inforp info_ptr, double file_gamma)) +PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr, + png_inforp info_ptr, png_fixed_point int_file_gamma)) +#endif + +#ifdef PNG_hIST_SUPPORTED +PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr, + png_inforp info_ptr, png_uint_16p *hist)); +#endif + +#ifdef PNG_hIST_SUPPORTED +PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_uint_16p hist)); +#endif + +PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr, + png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height, + int *bit_depth, int *color_type, int *interlace_method, + int *compression_method, int *filter_method)); + +PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr, + png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth, + int color_type, int interlace_method, int compression_method, + int filter_method)); + +#ifdef PNG_oFFs_SUPPORTED +PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr, + png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y, + int *unit_type)); +#endif + +#ifdef PNG_oFFs_SUPPORTED +PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr, + png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y, + int unit_type)); +#endif + +#ifdef PNG_pCAL_SUPPORTED +PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr, + png_inforp info_ptr, png_charp *purpose, png_int_32 *X0, + png_int_32 *X1, int *type, int *nparams, png_charp *units, + png_charpp *params)); +#endif + +#ifdef PNG_pCAL_SUPPORTED +PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1, + int type, int nparams, png_const_charp units, png_charpp params)); +#endif + +#ifdef PNG_pHYs_SUPPORTED +PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr, + png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, + int *unit_type)); +#endif + +#ifdef PNG_pHYs_SUPPORTED +PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr, + png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type)); +#endif + +PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr, + png_inforp info_ptr, png_colorp *palette, int *num_palette)); + +PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr, + png_inforp info_ptr, png_const_colorp palette, int num_palette)); + +#ifdef PNG_sBIT_SUPPORTED +PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr, + png_inforp info_ptr, png_color_8p *sig_bit)); +#endif + +#ifdef PNG_sBIT_SUPPORTED +PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_color_8p sig_bit)); +#endif + +#ifdef PNG_sRGB_SUPPORTED +PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr, + png_const_inforp info_ptr, int *file_srgb_intent)); +#endif + +#ifdef PNG_sRGB_SUPPORTED +PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr, + png_inforp info_ptr, int srgb_intent)); +PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr, + png_inforp info_ptr, int srgb_intent)); +#endif + +#ifdef PNG_iCCP_SUPPORTED +PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr, + png_inforp info_ptr, png_charpp name, int *compression_type, + png_bytepp profile, png_uint_32 *proflen)); +#endif + +#ifdef PNG_iCCP_SUPPORTED +PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_charp name, int compression_type, + png_const_bytep profile, png_uint_32 proflen)); +#endif + +#ifdef PNG_sPLT_SUPPORTED +PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr, + png_inforp info_ptr, png_sPLT_tpp entries)); +#endif + +#ifdef PNG_sPLT_SUPPORTED +PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)); +#endif + +#ifdef PNG_TEXT_SUPPORTED +/* png_get_text also returns the number of text chunks in *num_text */ +PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr, + png_inforp info_ptr, png_textp *text_ptr, int *num_text)); +#endif + +/* Note while png_set_text() will accept a structure whose text, + * language, and translated keywords are NULL pointers, the structure + * returned by png_get_text will always contain regular + * zero-terminated C strings. They might be empty strings but + * they will never be NULL pointers. + */ + +#ifdef PNG_TEXT_SUPPORTED +PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_textp text_ptr, int num_text)); +#endif + +#ifdef PNG_tIME_SUPPORTED +PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr, + png_inforp info_ptr, png_timep *mod_time)); +#endif + +#ifdef PNG_tIME_SUPPORTED +PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_timep mod_time)); +#endif + +#ifdef PNG_tRNS_SUPPORTED +PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr, + png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans, + png_color_16p *trans_color)); +#endif + +#ifdef PNG_tRNS_SUPPORTED +PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr, + png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans, + png_const_color_16p trans_color)); +#endif + +#ifdef PNG_sCAL_SUPPORTED +PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr, + png_const_inforp info_ptr, int *unit, double *width, double *height)) +#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \ + defined(PNG_FLOATING_POINT_SUPPORTED) +/* NOTE: this API is currently implemented using floating point arithmetic, + * consequently it can only be used on systems with floating point support. + * In any case the range of values supported by png_fixed_point is small and it + * is highly recommended that png_get_sCAL_s be used instead. + */ +PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed, + (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit, + png_fixed_point *width, png_fixed_point *height)) +#endif +PNG_EXPORT(169, png_uint_32, png_get_sCAL_s, + (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit, + png_charpp swidth, png_charpp sheight)); + +PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr, + png_inforp info_ptr, int unit, double width, double height)) +PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr, + png_inforp info_ptr, int unit, png_fixed_point width, + png_fixed_point height)) +PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr, + png_inforp info_ptr, int unit, + png_const_charp swidth, png_const_charp sheight)); +#endif /* PNG_sCAL_SUPPORTED */ + +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED +/* Provide the default handling for all unknown chunks or, optionally, for + * specific unknown chunks. + * + * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was + * ignored and the default was used, the per-chunk setting only had an effect on + * write. If you wish to have chunk-specific handling on read in code that must + * work on earlier versions you must use a user chunk callback to specify the + * desired handling (keep or discard.) + * + * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The + * parameter is interpreted as follows: + * + * READ: + * PNG_HANDLE_CHUNK_AS_DEFAULT: + * Known chunks: do normal libpng processing, do not keep the chunk (but + * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED) + * Unknown chunks: for a specific chunk use the global default, when used + * as the default discard the chunk data. + * PNG_HANDLE_CHUNK_NEVER: + * Discard the chunk data. + * PNG_HANDLE_CHUNK_IF_SAFE: + * Keep the chunk data if the chunk is not critical else raise a chunk + * error. + * PNG_HANDLE_CHUNK_ALWAYS: + * Keep the chunk data. + * + * If the chunk data is saved it can be retrieved using png_get_unknown_chunks, + * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent + * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks + * it simply resets the behavior to the libpng default. + * + * INTERACTION WTIH USER CHUNK CALLBACKS: + * The per-chunk handling is always used when there is a png_user_chunk_ptr + * callback and the callback returns 0; the chunk is then always stored *unless* + * it is critical and the per-chunk setting is other than ALWAYS. Notice that + * the global default is *not* used in this case. (In effect the per-chunk + * value is incremented to at least IF_SAFE.) + * + * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and + * per-chunk defaults will be honored. If you want to preserve the current + * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE + * as the default - if you don't do this libpng 1.6 will issue a warning. + * + * If you want unhandled unknown chunks to be discarded in libpng 1.6 and + * earlier simply return '1' (handled). + * + * PNG_HANDLE_AS_UNKNOWN_SUPPORTED: + * If this is *not* set known chunks will always be handled by libpng and + * will never be stored in the unknown chunk list. Known chunks listed to + * png_set_keep_unknown_chunks will have no effect. If it is set then known + * chunks listed with a keep other than AS_DEFAULT will *never* be processed + * by libpng, in addition critical chunks must either be processed by the + * callback or saved. + * + * The IHDR and IEND chunks must not be listed. Because this turns off the + * default handling for chunks that would otherwise be recognized the + * behavior of libpng transformations may well become incorrect! + * + * WRITE: + * When writing chunks the options only apply to the chunks specified by + * png_set_unknown_chunks (below), libpng will *always* write known chunks + * required by png_set_ calls and will always write the core critical chunks + * (as required for PLTE). + * + * Each chunk in the png_set_unknown_chunks list is looked up in the + * png_set_keep_unknown_chunks list to find the keep setting, this is then + * interpreted as follows: + * + * PNG_HANDLE_CHUNK_AS_DEFAULT: + * Write safe-to-copy chunks and write other chunks if the global + * default is set to _ALWAYS, otherwise don't write this chunk. + * PNG_HANDLE_CHUNK_NEVER: + * Do not write the chunk. + * PNG_HANDLE_CHUNK_IF_SAFE: + * Write the chunk if it is safe-to-copy, otherwise do not write it. + * PNG_HANDLE_CHUNK_ALWAYS: + * Write the chunk. + * + * Note that the default behavior is effectively the opposite of the read case - + * in read unknown chunks are not stored by default, in write they are written + * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different + * - on write the safe-to-copy bit is checked, on read the critical bit is + * checked and on read if the chunk is critical an error will be raised. + * + * num_chunks: + * =========== + * If num_chunks is positive, then the "keep" parameter specifies the manner + * for handling only those chunks appearing in the chunk_list array, + * otherwise the chunk list array is ignored. + * + * If num_chunks is 0 the "keep" parameter specifies the default behavior for + * unknown chunks, as described above. + * + * If num_chunks is negative, then the "keep" parameter specifies the manner + * for handling all unknown chunks plus all chunks recognized by libpng + * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to + * be processed by libpng. + */ +PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr, + int keep, png_const_bytep chunk_list, int num_chunks)); + +/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned; + * the result is therefore true (non-zero) if special handling is required, + * false for the default handling. + */ +PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr, + png_const_bytep chunk_name)); +#endif + +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED +PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr, + png_inforp info_ptr, png_const_unknown_chunkp unknowns, + int num_unknowns)); + /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added + * unknowns to the location currently stored in the png_struct. This is + * invariably the wrong value on write. To fix this call the following API + * for each chunk in the list with the correct location. If you know your + * code won't be compiled on earlier versions you can rely on + * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing + * the correct thing. + */ + +PNG_EXPORT(175, void, png_set_unknown_chunk_location, + (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location)); + +PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr, + png_inforp info_ptr, png_unknown_chunkpp entries)); +#endif + +/* Png_free_data() will turn off the "valid" flag for anything it frees. + * If you need to turn it off for a chunk that your application has freed, + * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK); + */ +PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr, + png_inforp info_ptr, int mask)); + +#ifdef PNG_INFO_IMAGE_SUPPORTED +/* The "params" pointer is currently not used and is for future expansion. */ +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr, + int transforms, png_voidp params)); +#endif +#ifdef PNG_WRITE_SUPPORTED +PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr, + int transforms, png_voidp params)); +#endif +#endif + +PNG_EXPORT(180, png_const_charp, png_get_copyright, + (png_const_structrp png_ptr)); +PNG_EXPORT(181, png_const_charp, png_get_header_ver, + (png_const_structrp png_ptr)); +PNG_EXPORT(182, png_const_charp, png_get_header_version, + (png_const_structrp png_ptr)); +PNG_EXPORT(183, png_const_charp, png_get_libpng_ver, + (png_const_structrp png_ptr)); + +#ifdef PNG_MNG_FEATURES_SUPPORTED +PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr, + png_uint_32 mng_features_permitted)); +#endif + +/* For use in png_set_keep_unknown, added to version 1.2.6 */ +#define PNG_HANDLE_CHUNK_AS_DEFAULT 0 +#define PNG_HANDLE_CHUNK_NEVER 1 +#define PNG_HANDLE_CHUNK_IF_SAFE 2 +#define PNG_HANDLE_CHUNK_ALWAYS 3 +#define PNG_HANDLE_CHUNK_LAST 4 + +/* Strip the prepended error numbers ("#nnn ") from error and warning + * messages before passing them to the error or warning handler. + */ +#ifdef PNG_ERROR_NUMBERS_SUPPORTED +PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr, + png_uint_32 strip_mode)); +#endif + +/* Added in libpng-1.2.6 */ +#ifdef PNG_SET_USER_LIMITS_SUPPORTED +PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr, + png_uint_32 user_width_max, png_uint_32 user_height_max)); +PNG_EXPORT(187, png_uint_32, png_get_user_width_max, + (png_const_structrp png_ptr)); +PNG_EXPORT(188, png_uint_32, png_get_user_height_max, + (png_const_structrp png_ptr)); +/* Added in libpng-1.4.0 */ +PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr, + png_uint_32 user_chunk_cache_max)); +PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max, + (png_const_structrp png_ptr)); +/* Added in libpng-1.4.1 */ +PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr, + png_alloc_size_t user_chunk_cache_max)); +PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max, + (png_const_structrp png_ptr)); +#endif + +#if defined(PNG_INCH_CONVERSIONS_SUPPORTED) +PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); + +PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); + +PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch, + (png_const_structrp png_ptr, png_const_inforp info_ptr)); + +PNG_FP_EXPORT(196, float, png_get_x_offset_inches, + (png_const_structrp png_ptr, png_const_inforp info_ptr)) +#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */ +PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed, + (png_const_structrp png_ptr, png_const_inforp info_ptr)) +#endif + +PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr, + png_const_inforp info_ptr)) +#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */ +PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed, + (png_const_structrp png_ptr, png_const_inforp info_ptr)) +#endif + +# ifdef PNG_pHYs_SUPPORTED +PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr, + png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, + int *unit_type)); +# endif /* PNG_pHYs_SUPPORTED */ +#endif /* PNG_INCH_CONVERSIONS_SUPPORTED */ + +/* Added in libpng-1.4.0 */ +#ifdef PNG_IO_STATE_SUPPORTED +PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr)); + +/* Removed from libpng 1.6; use png_get_io_chunk_type. */ +PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr), + PNG_DEPRECATED) + +PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type, + (png_const_structrp png_ptr)); + +/* The flags returned by png_get_io_state() are the following: */ +# define PNG_IO_NONE 0x0000 /* no I/O at this moment */ +# define PNG_IO_READING 0x0001 /* currently reading */ +# define PNG_IO_WRITING 0x0002 /* currently writing */ +# define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */ +# define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */ +# define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */ +# define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */ +# define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */ +# define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */ +#endif /* ?PNG_IO_STATE_SUPPORTED */ + +/* Interlace support. The following macros are always defined so that if + * libpng interlace handling is turned off the macros may be used to handle + * interlaced images within the application. + */ +#define PNG_INTERLACE_ADAM7_PASSES 7 + +/* Two macros to return the first row and first column of the original, + * full, image which appears in a given pass. 'pass' is in the range 0 + * to 6 and the result is in the range 0 to 7. + */ +#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7) +#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7) + +/* A macro to return the offset between pixels in the output row for a pair of + * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that + * follows. Note that ROW_OFFSET is the offset from one row to the next whereas + * COL_OFFSET is from one column to the next, within a row. + */ +#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8) +#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1)) + +/* Two macros to help evaluate the number of rows or columns in each + * pass. This is expressed as a shift - effectively log2 of the number or + * rows or columns in each 8x8 tile of the original image. + */ +#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3) +#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3) + +/* Hence two macros to determine the number of rows or columns in a given + * pass of an image given its height or width. In fact these macros may + * return non-zero even though the sub-image is empty, because the other + * dimension may be empty for a small image. + */ +#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\ + -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass)) +#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\ + -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass)) + +/* For the reader row callbacks (both progressive and sequential) it is + * necessary to find the row in the output image given a row in an interlaced + * image, so two more macros: + */ +#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \ + (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass)) +#define PNG_COL_FROM_PASS_COL(x_in, pass) \ + (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass)) + +/* Two macros which return a boolean (0 or 1) saying whether the given row + * or column is in a particular pass. These use a common utility macro that + * returns a mask for a given pass - the offset 'off' selects the row or + * column version. The mask has the appropriate bit set for each column in + * the tile. + */ +#define PNG_PASS_MASK(pass,off) ( \ + ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \ + ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0)) + +#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \ + ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1) +#define PNG_COL_IN_INTERLACE_PASS(x, pass) \ + ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1) + +#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED +/* With these routines we avoid an integer divide, which will be slower on + * most machines. However, it does take more operations than the corresponding + * divide method, so it may be slower on a few RISC systems. There are two + * shifts (by 8 or 16 bits) and an addition, versus a single integer divide. + * + * Note that the rounding factors are NOT supposed to be the same! 128 and + * 32768 are correct for the NODIV code; 127 and 32767 are correct for the + * standard method. + * + * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ] + */ + + /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */ + +# define png_composite(composite, fg, alpha, bg) \ + { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \ + * (png_uint_16)(alpha) \ + + (png_uint_16)(bg)*(png_uint_16)(255 \ + - (png_uint_16)(alpha)) + 128); \ + (composite) = (png_byte)((temp + (temp >> 8)) >> 8); } + +# define png_composite_16(composite, fg, alpha, bg) \ + { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \ + * (png_uint_32)(alpha) \ + + (png_uint_32)(bg)*(65535 \ + - (png_uint_32)(alpha)) + 32768); \ + (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); } + +#else /* Standard method using integer division */ + +# define png_composite(composite, fg, alpha, bg) \ + (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) + \ + (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \ + 127) / 255) + +# define png_composite_16(composite, fg, alpha, bg) \ + (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \ + (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \ + 32767) / 65535) +#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */ + +#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED +PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf)); +PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf)); +PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf)); +#endif + +PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr, + png_const_bytep buf)); +/* No png_get_int_16 -- may be added if there's a real need for it. */ + +/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */ +#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED +PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i)); +#endif +#ifdef PNG_SAVE_INT_32_SUPPORTED +PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i)); +#endif + +/* Place a 16-bit number into a buffer in PNG byte order. + * The parameter is declared unsigned int, not png_uint_16, + * just to avoid potential problems on pre-ANSI C compilers. + */ +#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED +PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i)); +/* No png_save_int_16 -- may be added if there's a real need for it. */ +#endif + +#ifdef PNG_USE_READ_MACROS +/* Inline macros to do direct reads of bytes from the input buffer. + * The png_get_int_32() routine assumes we are using two's complement + * format for negative values, which is almost certainly true. + */ +# define PNG_get_uint_32(buf) \ + (((png_uint_32)(*(buf)) << 24) + \ + ((png_uint_32)(*((buf) + 1)) << 16) + \ + ((png_uint_32)(*((buf) + 2)) << 8) + \ + ((png_uint_32)(*((buf) + 3)))) + + /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the + * function) incorrectly returned a value of type png_uint_32. + */ +# define PNG_get_uint_16(buf) \ + ((png_uint_16) \ + (((unsigned int)(*(buf)) << 8) + \ + ((unsigned int)(*((buf) + 1))))) + +# define PNG_get_int_32(buf) \ + ((png_int_32)((*(buf) & 0x80) \ + ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \ + : (png_int_32)png_get_uint_32(buf))) + + /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h, + * but defining a macro name prefixed with PNG_PREFIX. + */ +# ifndef PNG_PREFIX +# define png_get_uint_32(buf) PNG_get_uint_32(buf) +# define png_get_uint_16(buf) PNG_get_uint_16(buf) +# define png_get_int_32(buf) PNG_get_int_32(buf) +# endif +#else +# ifdef PNG_PREFIX + /* No macros; revert to the (redefined) function */ +# define PNG_get_uint_32 (png_get_uint_32) +# define PNG_get_uint_16 (png_get_uint_16) +# define PNG_get_int_32 (png_get_int_32) +# endif +#endif + +/******************************************************************************* + * SIMPLIFIED API + ******************************************************************************* + * + * Please read the documentation in libpng-manual.txt (TODO: write said + * documentation) if you don't understand what follows. + * + * The simplified API hides the details of both libpng and the PNG file format + * itself. It allows PNG files to be read into a very limited number of + * in-memory bitmap formats or to be written from the same formats. If these + * formats do not accomodate your needs then you can, and should, use the more + * sophisticated APIs above - these support a wide variety of in-memory formats + * and a wide variety of sophisticated transformations to those formats as well + * as a wide variety of APIs to manipulate ancillary information. + * + * To read a PNG file using the simplified API: + * + * 1) Declare a 'png_image' structure (see below) on the stack and set the + * version field to PNG_IMAGE_VERSION. + * 2) Call the appropriate png_image_begin_read... function. + * 3) Set the png_image 'format' member to the required sample format. + * 4) Allocate a buffer for the image and, if required, the color-map. + * 5) Call png_image_finish_read to read the image and, if required, the + * color-map into your buffers. + * + * There are no restrictions on the format of the PNG input itself; all valid + * color types, bit depths, and interlace methods are acceptable, and the + * input image is transformed as necessary to the requested in-memory format + * during the png_image_finish_read() step. The only caveat is that if you + * request a color-mapped image from a PNG that is full-color or makes + * complex use of an alpha channel the transformation is extremely lossy and the + * result may look terrible. + * + * To write a PNG file using the simplified API: + * + * 1) Declare a 'png_image' structure on the stack and memset() it to all zero. + * 2) Initialize the members of the structure that describe the image, setting + * the 'format' member to the format of the image samples. + * 3) Call the appropriate png_image_write... function with a pointer to the + * image and, if necessary, the color-map to write the PNG data. + * + * png_image is a structure that describes the in-memory format of an image + * when it is being read or defines the in-memory format of an image that you + * need to write: + */ +#define PNG_IMAGE_VERSION 1 + +typedef struct png_control *png_controlp; +typedef struct +{ + png_controlp opaque; /* Initialize to NULL, free with png_image_free */ + png_uint_32 version; /* Set to PNG_IMAGE_VERSION */ + png_uint_32 width; /* Image width in pixels (columns) */ + png_uint_32 height; /* Image height in pixels (rows) */ + png_uint_32 format; /* Image format as defined below */ + png_uint_32 flags; /* A bit mask containing informational flags */ + png_uint_32 colormap_entries; + /* Number of entries in the color-map */ + + /* In the event of an error or warning the following field will be set to a + * non-zero value and the 'message' field will contain a '\0' terminated + * string with the libpng error or warning message. If both warnings and + * an error were encountered, only the error is recorded. If there + * are multiple warnings, only the first one is recorded. + * + * The upper 30 bits of this value are reserved, the low two bits contain + * a value as follows: + */ +# define PNG_IMAGE_WARNING 1 +# define PNG_IMAGE_ERROR 2 + /* + * The result is a two bit code such that a value more than 1 indicates + * a failure in the API just called: + * + * 0 - no warning or error + * 1 - warning + * 2 - error + * 3 - error preceded by warning + */ +# define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1) + + png_uint_32 warning_or_error; + + char message[64]; +} png_image, *png_imagep; + +/* The samples of the image have one to four channels whose components have + * original values in the range 0 to 1.0: + * + * 1: A single gray or luminance channel (G). + * 2: A gray/luminance channel and an alpha channel (GA). + * 3: Three red, green, blue color channels (RGB). + * 4: Three color channels and an alpha channel (RGBA). + * + * The components are encoded in one of two ways: + * + * a) As a small integer, value 0..255, contained in a single byte. For the + * alpha channel the original value is simply value/255. For the color or + * luminance channels the value is encoded according to the sRGB specification + * and matches the 8-bit format expected by typical display devices. + * + * The color/gray channels are not scaled (pre-multiplied) by the alpha + * channel and are suitable for passing to color management software. + * + * b) As a value in the range 0..65535, contained in a 2-byte integer. All + * channels can be converted to the original value by dividing by 65535; all + * channels are linear. Color channels use the RGB encoding (RGB end-points) of + * the sRGB specification. This encoding is identified by the + * PNG_FORMAT_FLAG_LINEAR flag below. + * + * When the simplified API needs to convert between sRGB and linear colorspaces, + * the actual sRGB transfer curve defined in the sRGB specification (see the + * article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2 + * approximation used elsewhere in libpng. + * + * When an alpha channel is present it is expected to denote pixel coverage + * of the color or luminance channels and is returned as an associated alpha + * channel: the color/gray channels are scaled (pre-multiplied) by the alpha + * value. + * + * The samples are either contained directly in the image data, between 1 and 8 + * bytes per pixel according to the encoding, or are held in a color-map indexed + * by bytes in the image data. In the case of a color-map the color-map entries + * are individual samples, encoded as above, and the image data has one byte per + * pixel to select the relevant sample from the color-map. + */ + +/* PNG_FORMAT_* + * + * #defines to be used in png_image::format. Each #define identifies a + * particular layout of sample data and, if present, alpha values. There are + * separate defines for each of the two component encodings. + * + * A format is built up using single bit flag values. All combinations are + * valid. Formats can be built up from the flag values or you can use one of + * the predefined values below. When testing formats always use the FORMAT_FLAG + * macros to test for individual features - future versions of the library may + * add new flags. + * + * When reading or writing color-mapped images the format should be set to the + * format of the entries in the color-map then png_image_{read,write}_colormap + * called to read or write the color-map and set the format correctly for the + * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly! + * + * NOTE: libpng can be built with particular features disabled, if you see + * compiler errors because the definition of one of the following flags has been + * compiled out it is because libpng does not have the required support. It is + * possible, however, for the libpng configuration to enable the format on just + * read or just write; in that case you may see an error at run time. You can + * guard against this by checking for the definition of the appropriate + * "_SUPPORTED" macro, one of: + * + * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED + */ +#define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */ +#define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */ +#define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2 byte channels else 1 byte */ +#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */ + +#ifdef PNG_FORMAT_BGR_SUPPORTED +# define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */ +#endif + +#ifdef PNG_FORMAT_AFIRST_SUPPORTED +# define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */ +#endif + +/* Commonly used formats have predefined macros. + * + * First the single byte (sRGB) formats: + */ +#define PNG_FORMAT_GRAY 0 +#define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA +#define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST) +#define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR +#define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR) +#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA) +#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST) +#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA) +#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST) + +/* Then the linear 2-byte formats. When naming these "Y" is used to + * indicate a luminance (gray) channel. + */ +#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR +#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA) +#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR) +#define PNG_FORMAT_LINEAR_RGB_ALPHA \ + (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA) + +/* With color-mapped formats the image data is one byte for each pixel, the byte + * is an index into the color-map which is formatted as above. To obtain a + * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP + * to one of the above definitions, or you can use one of the definitions below. + */ +#define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP) +#define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP) +#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP) +#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP) +#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP) +#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP) + +/* PNG_IMAGE macros + * + * These are convenience macros to derive information from a png_image + * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the + * actual image sample values - either the entries in the color-map or the + * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values + * for the pixels and will always return 1 for color-mapped formats. The + * remaining macros return information about the rows in the image and the + * complete image. + * + * NOTE: All the macros that take a png_image::format parameter are compile time + * constants if the format parameter is, itself, a constant. Therefore these + * macros can be used in array declarations and case labels where required. + * Similarly the macros are also pre-processor constants (sizeof is not used) so + * they can be used in #if tests. + * + * First the information about the samples. + */ +#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\ + (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1) + /* Return the total number of channels in a given format: 1..4 */ + +#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\ + ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1) + /* Return the size in bytes of a single component of a pixel or color-map + * entry (as appropriate) in the image: 1 or 2. + */ + +#define PNG_IMAGE_SAMPLE_SIZE(fmt)\ + (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)) + /* This is the size of the sample data for one sample. If the image is + * color-mapped it is the size of one color-map entry (and image pixels are + * one byte in size), otherwise it is the size of one image pixel. + */ + +#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\ + (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256) + /* The maximum size of the color-map required by the format expressed in a + * count of components. This can be used to compile-time allocate a + * color-map: + * + * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)]; + * + * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)]; + * + * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the + * information from one of the png_image_begin_read_ APIs and dynamically + * allocate the required memory. + */ + +/* Corresponding information about the pixels */ +#define PNG_IMAGE_PIXEL_(test,fmt)\ + (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt)) + +#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\ + PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt) + /* The number of separate channels (components) in a pixel; 1 for a + * color-mapped image. + */ + +#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\ + PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt) + /* The size, in bytes, of each component in a pixel; 1 for a color-mapped + * image. + */ + +#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt) + /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */ + +/* Information about the whole row, or whole image */ +#define PNG_IMAGE_ROW_STRIDE(image)\ + (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width) + /* Return the total number of components in a single row of the image; this + * is the minimum 'row stride', the minimum count of components between each + * row. For a color-mapped image this is the minimum number of bytes in a + * row. + */ + +#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\ + (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride)) + /* Return the size, in bytes, of an image buffer given a png_image and a row + * stride - the number of components to leave space for in each row. + */ + +#define PNG_IMAGE_SIZE(image)\ + PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image)) + /* Return the size, in bytes, of the image in memory given just a png_image; + * the row stride is the minimum stride required for the image. + */ + +#define PNG_IMAGE_COLORMAP_SIZE(image)\ + (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries) + /* Return the size, in bytes, of the color-map of this image. If the image + * format is not a color-map format this will return a size sufficient for + * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if + * you don't want to allocate a color-map in this case. + */ + +/* PNG_IMAGE_FLAG_* + * + * Flags containing additional information about the image are held in the + * 'flags' field of png_image. + */ +#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01 + /* This indicates the the RGB values of the in-memory bitmap do not + * correspond to the red, green and blue end-points defined by sRGB. + */ + +#define PNG_IMAGE_FLAG_FAST 0x02 + /* On write emphasise speed over compression; the resultant PNG file will be + * larger but will be produced significantly faster, particular for large + * images. Do not use this option for images which will be distributed, only + * used it when producing intermediate files that will be read back in + * repeatedly. For a typical 24-bit image the option will double the read + * speed at the cost of increasing the image size by 25%, however for many + * more compressible images the PNG file can be 10 times larger with only a + * slight speed gain. + */ + +#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04 + /* On read if the image is a 16-bit per component image and there is no gAMA + * or sRGB chunk assume that the components are sRGB encoded. Notice that + * images output by the simplified API always have gamma information; setting + * this flag only affects the interpretation of 16-bit images from an + * external source. It is recommended that the application expose this flag + * to the user; the user can normally easily recognize the difference between + * linear and sRGB encoding. This flag has no effect on write - the data + * passed to the write APIs must have the correct encoding (as defined + * above.) + * + * If the flag is not set (the default) input 16-bit per component data is + * assumed to be linear. + * + * NOTE: the flag can only be set after the png_image_begin_read_ call, + * because that call initializes the 'flags' field. + */ + +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED +/* READ APIs + * --------- + * + * The png_image passed to the read APIs must have been initialized by setting + * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.) + */ +#ifdef PNG_STDIO_SUPPORTED +PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image, + const char *file_name)); + /* The named file is opened for read and the image header is filled in + * from the PNG header in the file. + */ + +PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image, + FILE* file)); + /* The PNG header is read from the stdio FILE object. */ +#endif /* PNG_STDIO_SUPPORTED */ + +PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image, + png_const_voidp memory, png_size_t size)); + /* The PNG header is read from the given memory buffer. */ + +PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image, + png_const_colorp background, void *buffer, png_int_32 row_stride, + void *colormap)); + /* Finish reading the image into the supplied buffer and clean up the + * png_image structure. + * + * row_stride is the step, in byte or 2-byte units as appropriate, + * between adjacent rows. A positive stride indicates that the top-most row + * is first in the buffer - the normal top-down arrangement. A negative + * stride indicates that the bottom-most row is first in the buffer. + * + * background need only be supplied if an alpha channel must be removed from + * a png_byte format and the removal is to be done by compositing on a solid + * color; otherwise it may be NULL and any composition will be done directly + * onto the buffer. The value is an sRGB color to use for the background, + * for grayscale output the green channel is used. + * + * background must be supplied when an alpha channel must be removed from a + * single byte color-mapped output format, in other words if: + * + * 1) The original format from png_image_begin_read_from_* had + * PNG_FORMAT_FLAG_ALPHA set. + * 2) The format set by the application does not. + * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and + * PNG_FORMAT_FLAG_LINEAR *not* set. + * + * For linear output removing the alpha channel is always done by compositing + * on black and background is ignored. + * + * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must + * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE. + * image->colormap_entries will be updated to the actual number of entries + * written to the colormap; this may be less than the original value. + */ + +PNG_EXPORT(238, void, png_image_free, (png_imagep image)); + /* Free any data allocated by libpng in image->opaque, setting the pointer to + * NULL. May be called at any time after the structure is initialized. + */ +#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */ + +#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED +#ifdef PNG_STDIO_SUPPORTED +/* WRITE APIS + * ---------- + * For write you must initialize a png_image structure to describe the image to + * be written. To do this use memset to set the whole structure to 0 then + * initialize fields describing your image. + * + * version: must be set to PNG_IMAGE_VERSION + * opaque: must be initialized to NULL + * width: image width in pixels + * height: image height in rows + * format: the format of the data (image and color-map) you wish to write + * flags: set to 0 unless one of the defined flags applies; set + * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB + * values do not correspond to the colors in sRGB. + * colormap_entries: set to the number of entries in the color-map (0 to 256) + */ +PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image, + const char *file, int convert_to_8bit, const void *buffer, + png_int_32 row_stride, const void *colormap)); + /* Write the image to the named file. */ + +PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file, + int convert_to_8_bit, const void *buffer, png_int_32 row_stride, + const void *colormap)); + /* Write the image to the given (FILE*). */ + +/* With both write APIs if image is in one of the linear formats with 16-bit + * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG + * gamma encoded according to the sRGB specification, otherwise a 16-bit linear + * encoded PNG file is written. + * + * With color-mapped data formats the colormap parameter point to a color-map + * with at least image->colormap_entries encoded in the specified format. If + * the format is linear the written PNG color-map will be converted to sRGB + * regardless of the convert_to_8_bit flag. + * + * With all APIs row_stride is handled as in the read APIs - it is the spacing + * from one row to the next in component sized units (1 or 2 bytes) and if + * negative indicates a bottom-up row layout in the buffer. + * + * Note that the write API does not support interlacing or sub-8-bit pixels. + */ +#endif /* PNG_STDIO_SUPPORTED */ +#endif /* PNG_SIMPLIFIED_WRITE_SUPPORTED */ +/******************************************************************************* + * END OF SIMPLIFIED API + ******************************************************************************/ + +#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED +PNG_EXPORT(242, void, png_set_check_for_invalid_index, + (png_structrp png_ptr, int allowed)); +# ifdef PNG_GET_PALETTE_MAX_SUPPORTED +PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr, + png_const_infop info_ptr)); +# endif +#endif /* CHECK_FOR_INVALID_INDEX */ + +/******************************************************************************* + * IMPLEMENTATION OPTIONS + ******************************************************************************* + * + * Support for arbitrary implementation-specific optimizations. The API allows + * particular options to be turned on or off. 'Option' is the number of the + * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given + * by the PNG_OPTION_ defines below. + * + * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions, + * are detected at run time, however sometimes it may be impossible + * to do this in user mode, in which case it is necessary to discover + * the capabilities in an OS specific way. Such capabilities are + * listed here when libpng has support for them and must be turned + * ON by the application if present. + * + * SOFTWARE: sometimes software optimizations actually result in performance + * decrease on some architectures or systems, or with some sets of + * PNG images. 'Software' options allow such optimizations to be + * selected at run time. + */ +#ifdef PNG_SET_OPTION_SUPPORTED +#ifdef PNG_ARM_NEON_API_SUPPORTED +# define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */ +#endif +#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */ +#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */ +#define PNG_OPTION_NEXT 6 /* Next option - numbers must be even */ + +/* Return values: NOTE: there are four values and 'off' is *not* zero */ +#define PNG_OPTION_UNSET 0 /* Unset - defaults to off */ +#define PNG_OPTION_INVALID 1 /* Option number out of range */ +#define PNG_OPTION_OFF 2 +#define PNG_OPTION_ON 3 + +PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option, + int onoff)); +#endif + +/******************************************************************************* + * END OF HARDWARE AND SOFTWARE OPTIONS + ******************************************************************************/ + +/* Maintainer: Put new public prototypes here ^, in libpng.3, and project + * defs, scripts/pnglibconf.h, and scripts/pnglibconf.h.prebuilt + */ + +/* The last ordinal number (this is the *last* one already used; the next + * one to use is one more than this.) Maintainer, remember to add an entry to + * scripts/symbols.def as well. + */ +#ifdef PNG_EXPORT_LAST_ORDINAL + PNG_EXPORT_LAST_ORDINAL(244); +#endif + +#ifdef __cplusplus +} +#endif + +#endif /* PNG_VERSION_INFO_ONLY */ +/* Do not put anything past this line */ +#endif /* PNG_H */ diff --git a/png/pngbar.jpg b/png/pngbar.jpg Binary files differnew file mode 100755 index 0000000..70ba8d8 --- /dev/null +++ b/png/pngbar.jpg diff --git a/png/pngbar.png b/png/pngbar.png Binary files differnew file mode 100755 index 0000000..49798c8 --- /dev/null +++ b/png/pngbar.png diff --git a/png/pngconf.h b/png/pngconf.h new file mode 100755 index 0000000..72ec81f --- /dev/null +++ b/png/pngconf.h @@ -0,0 +1,644 @@ + +/* pngconf.h - machine configurable file for libpng + * + * libpng version 1.6.12 - June 12, 2014 + * + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + */ + +/* Any machine specific code is near the front of this file, so if you + * are configuring libpng for a machine, you may want to read the section + * starting here down to where it starts to typedef png_color, png_text, + * and png_info. + */ + +#ifndef PNGCONF_H +#define PNGCONF_H + +/* To do: Do all of this in scripts/pnglibconf.dfa */ +#ifdef PNG_SAFE_LIMITS_SUPPORTED +# ifdef PNG_USER_WIDTH_MAX +# undef PNG_USER_WIDTH_MAX +# define PNG_USER_WIDTH_MAX 1000000L +# endif +# ifdef PNG_USER_HEIGHT_MAX +# undef PNG_USER_HEIGHT_MAX +# define PNG_USER_HEIGHT_MAX 1000000L +# endif +# ifdef PNG_USER_CHUNK_MALLOC_MAX +# undef PNG_USER_CHUNK_MALLOC_MAX +# define PNG_USER_CHUNK_MALLOC_MAX 4000000L +# endif +# ifdef PNG_USER_CHUNK_CACHE_MAX +# undef PNG_USER_CHUNK_CACHE_MAX +# define PNG_USER_CHUNK_CACHE_MAX 128 +# endif +#endif + +#ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */ + +/* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90") compliant C + * compiler for correct compilation. The following header files are required by + * the standard. If your compiler doesn't provide these header files, or they + * do not match the standard, you will need to provide/improve them. + */ +#include <limits.h> +#include <stddef.h> + +/* Library header files. These header files are all defined by ISOC90; libpng + * expects conformant implementations, however, an ISOC90 conformant system need + * not provide these header files if the functionality cannot be implemented. + * In this case it will be necessary to disable the relevant parts of libpng in + * the build of pnglibconf.h. + * + * Prior to 1.6.0 string.h was included here; the API changes in 1.6.0 to not + * include this unnecessary header file. + */ + +#ifdef PNG_STDIO_SUPPORTED + /* Required for the definition of FILE: */ +# include <stdio.h> +#endif + +#ifdef PNG_SETJMP_SUPPORTED + /* Required for the definition of jmp_buf and the declaration of longjmp: */ +# include <setjmp.h> +#endif + +#ifdef PNG_CONVERT_tIME_SUPPORTED + /* Required for struct tm: */ +# include <time.h> +#endif + +#endif /* PNG_BUILDING_SYMBOL_TABLE */ + +/* Prior to 1.6.0 it was possible to turn off 'const' in declarations using + * PNG_NO_CONST; this is no longer supported except for data declarations which + * apparently still cause problems in 2011 on some compilers. + */ +#define PNG_CONST const /* backward compatibility only */ + +/* This controls optimization of the reading of 16 and 32 bit values + * from PNG files. It can be set on a per-app-file basis - it + * just changes whether a macro is used when the function is called. + * The library builder sets the default; if read functions are not + * built into the library the macro implementation is forced on. + */ +#ifndef PNG_READ_INT_FUNCTIONS_SUPPORTED +# define PNG_USE_READ_MACROS +#endif +#if !defined(PNG_NO_USE_READ_MACROS) && !defined(PNG_USE_READ_MACROS) +# if PNG_DEFAULT_READ_MACROS +# define PNG_USE_READ_MACROS +# endif +#endif + +/* COMPILER SPECIFIC OPTIONS. + * + * These options are provided so that a variety of difficult compilers + * can be used. Some are fixed at build time (e.g. PNG_API_RULE + * below) but still have compiler specific implementations, others + * may be changed on a per-file basis when compiling against libpng. + */ + +/* The PNGARG macro was used in versions of libpng prior to 1.6.0 to protect + * against legacy (pre ISOC90) compilers that did not understand function + * prototypes. It is not required for modern C compilers. + */ +#ifndef PNGARG +# define PNGARG(arglist) arglist +#endif + +/* Function calling conventions. + * ============================= + * Normally it is not necessary to specify to the compiler how to call + * a function - it just does it - however on x86 systems derived from + * Microsoft and Borland C compilers ('IBM PC', 'DOS', 'Windows' systems + * and some others) there are multiple ways to call a function and the + * default can be changed on the compiler command line. For this reason + * libpng specifies the calling convention of every exported function and + * every function called via a user supplied function pointer. This is + * done in this file by defining the following macros: + * + * PNGAPI Calling convention for exported functions. + * PNGCBAPI Calling convention for user provided (callback) functions. + * PNGCAPI Calling convention used by the ANSI-C library (required + * for longjmp callbacks and sometimes used internally to + * specify the calling convention for zlib). + * + * These macros should never be overridden. If it is necessary to + * change calling convention in a private build this can be done + * by setting PNG_API_RULE (which defaults to 0) to one of the values + * below to select the correct 'API' variants. + * + * PNG_API_RULE=0 Use PNGCAPI - the 'C' calling convention - throughout. + * This is correct in every known environment. + * PNG_API_RULE=1 Use the operating system convention for PNGAPI and + * the 'C' calling convention (from PNGCAPI) for + * callbacks (PNGCBAPI). This is no longer required + * in any known environment - if it has to be used + * please post an explanation of the problem to the + * libpng mailing list. + * + * These cases only differ if the operating system does not use the C + * calling convention, at present this just means the above cases + * (x86 DOS/Windows sytems) and, even then, this does not apply to + * Cygwin running on those systems. + * + * Note that the value must be defined in pnglibconf.h so that what + * the application uses to call the library matches the conventions + * set when building the library. + */ + +/* Symbol export + * ============= + * When building a shared library it is almost always necessary to tell + * the compiler which symbols to export. The png.h macro 'PNG_EXPORT' + * is used to mark the symbols. On some systems these symbols can be + * extracted at link time and need no special processing by the compiler, + * on other systems the symbols are flagged by the compiler and just + * the declaration requires a special tag applied (unfortunately) in a + * compiler dependent way. Some systems can do either. + * + * A small number of older systems also require a symbol from a DLL to + * be flagged to the program that calls it. This is a problem because + * we do not know in the header file included by application code that + * the symbol will come from a shared library, as opposed to a statically + * linked one. For this reason the application must tell us by setting + * the magic flag PNG_USE_DLL to turn on the special processing before + * it includes png.h. + * + * Four additional macros are used to make this happen: + * + * PNG_IMPEXP The magic (if any) to cause a symbol to be exported from + * the build or imported if PNG_USE_DLL is set - compiler + * and system specific. + * + * PNG_EXPORT_TYPE(type) A macro that pre or appends PNG_IMPEXP to + * 'type', compiler specific. + * + * PNG_DLL_EXPORT Set to the magic to use during a libpng build to + * make a symbol exported from the DLL. Not used in the + * public header files; see pngpriv.h for how it is used + * in the libpng build. + * + * PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come + * from a DLL - used to define PNG_IMPEXP when + * PNG_USE_DLL is set. + */ + +/* System specific discovery. + * ========================== + * This code is used at build time to find PNG_IMPEXP, the API settings + * and PNG_EXPORT_TYPE(), it may also set a macro to indicate the DLL + * import processing is possible. On Windows systems it also sets + * compiler-specific macros to the values required to change the calling + * conventions of the various functions. + */ +#if defined(_Windows) || defined(_WINDOWS) || defined(WIN32) ||\ + defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__) + /* Windows system (DOS doesn't support DLLs). Includes builds under Cygwin or + * MinGW on any architecture currently supported by Windows. Also includes + * Watcom builds but these need special treatment because they are not + * compatible with GCC or Visual C because of different calling conventions. + */ +# if PNG_API_RULE == 2 + /* If this line results in an error, either because __watcall is not + * understood or because of a redefine just below you cannot use *this* + * build of the library with the compiler you are using. *This* build was + * build using Watcom and applications must also be built using Watcom! + */ +# define PNGCAPI __watcall +# endif + +# if defined(__GNUC__) || (defined(_MSC_VER) && (_MSC_VER >= 800)) +# define PNGCAPI __cdecl +# if PNG_API_RULE == 1 + /* If this line results in an error __stdcall is not understood and + * PNG_API_RULE should not have been set to '1'. + */ +# define PNGAPI __stdcall +# endif +# else + /* An older compiler, or one not detected (erroneously) above, + * if necessary override on the command line to get the correct + * variants for the compiler. + */ +# ifndef PNGCAPI +# define PNGCAPI _cdecl +# endif +# if PNG_API_RULE == 1 && !defined(PNGAPI) +# define PNGAPI _stdcall +# endif +# endif /* compiler/api */ + + /* NOTE: PNGCBAPI always defaults to PNGCAPI. */ + +# if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD) +# error "PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed" +# endif + +# if (defined(_MSC_VER) && _MSC_VER < 800) ||\ + (defined(__BORLANDC__) && __BORLANDC__ < 0x500) + /* older Borland and MSC + * compilers used '__export' and required this to be after + * the type. + */ +# ifndef PNG_EXPORT_TYPE +# define PNG_EXPORT_TYPE(type) type PNG_IMPEXP +# endif +# define PNG_DLL_EXPORT __export +# else /* newer compiler */ +# define PNG_DLL_EXPORT __declspec(dllexport) +# ifndef PNG_DLL_IMPORT +# define PNG_DLL_IMPORT __declspec(dllimport) +# endif +# endif /* compiler */ + +#else /* !Windows */ +# if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__) +# define PNGAPI _System +# else /* !Windows/x86 && !OS/2 */ + /* Use the defaults, or define PNG*API on the command line (but + * this will have to be done for every compile!) + */ +# endif /* other system, !OS/2 */ +#endif /* !Windows/x86 */ + +/* Now do all the defaulting . */ +#ifndef PNGCAPI +# define PNGCAPI +#endif +#ifndef PNGCBAPI +# define PNGCBAPI PNGCAPI +#endif +#ifndef PNGAPI +# define PNGAPI PNGCAPI +#endif + +/* PNG_IMPEXP may be set on the compilation system command line or (if not set) + * then in an internal header file when building the library, otherwise (when + * using the library) it is set here. + */ +#ifndef PNG_IMPEXP +# if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT) + /* This forces use of a DLL, disallowing static linking */ +# define PNG_IMPEXP PNG_DLL_IMPORT +# endif + +# ifndef PNG_IMPEXP +# define PNG_IMPEXP +# endif +#endif + +/* In 1.5.2 the definition of PNG_FUNCTION has been changed to always treat + * 'attributes' as a storage class - the attributes go at the start of the + * function definition, and attributes are always appended regardless of the + * compiler. This considerably simplifies these macros but may cause problems + * if any compilers both need function attributes and fail to handle them as + * a storage class (this is unlikely.) + */ +#ifndef PNG_FUNCTION +# define PNG_FUNCTION(type, name, args, attributes) attributes type name args +#endif + +#ifndef PNG_EXPORT_TYPE +# define PNG_EXPORT_TYPE(type) PNG_IMPEXP type +#endif + + /* The ordinal value is only relevant when preprocessing png.h for symbol + * table entries, so we discard it here. See the .dfn files in the + * scripts directory. + */ +#ifndef PNG_EXPORTA + +# define PNG_EXPORTA(ordinal, type, name, args, attributes)\ + PNG_FUNCTION(PNG_EXPORT_TYPE(type),(PNGAPI name),PNGARG(args), \ + extern attributes) +#endif + +/* ANSI-C (C90) does not permit a macro to be invoked with an empty argument, + * so make something non-empty to satisfy the requirement: + */ +#define PNG_EMPTY /*empty list*/ + +#define PNG_EXPORT(ordinal, type, name, args)\ + PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY) + +/* Use PNG_REMOVED to comment out a removed interface. */ +#ifndef PNG_REMOVED +# define PNG_REMOVED(ordinal, type, name, args, attributes) +#endif + +#ifndef PNG_CALLBACK +# define PNG_CALLBACK(type, name, args) type (PNGCBAPI name) PNGARG(args) +#endif + +/* Support for compiler specific function attributes. These are used + * so that where compiler support is available incorrect use of API + * functions in png.h will generate compiler warnings. + * + * Added at libpng-1.2.41. + */ + +#ifndef PNG_NO_PEDANTIC_WARNINGS +# ifndef PNG_PEDANTIC_WARNINGS_SUPPORTED +# define PNG_PEDANTIC_WARNINGS_SUPPORTED +# endif +#endif + +#ifdef PNG_PEDANTIC_WARNINGS_SUPPORTED + /* Support for compiler specific function attributes. These are used + * so that where compiler support is available, incorrect use of API + * functions in png.h will generate compiler warnings. Added at libpng + * version 1.2.41. Disabling these removes the warnings but may also produce + * less efficient code. + */ +# if defined(__clang__) && defined(__has_attribute) + /* Clang defines both __clang__ and __GNUC__. Check __clang__ first. */ +# if !defined(PNG_USE_RESULT) && __has_attribute(__warn_unused_result__) +# define PNG_USE_RESULT __attribute__((__warn_unused_result__)) +# endif +# if !defined(PNG_NORETURN) && __has_attribute(__noreturn__) +# define PNG_NORETURN __attribute__((__noreturn__)) +# endif +# if !defined(PNG_ALLOCATED) && __has_attribute(__malloc__) +# define PNG_ALLOCATED __attribute__((__malloc__)) +# endif +# if !defined(PNG_DEPRECATED) && __has_attribute(__deprecated__) +# define PNG_DEPRECATED __attribute__((__deprecated__)) +# endif +# if !defined(PNG_PRIVATE) +# ifdef __has_extension +# if __has_extension(attribute_unavailable_with_message) +# define PNG_PRIVATE __attribute__((__unavailable__(\ + "This function is not exported by libpng."))) +# endif +# endif +# endif +# ifndef PNG_RESTRICT +# define PNG_RESTRICT __restrict +# endif + +# elif defined(__GNUC__) +# ifndef PNG_USE_RESULT +# define PNG_USE_RESULT __attribute__((__warn_unused_result__)) +# endif +# ifndef PNG_NORETURN +# define PNG_NORETURN __attribute__((__noreturn__)) +# endif +# if __GNUC__ >= 3 +# ifndef PNG_ALLOCATED +# define PNG_ALLOCATED __attribute__((__malloc__)) +# endif +# ifndef PNG_DEPRECATED +# define PNG_DEPRECATED __attribute__((__deprecated__)) +# endif +# ifndef PNG_PRIVATE +# if 0 /* Doesn't work so we use deprecated instead*/ +# define PNG_PRIVATE \ + __attribute__((warning("This function is not exported by libpng."))) +# else +# define PNG_PRIVATE \ + __attribute__((__deprecated__)) +# endif +# endif +# if ((__GNUC__ > 3) || !defined(__GNUC_MINOR__) || (__GNUC_MINOR__ >= 1)) +# ifndef PNG_RESTRICT +# define PNG_RESTRICT __restrict +# endif +# endif /* __GNUC__.__GNUC_MINOR__ > 3.0 */ +# endif /* __GNUC__ >= 3 */ + +# elif defined(_MSC_VER) && (_MSC_VER >= 1300) +# ifndef PNG_USE_RESULT +# define PNG_USE_RESULT /* not supported */ +# endif +# ifndef PNG_NORETURN +# define PNG_NORETURN __declspec(noreturn) +# endif +# ifndef PNG_ALLOCATED +# if (_MSC_VER >= 1400) +# define PNG_ALLOCATED __declspec(restrict) +# endif +# endif +# ifndef PNG_DEPRECATED +# define PNG_DEPRECATED __declspec(deprecated) +# endif +# ifndef PNG_PRIVATE +# define PNG_PRIVATE __declspec(deprecated) +# endif +# ifndef PNG_RESTRICT +# if (_MSC_VER >= 1400) +# define PNG_RESTRICT __restrict +# endif +# endif + +# elif defined(__WATCOMC__) +# ifndef PNG_RESTRICT +# define PNG_RESTRICT __restrict +# endif +# endif +#endif /* PNG_PEDANTIC_WARNINGS */ + +#ifndef PNG_DEPRECATED +# define PNG_DEPRECATED /* Use of this function is deprecated */ +#endif +#ifndef PNG_USE_RESULT +# define PNG_USE_RESULT /* The result of this function must be checked */ +#endif +#ifndef PNG_NORETURN +# define PNG_NORETURN /* This function does not return */ +#endif +#ifndef PNG_ALLOCATED +# define PNG_ALLOCATED /* The result of the function is new memory */ +#endif +#ifndef PNG_PRIVATE +# define PNG_PRIVATE /* This is a private libpng function */ +#endif +#ifndef PNG_RESTRICT +# define PNG_RESTRICT /* The C99 "restrict" feature */ +#endif + +#ifndef PNG_FP_EXPORT /* A floating point API. */ +# ifdef PNG_FLOATING_POINT_SUPPORTED +# define PNG_FP_EXPORT(ordinal, type, name, args)\ + PNG_EXPORT(ordinal, type, name, args); +# else /* No floating point APIs */ +# define PNG_FP_EXPORT(ordinal, type, name, args) +# endif +#endif +#ifndef PNG_FIXED_EXPORT /* A fixed point API. */ +# ifdef PNG_FIXED_POINT_SUPPORTED +# define PNG_FIXED_EXPORT(ordinal, type, name, args)\ + PNG_EXPORT(ordinal, type, name, args); +# else /* No fixed point APIs */ +# define PNG_FIXED_EXPORT(ordinal, type, name, args) +# endif +#endif + +#ifndef PNG_BUILDING_SYMBOL_TABLE +/* Some typedefs to get us started. These should be safe on most of the common + * platforms. + * + * png_uint_32 and png_int_32 may, currently, be larger than required to hold a + * 32-bit value however this is not normally advisable. + * + * png_uint_16 and png_int_16 should always be two bytes in size - this is + * verified at library build time. + * + * png_byte must always be one byte in size. + * + * The checks below use constants from limits.h, as defined by the ISOC90 + * standard. + */ +#if CHAR_BIT == 8 && UCHAR_MAX == 255 + typedef unsigned char png_byte; +#else +# error "libpng requires 8 bit bytes" +#endif + +#if INT_MIN == -32768 && INT_MAX == 32767 + typedef int png_int_16; +#elif SHRT_MIN == -32768 && SHRT_MAX == 32767 + typedef short png_int_16; +#else +# error "libpng requires a signed 16 bit type" +#endif + +#if UINT_MAX == 65535 + typedef unsigned int png_uint_16; +#elif USHRT_MAX == 65535 + typedef unsigned short png_uint_16; +#else +# error "libpng requires an unsigned 16 bit type" +#endif + +#if INT_MIN < -2147483646 && INT_MAX > 2147483646 + typedef int png_int_32; +#elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646 + typedef long int png_int_32; +#else +# error "libpng requires a signed 32 bit (or more) type" +#endif + +#if UINT_MAX > 4294967294 + typedef unsigned int png_uint_32; +#elif ULONG_MAX > 4294967294 + typedef unsigned long int png_uint_32; +#else +# error "libpng requires an unsigned 32 bit (or more) type" +#endif + +/* Prior to 1.6.0 it was possible to disable the use of size_t, 1.6.0, however, + * requires an ISOC90 compiler and relies on consistent behavior of sizeof. + */ +typedef size_t png_size_t; +typedef ptrdiff_t png_ptrdiff_t; + +/* libpng needs to know the maximum value of 'size_t' and this controls the + * definition of png_alloc_size_t, below. This maximum value of size_t limits + * but does not control the maximum allocations the library makes - there is + * direct application control of this through png_set_user_limits(). + */ +#ifndef PNG_SMALL_SIZE_T + /* Compiler specific tests for systems where size_t is known to be less than + * 32 bits (some of these systems may no longer work because of the lack of + * 'far' support; see above.) + */ +# if (defined(__TURBOC__) && !defined(__FLAT__)) ||\ + (defined(_MSC_VER) && defined(MAXSEG_64K)) +# define PNG_SMALL_SIZE_T +# endif +#endif + +/* png_alloc_size_t is guaranteed to be no smaller than png_size_t, and no + * smaller than png_uint_32. Casts from png_size_t or png_uint_32 to + * png_alloc_size_t are not necessary; in fact, it is recommended not to use + * them at all so that the compiler can complain when something turns out to be + * problematic. + * + * Casts in the other direction (from png_alloc_size_t to png_size_t or + * png_uint_32) should be explicitly applied; however, we do not expect to + * encounter practical situations that require such conversions. + * + * PNG_SMALL_SIZE_T must be defined if the maximum value of size_t is less than + * 4294967295 - i.e. less than the maximum value of png_uint_32. + */ +#ifdef PNG_SMALL_SIZE_T + typedef png_uint_32 png_alloc_size_t; +#else + typedef png_size_t png_alloc_size_t; +#endif + +/* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler + * implementations of Intel CPU specific support of user-mode segmented address + * spaces, where 16-bit pointers address more than 65536 bytes of memory using + * separate 'segment' registers. The implementation requires two different + * types of pointer (only one of which includes the segment value.) + * + * If required this support is available in version 1.2 of libpng and may be + * available in versions through 1.5, although the correctness of the code has + * not been verified recently. + */ + +/* Typedef for floating-point numbers that are converted to fixed-point with a + * multiple of 100,000, e.g., gamma + */ +typedef png_int_32 png_fixed_point; + +/* Add typedefs for pointers */ +typedef void * png_voidp; +typedef const void * png_const_voidp; +typedef png_byte * png_bytep; +typedef const png_byte * png_const_bytep; +typedef png_uint_32 * png_uint_32p; +typedef const png_uint_32 * png_const_uint_32p; +typedef png_int_32 * png_int_32p; +typedef const png_int_32 * png_const_int_32p; +typedef png_uint_16 * png_uint_16p; +typedef const png_uint_16 * png_const_uint_16p; +typedef png_int_16 * png_int_16p; +typedef const png_int_16 * png_const_int_16p; +typedef char * png_charp; +typedef const char * png_const_charp; +typedef png_fixed_point * png_fixed_point_p; +typedef const png_fixed_point * png_const_fixed_point_p; +typedef png_size_t * png_size_tp; +typedef const png_size_t * png_const_size_tp; + +#ifdef PNG_STDIO_SUPPORTED +typedef FILE * png_FILE_p; +#endif + +#ifdef PNG_FLOATING_POINT_SUPPORTED +typedef double * png_doublep; +typedef const double * png_const_doublep; +#endif + +/* Pointers to pointers; i.e. arrays */ +typedef png_byte * * png_bytepp; +typedef png_uint_32 * * png_uint_32pp; +typedef png_int_32 * * png_int_32pp; +typedef png_uint_16 * * png_uint_16pp; +typedef png_int_16 * * png_int_16pp; +typedef const char * * png_const_charpp; +typedef char * * png_charpp; +typedef png_fixed_point * * png_fixed_point_pp; +#ifdef PNG_FLOATING_POINT_SUPPORTED +typedef double * * png_doublepp; +#endif + +/* Pointers to pointers to pointers; i.e., pointer to array */ +typedef char * * * png_charppp; + +#endif /* PNG_BUILDING_SYMBOL_TABLE */ + +#endif /* PNGCONF_H */ diff --git a/png/pngdebug.h b/png/pngdebug.h new file mode 100755 index 0000000..b43c59c --- /dev/null +++ b/png/pngdebug.h @@ -0,0 +1,154 @@ + +/* pngdebug.h - Debugging macros for libpng, also used in pngtest.c + * + * Copyright (c) 1998-2013 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * Last changed in libpng 1.6.8 [December 19, 2013] + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +/* Define PNG_DEBUG at compile time for debugging information. Higher + * numbers for PNG_DEBUG mean more debugging information. This has + * only been added since version 0.95 so it is not implemented throughout + * libpng yet, but more support will be added as needed. + * + * png_debug[1-2]?(level, message ,arg{0-2}) + * Expands to a statement (either a simple expression or a compound + * do..while(0) statement) that outputs a message with parameter + * substitution if PNG_DEBUG is defined to 2 or more. If PNG_DEBUG + * is undefined, 0 or 1 every png_debug expands to a simple expression + * (actually ((void)0)). + * + * level: level of detail of message, starting at 0. A level 'n' + * message is preceded by 'n' 3-space indentations (not implemented + * on Microsoft compilers unless PNG_DEBUG_FILE is also + * defined, to allow debug DLL compilation with no standard IO). + * message: a printf(3) style text string. A trailing '\n' is added + * to the message. + * arg: 0 to 2 arguments for printf(3) style substitution in message. + */ +#ifndef PNGDEBUG_H +#define PNGDEBUG_H +/* These settings control the formatting of messages in png.c and pngerror.c */ +/* Moved to pngdebug.h at 1.5.0 */ +# ifndef PNG_LITERAL_SHARP +# define PNG_LITERAL_SHARP 0x23 +# endif +# ifndef PNG_LITERAL_LEFT_SQUARE_BRACKET +# define PNG_LITERAL_LEFT_SQUARE_BRACKET 0x5b +# endif +# ifndef PNG_LITERAL_RIGHT_SQUARE_BRACKET +# define PNG_LITERAL_RIGHT_SQUARE_BRACKET 0x5d +# endif +# ifndef PNG_STRING_NEWLINE +# define PNG_STRING_NEWLINE "\n" +# endif + +#ifdef PNG_DEBUG +# if (PNG_DEBUG > 0) +# if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER) +# include <crtdbg.h> +# if (PNG_DEBUG > 1) +# ifndef _DEBUG +# define _DEBUG +# endif +# ifndef png_debug +# define png_debug(l,m) _RPT0(_CRT_WARN,m PNG_STRING_NEWLINE) +# endif +# ifndef png_debug1 +# define png_debug1(l,m,p1) _RPT1(_CRT_WARN,m PNG_STRING_NEWLINE,p1) +# endif +# ifndef png_debug2 +# define png_debug2(l,m,p1,p2) \ + _RPT2(_CRT_WARN,m PNG_STRING_NEWLINE,p1,p2) +# endif +# endif +# else /* PNG_DEBUG_FILE || !_MSC_VER */ +# ifndef PNG_STDIO_SUPPORTED +# include <stdio.h> /* not included yet */ +# endif +# ifndef PNG_DEBUG_FILE +# define PNG_DEBUG_FILE stderr +# endif /* PNG_DEBUG_FILE */ + +# if (PNG_DEBUG > 1) +# ifdef __STDC__ +# ifndef png_debug +# define png_debug(l,m) \ + do { \ + int num_tabs=l; \ + fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? " " : \ + (num_tabs==2 ? " " : (num_tabs>2 ? " " : "")))); \ + } while (0) +# endif +# ifndef png_debug1 +# define png_debug1(l,m,p1) \ + do { \ + int num_tabs=l; \ + fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? " " : \ + (num_tabs==2 ? " " : (num_tabs>2 ? " " : ""))),p1); \ + } while (0) +# endif +# ifndef png_debug2 +# define png_debug2(l,m,p1,p2) \ + do { \ + int num_tabs=l; \ + fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? " " : \ + (num_tabs==2 ? " " : (num_tabs>2 ? " " : ""))),p1,p2);\ + } while (0) +# endif +# else /* __STDC __ */ +# ifndef png_debug +# define png_debug(l,m) \ + do { \ + int num_tabs=l; \ + char format[256]; \ + snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \ + (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \ + m,PNG_STRING_NEWLINE); \ + fprintf(PNG_DEBUG_FILE,format); \ + } while (0) +# endif +# ifndef png_debug1 +# define png_debug1(l,m,p1) \ + do { \ + int num_tabs=l; \ + char format[256]; \ + snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \ + (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \ + m,PNG_STRING_NEWLINE); \ + fprintf(PNG_DEBUG_FILE,format,p1); \ + } while (0) +# endif +# ifndef png_debug2 +# define png_debug2(l,m,p1,p2) \ + do { \ + int num_tabs=l; \ + char format[256]; \ + snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \ + (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \ + m,PNG_STRING_NEWLINE); \ + fprintf(PNG_DEBUG_FILE,format,p1,p2); \ + } while (0) +# endif +# endif /* __STDC __ */ +# endif /* (PNG_DEBUG > 1) */ + +# endif /* _MSC_VER */ +# endif /* (PNG_DEBUG > 0) */ +#endif /* PNG_DEBUG */ +#ifndef png_debug +# define png_debug(l, m) ((void)0) +#endif +#ifndef png_debug1 +# define png_debug1(l, m, p1) ((void)0) +#endif +#ifndef png_debug2 +# define png_debug2(l, m, p1, p2) ((void)0) +#endif +#endif /* PNGDEBUG_H */ diff --git a/png/pngerror.c b/png/pngerror.c new file mode 100755 index 0000000..f21f4dd --- /dev/null +++ b/png/pngerror.c @@ -0,0 +1,961 @@ + +/* pngerror.c - stub functions for i/o and memory allocation + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * This file provides a location for all error handling. Users who + * need special error handling are expected to write replacement functions + * and use png_set_error_fn() to use those functions. See the instructions + * at each function. + */ + +#include "pngpriv.h" + +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) + +static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr, + png_const_charp error_message)),PNG_NORETURN); + +#ifdef PNG_WARNINGS_SUPPORTED +static void /* PRIVATE */ +png_default_warning PNGARG((png_const_structrp png_ptr, + png_const_charp warning_message)); +#endif /* PNG_WARNINGS_SUPPORTED */ + +/* This function is called whenever there is a fatal error. This function + * should not be changed. If there is a need to handle errors differently, + * you should supply a replacement error function and use png_set_error_fn() + * to replace the error function at run-time. + */ +#ifdef PNG_ERROR_TEXT_SUPPORTED +PNG_FUNCTION(void,PNGAPI +png_error,(png_const_structrp png_ptr, png_const_charp error_message), + PNG_NORETURN) +{ +#ifdef PNG_ERROR_NUMBERS_SUPPORTED + char msg[16]; + if (png_ptr != NULL) + { + if (png_ptr->flags& + (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) + { + if (*error_message == PNG_LITERAL_SHARP) + { + /* Strip "#nnnn " from beginning of error message. */ + int offset; + for (offset = 1; offset<15; offset++) + if (error_message[offset] == ' ') + break; + + if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT) + { + int i; + for (i = 0; i < offset - 1; i++) + msg[i] = error_message[i + 1]; + msg[i - 1] = '\0'; + error_message = msg; + } + + else + error_message += offset; + } + + else + { + if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT) + { + msg[0] = '0'; + msg[1] = '\0'; + error_message = msg; + } + } + } + } +#endif + if (png_ptr != NULL && png_ptr->error_fn != NULL) + (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), + error_message); + + /* If the custom handler doesn't exist, or if it returns, + use the default handler, which will not return. */ + png_default_error(png_ptr, error_message); +} +#else +PNG_FUNCTION(void,PNGAPI +png_err,(png_const_structrp png_ptr),PNG_NORETURN) +{ + /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed + * erroneously as '\0', instead of the empty string "". This was + * apparently an error, introduced in libpng-1.2.20, and png_default_error + * will crash in this case. + */ + if (png_ptr != NULL && png_ptr->error_fn != NULL) + (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), ""); + + /* If the custom handler doesn't exist, or if it returns, + use the default handler, which will not return. */ + png_default_error(png_ptr, ""); +} +#endif /* PNG_ERROR_TEXT_SUPPORTED */ + +/* Utility to safely appends strings to a buffer. This never errors out so + * error checking is not required in the caller. + */ +size_t +png_safecat(png_charp buffer, size_t bufsize, size_t pos, + png_const_charp string) +{ + if (buffer != NULL && pos < bufsize) + { + if (string != NULL) + while (*string != '\0' && pos < bufsize-1) + buffer[pos++] = *string++; + + buffer[pos] = '\0'; + } + + return pos; +} + +#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED) +/* Utility to dump an unsigned value into a buffer, given a start pointer and + * and end pointer (which should point just *beyond* the end of the buffer!) + * Returns the pointer to the start of the formatted string. + */ +png_charp +png_format_number(png_const_charp start, png_charp end, int format, + png_alloc_size_t number) +{ + int count = 0; /* number of digits output */ + int mincount = 1; /* minimum number required */ + int output = 0; /* digit output (for the fixed point format) */ + + *--end = '\0'; + + /* This is written so that the loop always runs at least once, even with + * number zero. + */ + while (end > start && (number != 0 || count < mincount)) + { + + static const char digits[] = "0123456789ABCDEF"; + + switch (format) + { + case PNG_NUMBER_FORMAT_fixed: + /* Needs five digits (the fraction) */ + mincount = 5; + if (output || number % 10 != 0) + { + *--end = digits[number % 10]; + output = 1; + } + number /= 10; + break; + + case PNG_NUMBER_FORMAT_02u: + /* Expects at least 2 digits. */ + mincount = 2; + /* FALL THROUGH */ + + case PNG_NUMBER_FORMAT_u: + *--end = digits[number % 10]; + number /= 10; + break; + + case PNG_NUMBER_FORMAT_02x: + /* This format expects at least two digits */ + mincount = 2; + /* FALL THROUGH */ + + case PNG_NUMBER_FORMAT_x: + *--end = digits[number & 0xf]; + number >>= 4; + break; + + default: /* an error */ + number = 0; + break; + } + + /* Keep track of the number of digits added */ + ++count; + + /* Float a fixed number here: */ + if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start) + { + /* End of the fraction, but maybe nothing was output? In that case + * drop the decimal point. If the number is a true zero handle that + * here. + */ + if (output != 0) + *--end = '.'; + else if (number == 0) /* and !output */ + *--end = '0'; + } + } + + return end; +} +#endif + +#ifdef PNG_WARNINGS_SUPPORTED +/* This function is called whenever there is a non-fatal error. This function + * should not be changed. If there is a need to handle warnings differently, + * you should supply a replacement warning function and use + * png_set_error_fn() to replace the warning function at run-time. + */ +void PNGAPI +png_warning(png_const_structrp png_ptr, png_const_charp warning_message) +{ + int offset = 0; + if (png_ptr != NULL) + { +#ifdef PNG_ERROR_NUMBERS_SUPPORTED + if (png_ptr->flags& + (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) +#endif + { + if (*warning_message == PNG_LITERAL_SHARP) + { + for (offset = 1; offset < 15; offset++) + if (warning_message[offset] == ' ') + break; + } + } + } + if (png_ptr != NULL && png_ptr->warning_fn != NULL) + (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr), + warning_message + offset); + else + png_default_warning(png_ptr, warning_message + offset); +} + +/* These functions support 'formatted' warning messages with up to + * PNG_WARNING_PARAMETER_COUNT parameters. In the format string the parameter + * is introduced by @<number>, where 'number' starts at 1. This follows the + * standard established by X/Open for internationalizable error messages. + */ +void +png_warning_parameter(png_warning_parameters p, int number, + png_const_charp string) +{ + if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT) + (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string); +} + +void +png_warning_parameter_unsigned(png_warning_parameters p, int number, int format, + png_alloc_size_t value) +{ + char buffer[PNG_NUMBER_BUFFER_SIZE]; + png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value)); +} + +void +png_warning_parameter_signed(png_warning_parameters p, int number, int format, + png_int_32 value) +{ + png_alloc_size_t u; + png_charp str; + char buffer[PNG_NUMBER_BUFFER_SIZE]; + + /* Avoid overflow by doing the negate in a png_alloc_size_t: */ + u = (png_alloc_size_t)value; + if (value < 0) + u = ~u + 1; + + str = PNG_FORMAT_NUMBER(buffer, format, u); + + if (value < 0 && str > buffer) + *--str = '-'; + + png_warning_parameter(p, number, str); +} + +void +png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p, + png_const_charp message) +{ + /* The internal buffer is just 192 bytes - enough for all our messages, + * overflow doesn't happen because this code checks! If someone figures + * out how to send us a message longer than 192 bytes, all that will + * happen is that the message will be truncated appropriately. + */ + size_t i = 0; /* Index in the msg[] buffer: */ + char msg[192]; + + /* Each iteration through the following loop writes at most one character + * to msg[i++] then returns here to validate that there is still space for + * the trailing '\0'. It may (in the case of a parameter) read more than + * one character from message[]; it must check for '\0' and continue to the + * test if it finds the end of string. + */ + while (i<(sizeof msg)-1 && *message != '\0') + { + /* '@' at end of string is now just printed (previously it was skipped); + * it is an error in the calling code to terminate the string with @. + */ + if (p != NULL && *message == '@' && message[1] != '\0') + { + int parameter_char = *++message; /* Consume the '@' */ + static const char valid_parameters[] = "123456789"; + int parameter = 0; + + /* Search for the parameter digit, the index in the string is the + * parameter to use. + */ + while (valid_parameters[parameter] != parameter_char && + valid_parameters[parameter] != '\0') + ++parameter; + + /* If the parameter digit is out of range it will just get printed. */ + if (parameter < PNG_WARNING_PARAMETER_COUNT) + { + /* Append this parameter */ + png_const_charp parm = p[parameter]; + png_const_charp pend = p[parameter] + (sizeof p[parameter]); + + /* No need to copy the trailing '\0' here, but there is no guarantee + * that parm[] has been initialized, so there is no guarantee of a + * trailing '\0': + */ + while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend) + msg[i++] = *parm++; + + /* Consume the parameter digit too: */ + ++message; + continue; + } + + /* else not a parameter and there is a character after the @ sign; just + * copy that. This is known not to be '\0' because of the test above. + */ + } + + /* At this point *message can't be '\0', even in the bad parameter case + * above where there is a lone '@' at the end of the message string. + */ + msg[i++] = *message++; + } + + /* i is always less than (sizeof msg), so: */ + msg[i] = '\0'; + + /* And this is the formatted message. It may be larger than + * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these + * are not (currently) formatted. + */ + png_warning(png_ptr, msg); +} +#endif /* PNG_WARNINGS_SUPPORTED */ + +#ifdef PNG_BENIGN_ERRORS_SUPPORTED +void PNGAPI +png_benign_error(png_const_structrp png_ptr, png_const_charp error_message) +{ + if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) + { +# ifdef PNG_READ_SUPPORTED + if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && + png_ptr->chunk_name != 0) + png_chunk_warning(png_ptr, error_message); + else +# endif + png_warning(png_ptr, error_message); + } + + else + { +# ifdef PNG_READ_SUPPORTED + if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && + png_ptr->chunk_name != 0) + png_chunk_error(png_ptr, error_message); + else +# endif + png_error(png_ptr, error_message); + } + +# ifndef PNG_ERROR_TEXT_SUPPORTED + PNG_UNUSED(error_message) +# endif +} + +void /* PRIVATE */ +png_app_warning(png_const_structrp png_ptr, png_const_charp error_message) +{ + if (png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) + png_warning(png_ptr, error_message); + else + png_error(png_ptr, error_message); + +# ifndef PNG_ERROR_TEXT_SUPPORTED + PNG_UNUSED(error_message) +# endif +} + +void /* PRIVATE */ +png_app_error(png_const_structrp png_ptr, png_const_charp error_message) +{ + if (png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) + png_warning(png_ptr, error_message); + else + png_error(png_ptr, error_message); + +# ifndef PNG_ERROR_TEXT_SUPPORTED + PNG_UNUSED(error_message) +# endif +} +#endif /* BENIGN_ERRORS */ + +/* These utilities are used internally to build an error message that relates + * to the current chunk. The chunk name comes from png_ptr->chunk_name, + * this is used to prefix the message. The message is limited in length + * to 63 bytes, the name characters are output as hex digits wrapped in [] + * if the character is invalid. + */ +#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) +static PNG_CONST char png_digit[16] = { + '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', + 'A', 'B', 'C', 'D', 'E', 'F' +}; + +#define PNG_MAX_ERROR_TEXT 196 /* Currently limited be profile_error in png.c */ +#if defined(PNG_WARNINGS_SUPPORTED) || \ + (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)) +static void /* PRIVATE */ +png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp + error_message) +{ + png_uint_32 chunk_name = png_ptr->chunk_name; + int iout = 0, ishift = 24; + + while (ishift >= 0) + { + int c = (int)(chunk_name >> ishift) & 0xff; + + ishift -= 8; + if (isnonalpha(c)) + { + buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET; + buffer[iout++] = png_digit[(c & 0xf0) >> 4]; + buffer[iout++] = png_digit[c & 0x0f]; + buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET; + } + + else + { + buffer[iout++] = (char)c; + } + } + + if (error_message == NULL) + buffer[iout] = '\0'; + + else + { + int iin = 0; + + buffer[iout++] = ':'; + buffer[iout++] = ' '; + + while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0') + buffer[iout++] = error_message[iin++]; + + /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */ + buffer[iout] = '\0'; + } +} +#endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */ + +#if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED) +PNG_FUNCTION(void,PNGAPI +png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message), + PNG_NORETURN) +{ + char msg[18+PNG_MAX_ERROR_TEXT]; + if (png_ptr == NULL) + png_error(png_ptr, error_message); + + else + { + png_format_buffer(png_ptr, msg, error_message); + png_error(png_ptr, msg); + } +} +#endif /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */ + +#ifdef PNG_WARNINGS_SUPPORTED +void PNGAPI +png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message) +{ + char msg[18+PNG_MAX_ERROR_TEXT]; + if (png_ptr == NULL) + png_warning(png_ptr, warning_message); + + else + { + png_format_buffer(png_ptr, msg, warning_message); + png_warning(png_ptr, msg); + } +} +#endif /* PNG_WARNINGS_SUPPORTED */ + +#ifdef PNG_READ_SUPPORTED +#ifdef PNG_BENIGN_ERRORS_SUPPORTED +void PNGAPI +png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp + error_message) +{ + if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) + png_chunk_warning(png_ptr, error_message); + + else + png_chunk_error(png_ptr, error_message); + +# ifndef PNG_ERROR_TEXT_SUPPORTED + PNG_UNUSED(error_message) +# endif +} +#endif +#endif /* PNG_READ_SUPPORTED */ + +void /* PRIVATE */ +png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error) +{ +# ifndef PNG_WARNINGS_SUPPORTED + PNG_UNUSED(message) +# endif + + /* This is always supported, but for just read or just write it + * unconditionally does the right thing. + */ +# if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED) + if (png_ptr->mode & PNG_IS_READ_STRUCT) +# endif + +# ifdef PNG_READ_SUPPORTED + { + if (error < PNG_CHUNK_ERROR) + png_chunk_warning(png_ptr, message); + + else + png_chunk_benign_error(png_ptr, message); + } +# endif + +# if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED) + else if (!(png_ptr->mode & PNG_IS_READ_STRUCT)) +# endif + +# ifdef PNG_WRITE_SUPPORTED + { + if (error < PNG_CHUNK_WRITE_ERROR) + png_app_warning(png_ptr, message); + + else + png_app_error(png_ptr, message); + } +# endif +} + +#ifdef PNG_ERROR_TEXT_SUPPORTED +#ifdef PNG_FLOATING_POINT_SUPPORTED +PNG_FUNCTION(void, +png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN) +{ +# define fixed_message "fixed point overflow in " +# define fixed_message_ln ((sizeof fixed_message)-1) + int iin; + char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT]; + memcpy(msg, fixed_message, fixed_message_ln); + iin = 0; + if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0) + { + msg[fixed_message_ln + iin] = name[iin]; + ++iin; + } + msg[fixed_message_ln + iin] = 0; + png_error(png_ptr, msg); +} +#endif +#endif + +#ifdef PNG_SETJMP_SUPPORTED +/* This API only exists if ANSI-C style error handling is used, + * otherwise it is necessary for png_default_error to be overridden. + */ +jmp_buf* PNGAPI +png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn, + size_t jmp_buf_size) +{ + /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value + * and it must not change after that. Libpng doesn't care how big the + * buffer is, just that it doesn't change. + * + * If the buffer size is no *larger* than the size of jmp_buf when libpng is + * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0 + * semantics that this call will not fail. If the size is larger, however, + * the buffer is allocated and this may fail, causing the function to return + * NULL. + */ + if (png_ptr == NULL) + return NULL; + + if (png_ptr->jmp_buf_ptr == NULL) + { + png_ptr->jmp_buf_size = 0; /* not allocated */ + + if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local)) + png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; + + else + { + png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *, + png_malloc_warn(png_ptr, jmp_buf_size)); + + if (png_ptr->jmp_buf_ptr == NULL) + return NULL; /* new NULL return on OOM */ + + png_ptr->jmp_buf_size = jmp_buf_size; + } + } + + else /* Already allocated: check the size */ + { + size_t size = png_ptr->jmp_buf_size; + + if (size == 0) + { + size = (sizeof png_ptr->jmp_buf_local); + if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local) + { + /* This is an internal error in libpng: somehow we have been left + * with a stack allocated jmp_buf when the application regained + * control. It's always possible to fix this up, but for the moment + * this is a png_error because that makes it easy to detect. + */ + png_error(png_ptr, "Libpng jmp_buf still allocated"); + /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */ + } + } + + if (size != jmp_buf_size) + { + png_warning(png_ptr, "Application jmp_buf size changed"); + return NULL; /* caller will probably crash: no choice here */ + } + } + + /* Finally fill in the function, now we have a satisfactory buffer. It is + * valid to change the function on every call. + */ + png_ptr->longjmp_fn = longjmp_fn; + return png_ptr->jmp_buf_ptr; +} + +void /* PRIVATE */ +png_free_jmpbuf(png_structrp png_ptr) +{ + if (png_ptr != NULL) + { + jmp_buf *jb = png_ptr->jmp_buf_ptr; + + /* A size of 0 is used to indicate a local, stack, allocation of the + * pointer; used here and in png.c + */ + if (jb != NULL && png_ptr->jmp_buf_size > 0) + { + + /* This stuff is so that a failure to free the error control structure + * does not leave libpng in a state with no valid error handling: the + * free always succeeds, if there is an error it gets ignored. + */ + if (jb != &png_ptr->jmp_buf_local) + { + /* Make an internal, libpng, jmp_buf to return here */ + jmp_buf free_jmp_buf; + + if (!setjmp(free_jmp_buf)) + { + png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */ + png_ptr->jmp_buf_size = 0; /* stack allocation */ + png_ptr->longjmp_fn = longjmp; + png_free(png_ptr, jb); /* Return to setjmp on error */ + } + } + } + + /* *Always* cancel everything out: */ + png_ptr->jmp_buf_size = 0; + png_ptr->jmp_buf_ptr = NULL; + png_ptr->longjmp_fn = 0; + } +} +#endif + +/* This is the default error handling function. Note that replacements for + * this function MUST NOT RETURN, or the program will likely crash. This + * function is used by default, or if the program supplies NULL for the + * error function pointer in png_set_error_fn(). + */ +static PNG_FUNCTION(void /* PRIVATE */, +png_default_error,(png_const_structrp png_ptr, png_const_charp error_message), + PNG_NORETURN) +{ +#ifdef PNG_CONSOLE_IO_SUPPORTED +#ifdef PNG_ERROR_NUMBERS_SUPPORTED + /* Check on NULL only added in 1.5.4 */ + if (error_message != NULL && *error_message == PNG_LITERAL_SHARP) + { + /* Strip "#nnnn " from beginning of error message. */ + int offset; + char error_number[16]; + for (offset = 0; offset<15; offset++) + { + error_number[offset] = error_message[offset + 1]; + if (error_message[offset] == ' ') + break; + } + + if ((offset > 1) && (offset < 15)) + { + error_number[offset - 1] = '\0'; + fprintf(stderr, "libpng error no. %s: %s", + error_number, error_message + offset + 1); + fprintf(stderr, PNG_STRING_NEWLINE); + } + + else + { + fprintf(stderr, "libpng error: %s, offset=%d", + error_message, offset); + fprintf(stderr, PNG_STRING_NEWLINE); + } + } + else +#endif + { + fprintf(stderr, "libpng error: %s", error_message ? error_message : + "undefined"); + fprintf(stderr, PNG_STRING_NEWLINE); + } +#else + PNG_UNUSED(error_message) /* Make compiler happy */ +#endif + png_longjmp(png_ptr, 1); +} + +PNG_FUNCTION(void,PNGAPI +png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN) +{ +#ifdef PNG_SETJMP_SUPPORTED + if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr) + png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val); +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(val) +#endif + + /* If control reaches this point, png_longjmp() must not return. The only + * choice is to terminate the whole process (or maybe the thread); to do + * this the ANSI-C abort() function is used unless a different method is + * implemented by overriding the default configuration setting for + * PNG_ABORT(). + */ + PNG_ABORT(); +} + +#ifdef PNG_WARNINGS_SUPPORTED +/* This function is called when there is a warning, but the library thinks + * it can continue anyway. Replacement functions don't have to do anything + * here if you don't want them to. In the default configuration, png_ptr is + * not used, but it is passed in case it may be useful. + */ +static void /* PRIVATE */ +png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message) +{ +#ifdef PNG_CONSOLE_IO_SUPPORTED +# ifdef PNG_ERROR_NUMBERS_SUPPORTED + if (*warning_message == PNG_LITERAL_SHARP) + { + int offset; + char warning_number[16]; + for (offset = 0; offset < 15; offset++) + { + warning_number[offset] = warning_message[offset + 1]; + if (warning_message[offset] == ' ') + break; + } + + if ((offset > 1) && (offset < 15)) + { + warning_number[offset + 1] = '\0'; + fprintf(stderr, "libpng warning no. %s: %s", + warning_number, warning_message + offset); + fprintf(stderr, PNG_STRING_NEWLINE); + } + + else + { + fprintf(stderr, "libpng warning: %s", + warning_message); + fprintf(stderr, PNG_STRING_NEWLINE); + } + } + else +# endif + + { + fprintf(stderr, "libpng warning: %s", warning_message); + fprintf(stderr, PNG_STRING_NEWLINE); + } +#else + PNG_UNUSED(warning_message) /* Make compiler happy */ +#endif + PNG_UNUSED(png_ptr) /* Make compiler happy */ +} +#endif /* PNG_WARNINGS_SUPPORTED */ + +/* This function is called when the application wants to use another method + * of handling errors and warnings. Note that the error function MUST NOT + * return to the calling routine or serious problems will occur. The return + * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1) + */ +void PNGAPI +png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr, + png_error_ptr error_fn, png_error_ptr warning_fn) +{ + if (png_ptr == NULL) + return; + + png_ptr->error_ptr = error_ptr; + png_ptr->error_fn = error_fn; +#ifdef PNG_WARNINGS_SUPPORTED + png_ptr->warning_fn = warning_fn; +#else + PNG_UNUSED(warning_fn) +#endif +} + + +/* This function returns a pointer to the error_ptr associated with the user + * functions. The application should free any memory associated with this + * pointer before png_write_destroy and png_read_destroy are called. + */ +png_voidp PNGAPI +png_get_error_ptr(png_const_structrp png_ptr) +{ + if (png_ptr == NULL) + return NULL; + + return ((png_voidp)png_ptr->error_ptr); +} + + +#ifdef PNG_ERROR_NUMBERS_SUPPORTED +void PNGAPI +png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode) +{ + if (png_ptr != NULL) + { + png_ptr->flags &= + ((~(PNG_FLAG_STRIP_ERROR_NUMBERS | + PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode); + } +} +#endif + +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ + defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) + /* Currently the above both depend on SETJMP_SUPPORTED, however it would be + * possible to implement without setjmp support just so long as there is some + * way to handle the error return here: + */ +PNG_FUNCTION(void /* PRIVATE */, (PNGCBAPI +png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message), + PNG_NORETURN) +{ + const png_const_structrp png_ptr = png_nonconst_ptr; + png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); + + /* An error is always logged here, overwriting anything (typically a warning) + * that is already there: + */ + if (image != NULL) + { + png_safecat(image->message, (sizeof image->message), 0, error_message); + image->warning_or_error |= PNG_IMAGE_ERROR; + + /* Retrieve the jmp_buf from within the png_control, making this work for + * C++ compilation too is pretty tricky: C++ wants a pointer to the first + * element of a jmp_buf, but C doesn't tell us the type of that. + */ + if (image->opaque != NULL && image->opaque->error_buf != NULL) + longjmp(png_control_jmp_buf(image->opaque), 1); + + /* Missing longjmp buffer, the following is to help debugging: */ + { + size_t pos = png_safecat(image->message, (sizeof image->message), 0, + "bad longjmp: "); + png_safecat(image->message, (sizeof image->message), pos, + error_message); + } + } + + /* Here on an internal programming error. */ + abort(); +} + +#ifdef PNG_WARNINGS_SUPPORTED +void /* PRIVATE */ PNGCBAPI +png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message) +{ + const png_const_structrp png_ptr = png_nonconst_ptr; + png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); + + /* A warning is only logged if there is no prior warning or error. */ + if (image->warning_or_error == 0) + { + png_safecat(image->message, (sizeof image->message), 0, warning_message); + image->warning_or_error |= PNG_IMAGE_WARNING; + } +} +#endif + +int /* PRIVATE */ +png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg) +{ + volatile png_imagep image = image_in; + volatile int result; + volatile png_voidp saved_error_buf; + jmp_buf safe_jmpbuf; + + /* Safely execute function(arg) with png_error returning to this function. */ + saved_error_buf = image->opaque->error_buf; + result = setjmp(safe_jmpbuf) == 0; + + if (result != 0) + { + + image->opaque->error_buf = safe_jmpbuf; + result = function(arg); + } + + image->opaque->error_buf = saved_error_buf; + + /* And do the cleanup prior to any failure return. */ + if (result == 0) + png_image_free(image); + + return result; +} +#endif /* SIMPLIFIED READ/WRITE */ +#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ diff --git a/png/pngget.c b/png/pngget.c new file mode 100755 index 0000000..9e205ad --- /dev/null +++ b/png/pngget.c @@ -0,0 +1,1198 @@ + +/* pngget.c - retrieval of values from info struct + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + */ + +#include "pngpriv.h" + +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) + +png_uint_32 PNGAPI +png_get_valid(png_const_structrp png_ptr, png_const_inforp info_ptr, + png_uint_32 flag) +{ + if (png_ptr != NULL && info_ptr != NULL) + return(info_ptr->valid & flag); + + return(0); +} + +png_size_t PNGAPI +png_get_rowbytes(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return(info_ptr->rowbytes); + + return(0); +} + +#ifdef PNG_INFO_IMAGE_SUPPORTED +png_bytepp PNGAPI +png_get_rows(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return(info_ptr->row_pointers); + + return(0); +} +#endif + +#ifdef PNG_EASY_ACCESS_SUPPORTED +/* Easy access to info, added in libpng-0.99 */ +png_uint_32 PNGAPI +png_get_image_width(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return info_ptr->width; + + return (0); +} + +png_uint_32 PNGAPI +png_get_image_height(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return info_ptr->height; + + return (0); +} + +png_byte PNGAPI +png_get_bit_depth(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return info_ptr->bit_depth; + + return (0); +} + +png_byte PNGAPI +png_get_color_type(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return info_ptr->color_type; + + return (0); +} + +png_byte PNGAPI +png_get_filter_type(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return info_ptr->filter_type; + + return (0); +} + +png_byte PNGAPI +png_get_interlace_type(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return info_ptr->interlace_type; + + return (0); +} + +png_byte PNGAPI +png_get_compression_type(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return info_ptr->compression_type; + + return (0); +} + +png_uint_32 PNGAPI +png_get_x_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp + info_ptr) +{ +#ifdef PNG_pHYs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) + { + png_debug1(1, "in %s retrieval function", + "png_get_x_pixels_per_meter"); + + if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER) + return (info_ptr->x_pixels_per_unit); + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return (0); +} + +png_uint_32 PNGAPI +png_get_y_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp + info_ptr) +{ +#ifdef PNG_pHYs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) + { + png_debug1(1, "in %s retrieval function", + "png_get_y_pixels_per_meter"); + + if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER) + return (info_ptr->y_pixels_per_unit); + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return (0); +} + +png_uint_32 PNGAPI +png_get_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ +#ifdef PNG_pHYs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) + { + png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter"); + + if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER && + info_ptr->x_pixels_per_unit == info_ptr->y_pixels_per_unit) + return (info_ptr->x_pixels_per_unit); + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return (0); +} + +#ifdef PNG_FLOATING_POINT_SUPPORTED +float PNGAPI +png_get_pixel_aspect_ratio(png_const_structrp png_ptr, png_const_inforp + info_ptr) +{ +#ifdef PNG_READ_pHYs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) + { + png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio"); + + if (info_ptr->x_pixels_per_unit != 0) + return ((float)((float)info_ptr->y_pixels_per_unit + /(float)info_ptr->x_pixels_per_unit)); + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return ((float)0.0); +} +#endif + +#ifdef PNG_FIXED_POINT_SUPPORTED +png_fixed_point PNGAPI +png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr, + png_const_inforp info_ptr) +{ +#ifdef PNG_READ_pHYs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) + && info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0 + && info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX + && info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX) + { + png_fixed_point res; + + png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio_fixed"); + + /* The following casts work because a PNG 4 byte integer only has a valid + * range of 0..2^31-1; otherwise the cast might overflow. + */ + if (png_muldiv(&res, (png_int_32)info_ptr->y_pixels_per_unit, PNG_FP_1, + (png_int_32)info_ptr->x_pixels_per_unit)) + return res; + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return 0; +} +#endif + +png_int_32 PNGAPI +png_get_x_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ +#ifdef PNG_oFFs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) + { + png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns"); + + if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER) + return (info_ptr->x_offset); + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return (0); +} + +png_int_32 PNGAPI +png_get_y_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ +#ifdef PNG_oFFs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) + { + png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns"); + + if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER) + return (info_ptr->y_offset); + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return (0); +} + +png_int_32 PNGAPI +png_get_x_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ +#ifdef PNG_oFFs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) + { + png_debug1(1, "in %s retrieval function", "png_get_x_offset_pixels"); + + if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL) + return (info_ptr->x_offset); + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return (0); +} + +png_int_32 PNGAPI +png_get_y_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ +#ifdef PNG_oFFs_SUPPORTED + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) + { + png_debug1(1, "in %s retrieval function", "png_get_y_offset_pixels"); + + if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL) + return (info_ptr->y_offset); + } +#else + PNG_UNUSED(png_ptr) + PNG_UNUSED(info_ptr) +#endif + + return (0); +} + +#ifdef PNG_INCH_CONVERSIONS_SUPPORTED +static png_uint_32 +ppi_from_ppm(png_uint_32 ppm) +{ +#if 0 + /* The conversion is *(2.54/100), in binary (32 digits): + * .00000110100000001001110101001001 + */ + png_uint_32 t1001, t1101; + ppm >>= 1; /* .1 */ + t1001 = ppm + (ppm >> 3); /* .1001 */ + t1101 = t1001 + (ppm >> 1); /* .1101 */ + ppm >>= 20; /* .000000000000000000001 */ + t1101 += t1101 >> 15; /* .1101000000000001101 */ + t1001 >>= 11; /* .000000000001001 */ + t1001 += t1001 >> 12; /* .000000000001001000000001001 */ + ppm += t1001; /* .000000000001001000001001001 */ + ppm += t1101; /* .110100000001001110101001001 */ + return (ppm + 16) >> 5;/* .00000110100000001001110101001001 */ +#else + /* The argument is a PNG unsigned integer, so it is not permitted + * to be bigger than 2^31. + */ + png_fixed_point result; + if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127, + 5000)) + return result; + + /* Overflow. */ + return 0; +#endif +} + +png_uint_32 PNGAPI +png_get_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + return ppi_from_ppm(png_get_pixels_per_meter(png_ptr, info_ptr)); +} + +png_uint_32 PNGAPI +png_get_x_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + return ppi_from_ppm(png_get_x_pixels_per_meter(png_ptr, info_ptr)); +} + +png_uint_32 PNGAPI +png_get_y_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + return ppi_from_ppm(png_get_y_pixels_per_meter(png_ptr, info_ptr)); +} + +#ifdef PNG_FIXED_POINT_SUPPORTED +static png_fixed_point +png_fixed_inches_from_microns(png_const_structrp png_ptr, png_int_32 microns) +{ + /* Convert from metres * 1,000,000 to inches * 100,000, meters to + * inches is simply *(100/2.54), so we want *(10/2.54) == 500/127. + * Notice that this can overflow - a warning is output and 0 is + * returned. + */ + return png_muldiv_warn(png_ptr, microns, 500, 127); +} + +png_fixed_point PNGAPI +png_get_x_offset_inches_fixed(png_const_structrp png_ptr, + png_const_inforp info_ptr) +{ + return png_fixed_inches_from_microns(png_ptr, + png_get_x_offset_microns(png_ptr, info_ptr)); +} +#endif + +#ifdef PNG_FIXED_POINT_SUPPORTED +png_fixed_point PNGAPI +png_get_y_offset_inches_fixed(png_const_structrp png_ptr, + png_const_inforp info_ptr) +{ + return png_fixed_inches_from_microns(png_ptr, + png_get_y_offset_microns(png_ptr, info_ptr)); +} +#endif + +#ifdef PNG_FLOATING_POINT_SUPPORTED +float PNGAPI +png_get_x_offset_inches(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + /* To avoid the overflow do the conversion directly in floating + * point. + */ + return (float)(png_get_x_offset_microns(png_ptr, info_ptr) * .00003937); +} +#endif + +#ifdef PNG_FLOATING_POINT_SUPPORTED +float PNGAPI +png_get_y_offset_inches(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + /* To avoid the overflow do the conversion directly in floating + * point. + */ + return (float)(png_get_y_offset_microns(png_ptr, info_ptr) * .00003937); +} +#endif + +#ifdef PNG_pHYs_SUPPORTED +png_uint_32 PNGAPI +png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr, + png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type) +{ + png_uint_32 retval = 0; + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) + { + png_debug1(1, "in %s retrieval function", "pHYs"); + + if (res_x != NULL) + { + *res_x = info_ptr->x_pixels_per_unit; + retval |= PNG_INFO_pHYs; + } + + if (res_y != NULL) + { + *res_y = info_ptr->y_pixels_per_unit; + retval |= PNG_INFO_pHYs; + } + + if (unit_type != NULL) + { + *unit_type = (int)info_ptr->phys_unit_type; + retval |= PNG_INFO_pHYs; + + if (*unit_type == 1) + { + if (res_x != NULL) *res_x = (png_uint_32)(*res_x * .0254 + .50); + if (res_y != NULL) *res_y = (png_uint_32)(*res_y * .0254 + .50); + } + } + } + + return (retval); +} +#endif /* PNG_pHYs_SUPPORTED */ +#endif /* PNG_INCH_CONVERSIONS_SUPPORTED */ + +/* png_get_channels really belongs in here, too, but it's been around longer */ + +#endif /* PNG_EASY_ACCESS_SUPPORTED */ + + +png_byte PNGAPI +png_get_channels(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return(info_ptr->channels); + + return (0); +} + +#ifdef PNG_READ_SUPPORTED +png_const_bytep PNGAPI +png_get_signature(png_const_structrp png_ptr, png_const_inforp info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return(info_ptr->signature); + + return (NULL); +} +#endif + +#ifdef PNG_bKGD_SUPPORTED +png_uint_32 PNGAPI +png_get_bKGD(png_const_structrp png_ptr, png_inforp info_ptr, + png_color_16p *background) +{ + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) + && background != NULL) + { + png_debug1(1, "in %s retrieval function", "bKGD"); + + *background = &(info_ptr->background); + return (PNG_INFO_bKGD); + } + + return (0); +} +#endif + +#ifdef PNG_cHRM_SUPPORTED +/* The XYZ APIs were added in 1.5.5 to take advantage of the code added at the + * same time to correct the rgb grayscale coefficient defaults obtained from the + * cHRM chunk in 1.5.4 + */ +# ifdef PNG_FLOATING_POINT_SUPPORTED +png_uint_32 PNGAPI +png_get_cHRM(png_const_structrp png_ptr, png_const_inforp info_ptr, + double *white_x, double *white_y, double *red_x, double *red_y, + double *green_x, double *green_y, double *blue_x, double *blue_y) +{ + /* Quiet API change: this code used to only return the end points if a cHRM + * chunk was present, but the end points can also come from iCCP or sRGB + * chunks, so in 1.6.0 the png_get_ APIs return the end points regardless and + * the png_set_ APIs merely check that set end points are mutually + * consistent. + */ + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS)) + { + png_debug1(1, "in %s retrieval function", "cHRM"); + + if (white_x != NULL) + *white_x = png_float(png_ptr, + info_ptr->colorspace.end_points_xy.whitex, "cHRM white X"); + if (white_y != NULL) + *white_y = png_float(png_ptr, + info_ptr->colorspace.end_points_xy.whitey, "cHRM white Y"); + if (red_x != NULL) + *red_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redx, + "cHRM red X"); + if (red_y != NULL) + *red_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redy, + "cHRM red Y"); + if (green_x != NULL) + *green_x = png_float(png_ptr, + info_ptr->colorspace.end_points_xy.greenx, "cHRM green X"); + if (green_y != NULL) + *green_y = png_float(png_ptr, + info_ptr->colorspace.end_points_xy.greeny, "cHRM green Y"); + if (blue_x != NULL) + *blue_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluex, + "cHRM blue X"); + if (blue_y != NULL) + *blue_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluey, + "cHRM blue Y"); + return (PNG_INFO_cHRM); + } + + return (0); +} + +png_uint_32 PNGAPI +png_get_cHRM_XYZ(png_const_structrp png_ptr, png_const_inforp info_ptr, + double *red_X, double *red_Y, double *red_Z, double *green_X, + double *green_Y, double *green_Z, double *blue_X, double *blue_Y, + double *blue_Z) +{ + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS)) + { + png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)"); + + if (red_X != NULL) + *red_X = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_X, + "cHRM red X"); + if (red_Y != NULL) + *red_Y = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Y, + "cHRM red Y"); + if (red_Z != NULL) + *red_Z = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Z, + "cHRM red Z"); + if (green_X != NULL) + *green_X = png_float(png_ptr, + info_ptr->colorspace.end_points_XYZ.green_X, "cHRM green X"); + if (green_Y != NULL) + *green_Y = png_float(png_ptr, + info_ptr->colorspace.end_points_XYZ.green_Y, "cHRM green Y"); + if (green_Z != NULL) + *green_Z = png_float(png_ptr, + info_ptr->colorspace.end_points_XYZ.green_Z, "cHRM green Z"); + if (blue_X != NULL) + *blue_X = png_float(png_ptr, + info_ptr->colorspace.end_points_XYZ.blue_X, "cHRM blue X"); + if (blue_Y != NULL) + *blue_Y = png_float(png_ptr, + info_ptr->colorspace.end_points_XYZ.blue_Y, "cHRM blue Y"); + if (blue_Z != NULL) + *blue_Z = png_float(png_ptr, + info_ptr->colorspace.end_points_XYZ.blue_Z, "cHRM blue Z"); + return (PNG_INFO_cHRM); + } + + return (0); +} +# endif + +# ifdef PNG_FIXED_POINT_SUPPORTED +png_uint_32 PNGAPI +png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr, + png_fixed_point *int_red_X, png_fixed_point *int_red_Y, + png_fixed_point *int_red_Z, png_fixed_point *int_green_X, + png_fixed_point *int_green_Y, png_fixed_point *int_green_Z, + png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y, + png_fixed_point *int_blue_Z) +{ + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS)) + { + png_debug1(1, "in %s retrieval function", "cHRM_XYZ"); + + if (int_red_X != NULL) + *int_red_X = info_ptr->colorspace.end_points_XYZ.red_X; + if (int_red_Y != NULL) + *int_red_Y = info_ptr->colorspace.end_points_XYZ.red_Y; + if (int_red_Z != NULL) + *int_red_Z = info_ptr->colorspace.end_points_XYZ.red_Z; + if (int_green_X != NULL) + *int_green_X = info_ptr->colorspace.end_points_XYZ.green_X; + if (int_green_Y != NULL) + *int_green_Y = info_ptr->colorspace.end_points_XYZ.green_Y; + if (int_green_Z != NULL) + *int_green_Z = info_ptr->colorspace.end_points_XYZ.green_Z; + if (int_blue_X != NULL) + *int_blue_X = info_ptr->colorspace.end_points_XYZ.blue_X; + if (int_blue_Y != NULL) + *int_blue_Y = info_ptr->colorspace.end_points_XYZ.blue_Y; + if (int_blue_Z != NULL) + *int_blue_Z = info_ptr->colorspace.end_points_XYZ.blue_Z; + return (PNG_INFO_cHRM); + } + + return (0); +} + +png_uint_32 PNGAPI +png_get_cHRM_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr, + png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x, + png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y, + png_fixed_point *blue_x, png_fixed_point *blue_y) +{ + png_debug1(1, "in %s retrieval function", "cHRM"); + + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS)) + { + if (white_x != NULL) + *white_x = info_ptr->colorspace.end_points_xy.whitex; + if (white_y != NULL) + *white_y = info_ptr->colorspace.end_points_xy.whitey; + if (red_x != NULL) + *red_x = info_ptr->colorspace.end_points_xy.redx; + if (red_y != NULL) + *red_y = info_ptr->colorspace.end_points_xy.redy; + if (green_x != NULL) + *green_x = info_ptr->colorspace.end_points_xy.greenx; + if (green_y != NULL) + *green_y = info_ptr->colorspace.end_points_xy.greeny; + if (blue_x != NULL) + *blue_x = info_ptr->colorspace.end_points_xy.bluex; + if (blue_y != NULL) + *blue_y = info_ptr->colorspace.end_points_xy.bluey; + return (PNG_INFO_cHRM); + } + + return (0); +} +# endif +#endif + +#ifdef PNG_gAMA_SUPPORTED +# ifdef PNG_FIXED_POINT_SUPPORTED +png_uint_32 PNGAPI +png_get_gAMA_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr, + png_fixed_point *file_gamma) +{ + png_debug1(1, "in %s retrieval function", "gAMA"); + + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) && + file_gamma != NULL) + { + *file_gamma = info_ptr->colorspace.gamma; + return (PNG_INFO_gAMA); + } + + return (0); +} +# endif + +# ifdef PNG_FLOATING_POINT_SUPPORTED +png_uint_32 PNGAPI +png_get_gAMA(png_const_structrp png_ptr, png_const_inforp info_ptr, + double *file_gamma) +{ + png_debug1(1, "in %s retrieval function", "gAMA(float)"); + + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) && + file_gamma != NULL) + { + *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma, + "png_get_gAMA"); + return (PNG_INFO_gAMA); + } + + return (0); +} +# endif +#endif + +#ifdef PNG_sRGB_SUPPORTED +png_uint_32 PNGAPI +png_get_sRGB(png_const_structrp png_ptr, png_const_inforp info_ptr, + int *file_srgb_intent) +{ + png_debug1(1, "in %s retrieval function", "sRGB"); + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB) + && file_srgb_intent != NULL) + { + *file_srgb_intent = info_ptr->colorspace.rendering_intent; + return (PNG_INFO_sRGB); + } + + return (0); +} +#endif + +#ifdef PNG_iCCP_SUPPORTED +png_uint_32 PNGAPI +png_get_iCCP(png_const_structrp png_ptr, png_inforp info_ptr, + png_charpp name, int *compression_type, + png_bytepp profile, png_uint_32 *proflen) +{ + png_debug1(1, "in %s retrieval function", "iCCP"); + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP) + && name != NULL && compression_type != NULL && profile != NULL && + proflen != NULL) + { + *name = info_ptr->iccp_name; + *profile = info_ptr->iccp_profile; + *proflen = png_get_uint_32(info_ptr->iccp_profile); + /* This is somewhat irrelevant since the profile data returned has + * actually been uncompressed. + */ + *compression_type = PNG_COMPRESSION_TYPE_BASE; + return (PNG_INFO_iCCP); + } + + return (0); +} +#endif + +#ifdef PNG_sPLT_SUPPORTED +int PNGAPI +png_get_sPLT(png_const_structrp png_ptr, png_inforp info_ptr, + png_sPLT_tpp spalettes) +{ + if (png_ptr != NULL && info_ptr != NULL && spalettes != NULL) + { + *spalettes = info_ptr->splt_palettes; + return info_ptr->splt_palettes_num; + } + + return (0); +} +#endif + +#ifdef PNG_hIST_SUPPORTED +png_uint_32 PNGAPI +png_get_hIST(png_const_structrp png_ptr, png_inforp info_ptr, + png_uint_16p *hist) +{ + png_debug1(1, "in %s retrieval function", "hIST"); + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) + && hist != NULL) + { + *hist = info_ptr->hist; + return (PNG_INFO_hIST); + } + + return (0); +} +#endif + +png_uint_32 PNGAPI +png_get_IHDR(png_const_structrp png_ptr, png_const_inforp info_ptr, + png_uint_32 *width, png_uint_32 *height, int *bit_depth, + int *color_type, int *interlace_type, int *compression_type, + int *filter_type) +{ + png_debug1(1, "in %s retrieval function", "IHDR"); + + if (png_ptr == NULL || info_ptr == NULL || width == NULL || + height == NULL || bit_depth == NULL || color_type == NULL) + return (0); + + *width = info_ptr->width; + *height = info_ptr->height; + *bit_depth = info_ptr->bit_depth; + *color_type = info_ptr->color_type; + + if (compression_type != NULL) + *compression_type = info_ptr->compression_type; + + if (filter_type != NULL) + *filter_type = info_ptr->filter_type; + + if (interlace_type != NULL) + *interlace_type = info_ptr->interlace_type; + + /* This is redundant if we can be sure that the info_ptr values were all + * assigned in png_set_IHDR(). We do the check anyhow in case an + * application has ignored our advice not to mess with the members + * of info_ptr directly. + */ + png_check_IHDR(png_ptr, info_ptr->width, info_ptr->height, + info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type, + info_ptr->compression_type, info_ptr->filter_type); + + return (1); +} + +#ifdef PNG_oFFs_SUPPORTED +png_uint_32 PNGAPI +png_get_oFFs(png_const_structrp png_ptr, png_const_inforp info_ptr, + png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type) +{ + png_debug1(1, "in %s retrieval function", "oFFs"); + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) + && offset_x != NULL && offset_y != NULL && unit_type != NULL) + { + *offset_x = info_ptr->x_offset; + *offset_y = info_ptr->y_offset; + *unit_type = (int)info_ptr->offset_unit_type; + return (PNG_INFO_oFFs); + } + + return (0); +} +#endif + +#ifdef PNG_pCAL_SUPPORTED +png_uint_32 PNGAPI +png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr, + png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams, + png_charp *units, png_charpp *params) +{ + png_debug1(1, "in %s retrieval function", "pCAL"); + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) + && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL && + nparams != NULL && units != NULL && params != NULL) + { + *purpose = info_ptr->pcal_purpose; + *X0 = info_ptr->pcal_X0; + *X1 = info_ptr->pcal_X1; + *type = (int)info_ptr->pcal_type; + *nparams = (int)info_ptr->pcal_nparams; + *units = info_ptr->pcal_units; + *params = info_ptr->pcal_params; + return (PNG_INFO_pCAL); + } + + return (0); +} +#endif + +#ifdef PNG_sCAL_SUPPORTED +# ifdef PNG_FIXED_POINT_SUPPORTED +# if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \ + defined(PNG_FLOATING_POINT_SUPPORTED) +png_uint_32 PNGAPI +png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr, + int *unit, png_fixed_point *width, png_fixed_point *height) +{ + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->valid & PNG_INFO_sCAL)) + { + *unit = info_ptr->scal_unit; + /*TODO: make this work without FP support; the API is currently eliminated + * if neither floating point APIs nor internal floating point arithmetic + * are enabled. + */ + *width = png_fixed(png_ptr, atof(info_ptr->scal_s_width), "sCAL width"); + *height = png_fixed(png_ptr, atof(info_ptr->scal_s_height), + "sCAL height"); + return (PNG_INFO_sCAL); + } + + return(0); +} +# endif /* FLOATING_ARITHMETIC */ +# endif /* FIXED_POINT */ +# ifdef PNG_FLOATING_POINT_SUPPORTED +png_uint_32 PNGAPI +png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr, + int *unit, double *width, double *height) +{ + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->valid & PNG_INFO_sCAL)) + { + *unit = info_ptr->scal_unit; + *width = atof(info_ptr->scal_s_width); + *height = atof(info_ptr->scal_s_height); + return (PNG_INFO_sCAL); + } + + return(0); +} +# endif /* FLOATING POINT */ +png_uint_32 PNGAPI +png_get_sCAL_s(png_const_structrp png_ptr, png_const_inforp info_ptr, + int *unit, png_charpp width, png_charpp height) +{ + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->valid & PNG_INFO_sCAL)) + { + *unit = info_ptr->scal_unit; + *width = info_ptr->scal_s_width; + *height = info_ptr->scal_s_height; + return (PNG_INFO_sCAL); + } + + return(0); +} +#endif /* sCAL */ + +#ifdef PNG_pHYs_SUPPORTED +png_uint_32 PNGAPI +png_get_pHYs(png_const_structrp png_ptr, png_const_inforp info_ptr, + png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type) +{ + png_uint_32 retval = 0; + + png_debug1(1, "in %s retrieval function", "pHYs"); + + if (png_ptr != NULL && info_ptr != NULL && + (info_ptr->valid & PNG_INFO_pHYs)) + { + if (res_x != NULL) + { + *res_x = info_ptr->x_pixels_per_unit; + retval |= PNG_INFO_pHYs; + } + + if (res_y != NULL) + { + *res_y = info_ptr->y_pixels_per_unit; + retval |= PNG_INFO_pHYs; + } + + if (unit_type != NULL) + { + *unit_type = (int)info_ptr->phys_unit_type; + retval |= PNG_INFO_pHYs; + } + } + + return (retval); +} +#endif /* pHYs */ + +png_uint_32 PNGAPI +png_get_PLTE(png_const_structrp png_ptr, png_inforp info_ptr, + png_colorp *palette, int *num_palette) +{ + png_debug1(1, "in %s retrieval function", "PLTE"); + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_PLTE) + && palette != NULL) + { + *palette = info_ptr->palette; + *num_palette = info_ptr->num_palette; + png_debug1(3, "num_palette = %d", *num_palette); + return (PNG_INFO_PLTE); + } + + return (0); +} + +#ifdef PNG_sBIT_SUPPORTED +png_uint_32 PNGAPI +png_get_sBIT(png_const_structrp png_ptr, png_inforp info_ptr, + png_color_8p *sig_bit) +{ + png_debug1(1, "in %s retrieval function", "sBIT"); + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) + && sig_bit != NULL) + { + *sig_bit = &(info_ptr->sig_bit); + return (PNG_INFO_sBIT); + } + + return (0); +} +#endif + +#ifdef PNG_TEXT_SUPPORTED +int PNGAPI +png_get_text(png_const_structrp png_ptr, png_inforp info_ptr, + png_textp *text_ptr, int *num_text) +{ + if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0) + { + png_debug1(1, "in 0x%lx retrieval function", + (unsigned long)png_ptr->chunk_name); + + if (text_ptr != NULL) + *text_ptr = info_ptr->text; + + if (num_text != NULL) + *num_text = info_ptr->num_text; + + return info_ptr->num_text; + } + + if (num_text != NULL) + *num_text = 0; + + return(0); +} +#endif + +#ifdef PNG_tIME_SUPPORTED +png_uint_32 PNGAPI +png_get_tIME(png_const_structrp png_ptr, png_inforp info_ptr, + png_timep *mod_time) +{ + png_debug1(1, "in %s retrieval function", "tIME"); + + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) + && mod_time != NULL) + { + *mod_time = &(info_ptr->mod_time); + return (PNG_INFO_tIME); + } + + return (0); +} +#endif + +#ifdef PNG_tRNS_SUPPORTED +png_uint_32 PNGAPI +png_get_tRNS(png_const_structrp png_ptr, png_inforp info_ptr, + png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color) +{ + png_uint_32 retval = 0; + if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS)) + { + png_debug1(1, "in %s retrieval function", "tRNS"); + + if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (trans_alpha != NULL) + { + *trans_alpha = info_ptr->trans_alpha; + retval |= PNG_INFO_tRNS; + } + + if (trans_color != NULL) + *trans_color = &(info_ptr->trans_color); + } + + else /* if (info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) */ + { + if (trans_color != NULL) + { + *trans_color = &(info_ptr->trans_color); + retval |= PNG_INFO_tRNS; + } + + if (trans_alpha != NULL) + *trans_alpha = NULL; + } + + if (num_trans != NULL) + { + *num_trans = info_ptr->num_trans; + retval |= PNG_INFO_tRNS; + } + } + + return (retval); +} +#endif + +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED +int PNGAPI +png_get_unknown_chunks(png_const_structrp png_ptr, png_inforp info_ptr, + png_unknown_chunkpp unknowns) +{ + if (png_ptr != NULL && info_ptr != NULL && unknowns != NULL) + { + *unknowns = info_ptr->unknown_chunks; + return info_ptr->unknown_chunks_num; + } + + return (0); +} +#endif + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +png_byte PNGAPI +png_get_rgb_to_gray_status (png_const_structrp png_ptr) +{ + return (png_byte)(png_ptr ? png_ptr->rgb_to_gray_status : 0); +} +#endif + +#ifdef PNG_USER_CHUNKS_SUPPORTED +png_voidp PNGAPI +png_get_user_chunk_ptr(png_const_structrp png_ptr) +{ + return (png_ptr ? png_ptr->user_chunk_ptr : NULL); +} +#endif + +png_size_t PNGAPI +png_get_compression_buffer_size(png_const_structrp png_ptr) +{ + if (png_ptr == NULL) + return 0; + +# ifdef PNG_WRITE_SUPPORTED + if (png_ptr->mode & PNG_IS_READ_STRUCT) +# endif + { +# ifdef PNG_SEQUENTIAL_READ_SUPPORTED + return png_ptr->IDAT_read_size; +# else + return PNG_IDAT_READ_SIZE; +# endif + } + +# ifdef PNG_WRITE_SUPPORTED + else + return png_ptr->zbuffer_size; +# endif +} + +#ifdef PNG_SET_USER_LIMITS_SUPPORTED +/* These functions were added to libpng 1.2.6 and were enabled + * by default in libpng-1.4.0 */ +png_uint_32 PNGAPI +png_get_user_width_max (png_const_structrp png_ptr) +{ + return (png_ptr ? png_ptr->user_width_max : 0); +} + +png_uint_32 PNGAPI +png_get_user_height_max (png_const_structrp png_ptr) +{ + return (png_ptr ? png_ptr->user_height_max : 0); +} + +/* This function was added to libpng 1.4.0 */ +png_uint_32 PNGAPI +png_get_chunk_cache_max (png_const_structrp png_ptr) +{ + return (png_ptr ? png_ptr->user_chunk_cache_max : 0); +} + +/* This function was added to libpng 1.4.1 */ +png_alloc_size_t PNGAPI +png_get_chunk_malloc_max (png_const_structrp png_ptr) +{ + return (png_ptr ? png_ptr->user_chunk_malloc_max : 0); +} +#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */ + +/* These functions were added to libpng 1.4.0 */ +#ifdef PNG_IO_STATE_SUPPORTED +png_uint_32 PNGAPI +png_get_io_state (png_const_structrp png_ptr) +{ + return png_ptr->io_state; +} + +png_uint_32 PNGAPI +png_get_io_chunk_type (png_const_structrp png_ptr) +{ + return png_ptr->chunk_name; +} +#endif /* ?PNG_IO_STATE_SUPPORTED */ + +#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED +# ifdef PNG_GET_PALETTE_MAX_SUPPORTED +int PNGAPI +png_get_palette_max(png_const_structp png_ptr, png_const_infop info_ptr) +{ + if (png_ptr != NULL && info_ptr != NULL) + return png_ptr->num_palette_max; + + return (-1); +} +# endif +#endif + +#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ diff --git a/png/pnginfo.h b/png/pnginfo.h new file mode 100755 index 0000000..26bf265 --- /dev/null +++ b/png/pnginfo.h @@ -0,0 +1,260 @@ + +/* pnginfo.h - header file for PNG reference library + * + * Copyright (c) 1998-2013 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * Last changed in libpng 1.6.1 [March 28, 2013] + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + + /* png_info is a structure that holds the information in a PNG file so + * that the application can find out the characteristics of the image. + * If you are reading the file, this structure will tell you what is + * in the PNG file. If you are writing the file, fill in the information + * you want to put into the PNG file, using png_set_*() functions, then + * call png_write_info(). + * + * The names chosen should be very close to the PNG specification, so + * consult that document for information about the meaning of each field. + * + * With libpng < 0.95, it was only possible to directly set and read the + * the values in the png_info_struct, which meant that the contents and + * order of the values had to remain fixed. With libpng 0.95 and later, + * however, there are now functions that abstract the contents of + * png_info_struct from the application, so this makes it easier to use + * libpng with dynamic libraries, and even makes it possible to use + * libraries that don't have all of the libpng ancillary chunk-handing + * functionality. In libpng-1.5.0 this was moved into a separate private + * file that is not visible to applications. + * + * The following members may have allocated storage attached that should be + * cleaned up before the structure is discarded: palette, trans, text, + * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile, + * splt_palettes, scal_unit, row_pointers, and unknowns. By default, these + * are automatically freed when the info structure is deallocated, if they were + * allocated internally by libpng. This behavior can be changed by means + * of the png_data_freer() function. + * + * More allocation details: all the chunk-reading functions that + * change these members go through the corresponding png_set_* + * functions. A function to clear these members is available: see + * png_free_data(). The png_set_* functions do not depend on being + * able to point info structure members to any of the storage they are + * passed (they make their own copies), EXCEPT that the png_set_text + * functions use the same storage passed to them in the text_ptr or + * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns + * functions do not make their own copies. + */ +#ifndef PNGINFO_H +#define PNGINFO_H + +struct png_info_def +{ + /* The following are necessary for every PNG file */ + png_uint_32 width; /* width of image in pixels (from IHDR) */ + png_uint_32 height; /* height of image in pixels (from IHDR) */ + png_uint_32 valid; /* valid chunk data (see PNG_INFO_ below) */ + png_size_t rowbytes; /* bytes needed to hold an untransformed row */ + png_colorp palette; /* array of color values (valid & PNG_INFO_PLTE) */ + png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */ + png_uint_16 num_trans; /* number of transparent palette color (tRNS) */ + png_byte bit_depth; /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */ + png_byte color_type; /* see PNG_COLOR_TYPE_ below (from IHDR) */ + /* The following three should have been named *_method not *_type */ + png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */ + png_byte filter_type; /* must be PNG_FILTER_TYPE_BASE (from IHDR) */ + png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */ + + /* The following are set by png_set_IHDR, called from the application on + * write, but the are never actually used by the write code. + */ + png_byte channels; /* number of data channels per pixel (1, 2, 3, 4) */ + png_byte pixel_depth; /* number of bits per pixel */ + png_byte spare_byte; /* to align the data, and for future use */ + +#ifdef PNG_READ_SUPPORTED + /* This is never set during write */ + png_byte signature[8]; /* magic bytes read by libpng from start of file */ +#endif + + /* The rest of the data is optional. If you are reading, check the + * valid field to see if the information in these are valid. If you + * are writing, set the valid field to those chunks you want written, + * and initialize the appropriate fields below. + */ + +#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED) + /* png_colorspace only contains 'flags' if neither GAMMA or COLORSPACE are + * defined. When COLORSPACE is switched on all the colorspace-defining + * chunks should be enabled, when GAMMA is switched on all the gamma-defining + * chunks should be enabled. If this is not done it becomes possible to read + * inconsistent PNG files and assign a probably incorrect interpretation to + * the information. (In other words, by carefully choosing which chunks to + * recognize the system configuration can select an interpretation for PNG + * files containing ambiguous data and this will result in inconsistent + * behavior between different libpng builds!) + */ + png_colorspace colorspace; +#endif + +#ifdef PNG_iCCP_SUPPORTED + /* iCCP chunk data. */ + png_charp iccp_name; /* profile name */ + png_bytep iccp_profile; /* International Color Consortium profile data */ + png_uint_32 iccp_proflen; /* ICC profile data length */ +#endif + +#ifdef PNG_TEXT_SUPPORTED + /* The tEXt, and zTXt chunks contain human-readable textual data in + * uncompressed, compressed, and optionally compressed forms, respectively. + * The data in "text" is an array of pointers to uncompressed, + * null-terminated C strings. Each chunk has a keyword that describes the + * textual data contained in that chunk. Keywords are not required to be + * unique, and the text string may be empty. Any number of text chunks may + * be in an image. + */ + int num_text; /* number of comments read or comments to write */ + int max_text; /* current size of text array */ + png_textp text; /* array of comments read or comments to write */ +#endif /* PNG_TEXT_SUPPORTED */ + +#ifdef PNG_tIME_SUPPORTED + /* The tIME chunk holds the last time the displayed image data was + * modified. See the png_time struct for the contents of this struct. + */ + png_time mod_time; +#endif + +#ifdef PNG_sBIT_SUPPORTED + /* The sBIT chunk specifies the number of significant high-order bits + * in the pixel data. Values are in the range [1, bit_depth], and are + * only specified for the channels in the pixel data. The contents of + * the low-order bits is not specified. Data is valid if + * (valid & PNG_INFO_sBIT) is non-zero. + */ + png_color_8 sig_bit; /* significant bits in color channels */ +#endif + +#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \ +defined(PNG_READ_BACKGROUND_SUPPORTED) + /* The tRNS chunk supplies transparency data for paletted images and + * other image types that don't need a full alpha channel. There are + * "num_trans" transparency values for a paletted image, stored in the + * same order as the palette colors, starting from index 0. Values + * for the data are in the range [0, 255], ranging from fully transparent + * to fully opaque, respectively. For non-paletted images, there is a + * single color specified that should be treated as fully transparent. + * Data is valid if (valid & PNG_INFO_tRNS) is non-zero. + */ + png_bytep trans_alpha; /* alpha values for paletted image */ + png_color_16 trans_color; /* transparent color for non-palette image */ +#endif + +#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) + /* The bKGD chunk gives the suggested image background color if the + * display program does not have its own background color and the image + * is needs to composited onto a background before display. The colors + * in "background" are normally in the same color space/depth as the + * pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero. + */ + png_color_16 background; +#endif + +#ifdef PNG_oFFs_SUPPORTED + /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards + * and downwards from the top-left corner of the display, page, or other + * application-specific co-ordinate space. See the PNG_OFFSET_ defines + * below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero. + */ + png_int_32 x_offset; /* x offset on page */ + png_int_32 y_offset; /* y offset on page */ + png_byte offset_unit_type; /* offset units type */ +#endif + +#ifdef PNG_pHYs_SUPPORTED + /* The pHYs chunk gives the physical pixel density of the image for + * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_ + * defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero. + */ + png_uint_32 x_pixels_per_unit; /* horizontal pixel density */ + png_uint_32 y_pixels_per_unit; /* vertical pixel density */ + png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */ +#endif + +#ifdef PNG_hIST_SUPPORTED + /* The hIST chunk contains the relative frequency or importance of the + * various palette entries, so that a viewer can intelligently select a + * reduced-color palette, if required. Data is an array of "num_palette" + * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST) + * is non-zero. + */ + png_uint_16p hist; +#endif + +#ifdef PNG_pCAL_SUPPORTED + /* The pCAL chunk describes a transformation between the stored pixel + * values and original physical data values used to create the image. + * The integer range [0, 2^bit_depth - 1] maps to the floating-point + * range given by [pcal_X0, pcal_X1], and are further transformed by a + * (possibly non-linear) transformation function given by "pcal_type" + * and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_ + * defines below, and the PNG-Group's PNG extensions document for a + * complete description of the transformations and how they should be + * implemented, and for a description of the ASCII parameter strings. + * Data values are valid if (valid & PNG_INFO_pCAL) non-zero. + */ + png_charp pcal_purpose; /* pCAL chunk description string */ + png_int_32 pcal_X0; /* minimum value */ + png_int_32 pcal_X1; /* maximum value */ + png_charp pcal_units; /* Latin-1 string giving physical units */ + png_charpp pcal_params; /* ASCII strings containing parameter values */ + png_byte pcal_type; /* equation type (see PNG_EQUATION_ below) */ + png_byte pcal_nparams; /* number of parameters given in pcal_params */ +#endif + +/* New members added in libpng-1.0.6 */ + png_uint_32 free_me; /* flags items libpng is responsible for freeing */ + +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED + /* Storage for unknown chunks that the library doesn't recognize. */ + png_unknown_chunkp unknown_chunks; + + /* The type of this field is limited by the type of + * png_struct::user_chunk_cache_max, else overflow can occur. + */ + int unknown_chunks_num; +#endif + +#ifdef PNG_sPLT_SUPPORTED + /* Data on sPLT chunks (there may be more than one). */ + png_sPLT_tp splt_palettes; + int splt_palettes_num; /* Match type returned by png_get API */ +#endif + +#ifdef PNG_sCAL_SUPPORTED + /* The sCAL chunk describes the actual physical dimensions of the + * subject matter of the graphic. The chunk contains a unit specification + * a byte value, and two ASCII strings representing floating-point + * values. The values are width and height corresponsing to one pixel + * in the image. Data values are valid if (valid & PNG_INFO_sCAL) is + * non-zero. + */ + png_byte scal_unit; /* unit of physical scale */ + png_charp scal_s_width; /* string containing height */ + png_charp scal_s_height; /* string containing width */ +#endif + +#ifdef PNG_INFO_IMAGE_SUPPORTED + /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS) + non-zero */ + /* Data valid if (valid & PNG_INFO_IDAT) non-zero */ + png_bytepp row_pointers; /* the image bits */ +#endif + +}; +#endif /* PNGINFO_H */ diff --git a/png/pnglibconf.h b/png/pnglibconf.h new file mode 100755 index 0000000..08ee25c --- /dev/null +++ b/png/pnglibconf.h @@ -0,0 +1,210 @@ +/* libpng 1.6.12 STANDARD API DEFINITION */ + +/* pnglibconf.h - library build configuration */ + +/* Libpng version 1.6.12 - June 12, 2014 */ + +/* Copyright (c) 1998-2014 Glenn Randers-Pehrson */ + +/* This code is released under the libpng license. */ +/* For conditions of distribution and use, see the disclaimer */ +/* and license in png.h */ + +/* pnglibconf.h */ +/* Machine generated file: DO NOT EDIT */ +/* Derived from: scripts/pnglibconf.dfa */ +#ifndef PNGLCONF_H +#define PNGLCONF_H +/* options */ +#define PNG_16BIT_SUPPORTED +#define PNG_ALIGNED_MEMORY_SUPPORTED +/*#undef PNG_ARM_NEON_API_SUPPORTED*/ +/*#undef PNG_ARM_NEON_CHECK_SUPPORTED*/ +#define PNG_BENIGN_ERRORS_SUPPORTED +#define PNG_BENIGN_READ_ERRORS_SUPPORTED +/*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/ +#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED +#define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED +#define PNG_COLORSPACE_SUPPORTED +#define PNG_CONSOLE_IO_SUPPORTED +#define PNG_CONVERT_tIME_SUPPORTED +#define PNG_EASY_ACCESS_SUPPORTED +/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/ +#define PNG_ERROR_TEXT_SUPPORTED +#define PNG_FIXED_POINT_SUPPORTED +#define PNG_FLOATING_ARITHMETIC_SUPPORTED +#define PNG_FLOATING_POINT_SUPPORTED +#define PNG_FORMAT_AFIRST_SUPPORTED +#define PNG_FORMAT_BGR_SUPPORTED +#define PNG_GAMMA_SUPPORTED +#define PNG_GET_PALETTE_MAX_SUPPORTED +#define PNG_HANDLE_AS_UNKNOWN_SUPPORTED +#define PNG_INCH_CONVERSIONS_SUPPORTED +#define PNG_INFO_IMAGE_SUPPORTED +#define PNG_IO_STATE_SUPPORTED +#define PNG_MNG_FEATURES_SUPPORTED +#define PNG_POINTER_INDEXING_SUPPORTED +#define PNG_PROGRESSIVE_READ_SUPPORTED +#define PNG_READ_16BIT_SUPPORTED +#define PNG_READ_ALPHA_MODE_SUPPORTED +#define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED +#define PNG_READ_BACKGROUND_SUPPORTED +#define PNG_READ_BGR_SUPPORTED +#define PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED +#define PNG_READ_COMPOSITE_NODIV_SUPPORTED +#define PNG_READ_COMPRESSED_TEXT_SUPPORTED +#define PNG_READ_EXPAND_16_SUPPORTED +#define PNG_READ_EXPAND_SUPPORTED +#define PNG_READ_FILLER_SUPPORTED +#define PNG_READ_GAMMA_SUPPORTED +#define PNG_READ_GET_PALETTE_MAX_SUPPORTED +#define PNG_READ_GRAY_TO_RGB_SUPPORTED +#define PNG_READ_INTERLACING_SUPPORTED +#define PNG_READ_INT_FUNCTIONS_SUPPORTED +#define PNG_READ_INVERT_ALPHA_SUPPORTED +#define PNG_READ_INVERT_SUPPORTED +#define PNG_READ_OPT_PLTE_SUPPORTED +#define PNG_READ_PACKSWAP_SUPPORTED +#define PNG_READ_PACK_SUPPORTED +#define PNG_READ_QUANTIZE_SUPPORTED +#define PNG_READ_RGB_TO_GRAY_SUPPORTED +#define PNG_READ_SCALE_16_TO_8_SUPPORTED +#define PNG_READ_SHIFT_SUPPORTED +#define PNG_READ_STRIP_16_TO_8_SUPPORTED +#define PNG_READ_STRIP_ALPHA_SUPPORTED +#define PNG_READ_SUPPORTED +#define PNG_READ_SWAP_ALPHA_SUPPORTED +#define PNG_READ_SWAP_SUPPORTED +#define PNG_READ_TEXT_SUPPORTED +#define PNG_READ_TRANSFORMS_SUPPORTED +#define PNG_READ_UNKNOWN_CHUNKS_SUPPORTED +#define PNG_READ_USER_CHUNKS_SUPPORTED +#define PNG_READ_USER_TRANSFORM_SUPPORTED +#define PNG_READ_bKGD_SUPPORTED +#define PNG_READ_cHRM_SUPPORTED +#define PNG_READ_gAMA_SUPPORTED +#define PNG_READ_hIST_SUPPORTED +#define PNG_READ_iCCP_SUPPORTED +#define PNG_READ_iTXt_SUPPORTED +#define PNG_READ_oFFs_SUPPORTED +#define PNG_READ_pCAL_SUPPORTED +#define PNG_READ_pHYs_SUPPORTED +#define PNG_READ_sBIT_SUPPORTED +#define PNG_READ_sCAL_SUPPORTED +#define PNG_READ_sPLT_SUPPORTED +#define PNG_READ_sRGB_SUPPORTED +#define PNG_READ_tEXt_SUPPORTED +#define PNG_READ_tIME_SUPPORTED +#define PNG_READ_tRNS_SUPPORTED +#define PNG_READ_zTXt_SUPPORTED +/*#undef PNG_SAFE_LIMITS_SUPPORTED*/ +#define PNG_SAVE_INT_32_SUPPORTED +#define PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED +#define PNG_SEQUENTIAL_READ_SUPPORTED +#define PNG_SETJMP_SUPPORTED +#define PNG_SET_CHUNK_CACHE_LIMIT_SUPPORTED +#define PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED +#define PNG_SET_OPTION_SUPPORTED +#define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED +#define PNG_SET_USER_LIMITS_SUPPORTED +#define PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED +#define PNG_SIMPLIFIED_READ_BGR_SUPPORTED +#define PNG_SIMPLIFIED_READ_SUPPORTED +#define PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED +#define PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED +#define PNG_SIMPLIFIED_WRITE_SUPPORTED +#define PNG_STDIO_SUPPORTED +#define PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED +#define PNG_TEXT_SUPPORTED +#define PNG_TIME_RFC1123_SUPPORTED +#define PNG_UNKNOWN_CHUNKS_SUPPORTED +#define PNG_USER_CHUNKS_SUPPORTED +#define PNG_USER_LIMITS_SUPPORTED +#define PNG_USER_MEM_SUPPORTED +#define PNG_USER_TRANSFORM_INFO_SUPPORTED +#define PNG_USER_TRANSFORM_PTR_SUPPORTED +#define PNG_WARNINGS_SUPPORTED +#define PNG_WRITE_16BIT_SUPPORTED +#define PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED +#define PNG_WRITE_BGR_SUPPORTED +#define PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED +#define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED +#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED +#define PNG_WRITE_FILLER_SUPPORTED +#define PNG_WRITE_FILTER_SUPPORTED +#define PNG_WRITE_FLUSH_SUPPORTED +#define PNG_WRITE_GET_PALETTE_MAX_SUPPORTED +#define PNG_WRITE_INTERLACING_SUPPORTED +#define PNG_WRITE_INT_FUNCTIONS_SUPPORTED +#define PNG_WRITE_INVERT_ALPHA_SUPPORTED +#define PNG_WRITE_INVERT_SUPPORTED +#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED +#define PNG_WRITE_PACKSWAP_SUPPORTED +#define PNG_WRITE_PACK_SUPPORTED +#define PNG_WRITE_SHIFT_SUPPORTED +#define PNG_WRITE_SUPPORTED +#define PNG_WRITE_SWAP_ALPHA_SUPPORTED +#define PNG_WRITE_SWAP_SUPPORTED +#define PNG_WRITE_TEXT_SUPPORTED +#define PNG_WRITE_TRANSFORMS_SUPPORTED +#define PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED +#define PNG_WRITE_USER_TRANSFORM_SUPPORTED +#define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED +#define PNG_WRITE_bKGD_SUPPORTED +#define PNG_WRITE_cHRM_SUPPORTED +#define PNG_WRITE_gAMA_SUPPORTED +#define PNG_WRITE_hIST_SUPPORTED +#define PNG_WRITE_iCCP_SUPPORTED +#define PNG_WRITE_iTXt_SUPPORTED +#define PNG_WRITE_oFFs_SUPPORTED +#define PNG_WRITE_pCAL_SUPPORTED +#define PNG_WRITE_pHYs_SUPPORTED +#define PNG_WRITE_sBIT_SUPPORTED +#define PNG_WRITE_sCAL_SUPPORTED +#define PNG_WRITE_sPLT_SUPPORTED +#define PNG_WRITE_sRGB_SUPPORTED +#define PNG_WRITE_tEXt_SUPPORTED +#define PNG_WRITE_tIME_SUPPORTED +#define PNG_WRITE_tRNS_SUPPORTED +#define PNG_WRITE_zTXt_SUPPORTED +#define PNG_bKGD_SUPPORTED +#define PNG_cHRM_SUPPORTED +#define PNG_gAMA_SUPPORTED +#define PNG_hIST_SUPPORTED +#define PNG_iCCP_SUPPORTED +#define PNG_iTXt_SUPPORTED +#define PNG_oFFs_SUPPORTED +#define PNG_pCAL_SUPPORTED +#define PNG_pHYs_SUPPORTED +#define PNG_sBIT_SUPPORTED +#define PNG_sCAL_SUPPORTED +#define PNG_sPLT_SUPPORTED +#define PNG_sRGB_SUPPORTED +#define PNG_tEXt_SUPPORTED +#define PNG_tIME_SUPPORTED +#define PNG_tRNS_SUPPORTED +#define PNG_zTXt_SUPPORTED +/* end of options */ +/* settings */ +#define PNG_API_RULE 0 +#define PNG_COST_SHIFT 3 +#define PNG_DEFAULT_READ_MACROS 1 +#define PNG_GAMMA_THRESHOLD_FIXED 5000 +#define PNG_IDAT_READ_SIZE PNG_ZBUF_SIZE +#define PNG_INFLATE_BUF_SIZE 1024 +#define PNG_MAX_GAMMA_8 11 +#define PNG_QUANTIZE_BLUE_BITS 5 +#define PNG_QUANTIZE_GREEN_BITS 5 +#define PNG_QUANTIZE_RED_BITS 5 +#define PNG_TEXT_Z_DEFAULT_COMPRESSION (-1) +#define PNG_TEXT_Z_DEFAULT_STRATEGY 0 +#define PNG_WEIGHT_SHIFT 8 +#define PNG_ZBUF_SIZE 8192 +#define PNG_ZLIB_VERNUM 0 /* unknown */ +#define PNG_Z_DEFAULT_COMPRESSION (-1) +#define PNG_Z_DEFAULT_NOFILTER_STRATEGY 0 +#define PNG_Z_DEFAULT_STRATEGY 1 +#define PNG_sCAL_PRECISION 5 +#define PNG_sRGB_PROFILE_CHECKS 2 +/* end of settings */ +#endif /* PNGLCONF_H */ diff --git a/png/pngmem.c b/png/pngmem.c new file mode 100755 index 0000000..8ee0866 --- /dev/null +++ b/png/pngmem.c @@ -0,0 +1,281 @@ + +/* pngmem.c - stub functions for memory allocation + * + * Last changed in libpng 1.6.8 [December 19, 2013] + * Copyright (c) 1998-2013 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * This file provides a location for all memory allocation. Users who + * need special memory handling are expected to supply replacement + * functions for png_malloc() and png_free(), and to use + * png_create_read_struct_2() and png_create_write_struct_2() to + * identify the replacement functions. + */ + +#include "pngpriv.h" + +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) +/* Free a png_struct */ +void /* PRIVATE */ +png_destroy_png_struct(png_structrp png_ptr) +{ + if (png_ptr != NULL) + { + /* png_free might call png_error and may certainly call + * png_get_mem_ptr, so fake a temporary png_struct to support this. + */ + png_struct dummy_struct = *png_ptr; + memset(png_ptr, 0, (sizeof *png_ptr)); + png_free(&dummy_struct, png_ptr); + +# ifdef PNG_SETJMP_SUPPORTED + /* We may have a jmp_buf left to deallocate. */ + png_free_jmpbuf(&dummy_struct); +# endif + } +} + +/* Allocate memory. For reasonable files, size should never exceed + * 64K. However, zlib may allocate more then 64K if you don't tell + * it not to. See zconf.h and png.h for more information. zlib does + * need to allocate exactly 64K, so whatever you call here must + * have the ability to do that. + */ +PNG_FUNCTION(png_voidp,PNGAPI +png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED) +{ + png_voidp ret; + + ret = png_malloc(png_ptr, size); + + if (ret != NULL) + memset(ret, 0, size); + + return ret; +} + +/* png_malloc_base, an internal function added at libpng 1.6.0, does the work of + * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED. + * Checking and error handling must happen outside this routine; it returns NULL + * if the allocation cannot be done (for any reason.) + */ +PNG_FUNCTION(png_voidp /* PRIVATE */, +png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size), + PNG_ALLOCATED) +{ + /* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS + * allocators have also been removed in 1.6.0, so any 16-bit system now has + * to implement a user memory handler. This checks to be sure it isn't + * called with big numbers. + */ +#ifndef PNG_USER_MEM_SUPPORTED + PNG_UNUSED(png_ptr) +#endif + + if (size > 0 && size <= PNG_SIZE_MAX +# ifdef PNG_MAX_MALLOC_64K + && size <= 65536U +# endif + ) + { +#ifdef PNG_USER_MEM_SUPPORTED + if (png_ptr != NULL && png_ptr->malloc_fn != NULL) + return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size); + + else +#endif + return malloc((size_t)size); /* checked for truncation above */ + } + + else + return NULL; +} + +#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\ + defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) +/* This is really here only to work round a spurious warning in GCC 4.6 and 4.7 + * that arises because of the checks in png_realloc_array that are repeated in + * png_malloc_array. + */ +static png_voidp +png_malloc_array_checked(png_const_structrp png_ptr, int nelements, + size_t element_size) +{ + png_alloc_size_t req = nelements; /* known to be > 0 */ + + if (req <= PNG_SIZE_MAX/element_size) + return png_malloc_base(png_ptr, req * element_size); + + /* The failure case when the request is too large */ + return NULL; +} + +PNG_FUNCTION(png_voidp /* PRIVATE */, +png_malloc_array,(png_const_structrp png_ptr, int nelements, + size_t element_size),PNG_ALLOCATED) +{ + if (nelements <= 0 || element_size == 0) + png_error(png_ptr, "internal error: array alloc"); + + return png_malloc_array_checked(png_ptr, nelements, element_size); +} + +PNG_FUNCTION(png_voidp /* PRIVATE */, +png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array, + int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED) +{ + /* These are internal errors: */ + if (add_elements <= 0 || element_size == 0 || old_elements < 0 || + (old_array == NULL && old_elements > 0)) + png_error(png_ptr, "internal error: array realloc"); + + /* Check for overflow on the elements count (so the caller does not have to + * check.) + */ + if (add_elements <= INT_MAX - old_elements) + { + png_voidp new_array = png_malloc_array_checked(png_ptr, + old_elements+add_elements, element_size); + + if (new_array != NULL) + { + /* Because png_malloc_array worked the size calculations below cannot + * overflow. + */ + if (old_elements > 0) + memcpy(new_array, old_array, element_size*(unsigned)old_elements); + + memset((char*)new_array + element_size*(unsigned)old_elements, 0, + element_size*(unsigned)add_elements); + + return new_array; + } + } + + return NULL; /* error */ +} +#endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */ + +/* Various functions that have different error handling are derived from this. + * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate + * function png_malloc_default is also provided. + */ +PNG_FUNCTION(png_voidp,PNGAPI +png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED) +{ + png_voidp ret; + + if (png_ptr == NULL) + return NULL; + + ret = png_malloc_base(png_ptr, size); + + if (ret == NULL) + png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */ + + return ret; +} + +#ifdef PNG_USER_MEM_SUPPORTED +PNG_FUNCTION(png_voidp,PNGAPI +png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size), + PNG_ALLOCATED PNG_DEPRECATED) +{ + png_voidp ret; + + if (png_ptr == NULL) + return NULL; + + /* Passing 'NULL' here bypasses the application provided memory handler. */ + ret = png_malloc_base(NULL/*use malloc*/, size); + + if (ret == NULL) + png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */ + + return ret; +} +#endif /* PNG_USER_MEM_SUPPORTED */ + +/* This function was added at libpng version 1.2.3. The png_malloc_warn() + * function will issue a png_warning and return NULL instead of issuing a + * png_error, if it fails to allocate the requested memory. + */ +PNG_FUNCTION(png_voidp,PNGAPI +png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size), + PNG_ALLOCATED) +{ + if (png_ptr != NULL) + { + png_voidp ret = png_malloc_base(png_ptr, size); + + if (ret != NULL) + return ret; + + png_warning(png_ptr, "Out of memory"); + } + + return NULL; +} + +/* Free a pointer allocated by png_malloc(). If ptr is NULL, return + * without taking any action. + */ +void PNGAPI +png_free(png_const_structrp png_ptr, png_voidp ptr) +{ + if (png_ptr == NULL || ptr == NULL) + return; + +#ifdef PNG_USER_MEM_SUPPORTED + if (png_ptr->free_fn != NULL) + png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr); + + else + png_free_default(png_ptr, ptr); +} + +PNG_FUNCTION(void,PNGAPI +png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED) +{ + if (png_ptr == NULL || ptr == NULL) + return; +#endif /* PNG_USER_MEM_SUPPORTED */ + + free(ptr); +} + +#ifdef PNG_USER_MEM_SUPPORTED +/* This function is called when the application wants to use another method + * of allocating and freeing memory. + */ +void PNGAPI +png_set_mem_fn(png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr + malloc_fn, png_free_ptr free_fn) +{ + if (png_ptr != NULL) + { + png_ptr->mem_ptr = mem_ptr; + png_ptr->malloc_fn = malloc_fn; + png_ptr->free_fn = free_fn; + } +} + +/* This function returns a pointer to the mem_ptr associated with the user + * functions. The application should free any memory associated with this + * pointer before png_write_destroy and png_read_destroy are called. + */ +png_voidp PNGAPI +png_get_mem_ptr(png_const_structrp png_ptr) +{ + if (png_ptr == NULL) + return NULL; + + return png_ptr->mem_ptr; +} +#endif /* PNG_USER_MEM_SUPPORTED */ +#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ diff --git a/png/pngnow.png b/png/pngnow.png Binary files differnew file mode 100755 index 0000000..82793eb --- /dev/null +++ b/png/pngnow.png diff --git a/png/pngpread.c b/png/pngpread.c new file mode 100755 index 0000000..819db03 --- /dev/null +++ b/png/pngpread.c @@ -0,0 +1,1286 @@ + +/* pngpread.c - read a png file in push mode + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +#include "pngpriv.h" + +#ifdef PNG_PROGRESSIVE_READ_SUPPORTED + +/* Push model modes */ +#define PNG_READ_SIG_MODE 0 +#define PNG_READ_CHUNK_MODE 1 +#define PNG_READ_IDAT_MODE 2 +#define PNG_SKIP_MODE 3 +#define PNG_READ_tEXt_MODE 4 +#define PNG_READ_zTXt_MODE 5 +#define PNG_READ_DONE_MODE 6 +#define PNG_READ_iTXt_MODE 7 +#define PNG_ERROR_MODE 8 + +void PNGAPI +png_process_data(png_structrp png_ptr, png_inforp info_ptr, + png_bytep buffer, png_size_t buffer_size) +{ + if (png_ptr == NULL || info_ptr == NULL) + return; + + png_push_restore_buffer(png_ptr, buffer, buffer_size); + + while (png_ptr->buffer_size) + { + png_process_some_data(png_ptr, info_ptr); + } +} + +png_size_t PNGAPI +png_process_data_pause(png_structrp png_ptr, int save) +{ + if (png_ptr != NULL) + { + /* It's easiest for the caller if we do the save, then the caller doesn't + * have to supply the same data again: + */ + if (save != 0) + png_push_save_buffer(png_ptr); + else + { + /* This includes any pending saved bytes: */ + png_size_t remaining = png_ptr->buffer_size; + png_ptr->buffer_size = 0; + + /* So subtract the saved buffer size, unless all the data + * is actually 'saved', in which case we just return 0 + */ + if (png_ptr->save_buffer_size < remaining) + return remaining - png_ptr->save_buffer_size; + } + } + + return 0; +} + +png_uint_32 PNGAPI +png_process_data_skip(png_structrp png_ptr) +{ + png_uint_32 remaining = 0; + + if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE && + png_ptr->skip_length > 0) + { + /* At the end of png_process_data the buffer size must be 0 (see the loop + * above) so we can detect a broken call here: + */ + if (png_ptr->buffer_size != 0) + png_error(png_ptr, + "png_process_data_skip called inside png_process_data"); + + /* If is impossible for there to be a saved buffer at this point - + * otherwise we could not be in SKIP mode. This will also happen if + * png_process_skip is called inside png_process_data (but only very + * rarely.) + */ + if (png_ptr->save_buffer_size != 0) + png_error(png_ptr, "png_process_data_skip called with saved data"); + + remaining = png_ptr->skip_length; + png_ptr->skip_length = 0; + png_ptr->process_mode = PNG_READ_CHUNK_MODE; + } + + return remaining; +} + +/* What we do with the incoming data depends on what we were previously + * doing before we ran out of data... + */ +void /* PRIVATE */ +png_process_some_data(png_structrp png_ptr, png_inforp info_ptr) +{ + if (png_ptr == NULL) + return; + + switch (png_ptr->process_mode) + { + case PNG_READ_SIG_MODE: + { + png_push_read_sig(png_ptr, info_ptr); + break; + } + + case PNG_READ_CHUNK_MODE: + { + png_push_read_chunk(png_ptr, info_ptr); + break; + } + + case PNG_READ_IDAT_MODE: + { + png_push_read_IDAT(png_ptr); + break; + } + + case PNG_SKIP_MODE: + { + png_push_crc_finish(png_ptr); + break; + } + + default: + { + png_ptr->buffer_size = 0; + break; + } + } +} + +/* Read any remaining signature bytes from the stream and compare them with + * the correct PNG signature. It is possible that this routine is called + * with bytes already read from the signature, either because they have been + * checked by the calling application, or because of multiple calls to this + * routine. + */ +void /* PRIVATE */ +png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr) +{ + png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */ + num_to_check = 8 - num_checked; + + if (png_ptr->buffer_size < num_to_check) + { + num_to_check = png_ptr->buffer_size; + } + + png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]), + num_to_check); + png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check); + + if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) + { + if (num_checked < 4 && + png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) + png_error(png_ptr, "Not a PNG file"); + + else + png_error(png_ptr, "PNG file corrupted by ASCII conversion"); + } + else + { + if (png_ptr->sig_bytes >= 8) + { + png_ptr->process_mode = PNG_READ_CHUNK_MODE; + } + } +} + +void /* PRIVATE */ +png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr) +{ + png_uint_32 chunk_name; +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED + int keep; /* unknown handling method */ +#endif + + /* First we make sure we have enough data for the 4 byte chunk name + * and the 4 byte chunk length before proceeding with decoding the + * chunk data. To fully decode each of these chunks, we also make + * sure we have enough data in the buffer for the 4 byte CRC at the + * end of every chunk (except IDAT, which is handled separately). + */ + if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) + { + png_byte chunk_length[4]; + png_byte chunk_tag[4]; + + if (png_ptr->buffer_size < 8) + { + png_push_save_buffer(png_ptr); + return; + } + + png_push_fill_buffer(png_ptr, chunk_length, 4); + png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length); + png_reset_crc(png_ptr); + png_crc_read(png_ptr, chunk_tag, 4); + png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag); + png_check_chunk_name(png_ptr, png_ptr->chunk_name); + png_ptr->mode |= PNG_HAVE_CHUNK_HEADER; + } + + chunk_name = png_ptr->chunk_name; + + if (chunk_name == png_IDAT) + { + if (png_ptr->mode & PNG_AFTER_IDAT) + png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT; + + /* If we reach an IDAT chunk, this means we have read all of the + * header chunks, and we can start reading the image (or if this + * is called after the image has been read - we have an error). + */ + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_error(png_ptr, "Missing IHDR before IDAT"); + + else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && + !(png_ptr->mode & PNG_HAVE_PLTE)) + png_error(png_ptr, "Missing PLTE before IDAT"); + + png_ptr->mode |= PNG_HAVE_IDAT; + png_ptr->process_mode = PNG_READ_IDAT_MODE; + + if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT)) + if (png_ptr->push_length == 0) + return; + + if (png_ptr->mode & PNG_AFTER_IDAT) + png_benign_error(png_ptr, "Too many IDATs found"); + } + + if (chunk_name == png_IHDR) + { + if (png_ptr->push_length != 13) + png_error(png_ptr, "Invalid IHDR length"); + + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length); + } + + else if (chunk_name == png_IEND) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length); + + png_ptr->process_mode = PNG_READ_DONE_MODE; + png_push_have_end(png_ptr, info_ptr); + } + +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED + else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep); + + if (chunk_name == png_PLTE) + png_ptr->mode |= PNG_HAVE_PLTE; + } +#endif + + else if (chunk_name == png_PLTE) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length); + } + + else if (chunk_name == png_IDAT) + { + png_ptr->idat_size = png_ptr->push_length; + png_ptr->process_mode = PNG_READ_IDAT_MODE; + png_push_have_info(png_ptr, info_ptr); + png_ptr->zstream.avail_out = + (uInt) PNG_ROWBYTES(png_ptr->pixel_depth, + png_ptr->iwidth) + 1; + png_ptr->zstream.next_out = png_ptr->row_buf; + return; + } + +#ifdef PNG_READ_gAMA_SUPPORTED + else if (png_ptr->chunk_name == png_gAMA) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_sBIT_SUPPORTED + else if (png_ptr->chunk_name == png_sBIT) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_cHRM_SUPPORTED + else if (png_ptr->chunk_name == png_cHRM) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_sRGB_SUPPORTED + else if (chunk_name == png_sRGB) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_iCCP_SUPPORTED + else if (png_ptr->chunk_name == png_iCCP) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_sPLT_SUPPORTED + else if (chunk_name == png_sPLT) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_tRNS_SUPPORTED + else if (chunk_name == png_tRNS) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_bKGD_SUPPORTED + else if (chunk_name == png_bKGD) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_hIST_SUPPORTED + else if (chunk_name == png_hIST) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_pHYs_SUPPORTED + else if (chunk_name == png_pHYs) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_oFFs_SUPPORTED + else if (chunk_name == png_oFFs) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length); + } +#endif + +#ifdef PNG_READ_pCAL_SUPPORTED + else if (chunk_name == png_pCAL) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_sCAL_SUPPORTED + else if (chunk_name == png_sCAL) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_tIME_SUPPORTED + else if (chunk_name == png_tIME) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_tEXt_SUPPORTED + else if (chunk_name == png_tEXt) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_zTXt_SUPPORTED + else if (chunk_name == png_zTXt) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length); + } + +#endif +#ifdef PNG_READ_iTXt_SUPPORTED + else if (chunk_name == png_iTXt) + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + + png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length); + } +#endif + + else + { + if (png_ptr->push_length + 4 > png_ptr->buffer_size) + { + png_push_save_buffer(png_ptr); + return; + } + png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, + PNG_HANDLE_CHUNK_AS_DEFAULT); + } + + png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; +} + +void /* PRIVATE */ +png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip) +{ + png_ptr->process_mode = PNG_SKIP_MODE; + png_ptr->skip_length = skip; +} + +void /* PRIVATE */ +png_push_crc_finish(png_structrp png_ptr) +{ + if (png_ptr->skip_length && png_ptr->save_buffer_size) + { + png_size_t save_size = png_ptr->save_buffer_size; + png_uint_32 skip_length = png_ptr->skip_length; + + /* We want the smaller of 'skip_length' and 'save_buffer_size', but + * they are of different types and we don't know which variable has the + * fewest bits. Carefully select the smaller and cast it to the type of + * the larger - this cannot overflow. Do not cast in the following test + * - it will break on either 16 or 64 bit platforms. + */ + if (skip_length < save_size) + save_size = (png_size_t)skip_length; + + else + skip_length = (png_uint_32)save_size; + + png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); + + png_ptr->skip_length -= skip_length; + png_ptr->buffer_size -= save_size; + png_ptr->save_buffer_size -= save_size; + png_ptr->save_buffer_ptr += save_size; + } + if (png_ptr->skip_length && png_ptr->current_buffer_size) + { + png_size_t save_size = png_ptr->current_buffer_size; + png_uint_32 skip_length = png_ptr->skip_length; + + /* We want the smaller of 'skip_length' and 'current_buffer_size', here, + * the same problem exists as above and the same solution. + */ + if (skip_length < save_size) + save_size = (png_size_t)skip_length; + + else + skip_length = (png_uint_32)save_size; + + png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); + + png_ptr->skip_length -= skip_length; + png_ptr->buffer_size -= save_size; + png_ptr->current_buffer_size -= save_size; + png_ptr->current_buffer_ptr += save_size; + } + if (!png_ptr->skip_length) + { + if (png_ptr->buffer_size < 4) + { + png_push_save_buffer(png_ptr); + return; + } + + png_crc_finish(png_ptr, 0); + png_ptr->process_mode = PNG_READ_CHUNK_MODE; + } +} + +void PNGCBAPI +png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length) +{ + png_bytep ptr; + + if (png_ptr == NULL) + return; + + ptr = buffer; + if (png_ptr->save_buffer_size) + { + png_size_t save_size; + + if (length < png_ptr->save_buffer_size) + save_size = length; + + else + save_size = png_ptr->save_buffer_size; + + memcpy(ptr, png_ptr->save_buffer_ptr, save_size); + length -= save_size; + ptr += save_size; + png_ptr->buffer_size -= save_size; + png_ptr->save_buffer_size -= save_size; + png_ptr->save_buffer_ptr += save_size; + } + if (length && png_ptr->current_buffer_size) + { + png_size_t save_size; + + if (length < png_ptr->current_buffer_size) + save_size = length; + + else + save_size = png_ptr->current_buffer_size; + + memcpy(ptr, png_ptr->current_buffer_ptr, save_size); + png_ptr->buffer_size -= save_size; + png_ptr->current_buffer_size -= save_size; + png_ptr->current_buffer_ptr += save_size; + } +} + +void /* PRIVATE */ +png_push_save_buffer(png_structrp png_ptr) +{ + if (png_ptr->save_buffer_size) + { + if (png_ptr->save_buffer_ptr != png_ptr->save_buffer) + { + png_size_t i, istop; + png_bytep sp; + png_bytep dp; + + istop = png_ptr->save_buffer_size; + for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer; + i < istop; i++, sp++, dp++) + { + *dp = *sp; + } + } + } + if (png_ptr->save_buffer_size + png_ptr->current_buffer_size > + png_ptr->save_buffer_max) + { + png_size_t new_max; + png_bytep old_buffer; + + if (png_ptr->save_buffer_size > PNG_SIZE_MAX - + (png_ptr->current_buffer_size + 256)) + { + png_error(png_ptr, "Potential overflow of save_buffer"); + } + + new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256; + old_buffer = png_ptr->save_buffer; + png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, + (png_size_t)new_max); + + if (png_ptr->save_buffer == NULL) + { + png_free(png_ptr, old_buffer); + png_error(png_ptr, "Insufficient memory for save_buffer"); + } + + memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size); + png_free(png_ptr, old_buffer); + png_ptr->save_buffer_max = new_max; + } + if (png_ptr->current_buffer_size) + { + memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size, + png_ptr->current_buffer_ptr, png_ptr->current_buffer_size); + png_ptr->save_buffer_size += png_ptr->current_buffer_size; + png_ptr->current_buffer_size = 0; + } + png_ptr->save_buffer_ptr = png_ptr->save_buffer; + png_ptr->buffer_size = 0; +} + +void /* PRIVATE */ +png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer, + png_size_t buffer_length) +{ + png_ptr->current_buffer = buffer; + png_ptr->current_buffer_size = buffer_length; + png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size; + png_ptr->current_buffer_ptr = png_ptr->current_buffer; +} + +void /* PRIVATE */ +png_push_read_IDAT(png_structrp png_ptr) +{ + if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) + { + png_byte chunk_length[4]; + png_byte chunk_tag[4]; + + /* TODO: this code can be commoned up with the same code in push_read */ + if (png_ptr->buffer_size < 8) + { + png_push_save_buffer(png_ptr); + return; + } + + png_push_fill_buffer(png_ptr, chunk_length, 4); + png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length); + png_reset_crc(png_ptr); + png_crc_read(png_ptr, chunk_tag, 4); + png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag); + png_ptr->mode |= PNG_HAVE_CHUNK_HEADER; + + if (png_ptr->chunk_name != png_IDAT) + { + png_ptr->process_mode = PNG_READ_CHUNK_MODE; + + if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) + png_error(png_ptr, "Not enough compressed data"); + + return; + } + + png_ptr->idat_size = png_ptr->push_length; + } + + if (png_ptr->idat_size && png_ptr->save_buffer_size) + { + png_size_t save_size = png_ptr->save_buffer_size; + png_uint_32 idat_size = png_ptr->idat_size; + + /* We want the smaller of 'idat_size' and 'current_buffer_size', but they + * are of different types and we don't know which variable has the fewest + * bits. Carefully select the smaller and cast it to the type of the + * larger - this cannot overflow. Do not cast in the following test - it + * will break on either 16 or 64 bit platforms. + */ + if (idat_size < save_size) + save_size = (png_size_t)idat_size; + + else + idat_size = (png_uint_32)save_size; + + png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); + + png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size); + + png_ptr->idat_size -= idat_size; + png_ptr->buffer_size -= save_size; + png_ptr->save_buffer_size -= save_size; + png_ptr->save_buffer_ptr += save_size; + } + + if (png_ptr->idat_size && png_ptr->current_buffer_size) + { + png_size_t save_size = png_ptr->current_buffer_size; + png_uint_32 idat_size = png_ptr->idat_size; + + /* We want the smaller of 'idat_size' and 'current_buffer_size', but they + * are of different types and we don't know which variable has the fewest + * bits. Carefully select the smaller and cast it to the type of the + * larger - this cannot overflow. + */ + if (idat_size < save_size) + save_size = (png_size_t)idat_size; + + else + idat_size = (png_uint_32)save_size; + + png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); + + png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size); + + png_ptr->idat_size -= idat_size; + png_ptr->buffer_size -= save_size; + png_ptr->current_buffer_size -= save_size; + png_ptr->current_buffer_ptr += save_size; + } + if (!png_ptr->idat_size) + { + if (png_ptr->buffer_size < 4) + { + png_push_save_buffer(png_ptr); + return; + } + + png_crc_finish(png_ptr, 0); + png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; + png_ptr->mode |= PNG_AFTER_IDAT; + png_ptr->zowner = 0; + } +} + +void /* PRIVATE */ +png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer, + png_size_t buffer_length) +{ + /* The caller checks for a non-zero buffer length. */ + if (!(buffer_length > 0) || buffer == NULL) + png_error(png_ptr, "No IDAT data (internal error)"); + + /* This routine must process all the data it has been given + * before returning, calling the row callback as required to + * handle the uncompressed results. + */ + png_ptr->zstream.next_in = buffer; + /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */ + png_ptr->zstream.avail_in = (uInt)buffer_length; + + /* Keep going until the decompressed data is all processed + * or the stream marked as finished. + */ + while (png_ptr->zstream.avail_in > 0 && + !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) + { + int ret; + + /* We have data for zlib, but we must check that zlib + * has someplace to put the results. It doesn't matter + * if we don't expect any results -- it may be the input + * data is just the LZ end code. + */ + if (!(png_ptr->zstream.avail_out > 0)) + { + /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */ + png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth, + png_ptr->iwidth) + 1); + + png_ptr->zstream.next_out = png_ptr->row_buf; + } + + /* Using Z_SYNC_FLUSH here means that an unterminated + * LZ stream (a stream with a missing end code) can still + * be handled, otherwise (Z_NO_FLUSH) a future zlib + * implementation might defer output and therefore + * change the current behavior (see comments in inflate.c + * for why this doesn't happen at present with zlib 1.2.5). + */ + ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH); + + /* Check for any failure before proceeding. */ + if (ret != Z_OK && ret != Z_STREAM_END) + { + /* Terminate the decompression. */ + png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; + png_ptr->zowner = 0; + + /* This may be a truncated stream (missing or + * damaged end code). Treat that as a warning. + */ + if (png_ptr->row_number >= png_ptr->num_rows || + png_ptr->pass > 6) + png_warning(png_ptr, "Truncated compressed data in IDAT"); + + else + png_error(png_ptr, "Decompression error in IDAT"); + + /* Skip the check on unprocessed input */ + return; + } + + /* Did inflate output any data? */ + if (png_ptr->zstream.next_out != png_ptr->row_buf) + { + /* Is this unexpected data after the last row? + * If it is, artificially terminate the LZ output + * here. + */ + if (png_ptr->row_number >= png_ptr->num_rows || + png_ptr->pass > 6) + { + /* Extra data. */ + png_warning(png_ptr, "Extra compressed data in IDAT"); + png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; + png_ptr->zowner = 0; + + /* Do no more processing; skip the unprocessed + * input check below. + */ + return; + } + + /* Do we have a complete row? */ + if (png_ptr->zstream.avail_out == 0) + png_push_process_row(png_ptr); + } + + /* And check for the end of the stream. */ + if (ret == Z_STREAM_END) + png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; + } + + /* All the data should have been processed, if anything + * is left at this point we have bytes of IDAT data + * after the zlib end code. + */ + if (png_ptr->zstream.avail_in > 0) + png_warning(png_ptr, "Extra compression data in IDAT"); +} + +void /* PRIVATE */ +png_push_process_row(png_structrp png_ptr) +{ + /* 1.5.6: row_info moved out of png_struct to a local here. */ + png_row_info row_info; + + row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */ + row_info.color_type = png_ptr->color_type; + row_info.bit_depth = png_ptr->bit_depth; + row_info.channels = png_ptr->channels; + row_info.pixel_depth = png_ptr->pixel_depth; + row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width); + + if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE) + { + if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST) + png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1, + png_ptr->prev_row + 1, png_ptr->row_buf[0]); + else + png_error(png_ptr, "bad adaptive filter value"); + } + + /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before + * 1.5.6, while the buffer really is this big in current versions of libpng + * it may not be in the future, so this was changed just to copy the + * interlaced row count: + */ + memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1); + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED + if (png_ptr->transformations) + png_do_read_transformations(png_ptr, &row_info); +#endif + + /* The transformed pixel depth should match the depth now in row_info. */ + if (png_ptr->transformed_pixel_depth == 0) + { + png_ptr->transformed_pixel_depth = row_info.pixel_depth; + if (row_info.pixel_depth > png_ptr->maximum_pixel_depth) + png_error(png_ptr, "progressive row overflow"); + } + + else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth) + png_error(png_ptr, "internal progressive row size calculation error"); + + +#ifdef PNG_READ_INTERLACING_SUPPORTED + /* Expand interlaced rows to full size */ + if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) + { + if (png_ptr->pass < 6) + png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass, + png_ptr->transformations); + + switch (png_ptr->pass) + { + case 0: + { + int i; + for (i = 0; i < 8 && png_ptr->pass == 0; i++) + { + png_push_have_row(png_ptr, png_ptr->row_buf + 1); + png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */ + } + + if (png_ptr->pass == 2) /* Pass 1 might be empty */ + { + for (i = 0; i < 4 && png_ptr->pass == 2; i++) + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + } + + if (png_ptr->pass == 4 && png_ptr->height <= 4) + { + for (i = 0; i < 2 && png_ptr->pass == 4; i++) + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + } + + if (png_ptr->pass == 6 && png_ptr->height <= 4) + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + + break; + } + + case 1: + { + int i; + for (i = 0; i < 8 && png_ptr->pass == 1; i++) + { + png_push_have_row(png_ptr, png_ptr->row_buf + 1); + png_read_push_finish_row(png_ptr); + } + + if (png_ptr->pass == 2) /* Skip top 4 generated rows */ + { + for (i = 0; i < 4 && png_ptr->pass == 2; i++) + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + } + + break; + } + + case 2: + { + int i; + + for (i = 0; i < 4 && png_ptr->pass == 2; i++) + { + png_push_have_row(png_ptr, png_ptr->row_buf + 1); + png_read_push_finish_row(png_ptr); + } + + for (i = 0; i < 4 && png_ptr->pass == 2; i++) + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + + if (png_ptr->pass == 4) /* Pass 3 might be empty */ + { + for (i = 0; i < 2 && png_ptr->pass == 4; i++) + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + } + + break; + } + + case 3: + { + int i; + + for (i = 0; i < 4 && png_ptr->pass == 3; i++) + { + png_push_have_row(png_ptr, png_ptr->row_buf + 1); + png_read_push_finish_row(png_ptr); + } + + if (png_ptr->pass == 4) /* Skip top two generated rows */ + { + for (i = 0; i < 2 && png_ptr->pass == 4; i++) + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + } + + break; + } + + case 4: + { + int i; + + for (i = 0; i < 2 && png_ptr->pass == 4; i++) + { + png_push_have_row(png_ptr, png_ptr->row_buf + 1); + png_read_push_finish_row(png_ptr); + } + + for (i = 0; i < 2 && png_ptr->pass == 4; i++) + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + + if (png_ptr->pass == 6) /* Pass 5 might be empty */ + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + + break; + } + + case 5: + { + int i; + + for (i = 0; i < 2 && png_ptr->pass == 5; i++) + { + png_push_have_row(png_ptr, png_ptr->row_buf + 1); + png_read_push_finish_row(png_ptr); + } + + if (png_ptr->pass == 6) /* Skip top generated row */ + { + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + + break; + } + + default: + case 6: + { + png_push_have_row(png_ptr, png_ptr->row_buf + 1); + png_read_push_finish_row(png_ptr); + + if (png_ptr->pass != 6) + break; + + png_push_have_row(png_ptr, NULL); + png_read_push_finish_row(png_ptr); + } + } + } + else + { + png_push_have_row(png_ptr, png_ptr->row_buf + 1); + png_read_push_finish_row(png_ptr); + } +} + +void /* PRIVATE */ +png_read_push_finish_row(png_structrp png_ptr) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2}; + + /* Height of interlace block. This is not currently used - if you need + * it, uncomment it here and in png.h + static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1}; + */ +#endif + + png_ptr->row_number++; + if (png_ptr->row_number < png_ptr->num_rows) + return; + + if (png_ptr->interlaced) + { + png_ptr->row_number = 0; + memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); + + do + { + png_ptr->pass++; + if ((png_ptr->pass == 1 && png_ptr->width < 5) || + (png_ptr->pass == 3 && png_ptr->width < 3) || + (png_ptr->pass == 5 && png_ptr->width < 2)) + png_ptr->pass++; + + if (png_ptr->pass > 7) + png_ptr->pass--; + + if (png_ptr->pass >= 7) + break; + + png_ptr->iwidth = (png_ptr->width + + png_pass_inc[png_ptr->pass] - 1 - + png_pass_start[png_ptr->pass]) / + png_pass_inc[png_ptr->pass]; + + if (png_ptr->transformations & PNG_INTERLACE) + break; + + png_ptr->num_rows = (png_ptr->height + + png_pass_yinc[png_ptr->pass] - 1 - + png_pass_ystart[png_ptr->pass]) / + png_pass_yinc[png_ptr->pass]; + + } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0); + } +} + +void /* PRIVATE */ +png_push_have_info(png_structrp png_ptr, png_inforp info_ptr) +{ + if (png_ptr->info_fn != NULL) + (*(png_ptr->info_fn))(png_ptr, info_ptr); +} + +void /* PRIVATE */ +png_push_have_end(png_structrp png_ptr, png_inforp info_ptr) +{ + if (png_ptr->end_fn != NULL) + (*(png_ptr->end_fn))(png_ptr, info_ptr); +} + +void /* PRIVATE */ +png_push_have_row(png_structrp png_ptr, png_bytep row) +{ + if (png_ptr->row_fn != NULL) + (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number, + (int)png_ptr->pass); +} + +void PNGAPI +png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row, + png_const_bytep new_row) +{ + if (png_ptr == NULL) + return; + + /* new_row is a flag here - if it is NULL then the app callback was called + * from an empty row (see the calls to png_struct::row_fn below), otherwise + * it must be png_ptr->row_buf+1 + */ + if (new_row != NULL) + png_combine_row(png_ptr, old_row, 1/*blocky display*/); +} + +void PNGAPI +png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr, + png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn, + png_progressive_end_ptr end_fn) +{ + if (png_ptr == NULL) + return; + + png_ptr->info_fn = info_fn; + png_ptr->row_fn = row_fn; + png_ptr->end_fn = end_fn; + + png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer); +} + +png_voidp PNGAPI +png_get_progressive_ptr(png_const_structrp png_ptr) +{ + if (png_ptr == NULL) + return (NULL); + + return png_ptr->io_ptr; +} +#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ diff --git a/png/pngpriv.h b/png/pngpriv.h new file mode 100755 index 0000000..c498313 --- /dev/null +++ b/png/pngpriv.h @@ -0,0 +1,1940 @@ + +/* pngpriv.h - private declarations for use inside libpng + * + * For conditions of distribution and use, see copyright notice in png.h + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * Last changed in libpng 1.6.10 [March 6, 1014]] + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +/* The symbols declared in this file (including the functions declared + * as extern) are PRIVATE. They are not part of the libpng public + * interface, and are not recommended for use by regular applications. + * Some of them may become public in the future; others may stay private, + * change in an incompatible way, or even disappear. + * Although the libpng users are not forbidden to include this header, + * they should be well aware of the issues that may arise from doing so. + */ + +#ifndef PNGPRIV_H +#define PNGPRIV_H + +/* Feature Test Macros. The following are defined here to ensure that correctly + * implemented libraries reveal the APIs libpng needs to build and hide those + * that are not needed and potentially damaging to the compilation. + * + * Feature Test Macros must be defined before any system header is included (see + * POSIX 1003.1 2.8.2 "POSIX Symbols." + * + * These macros only have an effect if the operating system supports either + * POSIX 1003.1 or C99, or both. On other operating systems (particularly + * Windows/Visual Studio) there is no effect; the OS specific tests below are + * still required (as of 2011-05-02.) + */ +#define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */ + +#ifndef PNG_VERSION_INFO_ONLY +/* Standard library headers not required by png.h: */ +# include <stdlib.h> +# include <string.h> +#endif + +#define PNGLIB_BUILD /*libpng is being built, not used*/ + +/* If HAVE_CONFIG_H is defined during the build then the build system must + * provide an appropriate "config.h" file on the include path. The header file + * must provide definitions as required below (search for "HAVE_CONFIG_H"); + * see configure.ac for more details of the requirements. The macro + * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on + * 'configure'; define this macro to prevent the configure build including the + * configure generated config.h. Libpng is expected to compile without *any* + * special build system support on a reasonably ANSI-C compliant system. + */ +#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H) +# include <config.h> + + /* Pick up the definition of 'restrict' from config.h if it was read: */ +# define PNG_RESTRICT restrict +#endif + +/* To support symbol prefixing it is necessary to know *before* including png.h + * whether the fixed point (and maybe other) APIs are exported, because if they + * are not internal definitions may be required. This is handled below just + * before png.h is included, but load the configuration now if it is available. + */ +#ifndef PNGLCONF_H +# include "pnglibconf.h" +#endif + +/* Local renames may change non-exported API functions from png.h */ +#if defined(PNG_PREFIX) && !defined(PNGPREFIX_H) +# include "pngprefix.h" +#endif + +#ifdef PNG_USER_CONFIG +# include "pngusr.h" + /* These should have been defined in pngusr.h */ +# ifndef PNG_USER_PRIVATEBUILD +# define PNG_USER_PRIVATEBUILD "Custom libpng build" +# endif +# ifndef PNG_USER_DLLFNAME_POSTFIX +# define PNG_USER_DLLFNAME_POSTFIX "Cb" +# endif +#endif + +/* Compile time options. + * ===================== + * In a multi-arch build the compiler may compile the code several times for the + * same object module, producing different binaries for different architectures. + * When this happens configure-time setting of the target host options cannot be + * done and this interferes with the handling of the ARM NEON optimizations, and + * possibly other similar optimizations. Put additional tests here; in general + * this is needed when the same option can be changed at both compile time and + * run time depending on the target OS (i.e. iOS vs Android.) + * + * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because + * this is not possible with certain compilers (Oracle SUN OS CC), as a result + * it is necessary to ensure that all extern functions that *might* be used + * regardless of $(CFLAGS) get declared in this file. The test on __ARM_NEON__ + * below is one example of this behavior because it is controlled by the + * presence or not of -mfpu=neon on the GCC command line, it is possible to do + * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely + * do this. + */ +#ifndef PNG_ARM_NEON_OPT + /* ARM NEON optimizations are being controlled by the compiler settings, + * typically the target FPU. If the FPU has been set to NEON (-mfpu=neon + * with GCC) then the compiler will define __ARM_NEON__ and we can rely + * unconditionally on NEON instructions not crashing, otherwise we must + * disable use of NEON instructions. + * + * NOTE: at present these optimizations depend on 'ALIGNED_MEMORY', so they + * can only be turned on automatically if that is supported too. If + * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail + * to compile with an appropriate #error if ALIGNED_MEMORY has been turned + * off. + */ +# if defined(__ARM_NEON__) && defined(PNG_ALIGNED_MEMORY_SUPPORTED) +# define PNG_ARM_NEON_OPT 2 +# else +# define PNG_ARM_NEON_OPT 0 +# endif +#endif + +#if PNG_ARM_NEON_OPT > 0 + /* NEON optimizations are to be at least considered by libpng, so enable the + * callbacks to do this. + */ +# define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon + + /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used + * if possible - if __ARM_NEON__ is set and the compiler version is not known + * to be broken. This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can + * be: + * + * 1 The intrinsics code (the default with __ARM_NEON__) + * 2 The hand coded assembler (the default without __ARM_NEON__) + * + * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however + * this is *NOT* supported and may cease to work even after a minor revision + * to libpng. It *is* valid to do this for testing purposes, e.g. speed + * testing or a new compiler, but the results should be communicated to the + * libpng implementation list for incorporation in the next minor release. + */ +# ifndef PNG_ARM_NEON_IMPLEMENTATION +# ifdef __ARM_NEON__ +# if defined(__clang__) + /* At present it is unknown by the libpng developers which versions + * of clang support the intrinsics, however some or perhaps all + * versions do not work with the assembler so this may be + * irrelevant, so just use the default (do nothing here.) + */ +# elif defined(__GNUC__) + /* GCC 4.5.4 NEON support is known to be broken. 4.6.3 is known to + * work, so if this *is* GCC, or G++, look for a version >4.5 + */ +# if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6) +# define PNG_ARM_NEON_IMPLEMENTATION 2 +# endif /* no GNUC support */ +# endif /* __GNUC__ */ +# else /* !defined __ARM_NEON__ */ + /* The 'intrinsics' code simply won't compile without this -mfpu=neon: + */ +# define PNG_ARM_NEON_IMPLEMENTATION 2 +# endif /* __ARM_NEON__ */ +# endif /* !defined PNG_ARM_NEON_IMPLEMENTATION */ + +# ifndef PNG_ARM_NEON_IMPLEMENTATION + /* Use the intrinsics code by default. */ +# define PNG_ARM_NEON_IMPLEMENTATION 1 +# endif +#endif /* PNG_ARM_NEON_OPT > 0 */ + +/* Is this a build of a DLL where compilation of the object modules requires + * different preprocessor settings to those required for a simple library? If + * so PNG_BUILD_DLL must be set. + * + * If libpng is used inside a DLL but that DLL does not export the libpng APIs + * PNG_BUILD_DLL must not be set. To avoid the code below kicking in build a + * static library of libpng then link the DLL against that. + */ +#ifndef PNG_BUILD_DLL +# ifdef DLL_EXPORT + /* This is set by libtool when files are compiled for a DLL; libtool + * always compiles twice, even on systems where it isn't necessary. Set + * PNG_BUILD_DLL in case it is necessary: + */ +# define PNG_BUILD_DLL +# else +# ifdef _WINDLL + /* This is set by the Microsoft Visual Studio IDE in projects that + * build a DLL. It can't easily be removed from those projects (it + * isn't visible in the Visual Studio UI) so it is a fairly reliable + * indication that PNG_IMPEXP needs to be set to the DLL export + * attributes. + */ +# define PNG_BUILD_DLL +# else +# ifdef __DLL__ + /* This is set by the Borland C system when compiling for a DLL + * (as above.) + */ +# define PNG_BUILD_DLL +# else + /* Add additional compiler cases here. */ +# endif +# endif +# endif +#endif /* Setting PNG_BUILD_DLL if required */ + +/* See pngconf.h for more details: the builder of the library may set this on + * the command line to the right thing for the specific compilation system or it + * may be automagically set above (at present we know of no system where it does + * need to be set on the command line.) + * + * PNG_IMPEXP must be set here when building the library to prevent pngconf.h + * setting it to the "import" setting for a DLL build. + */ +#ifndef PNG_IMPEXP +# ifdef PNG_BUILD_DLL +# define PNG_IMPEXP PNG_DLL_EXPORT +# else + /* Not building a DLL, or the DLL doesn't require specific export + * definitions. + */ +# define PNG_IMPEXP +# endif +#endif + +/* No warnings for private or deprecated functions in the build: */ +#ifndef PNG_DEPRECATED +# define PNG_DEPRECATED +#endif +#ifndef PNG_PRIVATE +# define PNG_PRIVATE +#endif + +/* Symbol preprocessing support. + * + * To enable listing global, but internal, symbols the following macros should + * always be used to declare an extern data or function object in this file. + */ +#ifndef PNG_INTERNAL_DATA +# define PNG_INTERNAL_DATA(type, name, array) extern type name array +#endif + +#ifndef PNG_INTERNAL_FUNCTION +# define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\ + extern PNG_FUNCTION(type, name, args, PNG_EMPTY attributes) +#endif + +#ifndef PNG_INTERNAL_CALLBACK +# define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\ + extern PNG_FUNCTION(type, (PNGCBAPI name), args, PNG_EMPTY attributes) +#endif + +/* If floating or fixed point APIs are disabled they may still be compiled + * internally. To handle this make sure they are declared as the appropriate + * internal extern function (otherwise the symbol prefixing stuff won't work and + * the functions will be used without definitions.) + * + * NOTE: although all the API functions are declared here they are not all + * actually built! Because the declarations are still made it is necessary to + * fake out types that they depend on. + */ +#ifndef PNG_FP_EXPORT +# ifndef PNG_FLOATING_POINT_SUPPORTED +# define PNG_FP_EXPORT(ordinal, type, name, args)\ + PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY); +# ifndef PNG_VERSION_INFO_ONLY + typedef struct png_incomplete png_double; + typedef png_double* png_doublep; + typedef const png_double* png_const_doublep; + typedef png_double** png_doublepp; +# endif +# endif +#endif +#ifndef PNG_FIXED_EXPORT +# ifndef PNG_FIXED_POINT_SUPPORTED +# define PNG_FIXED_EXPORT(ordinal, type, name, args)\ + PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY); +# endif +#endif + +#include "png.h" + +/* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */ +#ifndef PNG_DLL_EXPORT +# define PNG_DLL_EXPORT +#endif + +/* SECURITY and SAFETY: + * + * By default libpng is built without any internal limits on image size, + * individual heap (png_malloc) allocations or the total amount of memory used. + * If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used + * (unless individually overridden). These limits are believed to be fairly + * safe, but builders of secure systems should verify the values against the + * real system capabilities. + */ +#ifdef PNG_SAFE_LIMITS_SUPPORTED + /* 'safe' limits */ +# ifndef PNG_USER_WIDTH_MAX +# define PNG_USER_WIDTH_MAX 1000000 +# endif +# ifndef PNG_USER_HEIGHT_MAX +# define PNG_USER_HEIGHT_MAX 1000000 +# endif +# ifndef PNG_USER_CHUNK_CACHE_MAX +# define PNG_USER_CHUNK_CACHE_MAX 128 +# endif +# ifndef PNG_USER_CHUNK_MALLOC_MAX +# define PNG_USER_CHUNK_MALLOC_MAX 8000000 +# endif +#else + /* values for no limits */ +# ifndef PNG_USER_WIDTH_MAX +# define PNG_USER_WIDTH_MAX 0x7fffffff +# endif +# ifndef PNG_USER_HEIGHT_MAX +# define PNG_USER_HEIGHT_MAX 0x7fffffff +# endif +# ifndef PNG_USER_CHUNK_CACHE_MAX +# define PNG_USER_CHUNK_CACHE_MAX 0 +# endif +# ifndef PNG_USER_CHUNK_MALLOC_MAX +# define PNG_USER_CHUNK_MALLOC_MAX 0 +# endif +#endif + +/* Moved to pngpriv.h at libpng-1.5.0 */ +/* NOTE: some of these may have been used in external applications as + * these definitions were exposed in pngconf.h prior to 1.5. + */ + +/* If you are running on a machine where you cannot allocate more + * than 64K of memory at once, uncomment this. While libpng will not + * normally need that much memory in a chunk (unless you load up a very + * large file), zlib needs to know how big of a chunk it can use, and + * libpng thus makes sure to check any memory allocation to verify it + * will fit into memory. + * + * zlib provides 'MAXSEG_64K' which, if defined, indicates the + * same limit and pngconf.h (already included) sets the limit + * if certain operating systems are detected. + */ +#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K) +# define PNG_MAX_MALLOC_64K +#endif + +#ifndef PNG_UNUSED +/* Unused formal parameter warnings are silenced using the following macro + * which is expected to have no bad effects on performance (optimizing + * compilers will probably remove it entirely). Note that if you replace + * it with something other than whitespace, you must include the terminating + * semicolon. + */ +# define PNG_UNUSED(param) (void)param; +#endif + +/* Just a little check that someone hasn't tried to define something + * contradictory. + */ +#if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K) +# undef PNG_ZBUF_SIZE +# define PNG_ZBUF_SIZE 65536L +#endif + +/* If warnings or errors are turned off the code is disabled or redirected here. + * From 1.5.4 functions have been added to allow very limited formatting of + * error and warning messages - this code will also be disabled here. + */ +#ifdef PNG_WARNINGS_SUPPORTED +# define PNG_WARNING_PARAMETERS(p) png_warning_parameters p; +#else +# define png_warning_parameter(p,number,string) ((void)0) +# define png_warning_parameter_unsigned(p,number,format,value) ((void)0) +# define png_warning_parameter_signed(p,number,format,value) ((void)0) +# define png_formatted_warning(pp,p,message) ((void)(pp)) +# define PNG_WARNING_PARAMETERS(p) +#endif +#ifndef PNG_ERROR_TEXT_SUPPORTED +# define png_fixed_error(s1,s2) png_err(s1) +#endif + +/* C allows up-casts from (void*) to any pointer and (const void*) to any + * pointer to a const object. C++ regards this as a type error and requires an + * explicit, static, cast and provides the static_cast<> rune to ensure that + * const is not cast away. + */ +#ifdef __cplusplus +# define png_voidcast(type, value) static_cast<type>(value) +# define png_constcast(type, value) const_cast<type>(value) +# define png_aligncast(type, value) \ + static_cast<type>(static_cast<void*>(value)) +# define png_aligncastconst(type, value) \ + static_cast<type>(static_cast<const void*>(value)) +#else +# define png_voidcast(type, value) (value) +# define png_constcast(type, value) ((type)(value)) +# define png_aligncast(type, value) ((void*)(value)) +# define png_aligncastconst(type, value) ((const void*)(value)) +#endif /* __cplusplus */ + +/* Some fixed point APIs are still required even if not exported because + * they get used by the corresponding floating point APIs. This magic + * deals with this: + */ +#ifdef PNG_FIXED_POINT_SUPPORTED +# define PNGFAPI PNGAPI +#else +# define PNGFAPI /* PRIVATE */ +#endif + +#ifndef PNG_VERSION_INFO_ONLY +/* Other defines specific to compilers can go here. Try to keep + * them inside an appropriate ifdef/endif pair for portability. + */ +#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\ + defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) + /* png.c requires the following ANSI-C constants if the conversion of + * floating point to ASCII is implemented therein: + * + * DBL_DIG Maximum number of decimal digits (can be set to any constant) + * DBL_MIN Smallest normalized fp number (can be set to an arbitrary value) + * DBL_MAX Maximum floating point number (can be set to an arbitrary value) + */ +# include <float.h> + +# if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \ + defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC) + /* We need to check that <math.h> hasn't already been included earlier + * as it seems it doesn't agree with <fp.h>, yet we should really use + * <fp.h> if possible. + */ +# if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__) +# include <fp.h> +# endif +# else +# include <math.h> +# endif +# if defined(_AMIGA) && defined(__SASC) && defined(_M68881) + /* Amiga SAS/C: We must include builtin FPU functions when compiling using + * MATH=68881 + */ +# include <m68881.h> +# endif +#endif + +/* This provides the non-ANSI (far) memory allocation routines. */ +#if defined(__TURBOC__) && defined(__MSDOS__) +# include <mem.h> +# include <alloc.h> +#endif + +#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \ + defined(_WIN32) || defined(__WIN32__) +# include <windows.h> /* defines _WINDOWS_ macro */ +#endif +#endif /* PNG_VERSION_INFO_ONLY */ + +/* Moved here around 1.5.0beta36 from pngconf.h */ +/* Users may want to use these so they are not private. Any library + * functions that are passed far data must be model-independent. + */ + +/* Memory model/platform independent fns */ +#ifndef PNG_ABORT +# ifdef _WINDOWS_ +# define PNG_ABORT() ExitProcess(0) +# else +# define PNG_ABORT() abort() +# endif +#endif + +/* These macros may need to be architecture dependent. */ +#define PNG_ALIGN_NONE 0 /* do not use data alignment */ +#define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */ +#ifdef offsetof +# define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */ +#else +# define PNG_ALIGN_OFFSET -1 /* prevent the use of this */ +#endif +#define PNG_ALIGN_SIZE 3 /* use sizeof to determine alignment */ + +#ifndef PNG_ALIGN_TYPE + /* Default to using aligned access optimizations and requiring alignment to a + * multiple of the data type size. Override in a compiler specific fashion + * if necessary by inserting tests here: + */ +# define PNG_ALIGN_TYPE PNG_ALIGN_SIZE +#endif + +#if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE + /* This is used because in some compiler implementations non-aligned + * structure members are supported, so the offsetof approach below fails. + * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access + * is good for performance. Do not do this unless you have tested the result + * and understand it. + */ +# define png_alignof(type) (sizeof (type)) +#else +# if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET +# define png_alignof(type) offsetof(struct{char c; type t;}, t) +# else +# if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS +# define png_alignof(type) (1) +# endif + /* Else leave png_alignof undefined to prevent use thereof */ +# endif +#endif + +/* This implicitly assumes alignment is always to a power of 2. */ +#ifdef png_alignof +# define png_isaligned(ptr, type)\ + ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0) +#else +# define png_isaligned(ptr, type) 0 +#endif + +/* End of memory model/platform independent support */ +/* End of 1.5.0beta36 move from pngconf.h */ + +/* CONSTANTS and UTILITY MACROS + * These are used internally by libpng and not exposed in the API + */ + +/* Various modes of operation. Note that after an init, mode is set to + * zero automatically when the structure is created. Three of these + * are defined in png.h because they need to be visible to applications + * that call png_set_unknown_chunk(). + */ +/* #define PNG_HAVE_IHDR 0x01 (defined in png.h) */ +/* #define PNG_HAVE_PLTE 0x02 (defined in png.h) */ +#define PNG_HAVE_IDAT 0x04 +/* #define PNG_AFTER_IDAT 0x08 (defined in png.h) */ +#define PNG_HAVE_IEND 0x10 + /* 0x20 (unused) */ + /* 0x40 (unused) */ + /* 0x80 (unused) */ +#define PNG_HAVE_CHUNK_HEADER 0x100 +#define PNG_WROTE_tIME 0x200 +#define PNG_WROTE_INFO_BEFORE_PLTE 0x400 +#define PNG_BACKGROUND_IS_GRAY 0x800 +#define PNG_HAVE_PNG_SIGNATURE 0x1000 +#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */ + /* 0x4000 (unused) */ +#define PNG_IS_READ_STRUCT 0x8000 /* Else is a write struct */ + +/* Flags for the transformations the PNG library does on the image data */ +#define PNG_BGR 0x0001 +#define PNG_INTERLACE 0x0002 +#define PNG_PACK 0x0004 +#define PNG_SHIFT 0x0008 +#define PNG_SWAP_BYTES 0x0010 +#define PNG_INVERT_MONO 0x0020 +#define PNG_QUANTIZE 0x0040 +#define PNG_COMPOSE 0x0080 /* Was PNG_BACKGROUND */ +#define PNG_BACKGROUND_EXPAND 0x0100 +#define PNG_EXPAND_16 0x0200 /* Added to libpng 1.5.2 */ +#define PNG_16_TO_8 0x0400 /* Becomes 'chop' in 1.5.4 */ +#define PNG_RGBA 0x0800 +#define PNG_EXPAND 0x1000 +#define PNG_GAMMA 0x2000 +#define PNG_GRAY_TO_RGB 0x4000 +#define PNG_FILLER 0x8000 +#define PNG_PACKSWAP 0x10000 +#define PNG_SWAP_ALPHA 0x20000 +#define PNG_STRIP_ALPHA 0x40000 +#define PNG_INVERT_ALPHA 0x80000 +#define PNG_USER_TRANSFORM 0x100000 +#define PNG_RGB_TO_GRAY_ERR 0x200000 +#define PNG_RGB_TO_GRAY_WARN 0x400000 +#define PNG_RGB_TO_GRAY 0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */ +#define PNG_ENCODE_ALPHA 0x800000 /* Added to libpng-1.5.4 */ +#define PNG_ADD_ALPHA 0x1000000 /* Added to libpng-1.2.7 */ +#define PNG_EXPAND_tRNS 0x2000000 /* Added to libpng-1.2.9 */ +#define PNG_SCALE_16_TO_8 0x4000000 /* Added to libpng-1.5.4 */ + /* 0x8000000 unused */ + /* 0x10000000 unused */ + /* 0x20000000 unused */ + /* 0x40000000 unused */ +/* Flags for png_create_struct */ +#define PNG_STRUCT_PNG 0x0001 +#define PNG_STRUCT_INFO 0x0002 + +/* Scaling factor for filter heuristic weighting calculations */ +#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT)) +#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT)) + +/* Flags for the png_ptr->flags rather than declaring a byte for each one */ +#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY 0x0001 +#define PNG_FLAG_ZSTREAM_INITIALIZED 0x0002 /* Added to libpng-1.6.0 */ + /* 0x0004 unused */ +#define PNG_FLAG_ZSTREAM_ENDED 0x0008 /* Added to libpng-1.6.0 */ + /* 0x0010 unused */ + /* 0x0020 unused */ +#define PNG_FLAG_ROW_INIT 0x0040 +#define PNG_FLAG_FILLER_AFTER 0x0080 +#define PNG_FLAG_CRC_ANCILLARY_USE 0x0100 +#define PNG_FLAG_CRC_ANCILLARY_NOWARN 0x0200 +#define PNG_FLAG_CRC_CRITICAL_USE 0x0400 +#define PNG_FLAG_CRC_CRITICAL_IGNORE 0x0800 +#define PNG_FLAG_ASSUME_sRGB 0x1000 /* Added to libpng-1.5.4 */ +#define PNG_FLAG_OPTIMIZE_ALPHA 0x2000 /* Added to libpng-1.5.4 */ +#define PNG_FLAG_DETECT_UNINITIALIZED 0x4000 /* Added to libpng-1.5.4 */ +/* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS 0x8000 */ +/* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS 0x10000 */ +#define PNG_FLAG_LIBRARY_MISMATCH 0x20000 +#define PNG_FLAG_STRIP_ERROR_NUMBERS 0x40000 +#define PNG_FLAG_STRIP_ERROR_TEXT 0x80000 +#define PNG_FLAG_BENIGN_ERRORS_WARN 0x100000 /* Added to libpng-1.4.0 */ +#define PNG_FLAG_APP_WARNINGS_WARN 0x200000 /* Added to libpng-1.6.0 */ +#define PNG_FLAG_APP_ERRORS_WARN 0x400000 /* Added to libpng-1.6.0 */ + /* 0x800000 unused */ + /* 0x1000000 unused */ + /* 0x2000000 unused */ + /* 0x4000000 unused */ + /* 0x8000000 unused */ + /* 0x10000000 unused */ + /* 0x20000000 unused */ + /* 0x40000000 unused */ + +#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \ + PNG_FLAG_CRC_ANCILLARY_NOWARN) + +#define PNG_FLAG_CRC_CRITICAL_MASK (PNG_FLAG_CRC_CRITICAL_USE | \ + PNG_FLAG_CRC_CRITICAL_IGNORE) + +#define PNG_FLAG_CRC_MASK (PNG_FLAG_CRC_ANCILLARY_MASK | \ + PNG_FLAG_CRC_CRITICAL_MASK) + +/* Save typing and make code easier to understand */ + +#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \ + abs((int)((c1).green) - (int)((c2).green)) + \ + abs((int)((c1).blue) - (int)((c2).blue))) + +/* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255 + * by dividing by 257 *with rounding*. This macro is exact for the given range. + * See the discourse in pngrtran.c png_do_scale_16_to_8. The values in the + * macro were established by experiment (modifying the added value). The macro + * has a second variant that takes a value already scaled by 255 and divides by + * 65535 - this has a maximum error of .502. Over the range 0..65535*65535 it + * only gives off-by-one errors and only for 0.5% (1 in 200) of the values. + */ +#define PNG_DIV65535(v24) (((v24) + 32895) >> 16) +#define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255) + +/* Added to libpng-1.2.6 JB */ +#define PNG_ROWBYTES(pixel_bits, width) \ + ((pixel_bits) >= 8 ? \ + ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \ + (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) ) + +/* PNG_OUT_OF_RANGE returns true if value is outside the range + * ideal-delta..ideal+delta. Each argument is evaluated twice. + * "ideal" and "delta" should be constants, normally simple + * integers, "value" a variable. Added to libpng-1.2.6 JB + */ +#define PNG_OUT_OF_RANGE(value, ideal, delta) \ + ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) ) + +/* Conversions between fixed and floating point, only defined if + * required (to make sure the code doesn't accidentally use float + * when it is supposedly disabled.) + */ +#ifdef PNG_FLOATING_POINT_SUPPORTED +/* The floating point conversion can't overflow, though it can and + * does lose accuracy relative to the original fixed point value. + * In practice this doesn't matter because png_fixed_point only + * stores numbers with very low precision. The png_ptr and s + * arguments are unused by default but are there in case error + * checking becomes a requirement. + */ +#define png_float(png_ptr, fixed, s) (.00001 * (fixed)) + +/* The fixed point conversion performs range checking and evaluates + * its argument multiple times, so must be used with care. The + * range checking uses the PNG specification values for a signed + * 32 bit fixed point value except that the values are deliberately + * rounded-to-zero to an integral value - 21474 (21474.83 is roughly + * (2^31-1) * 100000). 's' is a string that describes the value being + * converted. + * + * NOTE: this macro will raise a png_error if the range check fails, + * therefore it is normally only appropriate to use this on values + * that come from API calls or other sources where an out of range + * error indicates a programming error, not a data error! + * + * NOTE: by default this is off - the macro is not used - because the + * function call saves a lot of code. + */ +#ifdef PNG_FIXED_POINT_MACRO_SUPPORTED +#define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\ + ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0)) +#endif +/* else the corresponding function is defined below, inside the scope of the + * cplusplus test. + */ +#endif + +/* Constants for known chunk types. If you need to add a chunk, define the name + * here. For historical reasons these constants have the form png_<name>; i.e. + * the prefix is lower case. Please use decimal values as the parameters to + * match the ISO PNG specification and to avoid relying on the C locale + * interpretation of character values. + * + * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values + * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string + * to be generated if required. + * + * PNG_32b correctly produces a value shifted by up to 24 bits, even on + * architectures where (int) is only 16 bits. + */ +#define PNG_32b(b,s) ((png_uint_32)(b) << (s)) +#define PNG_U32(b1,b2,b3,b4) \ + (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0)) + +/* Constants for known chunk types. + * + * MAINTAINERS: If you need to add a chunk, define the name here. + * For historical reasons these constants have the form png_<name>; i.e. + * the prefix is lower case. Please use decimal values as the parameters to + * match the ISO PNG specification and to avoid relying on the C locale + * interpretation of character values. Please keep the list sorted. + * + * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk + * type. In fact the specification does not express chunk types this way, + * however using a 32-bit value means that the chunk type can be read from the + * stream using exactly the same code as used for a 32-bit unsigned value and + * can be examined far more efficiently (using one arithmetic compare). + * + * Prior to 1.5.6 the chunk type constants were expressed as C strings. The + * libpng API still uses strings for 'unknown' chunks and a macro, + * PNG_STRING_FROM_CHUNK, allows a string to be generated if required. Notice + * that for portable code numeric values must still be used; the string "IHDR" + * is not portable and neither is PNG_U32('I', 'H', 'D', 'R'). + * + * In 1.7.0 the definitions will be made public in png.h to avoid having to + * duplicate the same definitions in application code. + */ +#define png_IDAT PNG_U32( 73, 68, 65, 84) +#define png_IEND PNG_U32( 73, 69, 78, 68) +#define png_IHDR PNG_U32( 73, 72, 68, 82) +#define png_PLTE PNG_U32( 80, 76, 84, 69) +#define png_bKGD PNG_U32( 98, 75, 71, 68) +#define png_cHRM PNG_U32( 99, 72, 82, 77) +#define png_fRAc PNG_U32(102, 82, 65, 99) /* registered, not defined */ +#define png_gAMA PNG_U32(103, 65, 77, 65) +#define png_gIFg PNG_U32(103, 73, 70, 103) +#define png_gIFt PNG_U32(103, 73, 70, 116) /* deprecated */ +#define png_gIFx PNG_U32(103, 73, 70, 120) +#define png_hIST PNG_U32(104, 73, 83, 84) +#define png_iCCP PNG_U32(105, 67, 67, 80) +#define png_iTXt PNG_U32(105, 84, 88, 116) +#define png_oFFs PNG_U32(111, 70, 70, 115) +#define png_pCAL PNG_U32(112, 67, 65, 76) +#define png_pHYs PNG_U32(112, 72, 89, 115) +#define png_sBIT PNG_U32(115, 66, 73, 84) +#define png_sCAL PNG_U32(115, 67, 65, 76) +#define png_sPLT PNG_U32(115, 80, 76, 84) +#define png_sRGB PNG_U32(115, 82, 71, 66) +#define png_sTER PNG_U32(115, 84, 69, 82) +#define png_tEXt PNG_U32(116, 69, 88, 116) +#define png_tIME PNG_U32(116, 73, 77, 69) +#define png_tRNS PNG_U32(116, 82, 78, 83) +#define png_zTXt PNG_U32(122, 84, 88, 116) + +/* The following will work on (signed char*) strings, whereas the get_uint_32 + * macro will fail on top-bit-set values because of the sign extension. + */ +#define PNG_CHUNK_FROM_STRING(s)\ + PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3]) + +/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is + * signed and the argument is a (char[]) This macro will fail miserably on + * systems where (char) is more than 8 bits. + */ +#define PNG_STRING_FROM_CHUNK(s,c)\ + (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\ + ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c))) + +/* Do the same but terminate with a null character. */ +#define PNG_CSTRING_FROM_CHUNK(s,c)\ + (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0) + +/* Test on flag values as defined in the spec (section 5.4): */ +#define PNG_CHUNK_ANCILLARY(c) (1 & ((c) >> 29)) +#define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLARY(c)) +#define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21)) +#define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13)) +#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5)) + +/* Gamma values (new at libpng-1.5.4): */ +#define PNG_GAMMA_MAC_OLD 151724 /* Assume '1.8' is really 2.2/1.45! */ +#define PNG_GAMMA_MAC_INVERSE 65909 +#define PNG_GAMMA_sRGB_INVERSE 45455 + +/* Almost everything below is C specific; the #defines above can be used in + * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot. + */ +#ifndef PNG_VERSION_INFO_ONLY + +#include "pngstruct.h" +#include "pnginfo.h" + +/* Validate the include paths - the include path used to generate pnglibconf.h + * must match that used in the build, or we must be using pnglibconf.h.prebuilt: + */ +#if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM +# error ZLIB_VERNUM != PNG_ZLIB_VERNUM \ + "-I (include path) error: see the notes in pngpriv.h" + /* This means that when pnglibconf.h was built the copy of zlib.h that it + * used is not the same as the one being used here. Because the build of + * libpng makes decisions to use inflateInit2 and inflateReset2 based on the + * zlib version number and because this affects handling of certain broken + * PNG files the -I directives must match. + * + * The most likely explanation is that you passed a -I in CFLAGS. This will + * not work; all the preprocessor directories and in particular all the -I + * directives must be in CPPFLAGS. + */ +#endif + +/* This is used for 16 bit gamma tables -- only the top level pointers are + * const; this could be changed: + */ +typedef const png_uint_16p * png_const_uint_16pp; + +/* Added to libpng-1.5.7: sRGB conversion tables */ +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ + defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED +PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]); + /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value, + * 0..65535. This table gives the closest 16-bit answers (no errors). + */ +#endif + +PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]); +PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]); + +#define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\ + ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)) + /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB + * encoded value with maximum error 0.646365. Note that the input is not a + * 16-bit value; it has been multiplied by 255! */ +#endif /* PNG_SIMPLIFIED_READ/WRITE */ + + +/* Inhibit C++ name-mangling for libpng functions but not for system calls. */ +#ifdef __cplusplus +extern "C" { +#endif /* __cplusplus */ + +/* Internal functions; these are not exported from a DLL however because they + * are used within several of the C source files they have to be C extern. + * + * All of these functions must be declared with PNG_INTERNAL_FUNCTION. + */ + +/* Zlib support */ +#define PNG_UNEXPECTED_ZLIB_RETURN (-7) +PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret), + PNG_EMPTY); + /* Used by the zlib handling functions to ensure that z_stream::msg is always + * set before they return. + */ + +#ifdef PNG_WRITE_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr, + png_compression_bufferp *list),PNG_EMPTY); + /* Free the buffer list used by the compressed write code. */ +#endif + +#if defined(PNG_FLOATING_POINT_SUPPORTED) && \ + !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \ + (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \ + defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \ + (defined(PNG_sCAL_SUPPORTED) && \ + defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)) +PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr, + double fp, png_const_charp text),PNG_EMPTY); +#endif + +/* Check the user version string for compatibility, returns false if the version + * numbers aren't compatible. + */ +PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr, + png_const_charp user_png_ver),PNG_EMPTY); + +/* Internal base allocator - no messages, NULL on failure to allocate. This + * does, however, call the application provided allocator and that could call + * png_error (although that would be a bug in the application implementation.) + */ +PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr, + png_alloc_size_t size),PNG_ALLOCATED); + +#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\ + defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) +/* Internal array allocator, outputs no error or warning messages on failure, + * just returns NULL. + */ +PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr, + int nelements, size_t element_size),PNG_ALLOCATED); + +/* The same but an existing array is extended by add_elements. This function + * also memsets the new elements to 0 and copies the old elements. The old + * array is not freed or altered. + */ +PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr, + png_const_voidp array, int old_elements, int add_elements, + size_t element_size),PNG_ALLOCATED); +#endif /* text, sPLT or unknown chunks */ + +/* Magic to create a struct when there is no struct to call the user supplied + * memory allocators. Because error handling has not been set up the memory + * handlers can't safely call png_error, but this is an obscure and undocumented + * restriction so libpng has to assume that the 'free' handler, at least, might + * call png_error. + */ +PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct, + (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn, + png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn, + png_free_ptr free_fn),PNG_ALLOCATED); + +/* Free memory from internal libpng struct */ +PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr), + PNG_EMPTY); + +/* Free an allocated jmp_buf (always succeeds) */ +PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY); + +/* Function to allocate memory for zlib. PNGAPI is disallowed. */ +PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size), + PNG_ALLOCATED); + +/* Function to free memory for zlib. PNGAPI is disallowed. */ +PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY); + +/* Next four functions are used internally as callbacks. PNGCBAPI is required + * but not PNG_EXPORT. PNGAPI added at libpng version 1.2.3, changed to + * PNGCBAPI at 1.5.0 + */ + +PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr, + png_bytep data, png_size_t length),PNG_EMPTY); + +#ifdef PNG_PROGRESSIVE_READ_SUPPORTED +PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr, + png_bytep buffer, png_size_t length),PNG_EMPTY); +#endif + +PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr, + png_bytep data, png_size_t length),PNG_EMPTY); + +#ifdef PNG_WRITE_FLUSH_SUPPORTED +# ifdef PNG_STDIO_SUPPORTED +PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr), + PNG_EMPTY); +# endif +#endif + +/* Reset the CRC variable */ +PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY); + +/* Write the "data" buffer to whatever output you are using */ +PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr, + png_const_bytep data, png_size_t length),PNG_EMPTY); + +/* Read and check the PNG file signature */ +PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); + +/* Read the chunk header (length + type name) */ +PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr), + PNG_EMPTY); + +/* Read data from whatever input you are using into the "data" buffer */ +PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data, + png_size_t length),PNG_EMPTY); + +/* Read bytes into buf, and update png_ptr->crc */ +PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf, + png_uint_32 length),PNG_EMPTY); + +/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */ +PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr, + png_uint_32 skip),PNG_EMPTY); + +/* Read the CRC from the file and compare it to the libpng calculated CRC */ +PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY); + +/* Calculate the CRC over a section of data. Note that we are only + * passing a maximum of 64K on systems that have this as a memory limit, + * since this is the maximum buffer size we can specify. + */ +PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr, + png_const_bytep ptr, png_size_t length),PNG_EMPTY); + +#ifdef PNG_WRITE_FLUSH_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY); +#endif + +/* Write various chunks */ + +/* Write the IHDR chunk, and update the png_struct with the necessary + * information. + */ +PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr, + png_uint_32 width, png_uint_32 height, int bit_depth, int color_type, + int compression_method, int filter_method, int interlace_method),PNG_EMPTY); + +PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr, + png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY); + +PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr, + png_const_bytep row_data, png_alloc_size_t row_data_length, int flush), + PNG_EMPTY); + +PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY); + +#ifdef PNG_WRITE_gAMA_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr, + png_fixed_point file_gamma),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_sBIT_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr, + png_const_color_8p sbit, int color_type),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_cHRM_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr, + const png_xy *xy), PNG_EMPTY); + /* The xy value must have been previously validated */ +#endif + +#ifdef PNG_WRITE_sRGB_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr, + int intent),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_iCCP_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr, + png_const_charp name, png_const_bytep profile), PNG_EMPTY); + /* The profile must have been previously validated for correctness, the + * length comes from the first four bytes. Only the base, deflate, + * compression is supported. + */ +#endif + +#ifdef PNG_WRITE_sPLT_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr, + png_const_sPLT_tp palette),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_tRNS_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr, + png_const_bytep trans, png_const_color_16p values, int number, + int color_type),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_bKGD_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr, + png_const_color_16p values, int color_type),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_hIST_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr, + png_const_uint_16p hist, int num_hist),PNG_EMPTY); +#endif + +/* Chunks that have keywords */ +#ifdef PNG_WRITE_tEXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr, + png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_zTXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp + key, png_const_charp text, png_size_t text_len, int compression),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_iTXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr, + int compression, png_const_charp key, png_const_charp lang, + png_const_charp lang_key, png_const_charp text),PNG_EMPTY); +#endif + +#ifdef PNG_TEXT_SUPPORTED /* Added at version 1.0.14 and 1.2.4 */ +PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr, + png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_oFFs_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr, + png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_pCAL_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr, + png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams, + png_const_charp units, png_charpp params),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_pHYs_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr, + png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit, + int unit_type),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_tIME_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr, + png_const_timep mod_time),PNG_EMPTY); +#endif + +#ifdef PNG_WRITE_sCAL_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr, + int unit, png_const_charp width, png_const_charp height),PNG_EMPTY); +#endif + +/* Called when finished processing a row of data */ +PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr), + PNG_EMPTY); + +/* Internal use only. Called before first row of data */ +PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr), + PNG_EMPTY); + +/* Combine a row of data, dealing with alpha, etc. if requested. 'row' is an + * array of png_ptr->width pixels. If the image is not interlaced or this + * is the final pass this just does a memcpy, otherwise the "display" flag + * is used to determine whether to copy pixels that are not in the current pass. + * + * Because 'png_do_read_interlace' (below) replicates pixels this allows this + * function to achieve the documented 'blocky' appearance during interlaced read + * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row' + * are not changed if they are not in the current pass, when display is 0. + * + * 'display' must be 0 or 1, otherwise the memcpy will be done regardless. + * + * The API always reads from the png_struct row buffer and always assumes that + * it is full width (png_do_read_interlace has already been called.) + * + * This function is only ever used to write to row buffers provided by the + * caller of the relevant libpng API and the row must have already been + * transformed by the read transformations. + * + * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed + * bitmasks for use within the code, otherwise runtime generated masks are used. + * The default is compile time masks. + */ +#ifndef PNG_USE_COMPILE_TIME_MASKS +# define PNG_USE_COMPILE_TIME_MASKS 1 +#endif +PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr, + png_bytep row, int display),PNG_EMPTY); + +#ifdef PNG_READ_INTERLACING_SUPPORTED +/* Expand an interlaced row: the 'row_info' describes the pass data that has + * been read in and must correspond to the pixels in 'row', the pixels are + * expanded (moved apart) in 'row' to match the final layout, when doing this + * the pixels are *replicated* to the intervening space. This is essential for + * the correct operation of png_combine_row, above. + */ +PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info, + png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY); +#endif + +/* GRR TO DO (2.0 or whenever): simplify other internal calling interfaces */ + +#ifdef PNG_WRITE_INTERLACING_SUPPORTED +/* Grab pixels out of a row for an interlaced pass */ +PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info, + png_bytep row, int pass),PNG_EMPTY); +#endif + +/* Unfilter a row: check the filter value before calling this, there is no point + * calling it for PNG_FILTER_VALUE_NONE. + */ +PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop + row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY); + +PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info, + png_bytep row, png_const_bytep prev_row),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop + row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop + row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop + row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop + row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop + row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop + row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY); + +/* Choose the best filter to use and filter the row data */ +PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr, + png_row_infop row_info),PNG_EMPTY); + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr, + png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY); + /* Read 'avail_out' bytes of data from the IDAT stream. If the output buffer + * is NULL the function checks, instead, for the end of the stream. In this + * case a benign error will be issued if the stream end is not found or if + * extra data has to be consumed. + */ +PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr), + PNG_EMPTY); + /* This cleans up when the IDAT LZ stream does not end when the last image + * byte is read; there is still some pending input. + */ + +PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr), + PNG_EMPTY); + /* Finish a row while reading, dealing with interlacing passes, etc. */ +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +/* Initialize the row buffers, etc. */ +PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY); + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +/* Optional call to update the users info structure */ +PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +#endif + +/* Shared transform functions, defined in pngtran.c */ +#if defined(PNG_WRITE_FILLER_SUPPORTED) || \ + defined(PNG_READ_STRIP_ALPHA_SUPPORTED) +PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info, + png_bytep row, int at_start),PNG_EMPTY); +#endif + +#ifdef PNG_16BIT_SUPPORTED +#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) +PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info, + png_bytep row),PNG_EMPTY); +#endif +#endif + +#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \ + defined(PNG_WRITE_PACKSWAP_SUPPORTED) +PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info, + png_bytep row),PNG_EMPTY); +#endif + +#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) +PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info, + png_bytep row),PNG_EMPTY); +#endif + +#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) +PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info, + png_bytep row),PNG_EMPTY); +#endif + +/* The following decodes the appropriate chunks, and does error correction, + * then calls the appropriate callback for the chunk if it is valid. + */ + +/* Decode the IHDR chunk */ +PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); + +#ifdef PNG_READ_bKGD_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_cHRM_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_gAMA_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_hIST_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_iCCP_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif /* PNG_READ_iCCP_SUPPORTED */ + +#ifdef PNG_READ_iTXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_oFFs_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_pCAL_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_pHYs_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_sBIT_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_sCAL_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_sPLT_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif /* PNG_READ_sPLT_SUPPORTED */ + +#ifdef PNG_READ_sRGB_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_tEXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_tIME_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_tRNS_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +#ifdef PNG_READ_zTXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +#endif + +PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_structrp png_ptr, + png_uint_32 chunk_name),PNG_EMPTY); + +PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY); + /* This is the function that gets called for unknown chunks. The 'keep' + * argument is either non-zero for a known chunk that has been set to be + * handled as unknown or zero for an unknown chunk. By default the function + * just skips the chunk or errors out if it is critical. + */ + +#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\ + defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED) +PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling, + (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY); + /* Exactly as the API png_handle_as_unknown() except that the argument is a + * 32-bit chunk name, not a string. + */ +#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */ + +/* Handle the transformations for reading and writing */ +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr, + png_row_infop row_info),PNG_EMPTY); +#endif +#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr, + png_row_infop row_info),PNG_EMPTY); +#endif + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr), + PNG_EMPTY); +#endif + +#ifdef PNG_PROGRESSIVE_READ_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_crc_skip,(png_structrp png_ptr, + png_uint_32 length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_crc_finish,(png_structrp png_ptr), + PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr), + PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr, + png_bytep buffer, png_size_t buffer_length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr, + png_bytep buffer, png_size_t buffer_length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr), + PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr, + png_bytep row),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr), + PNG_EMPTY); +# ifdef PNG_READ_tEXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +# endif +# ifdef PNG_READ_zTXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +# endif +# ifdef PNG_READ_iTXt_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr, + png_inforp info_ptr, png_uint_32 length),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr, + png_inforp info_ptr),PNG_EMPTY); +# endif + +#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ + +/* Added at libpng version 1.6.0 */ +#ifdef PNG_GAMMA_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY); + /* Set the colorspace gamma with a value provided by the application or by + * the gAMA chunk on read. The value will override anything set by an ICC + * profile. + */ + +PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr, + png_inforp info_ptr), PNG_EMPTY); + /* Synchronize the info 'valid' flags with the colorspace */ + +PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr, + png_inforp info_ptr), PNG_EMPTY); + /* Copy the png_struct colorspace to the info_struct and call the above to + * synchronize the flags. Checks for NULL info_ptr and does nothing. + */ +#endif + +/* Added at libpng version 1.4.0 */ +#ifdef PNG_COLORSPACE_SUPPORTED +/* These internal functions are for maintaining the colorspace structure within + * a png_info or png_struct (or, indeed, both). + */ +PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities, + (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy, + int preferred), PNG_EMPTY); + +PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints, + (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ, + int preferred), PNG_EMPTY); + +#ifdef PNG_sRGB_SUPPORTED +PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr, + png_colorspacerp colorspace, int intent), PNG_EMPTY); + /* This does set the colorspace gAMA and cHRM values too, but doesn't set the + * flags to write them, if it returns false there was a problem and an error + * message has already been output (but the colorspace may still need to be + * synced to record the invalid flag). + */ +#endif /* sRGB */ + +#ifdef PNG_iCCP_SUPPORTED +PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_const_charp name, + png_uint_32 profile_length, png_const_bytep profile, int color_type), + PNG_EMPTY); + /* The 'name' is used for information only */ + +/* Routines for checking parts of an ICC profile. */ +PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_const_charp name, + png_uint_32 profile_length), PNG_EMPTY); +PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_const_charp name, + png_uint_32 profile_length, + png_const_bytep profile /* first 132 bytes only */, int color_type), + PNG_EMPTY); +PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr, + png_colorspacerp colorspace, png_const_charp name, + png_uint_32 profile_length, + png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY); +#ifdef PNG_sRGB_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,( + png_const_structrp png_ptr, png_colorspacerp colorspace, + png_const_bytep profile, uLong adler), PNG_EMPTY); + /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may + * be zero to indicate that it is not available. It is used, if provided, + * as a fast check on the profile when checking to see if it is sRGB. + */ +#endif +#endif /* iCCP */ + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients, + (png_structrp png_ptr), PNG_EMPTY); + /* Set the rgb_to_gray coefficients from the colorspace Y values */ +#endif /* READ_RGB_TO_GRAY */ +#endif /* COLORSPACE */ + +/* Added at libpng version 1.4.0 */ +PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr, + png_uint_32 width, png_uint_32 height, int bit_depth, + int color_type, int interlace_type, int compression_type, + int filter_type),PNG_EMPTY); + +/* Added at libpng version 1.5.10 */ +#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \ + defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED) +PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes, + (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY); +#endif + +#if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED) +PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr, + png_const_charp name),PNG_NORETURN); +#endif + +/* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite + * the end. Always leaves the buffer nul terminated. Never errors out (and + * there is no error code.) + */ +PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize, + size_t pos, png_const_charp string),PNG_EMPTY); + +/* Various internal functions to handle formatted warning messages, currently + * only implemented for warnings. + */ +#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED) +/* Utility to dump an unsigned value into a buffer, given a start pointer and + * and end pointer (which should point just *beyond* the end of the buffer!) + * Returns the pointer to the start of the formatted string. This utility only + * does unsigned values. + */ +PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start, + png_charp end, int format, png_alloc_size_t number),PNG_EMPTY); + +/* Convenience macro that takes an array: */ +#define PNG_FORMAT_NUMBER(buffer,format,number) \ + png_format_number(buffer, buffer + (sizeof buffer), format, number) + +/* Suggested size for a number buffer (enough for 64 bits and a sign!) */ +#define PNG_NUMBER_BUFFER_SIZE 24 + +/* These are the integer formats currently supported, the name is formed from + * the standard printf(3) format string. + */ +#define PNG_NUMBER_FORMAT_u 1 /* chose unsigned API! */ +#define PNG_NUMBER_FORMAT_02u 2 +#define PNG_NUMBER_FORMAT_d 1 /* chose signed API! */ +#define PNG_NUMBER_FORMAT_02d 2 +#define PNG_NUMBER_FORMAT_x 3 +#define PNG_NUMBER_FORMAT_02x 4 +#define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */ +#endif + +#ifdef PNG_WARNINGS_SUPPORTED +/* New defines and members adding in libpng-1.5.4 */ +# define PNG_WARNING_PARAMETER_SIZE 32 +# define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */ + +/* An l-value of this type has to be passed to the APIs below to cache the + * values of the parameters to a formatted warning message. + */ +typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][ + PNG_WARNING_PARAMETER_SIZE]; + +PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p, + int number, png_const_charp string),PNG_EMPTY); + /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters, + * including the trailing '\0'. + */ +PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned, + (png_warning_parameters p, int number, int format, png_alloc_size_t value), + PNG_EMPTY); + /* Use png_alloc_size_t because it is an unsigned type as big as any we + * need to output. Use the following for a signed value. + */ +PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed, + (png_warning_parameters p, int number, int format, png_int_32 value), + PNG_EMPTY); + +PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr, + png_warning_parameters p, png_const_charp message),PNG_EMPTY); + /* 'message' follows the X/Open approach of using @1, @2 to insert + * parameters previously supplied using the above functions. Errors in + * specifying the parameters will simply result in garbage substitutions. + */ +#endif + +#ifdef PNG_BENIGN_ERRORS_SUPPORTED +/* Application errors (new in 1.6); use these functions (declared below) for + * errors in the parameters or order of API function calls on read. The + * 'warning' should be used for an error that can be handled completely; the + * 'error' for one which can be handled safely but which may lose application + * information or settings. + * + * By default these both result in a png_error call prior to release, while in a + * released version the 'warning' is just a warning. However if the application + * explicitly disables benign errors (explicitly permitting the code to lose + * information) they both turn into warnings. + * + * If benign errors aren't supported they end up as the corresponding base call + * (png_warning or png_error.) + */ +PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr, + png_const_charp message),PNG_EMPTY); + /* The application provided invalid parameters to an API function or called + * an API function at the wrong time, libpng can completely recover. + */ + +PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr, + png_const_charp message),PNG_EMPTY); + /* As above but libpng will ignore the call, or attempt some other partial + * recovery from the error. + */ +#else +# define png_app_warning(pp,s) png_warning(pp,s) +# define png_app_error(pp,s) png_error(pp,s) +#endif + +PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr, + png_const_charp message, int error),PNG_EMPTY); + /* Report a recoverable issue in chunk data. On read this is used to report + * a problem found while reading a particular chunk and the + * png_chunk_benign_error or png_chunk_warning function is used as + * appropriate. On write this is used to report an error that comes from + * data set via an application call to a png_set_ API and png_app_error or + * png_app_warning is used as appropriate. + * + * The 'error' parameter must have one of the following values: + */ +#define PNG_CHUNK_WARNING 0 /* never an error */ +#define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */ +#define PNG_CHUNK_ERROR 2 /* always an error */ + +/* ASCII to FP interfaces, currently only implemented if sCAL + * support is required. + */ +#if defined(PNG_sCAL_SUPPORTED) +/* MAX_DIGITS is actually the maximum number of characters in an sCAL + * width or height, derived from the precision (number of significant + * digits - a build time settable option) and assumptions about the + * maximum ridiculous exponent. + */ +#define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/) + +#ifdef PNG_FLOATING_POINT_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr, + png_charp ascii, png_size_t size, double fp, unsigned int precision), + PNG_EMPTY); +#endif /* FLOATING_POINT */ + +#ifdef PNG_FIXED_POINT_SUPPORTED +PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr, + png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY); +#endif /* FIXED_POINT */ +#endif /* sCAL */ + +#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED) +/* An internal API to validate the format of a floating point number. + * The result is the index of the next character. If the number is + * not valid it will be the index of a character in the supposed number. + * + * The format of a number is defined in the PNG extensions specification + * and this API is strictly conformant to that spec, not anyone elses! + * + * The format as a regular expression is: + * + * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)? + * + * or: + * + * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)? + * + * The complexity is that either integer or fraction must be present and the + * fraction is permitted to have no digits only if the integer is present. + * + * NOTE: The dangling E problem. + * There is a PNG valid floating point number in the following: + * + * PNG floating point numbers are not greedy. + * + * Working this out requires *TWO* character lookahead (because of the + * sign), the parser does not do this - it will fail at the 'r' - this + * doesn't matter for PNG sCAL chunk values, but it requires more care + * if the value were ever to be embedded in something more complex. Use + * ANSI-C strtod if you need the lookahead. + */ +/* State table for the parser. */ +#define PNG_FP_INTEGER 0 /* before or in integer */ +#define PNG_FP_FRACTION 1 /* before or in fraction */ +#define PNG_FP_EXPONENT 2 /* before or in exponent */ +#define PNG_FP_STATE 3 /* mask for the above */ +#define PNG_FP_SAW_SIGN 4 /* Saw +/- in current state */ +#define PNG_FP_SAW_DIGIT 8 /* Saw a digit in current state */ +#define PNG_FP_SAW_DOT 16 /* Saw a dot in current state */ +#define PNG_FP_SAW_E 32 /* Saw an E (or e) in current state */ +#define PNG_FP_SAW_ANY 60 /* Saw any of the above 4 */ + +/* These three values don't affect the parser. They are set but not used. + */ +#define PNG_FP_WAS_VALID 64 /* Preceding substring is a valid fp number */ +#define PNG_FP_NEGATIVE 128 /* A negative number, including "-0" */ +#define PNG_FP_NONZERO 256 /* A non-zero value */ +#define PNG_FP_STICKY 448 /* The above three flags */ + +/* This is available for the caller to store in 'state' if required. Do not + * call the parser after setting it (the parser sometimes clears it.) + */ +#define PNG_FP_INVALID 512 /* Available for callers as a distinct value */ + +/* Result codes for the parser (boolean - true meants ok, false means + * not ok yet.) + */ +#define PNG_FP_MAYBE 0 /* The number may be valid in the future */ +#define PNG_FP_OK 1 /* The number is valid */ + +/* Tests on the sticky non-zero and negative flags. To pass these checks + * the state must also indicate that the whole number is valid - this is + * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this + * is equivalent to PNG_FP_OK above.) + */ +#define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO) + /* NZ_MASK: the string is valid and a non-zero negative value */ +#define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO) + /* Z MASK: the string is valid and a non-zero value. */ + /* PNG_FP_SAW_DIGIT: the string is valid. */ +#define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT) +#define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK) +#define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK) + +/* The actual parser. This can be called repeatedly. It updates + * the index into the string and the state variable (which must + * be initialized to 0). It returns a result code, as above. There + * is no point calling the parser any more if it fails to advance to + * the end of the string - it is stuck on an invalid character (or + * terminated by '\0'). + * + * Note that the pointer will consume an E or even an E+ and then leave + * a 'maybe' state even though a preceding integer.fraction is valid. + * The PNG_FP_WAS_VALID flag indicates that a preceding substring was + * a valid number. It's possible to recover from this by calling + * the parser again (from the start, with state 0) but with a string + * that omits the last character (i.e. set the size to the index of + * the problem character.) This has not been tested within libpng. + */ +PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string, + png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY); + +/* This is the same but it checks a complete string and returns true + * only if it just contains a floating point number. As of 1.5.4 this + * function also returns the state at the end of parsing the number if + * it was valid (otherwise it returns 0.) This can be used for testing + * for negative or zero values using the sticky flag. + */ +PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string, + png_size_t size),PNG_EMPTY); +#endif /* pCAL || sCAL */ + +#if defined(PNG_GAMMA_SUPPORTED) ||\ + defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED) +/* Added at libpng version 1.5.0 */ +/* This is a utility to provide a*times/div (rounded) and indicate + * if there is an overflow. The result is a boolean - false (0) + * for overflow, true (1) if no overflow, in which case *res + * holds the result. + */ +PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a, + png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY); +#endif + +#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED) +/* Same deal, but issue a warning on overflow and return 0. */ +PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn, + (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by, + png_int_32 divided_by),PNG_EMPTY); +#endif + +#ifdef PNG_GAMMA_SUPPORTED +/* Calculate a reciprocal - used for gamma values. This returns + * 0 if the argument is 0 in order to maintain an undefined value; + * there are no warnings. + */ +PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a), + PNG_EMPTY); + +#ifdef PNG_READ_GAMMA_SUPPORTED +/* The same but gives a reciprocal of the product of two fixed point + * values. Accuracy is suitable for gamma calculations but this is + * not exact - use png_muldiv for that. Only required at present on read. + */ +PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a, + png_fixed_point b),PNG_EMPTY); +#endif + +/* Return true if the gamma value is significantly different from 1.0 */ +PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value), + PNG_EMPTY); +#endif + +#ifdef PNG_READ_GAMMA_SUPPORTED +/* Internal fixed point gamma correction. These APIs are called as + * required to convert single values - they don't need to be fast, + * they are not used when processing image pixel values. + * + * While the input is an 'unsigned' value it must actually be the + * correct bit value - 0..255 or 0..65535 as required. + */ +PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr, + unsigned int value, png_fixed_point gamma_value),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value, + png_fixed_point gamma_value),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value, + png_fixed_point gamma_value),PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr), + PNG_EMPTY); +PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr, + int bit_depth),PNG_EMPTY); +#endif + +/* SIMPLIFIED READ/WRITE SUPPORT */ +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ + defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) +/* The internal structure that png_image::opaque points to. */ +typedef struct png_control +{ + png_structp png_ptr; + png_infop info_ptr; + png_voidp error_buf; /* Always a jmp_buf at present. */ + + png_const_bytep memory; /* Memory buffer. */ + png_size_t size; /* Size of the memory buffer. */ + + unsigned int for_write :1; /* Otherwise it is a read structure */ + unsigned int owned_file :1; /* We own the file in io_ptr */ +} png_control; + +/* Return the pointer to the jmp_buf from a png_control: necessary because C + * does not reveal the type of the elements of jmp_buf. + */ +#ifdef __cplusplus +# define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0]) +#else +# define png_control_jmp_buf(pc) ((pc)->error_buf) +#endif + +/* Utility to safely execute a piece of libpng code catching and logging any + * errors that might occur. Returns true on success, false on failure (either + * of the function or as a result of a png_error.) + */ +PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr, + png_const_charp error_message),PNG_NORETURN); + +#ifdef PNG_WARNINGS_SUPPORTED +PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr, + png_const_charp warning_message),PNG_EMPTY); +#else +# define png_safe_warning 0/*dummy argument*/ +#endif + +PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image, + int (*function)(png_voidp), png_voidp arg),PNG_EMPTY); + +/* Utility to log an error; this also cleans up the png_image; the function + * always returns 0 (false). + */ +PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image, + png_const_charp error_message),PNG_EMPTY); + +#ifndef PNG_SIMPLIFIED_READ_SUPPORTED +/* png_image_free is used by the write code but not exported */ +PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY); +#endif /* !SIMPLIFIED_READ */ + +#endif /* SIMPLIFIED READ/WRITE */ + +/* These are initialization functions for hardware specific PNG filter + * optimizations; list these here then select the appropriate one at compile + * time using the macro PNG_FILTER_OPTIMIZATIONS. If the macro is not defined + * the generic code is used. + */ +#ifdef PNG_FILTER_OPTIMIZATIONS +PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr, + unsigned int bpp), PNG_EMPTY); + /* Just declare the optimization that will be used */ +#else + /* List *all* the possible optimizations here - this branch is required if + * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in + * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing. + */ +PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon, + (png_structp png_ptr, unsigned int bpp), PNG_EMPTY); +#endif + +/* Maintainer: Put new private prototypes here ^ */ + +#include "pngdebug.h" + +#ifdef __cplusplus +} +#endif + +#endif /* PNG_VERSION_INFO_ONLY */ +#endif /* PNGPRIV_H */ diff --git a/png/pngread.c b/png/pngread.c new file mode 100755 index 0000000..4bf2021 --- /dev/null +++ b/png/pngread.c @@ -0,0 +1,4098 @@ + +/* pngread.c - read a PNG file + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * This file contains routines that an application calls directly to + * read a PNG file or stream. + */ + +#include "pngpriv.h" +#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) +# include <errno.h> +#endif + +#ifdef PNG_READ_SUPPORTED + +/* Create a PNG structure for reading, and allocate any memory needed. */ +PNG_FUNCTION(png_structp,PNGAPI +png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr, + png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED) +{ +#ifndef PNG_USER_MEM_SUPPORTED + png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr, + error_fn, warn_fn, NULL, NULL, NULL); +#else + return png_create_read_struct_2(user_png_ver, error_ptr, error_fn, + warn_fn, NULL, NULL, NULL); +} + +/* Alternate create PNG structure for reading, and allocate any memory + * needed. + */ +PNG_FUNCTION(png_structp,PNGAPI +png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr, + png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr, + png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED) +{ + png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr, + error_fn, warn_fn, mem_ptr, malloc_fn, free_fn); +#endif /* PNG_USER_MEM_SUPPORTED */ + + if (png_ptr != NULL) + { + png_ptr->mode = PNG_IS_READ_STRUCT; + + /* Added in libpng-1.6.0; this can be used to detect a read structure if + * required (it will be zero in a write structure.) + */ +# ifdef PNG_SEQUENTIAL_READ_SUPPORTED + png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE; +# endif + +# ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED + png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN; + + /* In stable builds only warn if an application error can be completely + * handled. + */ +# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC + png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN; +# endif +# endif + + /* TODO: delay this, it can be done in png_init_io (if the app doesn't + * do it itself) avoiding setting the default function if it is not + * required. + */ + png_set_read_fn(png_ptr, NULL, NULL); + } + + return png_ptr; +} + + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read the information before the actual image data. This has been + * changed in v0.90 to allow reading a file that already has the magic + * bytes read from the stream. You can tell libpng how many bytes have + * been read from the beginning of the stream (up to the maximum of 8) + * via png_set_sig_bytes(), and we will only check the remaining bytes + * here. The application can then have access to the signature bytes we + * read if it is determined that this isn't a valid PNG file. + */ +void PNGAPI +png_read_info(png_structrp png_ptr, png_inforp info_ptr) +{ +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED + int keep; +#endif + + png_debug(1, "in png_read_info"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + /* Read and check the PNG file signature. */ + png_read_sig(png_ptr, info_ptr); + + for (;;) + { + png_uint_32 length = png_read_chunk_header(png_ptr); + png_uint_32 chunk_name = png_ptr->chunk_name; + + /* IDAT logic needs to happen here to simplify getting the two flags + * right. + */ + if (chunk_name == png_IDAT) + { + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "Missing IHDR before IDAT"); + + else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && + !(png_ptr->mode & PNG_HAVE_PLTE)) + png_chunk_error(png_ptr, "Missing PLTE before IDAT"); + + else if (png_ptr->mode & PNG_AFTER_IDAT) + png_chunk_benign_error(png_ptr, "Too many IDATs found"); + + png_ptr->mode |= PNG_HAVE_IDAT; + } + + else if (png_ptr->mode & PNG_HAVE_IDAT) + png_ptr->mode |= PNG_AFTER_IDAT; + + /* This should be a binary subdivision search or a hash for + * matching the chunk name rather than a linear search. + */ + if (chunk_name == png_IHDR) + png_handle_IHDR(png_ptr, info_ptr, length); + + else if (chunk_name == png_IEND) + png_handle_IEND(png_ptr, info_ptr, length); + +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED + else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0) + { + png_handle_unknown(png_ptr, info_ptr, length, keep); + + if (chunk_name == png_PLTE) + png_ptr->mode |= PNG_HAVE_PLTE; + + else if (chunk_name == png_IDAT) + { + png_ptr->idat_size = 0; /* It has been consumed */ + break; + } + } +#endif + else if (chunk_name == png_PLTE) + png_handle_PLTE(png_ptr, info_ptr, length); + + else if (chunk_name == png_IDAT) + { + png_ptr->idat_size = length; + break; + } + +#ifdef PNG_READ_bKGD_SUPPORTED + else if (chunk_name == png_bKGD) + png_handle_bKGD(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_cHRM_SUPPORTED + else if (chunk_name == png_cHRM) + png_handle_cHRM(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_gAMA_SUPPORTED + else if (chunk_name == png_gAMA) + png_handle_gAMA(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_hIST_SUPPORTED + else if (chunk_name == png_hIST) + png_handle_hIST(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_oFFs_SUPPORTED + else if (chunk_name == png_oFFs) + png_handle_oFFs(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_pCAL_SUPPORTED + else if (chunk_name == png_pCAL) + png_handle_pCAL(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_sCAL_SUPPORTED + else if (chunk_name == png_sCAL) + png_handle_sCAL(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_pHYs_SUPPORTED + else if (chunk_name == png_pHYs) + png_handle_pHYs(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_sBIT_SUPPORTED + else if (chunk_name == png_sBIT) + png_handle_sBIT(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_sRGB_SUPPORTED + else if (chunk_name == png_sRGB) + png_handle_sRGB(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_iCCP_SUPPORTED + else if (chunk_name == png_iCCP) + png_handle_iCCP(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_sPLT_SUPPORTED + else if (chunk_name == png_sPLT) + png_handle_sPLT(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_tEXt_SUPPORTED + else if (chunk_name == png_tEXt) + png_handle_tEXt(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_tIME_SUPPORTED + else if (chunk_name == png_tIME) + png_handle_tIME(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_tRNS_SUPPORTED + else if (chunk_name == png_tRNS) + png_handle_tRNS(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_zTXt_SUPPORTED + else if (chunk_name == png_zTXt) + png_handle_zTXt(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_iTXt_SUPPORTED + else if (chunk_name == png_iTXt) + png_handle_iTXt(png_ptr, info_ptr, length); +#endif + + else + png_handle_unknown(png_ptr, info_ptr, length, + PNG_HANDLE_CHUNK_AS_DEFAULT); + } +} +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +/* Optional call to update the users info_ptr structure */ +void PNGAPI +png_read_update_info(png_structrp png_ptr, png_inforp info_ptr) +{ + png_debug(1, "in png_read_update_info"); + + if (png_ptr != NULL) + { + if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0) + { + png_read_start_row(png_ptr); + +# ifdef PNG_READ_TRANSFORMS_SUPPORTED + png_read_transform_info(png_ptr, info_ptr); +# else + PNG_UNUSED(info_ptr) +# endif + } + + /* New in 1.6.0 this avoids the bug of doing the initializations twice */ + else + png_app_error(png_ptr, + "png_read_update_info/png_start_read_image: duplicate call"); + } +} + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Initialize palette, background, etc, after transformations + * are set, but before any reading takes place. This allows + * the user to obtain a gamma-corrected palette, for example. + * If the user doesn't call this, we will do it ourselves. + */ +void PNGAPI +png_start_read_image(png_structrp png_ptr) +{ + png_debug(1, "in png_start_read_image"); + + if (png_ptr != NULL) + { + if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0) + png_read_start_row(png_ptr); + + /* New in 1.6.0 this avoids the bug of doing the initializations twice */ + else + png_app_error(png_ptr, + "png_start_read_image/png_read_update_info: duplicate call"); + } +} +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +#ifdef PNG_MNG_FEATURES_SUPPORTED +/* Undoes intrapixel differencing, + * NOTE: this is apparently only supported in the 'sequential' reader. + */ +static void +png_do_read_intrapixel(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_read_intrapixel"); + + if ( + (row_info->color_type & PNG_COLOR_MASK_COLOR)) + { + int bytes_per_pixel; + png_uint_32 row_width = row_info->width; + + if (row_info->bit_depth == 8) + { + png_bytep rp; + png_uint_32 i; + + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + bytes_per_pixel = 3; + + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + bytes_per_pixel = 4; + + else + return; + + for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) + { + *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff); + *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff); + } + } + else if (row_info->bit_depth == 16) + { + png_bytep rp; + png_uint_32 i; + + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + bytes_per_pixel = 6; + + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + bytes_per_pixel = 8; + + else + return; + + for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) + { + png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1); + png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3); + png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5); + png_uint_32 red = (s0 + s1 + 65536) & 0xffff; + png_uint_32 blue = (s2 + s1 + 65536) & 0xffff; + *(rp ) = (png_byte)((red >> 8) & 0xff); + *(rp + 1) = (png_byte)(red & 0xff); + *(rp + 4) = (png_byte)((blue >> 8) & 0xff); + *(rp + 5) = (png_byte)(blue & 0xff); + } + } + } +} +#endif /* PNG_MNG_FEATURES_SUPPORTED */ + +void PNGAPI +png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row) +{ + png_row_info row_info; + + if (png_ptr == NULL) + return; + + png_debug2(1, "in png_read_row (row %lu, pass %d)", + (unsigned long)png_ptr->row_number, png_ptr->pass); + + /* png_read_start_row sets the information (in particular iwidth) for this + * interlace pass. + */ + if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) + png_read_start_row(png_ptr); + + /* 1.5.6: row_info moved out of png_struct to a local here. */ + row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */ + row_info.color_type = png_ptr->color_type; + row_info.bit_depth = png_ptr->bit_depth; + row_info.channels = png_ptr->channels; + row_info.pixel_depth = png_ptr->pixel_depth; + row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width); + + if (png_ptr->row_number == 0 && png_ptr->pass == 0) + { + /* Check for transforms that have been set but were defined out */ +#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED) + if (png_ptr->transformations & PNG_INVERT_MONO) + png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined"); +#endif + +#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED) + if (png_ptr->transformations & PNG_FILLER) + png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined"); +#endif + +#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \ + !defined(PNG_READ_PACKSWAP_SUPPORTED) + if (png_ptr->transformations & PNG_PACKSWAP) + png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined"); +#endif + +#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED) + if (png_ptr->transformations & PNG_PACK) + png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined"); +#endif + +#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) + if (png_ptr->transformations & PNG_SHIFT) + png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined"); +#endif + +#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED) + if (png_ptr->transformations & PNG_BGR) + png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined"); +#endif + +#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED) + if (png_ptr->transformations & PNG_SWAP_BYTES) + png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined"); +#endif + } + +#ifdef PNG_READ_INTERLACING_SUPPORTED + /* If interlaced and we do not need a new row, combine row and return. + * Notice that the pixels we have from previous rows have been transformed + * already; we can only combine like with like (transformed or + * untransformed) and, because of the libpng API for interlaced images, this + * means we must transform before de-interlacing. + */ + if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) + { + switch (png_ptr->pass) + { + case 0: + if (png_ptr->row_number & 0x07) + { + if (dsp_row != NULL) + png_combine_row(png_ptr, dsp_row, 1/*display*/); + png_read_finish_row(png_ptr); + return; + } + break; + + case 1: + if ((png_ptr->row_number & 0x07) || png_ptr->width < 5) + { + if (dsp_row != NULL) + png_combine_row(png_ptr, dsp_row, 1/*display*/); + + png_read_finish_row(png_ptr); + return; + } + break; + + case 2: + if ((png_ptr->row_number & 0x07) != 4) + { + if (dsp_row != NULL && (png_ptr->row_number & 4)) + png_combine_row(png_ptr, dsp_row, 1/*display*/); + + png_read_finish_row(png_ptr); + return; + } + break; + + case 3: + if ((png_ptr->row_number & 3) || png_ptr->width < 3) + { + if (dsp_row != NULL) + png_combine_row(png_ptr, dsp_row, 1/*display*/); + + png_read_finish_row(png_ptr); + return; + } + break; + + case 4: + if ((png_ptr->row_number & 3) != 2) + { + if (dsp_row != NULL && (png_ptr->row_number & 2)) + png_combine_row(png_ptr, dsp_row, 1/*display*/); + + png_read_finish_row(png_ptr); + return; + } + break; + + case 5: + if ((png_ptr->row_number & 1) || png_ptr->width < 2) + { + if (dsp_row != NULL) + png_combine_row(png_ptr, dsp_row, 1/*display*/); + + png_read_finish_row(png_ptr); + return; + } + break; + + default: + case 6: + if (!(png_ptr->row_number & 1)) + { + png_read_finish_row(png_ptr); + return; + } + break; + } + } +#endif + + if (!(png_ptr->mode & PNG_HAVE_IDAT)) + png_error(png_ptr, "Invalid attempt to read row data"); + + /* Fill the row with IDAT data: */ + png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1); + + if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE) + { + if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST) + png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1, + png_ptr->prev_row + 1, png_ptr->row_buf[0]); + else + png_error(png_ptr, "bad adaptive filter value"); + } + + /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before + * 1.5.6, while the buffer really is this big in current versions of libpng + * it may not be in the future, so this was changed just to copy the + * interlaced count: + */ + memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1); + +#ifdef PNG_MNG_FEATURES_SUPPORTED + if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && + (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING)) + { + /* Intrapixel differencing */ + png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1); + } +#endif + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED + if (png_ptr->transformations) + png_do_read_transformations(png_ptr, &row_info); +#endif + + /* The transformed pixel depth should match the depth now in row_info. */ + if (png_ptr->transformed_pixel_depth == 0) + { + png_ptr->transformed_pixel_depth = row_info.pixel_depth; + if (row_info.pixel_depth > png_ptr->maximum_pixel_depth) + png_error(png_ptr, "sequential row overflow"); + } + + else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth) + png_error(png_ptr, "internal sequential row size calculation error"); + +#ifdef PNG_READ_INTERLACING_SUPPORTED + /* Expand interlaced rows to full size */ + if (png_ptr->interlaced && + (png_ptr->transformations & PNG_INTERLACE)) + { + if (png_ptr->pass < 6) + png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass, + png_ptr->transformations); + + if (dsp_row != NULL) + png_combine_row(png_ptr, dsp_row, 1/*display*/); + + if (row != NULL) + png_combine_row(png_ptr, row, 0/*row*/); + } + + else +#endif + { + if (row != NULL) + png_combine_row(png_ptr, row, -1/*ignored*/); + + if (dsp_row != NULL) + png_combine_row(png_ptr, dsp_row, -1/*ignored*/); + } + png_read_finish_row(png_ptr); + + if (png_ptr->read_row_fn != NULL) + (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass); + +} +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read one or more rows of image data. If the image is interlaced, + * and png_set_interlace_handling() has been called, the rows need to + * contain the contents of the rows from the previous pass. If the + * image has alpha or transparency, and png_handle_alpha()[*] has been + * called, the rows contents must be initialized to the contents of the + * screen. + * + * "row" holds the actual image, and pixels are placed in it + * as they arrive. If the image is displayed after each pass, it will + * appear to "sparkle" in. "display_row" can be used to display a + * "chunky" progressive image, with finer detail added as it becomes + * available. If you do not want this "chunky" display, you may pass + * NULL for display_row. If you do not want the sparkle display, and + * you have not called png_handle_alpha(), you may pass NULL for rows. + * If you have called png_handle_alpha(), and the image has either an + * alpha channel or a transparency chunk, you must provide a buffer for + * rows. In this case, you do not have to provide a display_row buffer + * also, but you may. If the image is not interlaced, or if you have + * not called png_set_interlace_handling(), the display_row buffer will + * be ignored, so pass NULL to it. + * + * [*] png_handle_alpha() does not exist yet, as of this version of libpng + */ + +void PNGAPI +png_read_rows(png_structrp png_ptr, png_bytepp row, + png_bytepp display_row, png_uint_32 num_rows) +{ + png_uint_32 i; + png_bytepp rp; + png_bytepp dp; + + png_debug(1, "in png_read_rows"); + + if (png_ptr == NULL) + return; + + rp = row; + dp = display_row; + if (rp != NULL && dp != NULL) + for (i = 0; i < num_rows; i++) + { + png_bytep rptr = *rp++; + png_bytep dptr = *dp++; + + png_read_row(png_ptr, rptr, dptr); + } + + else if (rp != NULL) + for (i = 0; i < num_rows; i++) + { + png_bytep rptr = *rp; + png_read_row(png_ptr, rptr, NULL); + rp++; + } + + else if (dp != NULL) + for (i = 0; i < num_rows; i++) + { + png_bytep dptr = *dp; + png_read_row(png_ptr, NULL, dptr); + dp++; + } +} +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read the entire image. If the image has an alpha channel or a tRNS + * chunk, and you have called png_handle_alpha()[*], you will need to + * initialize the image to the current image that PNG will be overlaying. + * We set the num_rows again here, in case it was incorrectly set in + * png_read_start_row() by a call to png_read_update_info() or + * png_start_read_image() if png_set_interlace_handling() wasn't called + * prior to either of these functions like it should have been. You can + * only call this function once. If you desire to have an image for + * each pass of a interlaced image, use png_read_rows() instead. + * + * [*] png_handle_alpha() does not exist yet, as of this version of libpng + */ +void PNGAPI +png_read_image(png_structrp png_ptr, png_bytepp image) +{ + png_uint_32 i, image_height; + int pass, j; + png_bytepp rp; + + png_debug(1, "in png_read_image"); + + if (png_ptr == NULL) + return; + +#ifdef PNG_READ_INTERLACING_SUPPORTED + if (!(png_ptr->flags & PNG_FLAG_ROW_INIT)) + { + pass = png_set_interlace_handling(png_ptr); + /* And make sure transforms are initialized. */ + png_start_read_image(png_ptr); + } + else + { + if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE)) + { + /* Caller called png_start_read_image or png_read_update_info without + * first turning on the PNG_INTERLACE transform. We can fix this here, + * but the caller should do it! + */ + png_warning(png_ptr, "Interlace handling should be turned on when " + "using png_read_image"); + /* Make sure this is set correctly */ + png_ptr->num_rows = png_ptr->height; + } + + /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in + * the above error case. + */ + pass = png_set_interlace_handling(png_ptr); + } +#else + if (png_ptr->interlaced) + png_error(png_ptr, + "Cannot read interlaced image -- interlace handler disabled"); + + pass = 1; +#endif + + image_height=png_ptr->height; + + for (j = 0; j < pass; j++) + { + rp = image; + for (i = 0; i < image_height; i++) + { + png_read_row(png_ptr, *rp, NULL); + rp++; + } + } +} +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +/* Read the end of the PNG file. Will not read past the end of the + * file, will verify the end is accurate, and will read any comments + * or time information at the end of the file, if info is not NULL. + */ +void PNGAPI +png_read_end(png_structrp png_ptr, png_inforp info_ptr) +{ +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED + int keep; +#endif + + png_debug(1, "in png_read_end"); + + if (png_ptr == NULL) + return; + + /* If png_read_end is called in the middle of reading the rows there may + * still be pending IDAT data and an owned zstream. Deal with this here. + */ +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED + if (!png_chunk_unknown_handling(png_ptr, png_IDAT)) +#endif + png_read_finish_IDAT(png_ptr); + +#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED + /* Report invalid palette index; added at libng-1.5.10 */ + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && + png_ptr->num_palette_max > png_ptr->num_palette) + png_benign_error(png_ptr, "Read palette index exceeding num_palette"); +#endif + + do + { + png_uint_32 length = png_read_chunk_header(png_ptr); + png_uint_32 chunk_name = png_ptr->chunk_name; + + if (chunk_name == png_IEND) + png_handle_IEND(png_ptr, info_ptr, length); + + else if (chunk_name == png_IHDR) + png_handle_IHDR(png_ptr, info_ptr, length); + + else if (info_ptr == NULL) + png_crc_finish(png_ptr, length); + +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED + else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0) + { + if (chunk_name == png_IDAT) + { + if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT)) + png_benign_error(png_ptr, "Too many IDATs found"); + } + png_handle_unknown(png_ptr, info_ptr, length, keep); + if (chunk_name == png_PLTE) + png_ptr->mode |= PNG_HAVE_PLTE; + } +#endif + + else if (chunk_name == png_IDAT) + { + /* Zero length IDATs are legal after the last IDAT has been + * read, but not after other chunks have been read. + */ + if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT)) + png_benign_error(png_ptr, "Too many IDATs found"); + + png_crc_finish(png_ptr, length); + } + else if (chunk_name == png_PLTE) + png_handle_PLTE(png_ptr, info_ptr, length); + +#ifdef PNG_READ_bKGD_SUPPORTED + else if (chunk_name == png_bKGD) + png_handle_bKGD(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_cHRM_SUPPORTED + else if (chunk_name == png_cHRM) + png_handle_cHRM(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_gAMA_SUPPORTED + else if (chunk_name == png_gAMA) + png_handle_gAMA(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_hIST_SUPPORTED + else if (chunk_name == png_hIST) + png_handle_hIST(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_oFFs_SUPPORTED + else if (chunk_name == png_oFFs) + png_handle_oFFs(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_pCAL_SUPPORTED + else if (chunk_name == png_pCAL) + png_handle_pCAL(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_sCAL_SUPPORTED + else if (chunk_name == png_sCAL) + png_handle_sCAL(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_pHYs_SUPPORTED + else if (chunk_name == png_pHYs) + png_handle_pHYs(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_sBIT_SUPPORTED + else if (chunk_name == png_sBIT) + png_handle_sBIT(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_sRGB_SUPPORTED + else if (chunk_name == png_sRGB) + png_handle_sRGB(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_iCCP_SUPPORTED + else if (chunk_name == png_iCCP) + png_handle_iCCP(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_sPLT_SUPPORTED + else if (chunk_name == png_sPLT) + png_handle_sPLT(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_tEXt_SUPPORTED + else if (chunk_name == png_tEXt) + png_handle_tEXt(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_tIME_SUPPORTED + else if (chunk_name == png_tIME) + png_handle_tIME(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_tRNS_SUPPORTED + else if (chunk_name == png_tRNS) + png_handle_tRNS(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_zTXt_SUPPORTED + else if (chunk_name == png_zTXt) + png_handle_zTXt(png_ptr, info_ptr, length); +#endif + +#ifdef PNG_READ_iTXt_SUPPORTED + else if (chunk_name == png_iTXt) + png_handle_iTXt(png_ptr, info_ptr, length); +#endif + + else + png_handle_unknown(png_ptr, info_ptr, length, + PNG_HANDLE_CHUNK_AS_DEFAULT); + } while (!(png_ptr->mode & PNG_HAVE_IEND)); +} +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +/* Free all memory used in the read struct */ +static void +png_read_destroy(png_structrp png_ptr) +{ + png_debug(1, "in png_read_destroy"); + +#ifdef PNG_READ_GAMMA_SUPPORTED + png_destroy_gamma_table(png_ptr); +#endif + + png_free(png_ptr, png_ptr->big_row_buf); + png_free(png_ptr, png_ptr->big_prev_row); + png_free(png_ptr, png_ptr->read_buffer); + +#ifdef PNG_READ_QUANTIZE_SUPPORTED + png_free(png_ptr, png_ptr->palette_lookup); + png_free(png_ptr, png_ptr->quantize_index); +#endif + + if (png_ptr->free_me & PNG_FREE_PLTE) + png_zfree(png_ptr, png_ptr->palette); + png_ptr->free_me &= ~PNG_FREE_PLTE; + +#if defined(PNG_tRNS_SUPPORTED) || \ + defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) + if (png_ptr->free_me & PNG_FREE_TRNS) + png_free(png_ptr, png_ptr->trans_alpha); + png_ptr->free_me &= ~PNG_FREE_TRNS; +#endif + + inflateEnd(&png_ptr->zstream); + +#ifdef PNG_PROGRESSIVE_READ_SUPPORTED + png_free(png_ptr, png_ptr->save_buffer); +#endif + +#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) &&\ + defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) + png_free(png_ptr, png_ptr->unknown_chunk.data); +#endif + +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED + png_free(png_ptr, png_ptr->chunk_list); +#endif + + /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error + * callbacks are still set at this point. They are required to complete the + * destruction of the png_struct itself. + */ +} + +/* Free all memory used by the read */ +void PNGAPI +png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr, + png_infopp end_info_ptr_ptr) +{ + png_structrp png_ptr = NULL; + + png_debug(1, "in png_destroy_read_struct"); + + if (png_ptr_ptr != NULL) + png_ptr = *png_ptr_ptr; + + if (png_ptr == NULL) + return; + + /* libpng 1.6.0: use the API to destroy info structs to ensure consistent + * behavior. Prior to 1.6.0 libpng did extra 'info' destruction in this API. + * The extra was, apparently, unnecessary yet this hides memory leak bugs. + */ + png_destroy_info_struct(png_ptr, end_info_ptr_ptr); + png_destroy_info_struct(png_ptr, info_ptr_ptr); + + *png_ptr_ptr = NULL; + png_read_destroy(png_ptr); + png_destroy_png_struct(png_ptr); +} + +void PNGAPI +png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn) +{ + if (png_ptr == NULL) + return; + + png_ptr->read_row_fn = read_row_fn; +} + + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +#ifdef PNG_INFO_IMAGE_SUPPORTED +void PNGAPI +png_read_png(png_structrp png_ptr, png_inforp info_ptr, + int transforms, + voidp params) +{ + if (png_ptr == NULL || info_ptr == NULL) + return; + + /* png_read_info() gives us all of the information from the + * PNG file before the first IDAT (image data chunk). + */ + png_read_info(png_ptr, info_ptr); + if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep))) + png_error(png_ptr, "Image is too high to process with png_read_png()"); + + /* -------------- image transformations start here ------------------- */ + /* libpng 1.6.10: add code to cause a png_app_error if a selected TRANSFORM + * is not implemented. This will only happen in de-configured (non-default) + * libpng builds. The results can be unexpected - png_read_png may return + * short or mal-formed rows because the transform is skipped. + */ + + /* Tell libpng to strip 16-bit/color files down to 8 bits per color. + */ + if (transforms & PNG_TRANSFORM_SCALE_16) + /* Added at libpng-1.5.4. "strip_16" produces the same result that it + * did in earlier versions, while "scale_16" is now more accurate. + */ +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + png_set_scale_16(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_SCALE_16 not supported"); +#endif + + /* If both SCALE and STRIP are required pngrtran will effectively cancel the + * latter by doing SCALE first. This is ok and allows apps not to check for + * which is supported to get the right answer. + */ + if (transforms & PNG_TRANSFORM_STRIP_16) +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + png_set_strip_16(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_16 not supported"); +#endif + + /* Strip alpha bytes from the input data without combining with + * the background (not recommended). + */ + if (transforms & PNG_TRANSFORM_STRIP_ALPHA) +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + png_set_strip_alpha(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_ALPHA not supported"); +#endif + + /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single + * byte into separate bytes (useful for paletted and grayscale images). + */ + if (transforms & PNG_TRANSFORM_PACKING) +#ifdef PNG_READ_PACK_SUPPORTED + png_set_packing(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported"); +#endif + + /* Change the order of packed pixels to least significant bit first + * (not useful if you are using png_set_packing). + */ + if (transforms & PNG_TRANSFORM_PACKSWAP) +#ifdef PNG_READ_PACKSWAP_SUPPORTED + png_set_packswap(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported"); +#endif + + /* Expand paletted colors into true RGB triplets + * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel + * Expand paletted or RGB images with transparency to full alpha + * channels so the data will be available as RGBA quartets. + */ + if (transforms & PNG_TRANSFORM_EXPAND) +#ifdef PNG_READ_EXPAND_SUPPORTED + png_set_expand(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND not supported"); +#endif + + /* We don't handle background color or gamma transformation or quantizing. + */ + + /* Invert monochrome files to have 0 as white and 1 as black + */ + if (transforms & PNG_TRANSFORM_INVERT_MONO) +#ifdef PNG_READ_INVERT_SUPPORTED + png_set_invert_mono(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported"); +#endif + + /* If you want to shift the pixel values from the range [0,255] or + * [0,65535] to the original [0,7] or [0,31], or whatever range the + * colors were originally in: + */ + if (transforms & PNG_TRANSFORM_SHIFT) +#ifdef PNG_READ_SHIFT_SUPPORTED + if (info_ptr->valid & PNG_INFO_sBIT) + png_set_shift(png_ptr, &info_ptr->sig_bit); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported"); +#endif + + /* Flip the RGB pixels to BGR (or RGBA to BGRA) */ + if (transforms & PNG_TRANSFORM_BGR) +#ifdef PNG_READ_BGR_SUPPORTED + png_set_bgr(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported"); +#endif + + /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */ + if (transforms & PNG_TRANSFORM_SWAP_ALPHA) +#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED + png_set_swap_alpha(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported"); +#endif + + /* Swap bytes of 16-bit files to least significant byte first */ + if (transforms & PNG_TRANSFORM_SWAP_ENDIAN) +#ifdef PNG_READ_SWAP_SUPPORTED + png_set_swap(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported"); +#endif + +/* Added at libpng-1.2.41 */ + /* Invert the alpha channel from opacity to transparency */ + if (transforms & PNG_TRANSFORM_INVERT_ALPHA) +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED + png_set_invert_alpha(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported"); +#endif + +/* Added at libpng-1.2.41 */ + /* Expand grayscale image to RGB */ + if (transforms & PNG_TRANSFORM_GRAY_TO_RGB) +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + png_set_gray_to_rgb(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_GRAY_TO_RGB not supported"); +#endif + +/* Added at libpng-1.5.4 */ + if (transforms & PNG_TRANSFORM_EXPAND_16) +#ifdef PNG_READ_EXPAND_16_SUPPORTED + png_set_expand_16(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND_16 not supported"); +#endif + + /* We don't handle adding filler bytes */ + + /* We use png_read_image and rely on that for interlace handling, but we also + * call png_read_update_info therefore must turn on interlace handling now: + */ + (void)png_set_interlace_handling(png_ptr); + + /* Optional call to gamma correct and add the background to the palette + * and update info structure. REQUIRED if you are expecting libpng to + * update the palette for you (i.e., you selected such a transform above). + */ + png_read_update_info(png_ptr, info_ptr); + + /* -------------- image transformations end here ------------------- */ + + png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0); + if (info_ptr->row_pointers == NULL) + { + png_uint_32 iptr; + + info_ptr->row_pointers = png_voidcast(png_bytepp, png_malloc(png_ptr, + info_ptr->height * (sizeof (png_bytep)))); + + for (iptr=0; iptr<info_ptr->height; iptr++) + info_ptr->row_pointers[iptr] = NULL; + + info_ptr->free_me |= PNG_FREE_ROWS; + + for (iptr = 0; iptr < info_ptr->height; iptr++) + info_ptr->row_pointers[iptr] = png_voidcast(png_bytep, + png_malloc(png_ptr, info_ptr->rowbytes)); + } + + png_read_image(png_ptr, info_ptr->row_pointers); + info_ptr->valid |= PNG_INFO_IDAT; + + /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */ + png_read_end(png_ptr, info_ptr); + + PNG_UNUSED(params) +} +#endif /* PNG_INFO_IMAGE_SUPPORTED */ +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +#ifdef PNG_SIMPLIFIED_READ_SUPPORTED +/* SIMPLIFIED READ + * + * This code currently relies on the sequential reader, though it could easily + * be made to work with the progressive one. + */ +/* Arguments to png_image_finish_read: */ + +/* Encoding of PNG data (used by the color-map code) */ +# define P_NOTSET 0 /* File encoding not yet known */ +# define P_sRGB 1 /* 8-bit encoded to sRGB gamma */ +# define P_LINEAR 2 /* 16-bit linear: not encoded, NOT pre-multiplied! */ +# define P_FILE 3 /* 8-bit encoded to file gamma, not sRGB or linear */ +# define P_LINEAR8 4 /* 8-bit linear: only from a file value */ + +/* Color-map processing: after libpng has run on the PNG image further + * processing may be needed to conver the data to color-map indicies. + */ +#define PNG_CMAP_NONE 0 +#define PNG_CMAP_GA 1 /* Process GA data to a color-map with alpha */ +#define PNG_CMAP_TRANS 2 /* Process GA data to a background index */ +#define PNG_CMAP_RGB 3 /* Process RGB data */ +#define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */ + +/* The following document where the background is for each processing case. */ +#define PNG_CMAP_NONE_BACKGROUND 256 +#define PNG_CMAP_GA_BACKGROUND 231 +#define PNG_CMAP_TRANS_BACKGROUND 254 +#define PNG_CMAP_RGB_BACKGROUND 256 +#define PNG_CMAP_RGB_ALPHA_BACKGROUND 216 + +typedef struct +{ + /* Arguments: */ + png_imagep image; + png_voidp buffer; + png_int_32 row_stride; + png_voidp colormap; + png_const_colorp background; + /* Local variables: */ + png_voidp local_row; + png_voidp first_row; + ptrdiff_t row_bytes; /* step between rows */ + int file_encoding; /* E_ values above */ + png_fixed_point gamma_to_linear; /* For P_FILE, reciprocal of gamma */ + int colormap_processing; /* PNG_CMAP_ values above */ +} png_image_read_control; + +/* Do all the *safe* initialization - 'safe' means that png_error won't be + * called, so setting up the jmp_buf is not required. This means that anything + * called from here must *not* call png_malloc - it has to call png_malloc_warn + * instead so that control is returned safely back to this routine. + */ +static int +png_image_read_init(png_imagep image) +{ + if (image->opaque == NULL) + { + png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image, + png_safe_error, png_safe_warning); + + /* And set the rest of the structure to NULL to ensure that the various + * fields are consistent. + */ + memset(image, 0, (sizeof *image)); + image->version = PNG_IMAGE_VERSION; + + if (png_ptr != NULL) + { + png_infop info_ptr = png_create_info_struct(png_ptr); + + if (info_ptr != NULL) + { + png_controlp control = png_voidcast(png_controlp, + png_malloc_warn(png_ptr, (sizeof *control))); + + if (control != NULL) + { + memset(control, 0, (sizeof *control)); + + control->png_ptr = png_ptr; + control->info_ptr = info_ptr; + control->for_write = 0; + + image->opaque = control; + return 1; + } + + /* Error clean up */ + png_destroy_info_struct(png_ptr, &info_ptr); + } + + png_destroy_read_struct(&png_ptr, NULL, NULL); + } + + return png_image_error(image, "png_image_read: out of memory"); + } + + return png_image_error(image, "png_image_read: opaque pointer not NULL"); +} + +/* Utility to find the base format of a PNG file from a png_struct. */ +static png_uint_32 +png_image_format(png_structrp png_ptr) +{ + png_uint_32 format = 0; + + if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) + format |= PNG_FORMAT_FLAG_COLOR; + + if (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) + format |= PNG_FORMAT_FLAG_ALPHA; + + /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS + * sets the png_struct fields; that's all we are interested in here. The + * precise interaction with an app call to png_set_tRNS and PNG file reading + * is unclear. + */ + else if (png_ptr->num_trans > 0) + format |= PNG_FORMAT_FLAG_ALPHA; + + if (png_ptr->bit_depth == 16) + format |= PNG_FORMAT_FLAG_LINEAR; + + if (png_ptr->color_type & PNG_COLOR_MASK_PALETTE) + format |= PNG_FORMAT_FLAG_COLORMAP; + + return format; +} + +/* Is the given gamma significantly different from sRGB? The test is the same + * one used in pngrtran.c when deciding whether to do gamma correction. The + * arithmetic optimizes the division by using the fact that the inverse of the + * file sRGB gamma is 2.2 + */ +static int +png_gamma_not_sRGB(png_fixed_point g) +{ + if (g < PNG_FP_1) + { + /* An uninitialized gamma is assumed to be sRGB for the simplified API. */ + if (g == 0) + return 0; + + return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */); + } + + return 1; +} + +/* Do the main body of a 'png_image_begin_read' function; read the PNG file + * header and fill in all the information. This is executed in a safe context, + * unlike the init routine above. + */ +static int +png_image_read_header(png_voidp argument) +{ + png_imagep image = png_voidcast(png_imagep, argument); + png_structrp png_ptr = image->opaque->png_ptr; + png_inforp info_ptr = image->opaque->info_ptr; + + png_set_benign_errors(png_ptr, 1/*warn*/); + png_read_info(png_ptr, info_ptr); + + /* Do this the fast way; just read directly out of png_struct. */ + image->width = png_ptr->width; + image->height = png_ptr->height; + + { + png_uint_32 format = png_image_format(png_ptr); + + image->format = format; + +#ifdef PNG_COLORSPACE_SUPPORTED + /* Does the colorspace match sRGB? If there is no color endpoint + * (colorant) information assume yes, otherwise require the + * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set. If the + * colorspace has been determined to be invalid ignore it. + */ + if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags + & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB| + PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS)) + image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB; +#endif + } + + /* We need the maximum number of entries regardless of the format the + * application sets here. + */ + { + png_uint_32 cmap_entries; + + switch (png_ptr->color_type) + { + case PNG_COLOR_TYPE_GRAY: + cmap_entries = 1U << png_ptr->bit_depth; + break; + + case PNG_COLOR_TYPE_PALETTE: + cmap_entries = png_ptr->num_palette; + break; + + default: + cmap_entries = 256; + break; + } + + if (cmap_entries > 256) + cmap_entries = 256; + + image->colormap_entries = cmap_entries; + } + + return 1; +} + +#ifdef PNG_STDIO_SUPPORTED +int PNGAPI +png_image_begin_read_from_stdio(png_imagep image, FILE* file) +{ + if (image != NULL && image->version == PNG_IMAGE_VERSION) + { + if (file != NULL) + { + if (png_image_read_init(image)) + { + /* This is slightly evil, but png_init_io doesn't do anything other + * than this and we haven't changed the standard IO functions so + * this saves a 'safe' function. + */ + image->opaque->png_ptr->io_ptr = file; + return png_safe_execute(image, png_image_read_header, image); + } + } + + else + return png_image_error(image, + "png_image_begin_read_from_stdio: invalid argument"); + } + + else if (image != NULL) + return png_image_error(image, + "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION"); + + return 0; +} + +int PNGAPI +png_image_begin_read_from_file(png_imagep image, const char *file_name) +{ + if (image != NULL && image->version == PNG_IMAGE_VERSION) + { + if (file_name != NULL) + { + FILE *fp = fopen(file_name, "rb"); + + if (fp != NULL) + { + if (png_image_read_init(image)) + { + image->opaque->png_ptr->io_ptr = fp; + image->opaque->owned_file = 1; + return png_safe_execute(image, png_image_read_header, image); + } + + /* Clean up: just the opened file. */ + (void)fclose(fp); + } + + else + return png_image_error(image, strerror(errno)); + } + + else + return png_image_error(image, + "png_image_begin_read_from_file: invalid argument"); + } + + else if (image != NULL) + return png_image_error(image, + "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION"); + + return 0; +} +#endif /* PNG_STDIO_SUPPORTED */ + +static void PNGCBAPI +png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need) +{ + if (png_ptr != NULL) + { + png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr); + if (image != NULL) + { + png_controlp cp = image->opaque; + if (cp != NULL) + { + png_const_bytep memory = cp->memory; + png_size_t size = cp->size; + + if (memory != NULL && size >= need) + { + memcpy(out, memory, need); + cp->memory = memory + need; + cp->size = size - need; + return; + } + + png_error(png_ptr, "read beyond end of data"); + } + } + + png_error(png_ptr, "invalid memory read"); + } +} + +int PNGAPI png_image_begin_read_from_memory(png_imagep image, + png_const_voidp memory, png_size_t size) +{ + if (image != NULL && image->version == PNG_IMAGE_VERSION) + { + if (memory != NULL && size > 0) + { + if (png_image_read_init(image)) + { + /* Now set the IO functions to read from the memory buffer and + * store it into io_ptr. Again do this in-place to avoid calling a + * libpng function that requires error handling. + */ + image->opaque->memory = png_voidcast(png_const_bytep, memory); + image->opaque->size = size; + image->opaque->png_ptr->io_ptr = image; + image->opaque->png_ptr->read_data_fn = png_image_memory_read; + + return png_safe_execute(image, png_image_read_header, image); + } + } + + else + return png_image_error(image, + "png_image_begin_read_from_memory: invalid argument"); + } + + else if (image != NULL) + return png_image_error(image, + "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION"); + + return 0; +} + +/* Utility function to skip chunks that are not used by the simplified image + * read functions and an appropriate macro to call it. + */ +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED +static void +png_image_skip_unused_chunks(png_structrp png_ptr) +{ + /* Prepare the reader to ignore all recognized chunks whose data will not + * be used, i.e., all chunks recognized by libpng except for those + * involved in basic image reading: + * + * IHDR, PLTE, IDAT, IEND + * + * Or image data handling: + * + * tRNS, bKGD, gAMA, cHRM, sRGB, [iCCP] and sBIT. + * + * This provides a small performance improvement and eliminates any + * potential vulnerability to security problems in the unused chunks. + * + * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored + * too. This allows the simplified API to be compiled without iCCP support, + * however if the support is there the chunk is still checked to detect + * errors (which are unfortunately quite common.) + */ + { + static PNG_CONST png_byte chunks_to_process[] = { + 98, 75, 71, 68, '\0', /* bKGD */ + 99, 72, 82, 77, '\0', /* cHRM */ + 103, 65, 77, 65, '\0', /* gAMA */ +# ifdef PNG_READ_iCCP_SUPPORTED + 105, 67, 67, 80, '\0', /* iCCP */ +# endif + 115, 66, 73, 84, '\0', /* sBIT */ + 115, 82, 71, 66, '\0', /* sRGB */ + }; + + /* Ignore unknown chunks and all other chunks except for the + * IHDR, PLTE, tRNS, IDAT, and IEND chunks. + */ + png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER, + NULL, -1); + + /* But do not ignore image data handling chunks */ + png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT, + chunks_to_process, (sizeof chunks_to_process)/5); + } +} + +# define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p) +#else +# define PNG_SKIP_CHUNKS(p) ((void)0) +#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */ + +/* The following macro gives the exact rounded answer for all values in the + * range 0..255 (it actually divides by 51.2, but the rounding still generates + * the correct numbers 0..5 + */ +#define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8) + +/* Utility functions to make particular color-maps */ +static void +set_file_encoding(png_image_read_control *display) +{ + png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma; + if (png_gamma_significant(g)) + { + if (png_gamma_not_sRGB(g)) + { + display->file_encoding = P_FILE; + display->gamma_to_linear = png_reciprocal(g); + } + + else + display->file_encoding = P_sRGB; + } + + else + display->file_encoding = P_LINEAR8; +} + +static unsigned int +decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding) +{ + if (encoding == P_FILE) /* double check */ + encoding = display->file_encoding; + + if (encoding == P_NOTSET) /* must be the file encoding */ + { + set_file_encoding(display); + encoding = display->file_encoding; + } + + switch (encoding) + { + case P_FILE: + value = png_gamma_16bit_correct(value*257, display->gamma_to_linear); + break; + + case P_sRGB: + value = png_sRGB_table[value]; + break; + + case P_LINEAR: + break; + + case P_LINEAR8: + value *= 257; + break; + + default: + png_error(display->image->opaque->png_ptr, + "unexpected encoding (internal error)"); + break; + } + + return value; +} + +static png_uint_32 +png_colormap_compose(png_image_read_control *display, + png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha, + png_uint_32 background, int encoding) +{ + /* The file value is composed on the background, the background has the given + * encoding and so does the result, the file is encoded with P_FILE and the + * file and alpha are 8-bit values. The (output) encoding will always be + * P_LINEAR or P_sRGB. + */ + png_uint_32 f = decode_gamma(display, foreground, foreground_encoding); + png_uint_32 b = decode_gamma(display, background, encoding); + + /* The alpha is always an 8-bit value (it comes from the palette), the value + * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires. + */ + f = f * alpha + b * (255-alpha); + + if (encoding == P_LINEAR) + { + /* Scale to 65535; divide by 255, approximately (in fact this is extremely + * accurate, it divides by 255.00000005937181414556, with no overflow.) + */ + f *= 257; /* Now scaled by 65535 */ + f += f >> 16; + f = (f+32768) >> 16; + } + + else /* P_sRGB */ + f = PNG_sRGB_FROM_LINEAR(f); + + return f; +} + +/* NOTE: P_LINEAR values to this routine must be 16-bit, but P_FILE values must + * be 8-bit. + */ +static void +png_create_colormap_entry(png_image_read_control *display, + png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue, + png_uint_32 alpha, int encoding) +{ + png_imagep image = display->image; + const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) ? + P_LINEAR : P_sRGB; + const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 && + (red != green || green != blue); + + if (ip > 255) + png_error(image->opaque->png_ptr, "color-map index out of range"); + + /* Update the cache with whether the file gamma is significantly different + * from sRGB. + */ + if (encoding == P_FILE) + { + if (display->file_encoding == P_NOTSET) + set_file_encoding(display); + + /* Note that the cached value may be P_FILE too, but if it is then the + * gamma_to_linear member has been set. + */ + encoding = display->file_encoding; + } + + if (encoding == P_FILE) + { + png_fixed_point g = display->gamma_to_linear; + + red = png_gamma_16bit_correct(red*257, g); + green = png_gamma_16bit_correct(green*257, g); + blue = png_gamma_16bit_correct(blue*257, g); + + if (convert_to_Y || output_encoding == P_LINEAR) + { + alpha *= 257; + encoding = P_LINEAR; + } + + else + { + red = PNG_sRGB_FROM_LINEAR(red * 255); + green = PNG_sRGB_FROM_LINEAR(green * 255); + blue = PNG_sRGB_FROM_LINEAR(blue * 255); + encoding = P_sRGB; + } + } + + else if (encoding == P_LINEAR8) + { + /* This encoding occurs quite frequently in test cases because PngSuite + * includes a gAMA 1.0 chunk with most images. + */ + red *= 257; + green *= 257; + blue *= 257; + alpha *= 257; + encoding = P_LINEAR; + } + + else if (encoding == P_sRGB && (convert_to_Y || output_encoding == P_LINEAR)) + { + /* The values are 8-bit sRGB values, but must be converted to 16-bit + * linear. + */ + red = png_sRGB_table[red]; + green = png_sRGB_table[green]; + blue = png_sRGB_table[blue]; + alpha *= 257; + encoding = P_LINEAR; + } + + /* This is set if the color isn't gray but the output is. */ + if (encoding == P_LINEAR) + { + if (convert_to_Y != 0) + { + /* NOTE: these values are copied from png_do_rgb_to_gray */ + png_uint_32 y = (png_uint_32)6968 * red + (png_uint_32)23434 * green + + (png_uint_32)2366 * blue; + + if (output_encoding == P_LINEAR) + y = (y + 16384) >> 15; + + else + { + /* y is scaled by 32768, we need it scaled by 255: */ + y = (y + 128) >> 8; + y *= 255; + y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7); + encoding = P_sRGB; + } + + blue = red = green = y; + } + + else if (output_encoding == P_sRGB) + { + red = PNG_sRGB_FROM_LINEAR(red * 255); + green = PNG_sRGB_FROM_LINEAR(green * 255); + blue = PNG_sRGB_FROM_LINEAR(blue * 255); + alpha = PNG_DIV257(alpha); + encoding = P_sRGB; + } + } + + if (encoding != output_encoding) + png_error(image->opaque->png_ptr, "bad encoding (internal error)"); + + /* Store the value. */ + { +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + const int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 && + (image->format & PNG_FORMAT_FLAG_ALPHA) != 0; +# else +# define afirst 0 +# endif +# ifdef PNG_FORMAT_BGR_SUPPORTED + const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) ? 2 : 0; +# else +# define bgr 0 +# endif + + if (output_encoding == P_LINEAR) + { + png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap); + + entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format); + + /* The linear 16-bit values must be pre-multiplied by the alpha channel + * value, if less than 65535 (this is, effectively, composite on black + * if the alpha channel is removed.) + */ + switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format)) + { + case 4: + entry[afirst ? 0 : 3] = (png_uint_16)alpha; + /* FALL THROUGH */ + + case 3: + if (alpha < 65535) + { + if (alpha > 0) + { + blue = (blue * alpha + 32767U)/65535U; + green = (green * alpha + 32767U)/65535U; + red = (red * alpha + 32767U)/65535U; + } + + else + red = green = blue = 0; + } + entry[afirst + (2 ^ bgr)] = (png_uint_16)blue; + entry[afirst + 1] = (png_uint_16)green; + entry[afirst + bgr] = (png_uint_16)red; + break; + + case 2: + entry[1 ^ afirst] = (png_uint_16)alpha; + /* FALL THROUGH */ + + case 1: + if (alpha < 65535) + { + if (alpha > 0) + green = (green * alpha + 32767U)/65535U; + + else + green = 0; + } + entry[afirst] = (png_uint_16)green; + break; + + default: + break; + } + } + + else /* output encoding is P_sRGB */ + { + png_bytep entry = png_voidcast(png_bytep, display->colormap); + + entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format); + + switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format)) + { + case 4: + entry[afirst ? 0 : 3] = (png_byte)alpha; + case 3: + entry[afirst + (2 ^ bgr)] = (png_byte)blue; + entry[afirst + 1] = (png_byte)green; + entry[afirst + bgr] = (png_byte)red; + break; + + case 2: + entry[1 ^ afirst] = (png_byte)alpha; + case 1: + entry[afirst] = (png_byte)green; + break; + + default: + break; + } + } + +# ifdef afirst +# undef afirst +# endif +# ifdef bgr +# undef bgr +# endif + } +} + +static int +make_gray_file_colormap(png_image_read_control *display) +{ + unsigned int i; + + for (i=0; i<256; ++i) + png_create_colormap_entry(display, i, i, i, i, 255, P_FILE); + + return i; +} + +static int +make_gray_colormap(png_image_read_control *display) +{ + unsigned int i; + + for (i=0; i<256; ++i) + png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB); + + return i; +} +#define PNG_GRAY_COLORMAP_ENTRIES 256 + +static int +make_ga_colormap(png_image_read_control *display) +{ + unsigned int i, a; + + /* Alpha is retained, the output will be a color-map with entries + * selected by six levels of alpha. One transparent entry, 6 gray + * levels for all the intermediate alpha values, leaving 230 entries + * for the opaque grays. The color-map entries are the six values + * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the + * relevant entry. + * + * if (alpha > 229) // opaque + * { + * // The 231 entries are selected to make the math below work: + * base = 0; + * entry = (231 * gray + 128) >> 8; + * } + * else if (alpha < 26) // transparent + * { + * base = 231; + * entry = 0; + * } + * else // partially opaque + * { + * base = 226 + 6 * PNG_DIV51(alpha); + * entry = PNG_DIV51(gray); + * } + */ + i = 0; + while (i < 231) + { + unsigned int gray = (i * 256 + 115) / 231; + png_create_colormap_entry(display, i++, gray, gray, gray, 255, P_sRGB); + } + + /* 255 is used here for the component values for consistency with the code + * that undoes premultiplication in pngwrite.c. + */ + png_create_colormap_entry(display, i++, 255, 255, 255, 0, P_sRGB); + + for (a=1; a<5; ++a) + { + unsigned int g; + + for (g=0; g<6; ++g) + png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51, + P_sRGB); + } + + return i; +} + +#define PNG_GA_COLORMAP_ENTRIES 256 + +static int +make_rgb_colormap(png_image_read_control *display) +{ + unsigned int i, r; + + /* Build a 6x6x6 opaque RGB cube */ + for (i=r=0; r<6; ++r) + { + unsigned int g; + + for (g=0; g<6; ++g) + { + unsigned int b; + + for (b=0; b<6; ++b) + png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255, + P_sRGB); + } + } + + return i; +} + +#define PNG_RGB_COLORMAP_ENTRIES 216 + +/* Return a palette index to the above palette given three 8-bit sRGB values. */ +#define PNG_RGB_INDEX(r,g,b) \ + ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b))) + +static int +png_image_read_colormap(png_voidp argument) +{ + png_image_read_control *display = + png_voidcast(png_image_read_control*, argument); + const png_imagep image = display->image; + + const png_structrp png_ptr = image->opaque->png_ptr; + const png_uint_32 output_format = image->format; + const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) ? + P_LINEAR : P_sRGB; + + unsigned int cmap_entries; + unsigned int output_processing; /* Output processing option */ + unsigned int data_encoding = P_NOTSET; /* Encoding libpng must produce */ + + /* Background information; the background color and the index of this color + * in the color-map if it exists (else 256). + */ + unsigned int background_index = 256; + png_uint_32 back_r, back_g, back_b; + + /* Flags to accumulate things that need to be done to the input. */ + int expand_tRNS = 0; + + /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is + * very difficult to do, the results look awful, and it is difficult to see + * what possible use it is because the application can't control the + * color-map. + */ + if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 || + png_ptr->num_trans > 0) /* alpha in input */ && + ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */) + { + if (output_encoding == P_LINEAR) /* compose on black */ + back_b = back_g = back_r = 0; + + else if (display->background == NULL /* no way to remove it */) + png_error(png_ptr, + "a background color must be supplied to remove alpha/transparency"); + + /* Get a copy of the background color (this avoids repeating the checks + * below.) The encoding is 8-bit sRGB or 16-bit linear, depending on the + * output format. + */ + else + { + back_g = display->background->green; + if (output_format & PNG_FORMAT_FLAG_COLOR) + { + back_r = display->background->red; + back_b = display->background->blue; + } + else + back_b = back_r = back_g; + } + } + + else if (output_encoding == P_LINEAR) + back_b = back_r = back_g = 65535; + + else + back_b = back_r = back_g = 255; + + /* Default the input file gamma if required - this is necessary because + * libpng assumes that if no gamma information is present the data is in the + * output format, but the simplified API deduces the gamma from the input + * format. + */ + if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0) + { + /* Do this directly, not using the png_colorspace functions, to ensure + * that it happens even if the colorspace is invalid (though probably if + * it is the setting will be ignored) Note that the same thing can be + * achieved at the application interface with png_set_gAMA. + */ + if (png_ptr->bit_depth == 16 && + (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0) + png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR; + + else + png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE; + + png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA; + } + + /* Decide what to do based on the PNG color type of the input data. The + * utility function png_create_colormap_entry deals with most aspects of the + * output transformations; this code works out how to produce bytes of + * color-map entries from the original format. + */ + switch (png_ptr->color_type) + { + case PNG_COLOR_TYPE_GRAY: + if (png_ptr->bit_depth <= 8) + { + /* There at most 256 colors in the output, regardless of + * transparency. + */ + unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0; + + cmap_entries = 1U << png_ptr->bit_depth; + if (cmap_entries > image->colormap_entries) + png_error(png_ptr, "gray[8] color-map: too few entries"); + + step = 255 / (cmap_entries - 1); + output_processing = PNG_CMAP_NONE; + + /* If there is a tRNS chunk then this either selects a transparent + * value or, if the output has no alpha, the background color. + */ + if (png_ptr->num_trans > 0) + { + trans = png_ptr->trans_color.gray; + + if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) + back_alpha = output_encoding == P_LINEAR ? 65535 : 255; + } + + /* png_create_colormap_entry just takes an RGBA and writes the + * corresponding color-map entry using the format from 'image', + * including the required conversion to sRGB or linear as + * appropriate. The input values are always either sRGB (if the + * gamma correction flag is 0) or 0..255 scaled file encoded values + * (if the function must gamma correct them). + */ + for (i=val=0; i<cmap_entries; ++i, val += step) + { + /* 'i' is a file value. While this will result in duplicated + * entries for 8-bit non-sRGB encoded files it is necessary to + * have non-gamma corrected values to do tRNS handling. + */ + if (i != trans) + png_create_colormap_entry(display, i, val, val, val, 255, + P_FILE/*8-bit with file gamma*/); + + /* Else this entry is transparent. The colors don't matter if + * there is an alpha channel (back_alpha == 0), but it does no + * harm to pass them in; the values are not set above so this + * passes in white. + * + * NOTE: this preserves the full precision of the application + * supplied background color when it is used. + */ + else + png_create_colormap_entry(display, i, back_r, back_g, back_b, + back_alpha, output_encoding); + } + + /* We need libpng to preserve the original encoding. */ + data_encoding = P_FILE; + + /* The rows from libpng, while technically gray values, are now also + * color-map indicies; however, they may need to be expanded to 1 + * byte per pixel. This is what png_set_packing does (i.e., it + * unpacks the bit values into bytes.) + */ + if (png_ptr->bit_depth < 8) + png_set_packing(png_ptr); + } + + else /* bit depth is 16 */ + { + /* The 16-bit input values can be converted directly to 8-bit gamma + * encoded values; however, if a tRNS chunk is present 257 color-map + * entries are required. This means that the extra entry requires + * special processing; add an alpha channel, sacrifice gray level + * 254 and convert transparent (alpha==0) entries to that. + * + * Use libpng to chop the data to 8 bits. Convert it to sRGB at the + * same time to minimize quality loss. If a tRNS chunk is present + * this means libpng must handle it too; otherwise it is impossible + * to do the exact match on the 16-bit value. + * + * If the output has no alpha channel *and* the background color is + * gray then it is possible to let libpng handle the substitution by + * ensuring that the corresponding gray level matches the background + * color exactly. + */ + data_encoding = P_sRGB; + + if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries) + png_error(png_ptr, "gray[16] color-map: too few entries"); + + cmap_entries = make_gray_colormap(display); + + if (png_ptr->num_trans > 0) + { + unsigned int back_alpha; + + if (output_format & PNG_FORMAT_FLAG_ALPHA) + back_alpha = 0; + + else + { + if (back_r == back_g && back_g == back_b) + { + /* Background is gray; no special processing will be + * required. + */ + png_color_16 c; + png_uint_32 gray = back_g; + + if (output_encoding == P_LINEAR) + { + gray = PNG_sRGB_FROM_LINEAR(gray * 255); + + /* And make sure the corresponding palette entry + * matches. + */ + png_create_colormap_entry(display, gray, back_g, back_g, + back_g, 65535, P_LINEAR); + } + + /* The background passed to libpng, however, must be the + * sRGB value. + */ + c.index = 0; /*unused*/ + c.gray = c.red = c.green = c.blue = (png_uint_16)gray; + + /* NOTE: does this work without expanding tRNS to alpha? + * It should be the color->gray case below apparently + * doesn't. + */ + png_set_background_fixed(png_ptr, &c, + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, + 0/*gamma: not used*/); + + output_processing = PNG_CMAP_NONE; + break; + } + + back_alpha = output_encoding == P_LINEAR ? 65535 : 255; + } + + /* output_processing means that the libpng-processed row will be + * 8-bit GA and it has to be processing to single byte color-map + * values. Entry 254 is replaced by either a completely + * transparent entry or by the background color at full + * precision (and the background color is not a simple gray leve + * in this case.) + */ + expand_tRNS = 1; + output_processing = PNG_CMAP_TRANS; + background_index = 254; + + /* And set (overwrite) color-map entry 254 to the actual + * background color at full precision. + */ + png_create_colormap_entry(display, 254, back_r, back_g, back_b, + back_alpha, output_encoding); + } + + else + output_processing = PNG_CMAP_NONE; + } + break; + + case PNG_COLOR_TYPE_GRAY_ALPHA: + /* 8-bit or 16-bit PNG with two channels - gray and alpha. A minimum + * of 65536 combinations. If, however, the alpha channel is to be + * removed there are only 256 possibilities if the background is gray. + * (Otherwise there is a subset of the 65536 possibilities defined by + * the triangle between black, white and the background color.) + * + * Reduce 16-bit files to 8-bit and sRGB encode the result. No need to + * worry about tRNS matching - tRNS is ignored if there is an alpha + * channel. + */ + data_encoding = P_sRGB; + + if (output_format & PNG_FORMAT_FLAG_ALPHA) + { + if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries) + png_error(png_ptr, "gray+alpha color-map: too few entries"); + + cmap_entries = make_ga_colormap(display); + + background_index = PNG_CMAP_GA_BACKGROUND; + output_processing = PNG_CMAP_GA; + } + + else /* alpha is removed */ + { + /* Alpha must be removed as the PNG data is processed when the + * background is a color because the G and A channels are + * independent and the vector addition (non-parallel vectors) is a + * 2-D problem. + * + * This can be reduced to the same algorithm as above by making a + * colormap containing gray levels (for the opaque grays), a + * background entry (for a transparent pixel) and a set of four six + * level color values, one set for each intermediate alpha value. + * See the comments in make_ga_colormap for how this works in the + * per-pixel processing. + * + * If the background is gray, however, we only need a 256 entry gray + * level color map. It is sufficient to make the entry generated + * for the background color be exactly the color specified. + */ + if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 || + (back_r == back_g && back_g == back_b)) + { + /* Background is gray; no special processing will be required. */ + png_color_16 c; + png_uint_32 gray = back_g; + + if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries) + png_error(png_ptr, "gray-alpha color-map: too few entries"); + + cmap_entries = make_gray_colormap(display); + + if (output_encoding == P_LINEAR) + { + gray = PNG_sRGB_FROM_LINEAR(gray * 255); + + /* And make sure the corresponding palette entry matches. */ + png_create_colormap_entry(display, gray, back_g, back_g, + back_g, 65535, P_LINEAR); + } + + /* The background passed to libpng, however, must be the sRGB + * value. + */ + c.index = 0; /*unused*/ + c.gray = c.red = c.green = c.blue = (png_uint_16)gray; + + png_set_background_fixed(png_ptr, &c, + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, + 0/*gamma: not used*/); + + output_processing = PNG_CMAP_NONE; + } + + else + { + png_uint_32 i, a; + + /* This is the same as png_make_ga_colormap, above, except that + * the entries are all opaque. + */ + if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries) + png_error(png_ptr, "ga-alpha color-map: too few entries"); + + i = 0; + while (i < 231) + { + png_uint_32 gray = (i * 256 + 115) / 231; + png_create_colormap_entry(display, i++, gray, gray, gray, + 255, P_sRGB); + } + + /* NOTE: this preserves the full precision of the application + * background color. + */ + background_index = i; + png_create_colormap_entry(display, i++, back_r, back_g, back_b, + output_encoding == P_LINEAR ? 65535U : 255U, output_encoding); + + /* For non-opaque input composite on the sRGB background - this + * requires inverting the encoding for each component. The input + * is still converted to the sRGB encoding because this is a + * reasonable approximate to the logarithmic curve of human + * visual sensitivity, at least over the narrow range which PNG + * represents. Consequently 'G' is always sRGB encoded, while + * 'A' is linear. We need the linear background colors. + */ + if (output_encoding == P_sRGB) /* else already linear */ + { + /* This may produce a value not exactly matching the + * background, but that's ok because these numbers are only + * used when alpha != 0 + */ + back_r = png_sRGB_table[back_r]; + back_g = png_sRGB_table[back_g]; + back_b = png_sRGB_table[back_b]; + } + + for (a=1; a<5; ++a) + { + unsigned int g; + + /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled + * by an 8-bit alpha value (0..255). + */ + png_uint_32 alpha = 51 * a; + png_uint_32 back_rx = (255-alpha) * back_r; + png_uint_32 back_gx = (255-alpha) * back_g; + png_uint_32 back_bx = (255-alpha) * back_b; + + for (g=0; g<6; ++g) + { + png_uint_32 gray = png_sRGB_table[g*51] * alpha; + + png_create_colormap_entry(display, i++, + PNG_sRGB_FROM_LINEAR(gray + back_rx), + PNG_sRGB_FROM_LINEAR(gray + back_gx), + PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, P_sRGB); + } + } + + cmap_entries = i; + output_processing = PNG_CMAP_GA; + } + } + break; + + case PNG_COLOR_TYPE_RGB: + case PNG_COLOR_TYPE_RGB_ALPHA: + /* Exclude the case where the output is gray; we can always handle this + * with the cases above. + */ + if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0) + { + /* The color-map will be grayscale, so we may as well convert the + * input RGB values to a simple grayscale and use the grayscale + * code above. + * + * NOTE: calling this apparently damages the recognition of the + * transparent color in background color handling; call + * png_set_tRNS_to_alpha before png_set_background_fixed. + */ + png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1, + -1); + data_encoding = P_sRGB; + + /* The output will now be one or two 8-bit gray or gray+alpha + * channels. The more complex case arises when the input has alpha. + */ + if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + png_ptr->num_trans > 0) && + (output_format & PNG_FORMAT_FLAG_ALPHA) != 0) + { + /* Both input and output have an alpha channel, so no background + * processing is required; just map the GA bytes to the right + * color-map entry. + */ + expand_tRNS = 1; + + if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries) + png_error(png_ptr, "rgb[ga] color-map: too few entries"); + + cmap_entries = make_ga_colormap(display); + background_index = PNG_CMAP_GA_BACKGROUND; + output_processing = PNG_CMAP_GA; + } + + else + { + /* Either the input or the output has no alpha channel, so there + * will be no non-opaque pixels in the color-map; it will just be + * grayscale. + */ + if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries) + png_error(png_ptr, "rgb[gray] color-map: too few entries"); + + /* Ideally this code would use libpng to do the gamma correction, + * but if an input alpha channel is to be removed we will hit the + * libpng bug in gamma+compose+rgb-to-gray (the double gamma + * correction bug). Fix this by dropping the gamma correction in + * this case and doing it in the palette; this will result in + * duplicate palette entries, but that's better than the + * alternative of double gamma correction. + */ + if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + png_ptr->num_trans > 0) && + png_gamma_not_sRGB(png_ptr->colorspace.gamma)) + { + cmap_entries = make_gray_file_colormap(display); + data_encoding = P_FILE; + } + + else + cmap_entries = make_gray_colormap(display); + + /* But if the input has alpha or transparency it must be removed + */ + if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + png_ptr->num_trans > 0) + { + png_color_16 c; + png_uint_32 gray = back_g; + + /* We need to ensure that the application background exists in + * the colormap and that completely transparent pixels map to + * it. Achieve this simply by ensuring that the entry + * selected for the background really is the background color. + */ + if (data_encoding == P_FILE) /* from the fixup above */ + { + /* The app supplied a gray which is in output_encoding, we + * need to convert it to a value of the input (P_FILE) + * encoding then set this palette entry to the required + * output encoding. + */ + if (output_encoding == P_sRGB) + gray = png_sRGB_table[gray]; /* now P_LINEAR */ + + gray = PNG_DIV257(png_gamma_16bit_correct(gray, + png_ptr->colorspace.gamma)); /* now P_FILE */ + + /* And make sure the corresponding palette entry contains + * exactly the required sRGB value. + */ + png_create_colormap_entry(display, gray, back_g, back_g, + back_g, 0/*unused*/, output_encoding); + } + + else if (output_encoding == P_LINEAR) + { + gray = PNG_sRGB_FROM_LINEAR(gray * 255); + + /* And make sure the corresponding palette entry matches. + */ + png_create_colormap_entry(display, gray, back_g, back_g, + back_g, 0/*unused*/, P_LINEAR); + } + + /* The background passed to libpng, however, must be the + * output (normally sRGB) value. + */ + c.index = 0; /*unused*/ + c.gray = c.red = c.green = c.blue = (png_uint_16)gray; + + /* NOTE: the following is apparently a bug in libpng. Without + * it the transparent color recognition in + * png_set_background_fixed seems to go wrong. + */ + expand_tRNS = 1; + png_set_background_fixed(png_ptr, &c, + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, + 0/*gamma: not used*/); + } + + output_processing = PNG_CMAP_NONE; + } + } + + else /* output is color */ + { + /* We could use png_quantize here so long as there is no transparent + * color or alpha; png_quantize ignores alpha. Easier overall just + * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube. + * Consequently we always want libpng to produce sRGB data. + */ + data_encoding = P_sRGB; + + /* Is there any transparency or alpha? */ + if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + png_ptr->num_trans > 0) + { + /* Is there alpha in the output too? If so all four channels are + * processed into a special RGB cube with alpha support. + */ + if (output_format & PNG_FORMAT_FLAG_ALPHA) + { + png_uint_32 r; + + if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries) + png_error(png_ptr, "rgb+alpha color-map: too few entries"); + + cmap_entries = make_rgb_colormap(display); + + /* Add a transparent entry. */ + png_create_colormap_entry(display, cmap_entries, 255, 255, + 255, 0, P_sRGB); + + /* This is stored as the background index for the processing + * algorithm. + */ + background_index = cmap_entries++; + + /* Add 27 r,g,b entries each with alpha 0.5. */ + for (r=0; r<256; r = (r << 1) | 0x7f) + { + png_uint_32 g; + + for (g=0; g<256; g = (g << 1) | 0x7f) + { + png_uint_32 b; + + /* This generates components with the values 0, 127 and + * 255 + */ + for (b=0; b<256; b = (b << 1) | 0x7f) + png_create_colormap_entry(display, cmap_entries++, + r, g, b, 128, P_sRGB); + } + } + + expand_tRNS = 1; + output_processing = PNG_CMAP_RGB_ALPHA; + } + + else + { + /* Alpha/transparency must be removed. The background must + * exist in the color map (achieved by setting adding it after + * the 666 color-map). If the standard processing code will + * pick up this entry automatically that's all that is + * required; libpng can be called to do the background + * processing. + */ + unsigned int sample_size = + PNG_IMAGE_SAMPLE_SIZE(output_format); + png_uint_32 r, g, b; /* sRGB background */ + + if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries) + png_error(png_ptr, "rgb-alpha color-map: too few entries"); + + cmap_entries = make_rgb_colormap(display); + + png_create_colormap_entry(display, cmap_entries, back_r, + back_g, back_b, 0/*unused*/, output_encoding); + + if (output_encoding == P_LINEAR) + { + r = PNG_sRGB_FROM_LINEAR(back_r * 255); + g = PNG_sRGB_FROM_LINEAR(back_g * 255); + b = PNG_sRGB_FROM_LINEAR(back_b * 255); + } + + else + { + r = back_r; + g = back_g; + b = back_g; + } + + /* Compare the newly-created color-map entry with the one the + * PNG_CMAP_RGB algorithm will use. If the two entries don't + * match, add the new one and set this as the background + * index. + */ + if (memcmp((png_const_bytep)display->colormap + + sample_size * cmap_entries, + (png_const_bytep)display->colormap + + sample_size * PNG_RGB_INDEX(r,g,b), + sample_size) != 0) + { + /* The background color must be added. */ + background_index = cmap_entries++; + + /* Add 27 r,g,b entries each with created by composing with + * the background at alpha 0.5. + */ + for (r=0; r<256; r = (r << 1) | 0x7f) + { + for (g=0; g<256; g = (g << 1) | 0x7f) + { + /* This generates components with the values 0, 127 + * and 255 + */ + for (b=0; b<256; b = (b << 1) | 0x7f) + png_create_colormap_entry(display, cmap_entries++, + png_colormap_compose(display, r, P_sRGB, 128, + back_r, output_encoding), + png_colormap_compose(display, g, P_sRGB, 128, + back_g, output_encoding), + png_colormap_compose(display, b, P_sRGB, 128, + back_b, output_encoding), + 0/*unused*/, output_encoding); + } + } + + expand_tRNS = 1; + output_processing = PNG_CMAP_RGB_ALPHA; + } + + else /* background color is in the standard color-map */ + { + png_color_16 c; + + c.index = 0; /*unused*/ + c.red = (png_uint_16)back_r; + c.gray = c.green = (png_uint_16)back_g; + c.blue = (png_uint_16)back_b; + + png_set_background_fixed(png_ptr, &c, + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, + 0/*gamma: not used*/); + + output_processing = PNG_CMAP_RGB; + } + } + } + + else /* no alpha or transparency in the input */ + { + /* Alpha in the output is irrelevant, simply map the opaque input + * pixels to the 6x6x6 color-map. + */ + if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries) + png_error(png_ptr, "rgb color-map: too few entries"); + + cmap_entries = make_rgb_colormap(display); + output_processing = PNG_CMAP_RGB; + } + } + break; + + case PNG_COLOR_TYPE_PALETTE: + /* It's already got a color-map. It may be necessary to eliminate the + * tRNS entries though. + */ + { + unsigned int num_trans = png_ptr->num_trans; + png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL; + png_const_colorp colormap = png_ptr->palette; + const int do_background = trans != NULL && + (output_format & PNG_FORMAT_FLAG_ALPHA) == 0; + unsigned int i; + + /* Just in case: */ + if (trans == NULL) + num_trans = 0; + + output_processing = PNG_CMAP_NONE; + data_encoding = P_FILE; /* Don't change from color-map indicies */ + cmap_entries = png_ptr->num_palette; + if (cmap_entries > 256) + cmap_entries = 256; + + if (cmap_entries > image->colormap_entries) + png_error(png_ptr, "palette color-map: too few entries"); + + for (i=0; i < cmap_entries; ++i) + { + if (do_background && i < num_trans && trans[i] < 255) + { + if (trans[i] == 0) + png_create_colormap_entry(display, i, back_r, back_g, + back_b, 0, output_encoding); + + else + { + /* Must compose the PNG file color in the color-map entry + * on the sRGB color in 'back'. + */ + png_create_colormap_entry(display, i, + png_colormap_compose(display, colormap[i].red, P_FILE, + trans[i], back_r, output_encoding), + png_colormap_compose(display, colormap[i].green, P_FILE, + trans[i], back_g, output_encoding), + png_colormap_compose(display, colormap[i].blue, P_FILE, + trans[i], back_b, output_encoding), + output_encoding == P_LINEAR ? trans[i] * 257U : + trans[i], + output_encoding); + } + } + + else + png_create_colormap_entry(display, i, colormap[i].red, + colormap[i].green, colormap[i].blue, + i < num_trans ? trans[i] : 255U, P_FILE/*8-bit*/); + } + + /* The PNG data may have indicies packed in fewer than 8 bits, it + * must be expanded if so. + */ + if (png_ptr->bit_depth < 8) + png_set_packing(png_ptr); + } + break; + + default: + png_error(png_ptr, "invalid PNG color type"); + /*NOT REACHED*/ + break; + } + + /* Now deal with the output processing */ + if (expand_tRNS && png_ptr->num_trans > 0 && + (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0) + png_set_tRNS_to_alpha(png_ptr); + + switch (data_encoding) + { + default: + png_error(png_ptr, "bad data option (internal error)"); + break; + + case P_sRGB: + /* Change to 8-bit sRGB */ + png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB); + /* FALL THROUGH */ + + case P_FILE: + if (png_ptr->bit_depth > 8) + png_set_scale_16(png_ptr); + break; + } + + if (cmap_entries > 256 || cmap_entries > image->colormap_entries) + png_error(png_ptr, "color map overflow (BAD internal error)"); + + image->colormap_entries = cmap_entries; + + /* Double check using the recorded background index */ + switch (output_processing) + { + case PNG_CMAP_NONE: + if (background_index != PNG_CMAP_NONE_BACKGROUND) + goto bad_background; + break; + + case PNG_CMAP_GA: + if (background_index != PNG_CMAP_GA_BACKGROUND) + goto bad_background; + break; + + case PNG_CMAP_TRANS: + if (background_index >= cmap_entries || + background_index != PNG_CMAP_TRANS_BACKGROUND) + goto bad_background; + break; + + case PNG_CMAP_RGB: + if (background_index != PNG_CMAP_RGB_BACKGROUND) + goto bad_background; + break; + + case PNG_CMAP_RGB_ALPHA: + if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND) + goto bad_background; + break; + + default: + png_error(png_ptr, "bad processing option (internal error)"); + + bad_background: + png_error(png_ptr, "bad background index (internal error)"); + } + + display->colormap_processing = output_processing; + + return 1/*ok*/; +} + +/* The final part of the color-map read called from png_image_finish_read. */ +static int +png_image_read_and_map(png_voidp argument) +{ + png_image_read_control *display = png_voidcast(png_image_read_control*, + argument); + png_imagep image = display->image; + png_structrp png_ptr = image->opaque->png_ptr; + int passes; + + /* Called when the libpng data must be transformed into the color-mapped + * form. There is a local row buffer in display->local and this routine must + * do the interlace handling. + */ + switch (png_ptr->interlaced) + { + case PNG_INTERLACE_NONE: + passes = 1; + break; + + case PNG_INTERLACE_ADAM7: + passes = PNG_INTERLACE_ADAM7_PASSES; + break; + + default: + png_error(png_ptr, "unknown interlace type"); + } + + { + png_uint_32 height = image->height; + png_uint_32 width = image->width; + int proc = display->colormap_processing; + png_bytep first_row = png_voidcast(png_bytep, display->first_row); + ptrdiff_t step_row = display->row_bytes; + int pass; + + for (pass = 0; pass < passes; ++pass) + { + unsigned int startx, stepx, stepy; + png_uint_32 y; + + if (png_ptr->interlaced == PNG_INTERLACE_ADAM7) + { + /* The row may be empty for a short image: */ + if (PNG_PASS_COLS(width, pass) == 0) + continue; + + startx = PNG_PASS_START_COL(pass); + stepx = PNG_PASS_COL_OFFSET(pass); + y = PNG_PASS_START_ROW(pass); + stepy = PNG_PASS_ROW_OFFSET(pass); + } + + else + { + y = 0; + startx = 0; + stepx = stepy = 1; + } + + for (; y<height; y += stepy) + { + png_bytep inrow = png_voidcast(png_bytep, display->local_row); + png_bytep outrow = first_row + y * step_row; + png_const_bytep end_row = outrow + width; + + /* Read read the libpng data into the temporary buffer. */ + png_read_row(png_ptr, inrow, NULL); + + /* Now process the row according to the processing option, note + * that the caller verifies that the format of the libpng output + * data is as required. + */ + outrow += startx; + switch (proc) + { + case PNG_CMAP_GA: + for (; outrow < end_row; outrow += stepx) + { + /* The data is always in the PNG order */ + unsigned int gray = *inrow++; + unsigned int alpha = *inrow++; + unsigned int entry; + + /* NOTE: this code is copied as a comment in + * make_ga_colormap above. Please update the + * comment if you change this code! + */ + if (alpha > 229) /* opaque */ + { + entry = (231 * gray + 128) >> 8; + } + else if (alpha < 26) /* transparent */ + { + entry = 231; + } + else /* partially opaque */ + { + entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray); + } + + *outrow = (png_byte)entry; + } + break; + + case PNG_CMAP_TRANS: + for (; outrow < end_row; outrow += stepx) + { + png_byte gray = *inrow++; + png_byte alpha = *inrow++; + + if (alpha == 0) + *outrow = PNG_CMAP_TRANS_BACKGROUND; + + else if (gray != PNG_CMAP_TRANS_BACKGROUND) + *outrow = gray; + + else + *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1); + } + break; + + case PNG_CMAP_RGB: + for (; outrow < end_row; outrow += stepx) + { + *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]); + inrow += 3; + } + break; + + case PNG_CMAP_RGB_ALPHA: + for (; outrow < end_row; outrow += stepx) + { + unsigned int alpha = inrow[3]; + + /* Because the alpha entries only hold alpha==0.5 values + * split the processing at alpha==0.25 (64) and 0.75 + * (196). + */ + + if (alpha >= 196) + *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], + inrow[2]); + + else if (alpha < 64) + *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND; + + else + { + /* Likewise there are three entries for each of r, g + * and b. We could select the entry by popcount on + * the top two bits on those architectures that + * support it, this is what the code below does, + * crudely. + */ + unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1; + + /* Here are how the values map: + * + * 0x00 .. 0x3f -> 0 + * 0x40 .. 0xbf -> 1 + * 0xc0 .. 0xff -> 2 + * + * So, as above with the explicit alpha checks, the + * breakpoints are at 64 and 196. + */ + if (inrow[0] & 0x80) back_i += 9; /* red */ + if (inrow[0] & 0x40) back_i += 9; + if (inrow[0] & 0x80) back_i += 3; /* green */ + if (inrow[0] & 0x40) back_i += 3; + if (inrow[0] & 0x80) back_i += 1; /* blue */ + if (inrow[0] & 0x40) back_i += 1; + + *outrow = (png_byte)back_i; + } + + inrow += 4; + } + break; + + default: + break; + } + } + } + } + + return 1; +} + +static int +png_image_read_colormapped(png_voidp argument) +{ + png_image_read_control *display = png_voidcast(png_image_read_control*, + argument); + png_imagep image = display->image; + png_controlp control = image->opaque; + png_structrp png_ptr = control->png_ptr; + png_inforp info_ptr = control->info_ptr; + + int passes = 0; /* As a flag */ + + PNG_SKIP_CHUNKS(png_ptr); + + /* Update the 'info' structure and make sure the result is as required; first + * make sure to turn on the interlace handling if it will be required + * (because it can't be turned on *after* the call to png_read_update_info!) + */ + if (display->colormap_processing == PNG_CMAP_NONE) + passes = png_set_interlace_handling(png_ptr); + + png_read_update_info(png_ptr, info_ptr); + + /* The expected output can be deduced from the colormap_processing option. */ + switch (display->colormap_processing) + { + case PNG_CMAP_NONE: + /* Output must be one channel and one byte per pixel, the output + * encoding can be anything. + */ + if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE || + info_ptr->color_type == PNG_COLOR_TYPE_GRAY) && + info_ptr->bit_depth == 8) + break; + + goto bad_output; + + case PNG_CMAP_TRANS: + case PNG_CMAP_GA: + /* Output must be two channels and the 'G' one must be sRGB, the latter + * can be checked with an exact number because it should have been set + * to this number above! + */ + if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && + info_ptr->bit_depth == 8 && + png_ptr->screen_gamma == PNG_GAMMA_sRGB && + image->colormap_entries == 256) + break; + + goto bad_output; + + case PNG_CMAP_RGB: + /* Output must be 8-bit sRGB encoded RGB */ + if (info_ptr->color_type == PNG_COLOR_TYPE_RGB && + info_ptr->bit_depth == 8 && + png_ptr->screen_gamma == PNG_GAMMA_sRGB && + image->colormap_entries == 216) + break; + + goto bad_output; + + case PNG_CMAP_RGB_ALPHA: + /* Output must be 8-bit sRGB encoded RGBA */ + if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA && + info_ptr->bit_depth == 8 && + png_ptr->screen_gamma == PNG_GAMMA_sRGB && + image->colormap_entries == 244 /* 216 + 1 + 27 */) + break; + + /* goto bad_output; */ + /* FALL THROUGH */ + + default: + bad_output: + png_error(png_ptr, "bad color-map processing (internal error)"); + } + + /* Now read the rows. Do this here if it is possible to read directly into + * the output buffer, otherwise allocate a local row buffer of the maximum + * size libpng requires and call the relevant processing routine safely. + */ + { + png_voidp first_row = display->buffer; + ptrdiff_t row_bytes = display->row_stride; + + /* The following expression is designed to work correctly whether it gives + * a signed or an unsigned result. + */ + if (row_bytes < 0) + { + char *ptr = png_voidcast(char*, first_row); + ptr += (image->height-1) * (-row_bytes); + first_row = png_voidcast(png_voidp, ptr); + } + + display->first_row = first_row; + display->row_bytes = row_bytes; + } + + if (passes == 0) + { + int result; + png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr)); + + display->local_row = row; + result = png_safe_execute(image, png_image_read_and_map, display); + display->local_row = NULL; + png_free(png_ptr, row); + + return result; + } + + else + { + png_alloc_size_t row_bytes = display->row_bytes; + + while (--passes >= 0) + { + png_uint_32 y = image->height; + png_bytep row = png_voidcast(png_bytep, display->first_row); + + while (y-- > 0) + { + png_read_row(png_ptr, row, NULL); + row += row_bytes; + } + } + + return 1; + } +} + +/* Just the row reading part of png_image_read. */ +static int +png_image_read_composite(png_voidp argument) +{ + png_image_read_control *display = png_voidcast(png_image_read_control*, + argument); + png_imagep image = display->image; + png_structrp png_ptr = image->opaque->png_ptr; + int passes; + + switch (png_ptr->interlaced) + { + case PNG_INTERLACE_NONE: + passes = 1; + break; + + case PNG_INTERLACE_ADAM7: + passes = PNG_INTERLACE_ADAM7_PASSES; + break; + + default: + png_error(png_ptr, "unknown interlace type"); + } + + { + png_uint_32 height = image->height; + png_uint_32 width = image->width; + ptrdiff_t step_row = display->row_bytes; + unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1; + int pass; + + for (pass = 0; pass < passes; ++pass) + { + unsigned int startx, stepx, stepy; + png_uint_32 y; + + if (png_ptr->interlaced == PNG_INTERLACE_ADAM7) + { + /* The row may be empty for a short image: */ + if (PNG_PASS_COLS(width, pass) == 0) + continue; + + startx = PNG_PASS_START_COL(pass) * channels; + stepx = PNG_PASS_COL_OFFSET(pass) * channels; + y = PNG_PASS_START_ROW(pass); + stepy = PNG_PASS_ROW_OFFSET(pass); + } + + else + { + y = 0; + startx = 0; + stepx = channels; + stepy = 1; + } + + for (; y<height; y += stepy) + { + png_bytep inrow = png_voidcast(png_bytep, display->local_row); + png_bytep outrow; + png_const_bytep end_row; + + /* Read the row, which is packed: */ + png_read_row(png_ptr, inrow, NULL); + + outrow = png_voidcast(png_bytep, display->first_row); + outrow += y * step_row; + end_row = outrow + width * channels; + + /* Now do the composition on each pixel in this row. */ + outrow += startx; + for (; outrow < end_row; outrow += stepx) + { + png_byte alpha = inrow[channels]; + + if (alpha > 0) /* else no change to the output */ + { + unsigned int c; + + for (c=0; c<channels; ++c) + { + png_uint_32 component = inrow[c]; + + if (alpha < 255) /* else just use component */ + { + /* This is PNG_OPTIMIZED_ALPHA, the component value + * is a linear 8-bit value. Combine this with the + * current outrow[c] value which is sRGB encoded. + * Arithmetic here is 16-bits to preserve the output + * values correctly. + */ + component *= 257*255; /* =65535 */ + component += (255-alpha)*png_sRGB_table[outrow[c]]; + + /* So 'component' is scaled by 255*65535 and is + * therefore appropriate for the sRGB to linear + * conversion table. + */ + component = PNG_sRGB_FROM_LINEAR(component); + } + + outrow[c] = (png_byte)component; + } + } + + inrow += channels+1; /* components and alpha channel */ + } + } + } + } + + return 1; +} + +/* The do_local_background case; called when all the following transforms are to + * be done: + * + * PNG_RGB_TO_GRAY + * PNG_COMPOSITE + * PNG_GAMMA + * + * This is a work-around for the fact that both the PNG_RGB_TO_GRAY and + * PNG_COMPOSITE code performs gamma correction, so we get double gamma + * correction. The fix-up is to prevent the PNG_COMPOSITE operation from + * happening inside libpng, so this routine sees an 8 or 16-bit gray+alpha + * row and handles the removal or pre-multiplication of the alpha channel. + */ +static int +png_image_read_background(png_voidp argument) +{ + png_image_read_control *display = png_voidcast(png_image_read_control*, + argument); + png_imagep image = display->image; + png_structrp png_ptr = image->opaque->png_ptr; + png_inforp info_ptr = image->opaque->info_ptr; + png_uint_32 height = image->height; + png_uint_32 width = image->width; + int pass, passes; + + /* Double check the convoluted logic below. We expect to get here with + * libpng doing rgb to gray and gamma correction but background processing + * left to the png_image_read_background function. The rows libpng produce + * might be 8 or 16-bit but should always have two channels; gray plus alpha. + */ + if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0) + png_error(png_ptr, "lost rgb to gray"); + + if ((png_ptr->transformations & PNG_COMPOSE) != 0) + png_error(png_ptr, "unexpected compose"); + + if (png_get_channels(png_ptr, info_ptr) != 2) + png_error(png_ptr, "lost/gained channels"); + + /* Expect the 8-bit case to always remove the alpha channel */ + if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 && + (image->format & PNG_FORMAT_FLAG_ALPHA) != 0) + png_error(png_ptr, "unexpected 8-bit transformation"); + + switch (png_ptr->interlaced) + { + case PNG_INTERLACE_NONE: + passes = 1; + break; + + case PNG_INTERLACE_ADAM7: + passes = PNG_INTERLACE_ADAM7_PASSES; + break; + + default: + png_error(png_ptr, "unknown interlace type"); + } + + /* Use direct access to info_ptr here because otherwise the simplified API + * would require PNG_EASY_ACCESS_SUPPORTED (just for this.) Note this is + * checking the value after libpng expansions, not the original value in the + * PNG. + */ + switch (info_ptr->bit_depth) + { + default: + png_error(png_ptr, "unexpected bit depth"); + break; + + case 8: + /* 8-bit sRGB gray values with an alpha channel; the alpha channel is + * to be removed by composing on a background: either the row if + * display->background is NULL or display->background->green if not. + * Unlike the code above ALPHA_OPTIMIZED has *not* been done. + */ + { + png_bytep first_row = png_voidcast(png_bytep, display->first_row); + ptrdiff_t step_row = display->row_bytes; + + for (pass = 0; pass < passes; ++pass) + { + png_bytep row = png_voidcast(png_bytep, + display->first_row); + unsigned int startx, stepx, stepy; + png_uint_32 y; + + if (png_ptr->interlaced == PNG_INTERLACE_ADAM7) + { + /* The row may be empty for a short image: */ + if (PNG_PASS_COLS(width, pass) == 0) + continue; + + startx = PNG_PASS_START_COL(pass); + stepx = PNG_PASS_COL_OFFSET(pass); + y = PNG_PASS_START_ROW(pass); + stepy = PNG_PASS_ROW_OFFSET(pass); + } + + else + { + y = 0; + startx = 0; + stepx = stepy = 1; + } + + if (display->background == NULL) + { + for (; y<height; y += stepy) + { + png_bytep inrow = png_voidcast(png_bytep, + display->local_row); + png_bytep outrow = first_row + y * step_row; + png_const_bytep end_row = outrow + width; + + /* Read the row, which is packed: */ + png_read_row(png_ptr, inrow, NULL); + + /* Now do the composition on each pixel in this row. */ + outrow += startx; + for (; outrow < end_row; outrow += stepx) + { + png_byte alpha = inrow[1]; + + if (alpha > 0) /* else no change to the output */ + { + png_uint_32 component = inrow[0]; + + if (alpha < 255) /* else just use component */ + { + /* Since PNG_OPTIMIZED_ALPHA was not set it is + * necessary to invert the sRGB transfer + * function and multiply the alpha out. + */ + component = png_sRGB_table[component] * alpha; + component += png_sRGB_table[outrow[0]] * + (255-alpha); + component = PNG_sRGB_FROM_LINEAR(component); + } + + outrow[0] = (png_byte)component; + } + + inrow += 2; /* gray and alpha channel */ + } + } + } + + else /* constant background value */ + { + png_byte background8 = display->background->green; + png_uint_16 background = png_sRGB_table[background8]; + + for (; y<height; y += stepy) + { + png_bytep inrow = png_voidcast(png_bytep, + display->local_row); + png_bytep outrow = first_row + y * step_row; + png_const_bytep end_row = outrow + width; + + /* Read the row, which is packed: */ + png_read_row(png_ptr, inrow, NULL); + + /* Now do the composition on each pixel in this row. */ + outrow += startx; + for (; outrow < end_row; outrow += stepx) + { + png_byte alpha = inrow[1]; + + if (alpha > 0) /* else use background */ + { + png_uint_32 component = inrow[0]; + + if (alpha < 255) /* else just use component */ + { + component = png_sRGB_table[component] * alpha; + component += background * (255-alpha); + component = PNG_sRGB_FROM_LINEAR(component); + } + + outrow[0] = (png_byte)component; + } + + else + outrow[0] = background8; + + inrow += 2; /* gray and alpha channel */ + } + + row += display->row_bytes; + } + } + } + } + break; + + case 16: + /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must + * still be done and, maybe, the alpha channel removed. This code also + * handles the alpha-first option. + */ + { + png_uint_16p first_row = png_voidcast(png_uint_16p, + display->first_row); + /* The division by two is safe because the caller passed in a + * stride which was multiplied by 2 (below) to get row_bytes. + */ + ptrdiff_t step_row = display->row_bytes / 2; + int preserve_alpha = (image->format & PNG_FORMAT_FLAG_ALPHA) != 0; + unsigned int outchannels = 1+preserve_alpha; + int swap_alpha = 0; + +# ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED + if (preserve_alpha && (image->format & PNG_FORMAT_FLAG_AFIRST)) + swap_alpha = 1; +# endif + + for (pass = 0; pass < passes; ++pass) + { + unsigned int startx, stepx, stepy; + png_uint_32 y; + + /* The 'x' start and step are adjusted to output components here. + */ + if (png_ptr->interlaced == PNG_INTERLACE_ADAM7) + { + /* The row may be empty for a short image: */ + if (PNG_PASS_COLS(width, pass) == 0) + continue; + + startx = PNG_PASS_START_COL(pass) * outchannels; + stepx = PNG_PASS_COL_OFFSET(pass) * outchannels; + y = PNG_PASS_START_ROW(pass); + stepy = PNG_PASS_ROW_OFFSET(pass); + } + + else + { + y = 0; + startx = 0; + stepx = outchannels; + stepy = 1; + } + + for (; y<height; y += stepy) + { + png_const_uint_16p inrow; + png_uint_16p outrow = first_row + y*step_row; + png_uint_16p end_row = outrow + width * outchannels; + + /* Read the row, which is packed: */ + png_read_row(png_ptr, png_voidcast(png_bytep, + display->local_row), NULL); + inrow = png_voidcast(png_const_uint_16p, display->local_row); + + /* Now do the pre-multiplication on each pixel in this row. + */ + outrow += startx; + for (; outrow < end_row; outrow += stepx) + { + png_uint_32 component = inrow[0]; + png_uint_16 alpha = inrow[1]; + + if (alpha > 0) /* else 0 */ + { + if (alpha < 65535) /* else just use component */ + { + component *= alpha; + component += 32767; + component /= 65535; + } + } + + else + component = 0; + + outrow[swap_alpha] = (png_uint_16)component; + if (preserve_alpha != 0) + outrow[1 ^ swap_alpha] = alpha; + + inrow += 2; /* components and alpha channel */ + } + } + } + } + break; + } + + return 1; +} + +/* The guts of png_image_finish_read as a png_safe_execute callback. */ +static int +png_image_read_direct(png_voidp argument) +{ + png_image_read_control *display = png_voidcast(png_image_read_control*, + argument); + png_imagep image = display->image; + png_structrp png_ptr = image->opaque->png_ptr; + png_inforp info_ptr = image->opaque->info_ptr; + + png_uint_32 format = image->format; + int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0; + int do_local_compose = 0; + int do_local_background = 0; /* to avoid double gamma correction bug */ + int passes = 0; + + /* Add transforms to ensure the correct output format is produced then check + * that the required implementation support is there. Always expand; always + * need 8 bits minimum, no palette and expanded tRNS. + */ + png_set_expand(png_ptr); + + /* Now check the format to see if it was modified. */ + { + png_uint_32 base_format = png_image_format(png_ptr) & + ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */; + png_uint_32 change = format ^ base_format; + png_fixed_point output_gamma; + int mode; /* alpha mode */ + + /* Do this first so that we have a record if rgb to gray is happening. */ + if (change & PNG_FORMAT_FLAG_COLOR) + { + /* gray<->color transformation required. */ + if (format & PNG_FORMAT_FLAG_COLOR) + png_set_gray_to_rgb(png_ptr); + + else + { + /* libpng can't do both rgb to gray and + * background/pre-multiplication if there is also significant gamma + * correction, because both operations require linear colors and + * the code only supports one transform doing the gamma correction. + * Handle this by doing the pre-multiplication or background + * operation in this code, if necessary. + * + * TODO: fix this by rewriting pngrtran.c (!) + * + * For the moment (given that fixing this in pngrtran.c is an + * enormous change) 'do_local_background' is used to indicate that + * the problem exists. + */ + if (base_format & PNG_FORMAT_FLAG_ALPHA) + do_local_background = 1/*maybe*/; + + png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, + PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT); + } + + change &= ~PNG_FORMAT_FLAG_COLOR; + } + + /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise. + */ + { + png_fixed_point input_gamma_default; + + if ((base_format & PNG_FORMAT_FLAG_LINEAR) && + (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0) + input_gamma_default = PNG_GAMMA_LINEAR; + else + input_gamma_default = PNG_DEFAULT_sRGB; + + /* Call png_set_alpha_mode to set the default for the input gamma; the + * output gamma is set by a second call below. + */ + png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default); + } + + if (linear != 0) + { + /* If there *is* an alpha channel in the input it must be multiplied + * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG. + */ + if (base_format & PNG_FORMAT_FLAG_ALPHA) + mode = PNG_ALPHA_STANDARD; /* associated alpha */ + + else + mode = PNG_ALPHA_PNG; + + output_gamma = PNG_GAMMA_LINEAR; + } + + else + { + mode = PNG_ALPHA_PNG; + output_gamma = PNG_DEFAULT_sRGB; + } + + /* If 'do_local_background' is set check for the presence of gamma + * correction; this is part of the work-round for the libpng bug + * described above. + * + * TODO: fix libpng and remove this. + */ + if (do_local_background != 0) + { + png_fixed_point gtest; + + /* This is 'png_gamma_threshold' from pngrtran.c; the test used for + * gamma correction, the screen gamma hasn't been set on png_struct + * yet; it's set below. png_struct::gamma, however, is set to the + * final value. + */ + if (png_muldiv(>est, output_gamma, png_ptr->colorspace.gamma, + PNG_FP_1) && !png_gamma_significant(gtest)) + do_local_background = 0; + + else if (mode == PNG_ALPHA_STANDARD) + { + do_local_background = 2/*required*/; + mode = PNG_ALPHA_PNG; /* prevent libpng doing it */ + } + + /* else leave as 1 for the checks below */ + } + + /* If the bit-depth changes then handle that here. */ + if (change & PNG_FORMAT_FLAG_LINEAR) + { + if (linear /*16-bit output*/) + png_set_expand_16(png_ptr); + + else /* 8-bit output */ + png_set_scale_16(png_ptr); + + change &= ~PNG_FORMAT_FLAG_LINEAR; + } + + /* Now the background/alpha channel changes. */ + if (change & PNG_FORMAT_FLAG_ALPHA) + { + /* Removing an alpha channel requires composition for the 8-bit + * formats; for the 16-bit it is already done, above, by the + * pre-multiplication and the channel just needs to be stripped. + */ + if (base_format & PNG_FORMAT_FLAG_ALPHA) + { + /* If RGB->gray is happening the alpha channel must be left and the + * operation completed locally. + * + * TODO: fix libpng and remove this. + */ + if (do_local_background != 0) + do_local_background = 2/*required*/; + + /* 16-bit output: just remove the channel */ + else if (linear != 0) /* compose on black (well, pre-multiply) */ + png_set_strip_alpha(png_ptr); + + /* 8-bit output: do an appropriate compose */ + else if (display->background != NULL) + { + png_color_16 c; + + c.index = 0; /*unused*/ + c.red = display->background->red; + c.green = display->background->green; + c.blue = display->background->blue; + c.gray = display->background->green; + + /* This is always an 8-bit sRGB value, using the 'green' channel + * for gray is much better than calculating the luminance here; + * we can get off-by-one errors in that calculation relative to + * the app expectations and that will show up in transparent + * pixels. + */ + png_set_background_fixed(png_ptr, &c, + PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/, + 0/*gamma: not used*/); + } + + else /* compose on row: implemented below. */ + { + do_local_compose = 1; + /* This leaves the alpha channel in the output, so it has to be + * removed by the code below. Set the encoding to the 'OPTIMIZE' + * one so the code only has to hack on the pixels that require + * composition. + */ + mode = PNG_ALPHA_OPTIMIZED; + } + } + + else /* output needs an alpha channel */ + { + /* This is tricky because it happens before the swap operation has + * been accomplished; however, the swap does *not* swap the added + * alpha channel (weird API), so it must be added in the correct + * place. + */ + png_uint_32 filler; /* opaque filler */ + int where; + + if (linear != 0) + filler = 65535; + + else + filler = 255; + +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + { + where = PNG_FILLER_BEFORE; + change &= ~PNG_FORMAT_FLAG_AFIRST; + } + + else +# endif + where = PNG_FILLER_AFTER; + + png_set_add_alpha(png_ptr, filler, where); + } + + /* This stops the (irrelevant) call to swap_alpha below. */ + change &= ~PNG_FORMAT_FLAG_ALPHA; + } + + /* Now set the alpha mode correctly; this is always done, even if there is + * no alpha channel in either the input or the output because it correctly + * sets the output gamma. + */ + png_set_alpha_mode_fixed(png_ptr, mode, output_gamma); + +# ifdef PNG_FORMAT_BGR_SUPPORTED + if (change & PNG_FORMAT_FLAG_BGR) + { + /* Check only the output format; PNG is never BGR; don't do this if + * the output is gray, but fix up the 'format' value in that case. + */ + if (format & PNG_FORMAT_FLAG_COLOR) + png_set_bgr(png_ptr); + + else + format &= ~PNG_FORMAT_FLAG_BGR; + + change &= ~PNG_FORMAT_FLAG_BGR; + } +# endif + +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (change & PNG_FORMAT_FLAG_AFIRST) + { + /* Only relevant if there is an alpha channel - it's particularly + * important to handle this correctly because do_local_compose may + * be set above and then libpng will keep the alpha channel for this + * code to remove. + */ + if (format & PNG_FORMAT_FLAG_ALPHA) + { + /* Disable this if doing a local background, + * TODO: remove this when local background is no longer required. + */ + if (do_local_background != 2) + png_set_swap_alpha(png_ptr); + } + + else + format &= ~PNG_FORMAT_FLAG_AFIRST; + + change &= ~PNG_FORMAT_FLAG_AFIRST; + } +# endif + + /* If the *output* is 16-bit then we need to check for a byte-swap on this + * architecture. + */ + if (linear != 0) + { + PNG_CONST png_uint_16 le = 0x0001; + + if (*(png_const_bytep)&le) + png_set_swap(png_ptr); + } + + /* If change is not now 0 some transformation is missing - error out. */ + if (change != 0) + png_error(png_ptr, "png_read_image: unsupported transformation"); + } + + PNG_SKIP_CHUNKS(png_ptr); + + /* Update the 'info' structure and make sure the result is as required; first + * make sure to turn on the interlace handling if it will be required + * (because it can't be turned on *after* the call to png_read_update_info!) + * + * TODO: remove the do_local_background fixup below. + */ + if (do_local_compose == 0 && do_local_background != 2) + passes = png_set_interlace_handling(png_ptr); + + png_read_update_info(png_ptr, info_ptr); + + { + png_uint_32 info_format = 0; + + if (info_ptr->color_type & PNG_COLOR_MASK_COLOR) + info_format |= PNG_FORMAT_FLAG_COLOR; + + if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA) + { + /* do_local_compose removes this channel below. */ + if (do_local_compose == 0) + { + /* do_local_background does the same if required. */ + if (do_local_background != 2 || + (format & PNG_FORMAT_FLAG_ALPHA) != 0) + info_format |= PNG_FORMAT_FLAG_ALPHA; + } + } + + else if (do_local_compose != 0) /* internal error */ + png_error(png_ptr, "png_image_read: alpha channel lost"); + + if (info_ptr->bit_depth == 16) + info_format |= PNG_FORMAT_FLAG_LINEAR; + +# ifdef PNG_FORMAT_BGR_SUPPORTED + if (png_ptr->transformations & PNG_BGR) + info_format |= PNG_FORMAT_FLAG_BGR; +# endif + +# ifdef PNG_FORMAT_AFIRST_SUPPORTED + if (do_local_background == 2) + { + if (format & PNG_FORMAT_FLAG_AFIRST) + info_format |= PNG_FORMAT_FLAG_AFIRST; + } + + if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 || + ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 && + (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0)) + { + if (do_local_background == 2) + png_error(png_ptr, "unexpected alpha swap transformation"); + + info_format |= PNG_FORMAT_FLAG_AFIRST; + } +# endif + + /* This is actually an internal error. */ + if (info_format != format) + png_error(png_ptr, "png_read_image: invalid transformations"); + } + + /* Now read the rows. If do_local_compose is set then it is necessary to use + * a local row buffer. The output will be GA, RGBA or BGRA and must be + * converted to G, RGB or BGR as appropriate. The 'local_row' member of the + * display acts as a flag. + */ + { + png_voidp first_row = display->buffer; + ptrdiff_t row_bytes = display->row_stride; + + if (linear != 0) + row_bytes *= 2; + + /* The following expression is designed to work correctly whether it gives + * a signed or an unsigned result. + */ + if (row_bytes < 0) + { + char *ptr = png_voidcast(char*, first_row); + ptr += (image->height-1) * (-row_bytes); + first_row = png_voidcast(png_voidp, ptr); + } + + display->first_row = first_row; + display->row_bytes = row_bytes; + } + + if (do_local_compose != 0) + { + int result; + png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr)); + + display->local_row = row; + result = png_safe_execute(image, png_image_read_composite, display); + display->local_row = NULL; + png_free(png_ptr, row); + + return result; + } + + else if (do_local_background == 2) + { + int result; + png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr)); + + display->local_row = row; + result = png_safe_execute(image, png_image_read_background, display); + display->local_row = NULL; + png_free(png_ptr, row); + + return result; + } + + else + { + png_alloc_size_t row_bytes = display->row_bytes; + + while (--passes >= 0) + { + png_uint_32 y = image->height; + png_bytep row = png_voidcast(png_bytep, display->first_row); + + while (y-- > 0) + { + png_read_row(png_ptr, row, NULL); + row += row_bytes; + } + } + + return 1; + } +} + +int PNGAPI +png_image_finish_read(png_imagep image, png_const_colorp background, + void *buffer, png_int_32 row_stride, void *colormap) +{ + if (image != NULL && image->version == PNG_IMAGE_VERSION) + { + png_uint_32 check; + + if (row_stride == 0) + row_stride = PNG_IMAGE_ROW_STRIDE(*image); + + if (row_stride < 0) + check = -row_stride; + + else + check = row_stride; + + if (image->opaque != NULL && buffer != NULL && + check >= PNG_IMAGE_ROW_STRIDE(*image)) + { + if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 || + (image->colormap_entries > 0 && colormap != NULL)) + { + int result; + png_image_read_control display; + + memset(&display, 0, (sizeof display)); + display.image = image; + display.buffer = buffer; + display.row_stride = row_stride; + display.colormap = colormap; + display.background = background; + display.local_row = NULL; + + /* Choose the correct 'end' routine; for the color-map case all the + * setup has already been done. + */ + if (image->format & PNG_FORMAT_FLAG_COLORMAP) + result = + png_safe_execute(image, png_image_read_colormap, &display) && + png_safe_execute(image, png_image_read_colormapped, &display); + + else + result = + png_safe_execute(image, png_image_read_direct, &display); + + png_image_free(image); + return result; + } + + else + return png_image_error(image, + "png_image_finish_read[color-map]: no color-map"); + } + + else + return png_image_error(image, + "png_image_finish_read: invalid argument"); + } + + else if (image != NULL) + return png_image_error(image, + "png_image_finish_read: damaged PNG_IMAGE_VERSION"); + + return 0; +} + +#endif /* PNG_SIMPLIFIED_READ_SUPPORTED */ +#endif /* PNG_READ_SUPPORTED */ diff --git a/png/pngrio.c b/png/pngrio.c new file mode 100755 index 0000000..d75ac5b --- /dev/null +++ b/png/pngrio.c @@ -0,0 +1,120 @@ + +/* pngrio.c - functions for data input + * + * Last changed in libpng 1.6.9 [February 6, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * This file provides a location for all input. Users who need + * special handling are expected to write a function that has the same + * arguments as this and performs a similar function, but that possibly + * has a different input method. Note that you shouldn't change this + * function, but rather write a replacement function and then make + * libpng use it at run time with png_set_read_fn(...). + */ + +#include "pngpriv.h" + +#ifdef PNG_READ_SUPPORTED + +/* Read the data from whatever input you are using. The default routine + * reads from a file pointer. Note that this routine sometimes gets called + * with very small lengths, so you should implement some kind of simple + * buffering if you are using unbuffered reads. This should never be asked + * to read more then 64K on a 16 bit machine. + */ +void /* PRIVATE */ +png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length) +{ + png_debug1(4, "reading %d bytes", (int)length); + + if (png_ptr->read_data_fn != NULL) + (*(png_ptr->read_data_fn))(png_ptr, data, length); + + else + png_error(png_ptr, "Call to NULL read function"); +} + +#ifdef PNG_STDIO_SUPPORTED +/* This is the function that does the actual reading of data. If you are + * not reading from a standard C stream, you should create a replacement + * read_data function and use it at run time with png_set_read_fn(), rather + * than changing the library. + */ +void PNGCBAPI +png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length) +{ + png_size_t check; + + if (png_ptr == NULL) + return; + + /* fread() returns 0 on error, so it is OK to store this in a png_size_t + * instead of an int, which is what fread() actually returns. + */ + check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr)); + + if (check != length) + png_error(png_ptr, "Read Error"); +} +#endif + +/* This function allows the application to supply a new input function + * for libpng if standard C streams aren't being used. + * + * This function takes as its arguments: + * + * png_ptr - pointer to a png input data structure + * + * io_ptr - pointer to user supplied structure containing info about + * the input functions. May be NULL. + * + * read_data_fn - pointer to a new input function that takes as its + * arguments a pointer to a png_struct, a pointer to + * a location where input data can be stored, and a 32-bit + * unsigned int that is the number of bytes to be read. + * To exit and output any fatal error messages the new write + * function should call png_error(png_ptr, "Error msg"). + * May be NULL, in which case libpng's default function will + * be used. + */ +void PNGAPI +png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr, + png_rw_ptr read_data_fn) +{ + if (png_ptr == NULL) + return; + + png_ptr->io_ptr = io_ptr; + +#ifdef PNG_STDIO_SUPPORTED + if (read_data_fn != NULL) + png_ptr->read_data_fn = read_data_fn; + + else + png_ptr->read_data_fn = png_default_read_data; +#else + png_ptr->read_data_fn = read_data_fn; +#endif + +#ifdef PNG_WRITE_SUPPORTED + /* It is an error to write to a read device */ + if (png_ptr->write_data_fn != NULL) + { + png_ptr->write_data_fn = NULL; + png_warning(png_ptr, + "Can't set both read_data_fn and write_data_fn in the" + " same structure"); + } +#endif + +#ifdef PNG_WRITE_FLUSH_SUPPORTED + png_ptr->output_flush_fn = NULL; +#endif +} +#endif /* PNG_READ_SUPPORTED */ diff --git a/png/pngrtran.c b/png/pngrtran.c new file mode 100755 index 0000000..5b89423 --- /dev/null +++ b/png/pngrtran.c @@ -0,0 +1,4991 @@ + +/* pngrtran.c - transforms the data in a row for PNG readers + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * This file contains functions optionally called by an application + * in order to tell libpng how to handle data when reading a PNG. + * Transformations that are used in both reading and writing are + * in pngtrans.c. + */ + +#include "pngpriv.h" + +#ifdef PNG_READ_SUPPORTED + +/* Set the action on getting a CRC error for an ancillary or critical chunk. */ +void PNGAPI +png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action) +{ + png_debug(1, "in png_set_crc_action"); + + if (png_ptr == NULL) + return; + + /* Tell libpng how we react to CRC errors in critical chunks */ + switch (crit_action) + { + case PNG_CRC_NO_CHANGE: /* Leave setting as is */ + break; + + case PNG_CRC_WARN_USE: /* Warn/use data */ + png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; + png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE; + break; + + case PNG_CRC_QUIET_USE: /* Quiet/use data */ + png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; + png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE | + PNG_FLAG_CRC_CRITICAL_IGNORE; + break; + + case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */ + png_warning(png_ptr, + "Can't discard critical data on CRC error"); + case PNG_CRC_ERROR_QUIT: /* Error/quit */ + + case PNG_CRC_DEFAULT: + default: + png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; + break; + } + + /* Tell libpng how we react to CRC errors in ancillary chunks */ + switch (ancil_action) + { + case PNG_CRC_NO_CHANGE: /* Leave setting as is */ + break; + + case PNG_CRC_WARN_USE: /* Warn/use data */ + png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; + png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE; + break; + + case PNG_CRC_QUIET_USE: /* Quiet/use data */ + png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; + png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE | + PNG_FLAG_CRC_ANCILLARY_NOWARN; + break; + + case PNG_CRC_ERROR_QUIT: /* Error/quit */ + png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; + png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN; + break; + + case PNG_CRC_WARN_DISCARD: /* Warn/discard data */ + + case PNG_CRC_DEFAULT: + default: + png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; + break; + } +} + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +/* Is it OK to set a transformation now? Only if png_start_read_image or + * png_read_update_info have not been called. It is not necessary for the IHDR + * to have been read in all cases, the parameter allows for this check too. + */ +static int +png_rtran_ok(png_structrp png_ptr, int need_IHDR) +{ + if (png_ptr != NULL) + { + if (png_ptr->flags & PNG_FLAG_ROW_INIT) + png_app_error(png_ptr, + "invalid after png_start_read_image or png_read_update_info"); + + else if (need_IHDR && (png_ptr->mode & PNG_HAVE_IHDR) == 0) + png_app_error(png_ptr, "invalid before the PNG header has been read"); + + else + { + /* Turn on failure to initialize correctly for all transforms. */ + png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED; + + return 1; /* Ok */ + } + } + + return 0; /* no png_error possible! */ +} +#endif + +#ifdef PNG_READ_BACKGROUND_SUPPORTED +/* Handle alpha and tRNS via a background color */ +void PNGFAPI +png_set_background_fixed(png_structrp png_ptr, + png_const_color_16p background_color, int background_gamma_code, + int need_expand, png_fixed_point background_gamma) +{ + png_debug(1, "in png_set_background_fixed"); + + if (!png_rtran_ok(png_ptr, 0) || background_color == NULL) + return; + + if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN) + { + png_warning(png_ptr, "Application must supply a known background gamma"); + return; + } + + png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + + png_ptr->background = *background_color; + png_ptr->background_gamma = background_gamma; + png_ptr->background_gamma_type = (png_byte)(background_gamma_code); + if (need_expand != 0) + png_ptr->transformations |= PNG_BACKGROUND_EXPAND; + else + png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_background(png_structrp png_ptr, + png_const_color_16p background_color, int background_gamma_code, + int need_expand, double background_gamma) +{ + png_set_background_fixed(png_ptr, background_color, background_gamma_code, + need_expand, png_fixed(png_ptr, background_gamma, "png_set_background")); +} +# endif /* FLOATING_POINT */ +#endif /* READ_BACKGROUND */ + +/* Scale 16-bit depth files to 8-bit depth. If both of these are set then the + * one that pngrtran does first (scale) happens. This is necessary to allow the + * TRANSFORM and API behavior to be somewhat consistent, and it's simpler. + */ +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED +void PNGAPI +png_set_scale_16(png_structrp png_ptr) +{ + png_debug(1, "in png_set_scale_16"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= PNG_SCALE_16_TO_8; +} +#endif + +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED +/* Chop 16-bit depth files to 8-bit depth */ +void PNGAPI +png_set_strip_16(png_structrp png_ptr) +{ + png_debug(1, "in png_set_strip_16"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= PNG_16_TO_8; +} +#endif + +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED +void PNGAPI +png_set_strip_alpha(png_structrp png_ptr) +{ + png_debug(1, "in png_set_strip_alpha"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= PNG_STRIP_ALPHA; +} +#endif + +#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED) +static png_fixed_point +translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma, + int is_screen) +{ + /* Check for flag values. The main reason for having the old Mac value as a + * flag is that it is pretty near impossible to work out what the correct + * value is from Apple documentation - a working Mac system is needed to + * discover the value! + */ + if (output_gamma == PNG_DEFAULT_sRGB || + output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB) + { + /* If there is no sRGB support this just sets the gamma to the standard + * sRGB value. (This is a side effect of using this function!) + */ +# ifdef PNG_READ_sRGB_SUPPORTED + png_ptr->flags |= PNG_FLAG_ASSUME_sRGB; +# else + PNG_UNUSED(png_ptr) +# endif + if (is_screen != 0) + output_gamma = PNG_GAMMA_sRGB; + else + output_gamma = PNG_GAMMA_sRGB_INVERSE; + } + + else if (output_gamma == PNG_GAMMA_MAC_18 || + output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18) + { + if (is_screen != 0) + output_gamma = PNG_GAMMA_MAC_OLD; + else + output_gamma = PNG_GAMMA_MAC_INVERSE; + } + + return output_gamma; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +static png_fixed_point +convert_gamma_value(png_structrp png_ptr, double output_gamma) +{ + /* The following silently ignores cases where fixed point (times 100,000) + * gamma values are passed to the floating point API. This is safe and it + * means the fixed point constants work just fine with the floating point + * API. The alternative would just lead to undetected errors and spurious + * bug reports. Negative values fail inside the _fixed API unless they + * correspond to the flag values. + */ + if (output_gamma > 0 && output_gamma < 128) + output_gamma *= PNG_FP_1; + + /* This preserves -1 and -2 exactly: */ + output_gamma = floor(output_gamma + .5); + + if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN) + png_fixed_error(png_ptr, "gamma value"); + + return (png_fixed_point)output_gamma; +} +# endif +#endif /* READ_ALPHA_MODE || READ_GAMMA */ + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED +void PNGFAPI +png_set_alpha_mode_fixed(png_structrp png_ptr, int mode, + png_fixed_point output_gamma) +{ + int compose = 0; + png_fixed_point file_gamma; + + png_debug(1, "in png_set_alpha_mode"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/); + + /* Validate the value to ensure it is in a reasonable range. The value + * is expected to be 1 or greater, but this range test allows for some + * viewing correction values. The intent is to weed out users of this API + * who use the inverse of the gamma value accidentally! Since some of these + * values are reasonable this may have to be changed. + */ + if (output_gamma < 70000 || output_gamma > 300000) + png_error(png_ptr, "output gamma out of expected range"); + + /* The default file gamma is the inverse of the output gamma; the output + * gamma may be changed below so get the file value first: + */ + file_gamma = png_reciprocal(output_gamma); + + /* There are really 8 possibilities here, composed of any combination + * of: + * + * premultiply the color channels + * do not encode non-opaque pixels + * encode the alpha as well as the color channels + * + * The differences disappear if the input/output ('screen') gamma is 1.0, + * because then the encoding is a no-op and there is only the choice of + * premultiplying the color channels or not. + * + * png_set_alpha_mode and png_set_background interact because both use + * png_compose to do the work. Calling both is only useful when + * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along + * with a default gamma value. Otherwise PNG_COMPOSE must not be set. + */ + switch (mode) + { + case PNG_ALPHA_PNG: /* default: png standard */ + /* No compose, but it may be set by png_set_background! */ + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + break; + + case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */ + compose = 1; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + /* The output is linear: */ + output_gamma = PNG_FP_1; + break; + + case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */ + compose = 1; + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA; + /* output_gamma records the encoding of opaque pixels! */ + break; + + case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */ + compose = 1; + png_ptr->transformations |= PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + break; + + default: + png_error(png_ptr, "invalid alpha mode"); + } + + /* Only set the default gamma if the file gamma has not been set (this has + * the side effect that the gamma in a second call to png_set_alpha_mode will + * be ignored.) + */ + if (png_ptr->colorspace.gamma == 0) + { + png_ptr->colorspace.gamma = file_gamma; + png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA; + } + + /* But always set the output gamma: */ + png_ptr->screen_gamma = output_gamma; + + /* Finally, if pre-multiplying, set the background fields to achieve the + * desired result. + */ + if (compose != 0) + { + /* And obtain alpha pre-multiplication by composing on black: */ + memset(&png_ptr->background, 0, (sizeof png_ptr->background)); + png_ptr->background_gamma = png_ptr->colorspace.gamma; /* just in case */ + png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE; + png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND; + + if (png_ptr->transformations & PNG_COMPOSE) + png_error(png_ptr, + "conflicting calls to set alpha mode and background"); + + png_ptr->transformations |= PNG_COMPOSE; + } +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma) +{ + png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr, + output_gamma)); +} +# endif +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED +/* Dither file to 8-bit. Supply a palette, the current number + * of elements in the palette, the maximum number of elements + * allowed, and a histogram if possible. If the current number + * of colors is greater then the maximum number, the palette will be + * modified to fit in the maximum number. "full_quantize" indicates + * whether we need a quantizing cube set up for RGB images, or if we + * simply are reducing the number of colors in a paletted image. + */ + +typedef struct png_dsort_struct +{ + struct png_dsort_struct * next; + png_byte left; + png_byte right; +} png_dsort; +typedef png_dsort * png_dsortp; +typedef png_dsort * * png_dsortpp; + +void PNGAPI +png_set_quantize(png_structrp png_ptr, png_colorp palette, + int num_palette, int maximum_colors, png_const_uint_16p histogram, + int full_quantize) +{ + png_debug(1, "in png_set_quantize"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= PNG_QUANTIZE; + + if (full_quantize == 0) + { + int i; + + png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * (sizeof (png_byte)))); + for (i = 0; i < num_palette; i++) + png_ptr->quantize_index[i] = (png_byte)i; + } + + if (num_palette > maximum_colors) + { + if (histogram != NULL) + { + /* This is easy enough, just throw out the least used colors. + * Perhaps not the best solution, but good enough. + */ + + int i; + + /* Initialize an array to sort colors */ + png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * (sizeof (png_byte)))); + + /* Initialize the quantize_sort array */ + for (i = 0; i < num_palette; i++) + png_ptr->quantize_sort[i] = (png_byte)i; + + /* Find the least used palette entries by starting a + * bubble sort, and running it until we have sorted + * out enough colors. Note that we don't care about + * sorting all the colors, just finding which are + * least used. + */ + + for (i = num_palette - 1; i >= maximum_colors; i--) + { + int done; /* To stop early if the list is pre-sorted */ + int j; + + done = 1; + for (j = 0; j < i; j++) + { + if (histogram[png_ptr->quantize_sort[j]] + < histogram[png_ptr->quantize_sort[j + 1]]) + { + png_byte t; + + t = png_ptr->quantize_sort[j]; + png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1]; + png_ptr->quantize_sort[j + 1] = t; + done = 0; + } + } + + if (done != 0) + break; + } + + /* Swap the palette around, and set up a table, if necessary */ + if (full_quantize != 0) + { + int j = num_palette; + + /* Put all the useful colors within the max, but don't + * move the others. + */ + for (i = 0; i < maximum_colors; i++) + { + if ((int)png_ptr->quantize_sort[i] >= maximum_colors) + { + do + j--; + while ((int)png_ptr->quantize_sort[j] >= maximum_colors); + + palette[i] = palette[j]; + } + } + } + else + { + int j = num_palette; + + /* Move all the used colors inside the max limit, and + * develop a translation table. + */ + for (i = 0; i < maximum_colors; i++) + { + /* Only move the colors we need to */ + if ((int)png_ptr->quantize_sort[i] >= maximum_colors) + { + png_color tmp_color; + + do + j--; + while ((int)png_ptr->quantize_sort[j] >= maximum_colors); + + tmp_color = palette[j]; + palette[j] = palette[i]; + palette[i] = tmp_color; + /* Indicate where the color went */ + png_ptr->quantize_index[j] = (png_byte)i; + png_ptr->quantize_index[i] = (png_byte)j; + } + } + + /* Find closest color for those colors we are not using */ + for (i = 0; i < num_palette; i++) + { + if ((int)png_ptr->quantize_index[i] >= maximum_colors) + { + int min_d, k, min_k, d_index; + + /* Find the closest color to one we threw out */ + d_index = png_ptr->quantize_index[i]; + min_d = PNG_COLOR_DIST(palette[d_index], palette[0]); + for (k = 1, min_k = 0; k < maximum_colors; k++) + { + int d; + + d = PNG_COLOR_DIST(palette[d_index], palette[k]); + + if (d < min_d) + { + min_d = d; + min_k = k; + } + } + /* Point to closest color */ + png_ptr->quantize_index[i] = (png_byte)min_k; + } + } + } + png_free(png_ptr, png_ptr->quantize_sort); + png_ptr->quantize_sort = NULL; + } + else + { + /* This is much harder to do simply (and quickly). Perhaps + * we need to go through a median cut routine, but those + * don't always behave themselves with only a few colors + * as input. So we will just find the closest two colors, + * and throw out one of them (chosen somewhat randomly). + * [We don't understand this at all, so if someone wants to + * work on improving it, be our guest - AED, GRP] + */ + int i; + int max_d; + int num_new_palette; + png_dsortp t; + png_dsortpp hash; + + t = NULL; + + /* Initialize palette index arrays */ + png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * (sizeof (png_byte)))); + png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr, + (png_uint_32)(num_palette * (sizeof (png_byte)))); + + /* Initialize the sort array */ + for (i = 0; i < num_palette; i++) + { + png_ptr->index_to_palette[i] = (png_byte)i; + png_ptr->palette_to_index[i] = (png_byte)i; + } + + hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 * + (sizeof (png_dsortp)))); + + num_new_palette = num_palette; + + /* Initial wild guess at how far apart the farthest pixel + * pair we will be eliminating will be. Larger + * numbers mean more areas will be allocated, Smaller + * numbers run the risk of not saving enough data, and + * having to do this all over again. + * + * I have not done extensive checking on this number. + */ + max_d = 96; + + while (num_new_palette > maximum_colors) + { + for (i = 0; i < num_new_palette - 1; i++) + { + int j; + + for (j = i + 1; j < num_new_palette; j++) + { + int d; + + d = PNG_COLOR_DIST(palette[i], palette[j]); + + if (d <= max_d) + { + + t = (png_dsortp)png_malloc_warn(png_ptr, + (png_uint_32)(sizeof (png_dsort))); + + if (t == NULL) + break; + + t->next = hash[d]; + t->left = (png_byte)i; + t->right = (png_byte)j; + hash[d] = t; + } + } + if (t == NULL) + break; + } + + if (t != NULL) + for (i = 0; i <= max_d; i++) + { + if (hash[i] != NULL) + { + png_dsortp p; + + for (p = hash[i]; p; p = p->next) + { + if ((int)png_ptr->index_to_palette[p->left] + < num_new_palette && + (int)png_ptr->index_to_palette[p->right] + < num_new_palette) + { + int j, next_j; + + if (num_new_palette & 0x01) + { + j = p->left; + next_j = p->right; + } + else + { + j = p->right; + next_j = p->left; + } + + num_new_palette--; + palette[png_ptr->index_to_palette[j]] + = palette[num_new_palette]; + if (full_quantize == 0) + { + int k; + + for (k = 0; k < num_palette; k++) + { + if (png_ptr->quantize_index[k] == + png_ptr->index_to_palette[j]) + png_ptr->quantize_index[k] = + png_ptr->index_to_palette[next_j]; + + if ((int)png_ptr->quantize_index[k] == + num_new_palette) + png_ptr->quantize_index[k] = + png_ptr->index_to_palette[j]; + } + } + + png_ptr->index_to_palette[png_ptr->palette_to_index + [num_new_palette]] = png_ptr->index_to_palette[j]; + + png_ptr->palette_to_index[png_ptr->index_to_palette[j]] + = png_ptr->palette_to_index[num_new_palette]; + + png_ptr->index_to_palette[j] = + (png_byte)num_new_palette; + + png_ptr->palette_to_index[num_new_palette] = + (png_byte)j; + } + if (num_new_palette <= maximum_colors) + break; + } + if (num_new_palette <= maximum_colors) + break; + } + } + + for (i = 0; i < 769; i++) + { + if (hash[i] != NULL) + { + png_dsortp p = hash[i]; + while (p) + { + t = p->next; + png_free(png_ptr, p); + p = t; + } + } + hash[i] = 0; + } + max_d += 96; + } + png_free(png_ptr, hash); + png_free(png_ptr, png_ptr->palette_to_index); + png_free(png_ptr, png_ptr->index_to_palette); + png_ptr->palette_to_index = NULL; + png_ptr->index_to_palette = NULL; + } + num_palette = maximum_colors; + } + if (png_ptr->palette == NULL) + { + png_ptr->palette = palette; + } + png_ptr->num_palette = (png_uint_16)num_palette; + + if (full_quantize != 0) + { + int i; + png_bytep distance; + int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS + + PNG_QUANTIZE_BLUE_BITS; + int num_red = (1 << PNG_QUANTIZE_RED_BITS); + int num_green = (1 << PNG_QUANTIZE_GREEN_BITS); + int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS); + png_size_t num_entries = ((png_size_t)1 << total_bits); + + png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr, + (png_uint_32)(num_entries * (sizeof (png_byte)))); + + distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries * + (sizeof (png_byte)))); + + memset(distance, 0xff, num_entries * (sizeof (png_byte))); + + for (i = 0; i < num_palette; i++) + { + int ir, ig, ib; + int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS)); + int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS)); + int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS)); + + for (ir = 0; ir < num_red; ir++) + { + /* int dr = abs(ir - r); */ + int dr = ((ir > r) ? ir - r : r - ir); + int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS + + PNG_QUANTIZE_GREEN_BITS)); + + for (ig = 0; ig < num_green; ig++) + { + /* int dg = abs(ig - g); */ + int dg = ((ig > g) ? ig - g : g - ig); + int dt = dr + dg; + int dm = ((dr > dg) ? dr : dg); + int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS); + + for (ib = 0; ib < num_blue; ib++) + { + int d_index = index_g | ib; + /* int db = abs(ib - b); */ + int db = ((ib > b) ? ib - b : b - ib); + int dmax = ((dm > db) ? dm : db); + int d = dmax + dt + db; + + if (d < (int)distance[d_index]) + { + distance[d_index] = (png_byte)d; + png_ptr->palette_lookup[d_index] = (png_byte)i; + } + } + } + } + } + + png_free(png_ptr, distance); + } +} +#endif /* PNG_READ_QUANTIZE_SUPPORTED */ + +#ifdef PNG_READ_GAMMA_SUPPORTED +void PNGFAPI +png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma, + png_fixed_point file_gamma) +{ + png_debug(1, "in png_set_gamma_fixed"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + /* New in libpng-1.5.4 - reserve particular negative values as flags. */ + scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/); + file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/); + + /* Checking the gamma values for being >0 was added in 1.5.4 along with the + * premultiplied alpha support; this actually hides an undocumented feature + * of the previous implementation which allowed gamma processing to be + * disabled in background handling. There is no evidence (so far) that this + * was being used; however, png_set_background itself accepted and must still + * accept '0' for the gamma value it takes, because it isn't always used. + * + * Since this is an API change (albeit a very minor one that removes an + * undocumented API feature) the following checks were only enabled in + * libpng-1.6.0. + */ + if (file_gamma <= 0) + png_error(png_ptr, "invalid file gamma in png_set_gamma"); + + if (scrn_gamma <= 0) + png_error(png_ptr, "invalid screen gamma in png_set_gamma"); + + /* Set the gamma values unconditionally - this overrides the value in the PNG + * file if a gAMA chunk was present. png_set_alpha_mode provides a + * different, easier, way to default the file gamma. + */ + png_ptr->colorspace.gamma = file_gamma; + png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA; + png_ptr->screen_gamma = scrn_gamma; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma) +{ + png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma), + convert_gamma_value(png_ptr, file_gamma)); +} +# endif /* FLOATING_POINT_SUPPORTED */ +#endif /* READ_GAMMA */ + +#ifdef PNG_READ_EXPAND_SUPPORTED +/* Expand paletted images to RGB, expand grayscale images of + * less than 8-bit depth to 8-bit depth, and expand tRNS chunks + * to alpha channels. + */ +void PNGAPI +png_set_expand(png_structrp png_ptr) +{ + png_debug(1, "in png_set_expand"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); +} + +/* GRR 19990627: the following three functions currently are identical + * to png_set_expand(). However, it is entirely reasonable that someone + * might wish to expand an indexed image to RGB but *not* expand a single, + * fully transparent palette entry to a full alpha channel--perhaps instead + * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace + * the transparent color with a particular RGB value, or drop tRNS entirely. + * IOW, a future version of the library may make the transformations flag + * a bit more fine-grained, with separate bits for each of these three + * functions. + * + * More to the point, these functions make it obvious what libpng will be + * doing, whereas "expand" can (and does) mean any number of things. + * + * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified + * to expand only the sample depth but not to expand the tRNS to alpha + * and its name was changed to png_set_expand_gray_1_2_4_to_8(). + */ + +/* Expand paletted images to RGB. */ +void PNGAPI +png_set_palette_to_rgb(png_structrp png_ptr) +{ + png_debug(1, "in png_set_palette_to_rgb"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); +} + +/* Expand grayscale images of less than 8-bit depth to 8 bits. */ +void PNGAPI +png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr) +{ + png_debug(1, "in png_set_expand_gray_1_2_4_to_8"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= PNG_EXPAND; +} + +/* Expand tRNS chunks to alpha channels. */ +void PNGAPI +png_set_tRNS_to_alpha(png_structrp png_ptr) +{ + png_debug(1, "in png_set_tRNS_to_alpha"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS); +} +#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */ + +#ifdef PNG_READ_EXPAND_16_SUPPORTED +/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise + * it may not work correctly.) + */ +void PNGAPI +png_set_expand_16(png_structrp png_ptr) +{ + png_debug(1, "in png_set_expand_16"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS); +} +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED +void PNGAPI +png_set_gray_to_rgb(png_structrp png_ptr) +{ + png_debug(1, "in png_set_gray_to_rgb"); + + if (!png_rtran_ok(png_ptr, 0)) + return; + + /* Because rgb must be 8 bits or more: */ + png_set_expand_gray_1_2_4_to_8(png_ptr); + png_ptr->transformations |= PNG_GRAY_TO_RGB; +} +#endif + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +void PNGFAPI +png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action, + png_fixed_point red, png_fixed_point green) +{ + png_debug(1, "in png_set_rgb_to_gray"); + + /* Need the IHDR here because of the check on color_type below. */ + /* TODO: fix this */ + if (!png_rtran_ok(png_ptr, 1)) + return; + + switch(error_action) + { + case PNG_ERROR_ACTION_NONE: + png_ptr->transformations |= PNG_RGB_TO_GRAY; + break; + + case PNG_ERROR_ACTION_WARN: + png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN; + break; + + case PNG_ERROR_ACTION_ERROR: + png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR; + break; + + default: + png_error(png_ptr, "invalid error action to rgb_to_gray"); + break; + } + + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) +#ifdef PNG_READ_EXPAND_SUPPORTED + png_ptr->transformations |= PNG_EXPAND; +#else + { + /* Make this an error in 1.6 because otherwise the application may assume + * that it just worked and get a memory overwrite. + */ + png_error(png_ptr, + "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED"); + + /* png_ptr->transformations &= ~PNG_RGB_TO_GRAY; */ + } +#endif + { + if (red >= 0 && green >= 0 && red + green <= PNG_FP_1) + { + png_uint_16 red_int, green_int; + + /* NOTE: this calculation does not round, but this behavior is retained + * for consistency, the inaccuracy is very small. The code here always + * overwrites the coefficients, regardless of whether they have been + * defaulted or set already. + */ + red_int = (png_uint_16)(((png_uint_32)red*32768)/100000); + green_int = (png_uint_16)(((png_uint_32)green*32768)/100000); + + png_ptr->rgb_to_gray_red_coeff = red_int; + png_ptr->rgb_to_gray_green_coeff = green_int; + png_ptr->rgb_to_gray_coefficients_set = 1; + } + + else + { + if (red >= 0 && green >= 0) + png_app_warning(png_ptr, + "ignoring out of range rgb_to_gray coefficients"); + + /* Use the defaults, from the cHRM chunk if set, else the historical + * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See + * png_do_rgb_to_gray for more discussion of the values. In this case + * the coefficients are not marked as 'set' and are not overwritten if + * something has already provided a default. + */ + if (png_ptr->rgb_to_gray_red_coeff == 0 && + png_ptr->rgb_to_gray_green_coeff == 0) + { + png_ptr->rgb_to_gray_red_coeff = 6968; + png_ptr->rgb_to_gray_green_coeff = 23434; + /* png_ptr->rgb_to_gray_blue_coeff = 2366; */ + } + } + } +} + +#ifdef PNG_FLOATING_POINT_SUPPORTED +/* Convert a RGB image to a grayscale of the same width. This allows us, + * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image. + */ + +void PNGAPI +png_set_rgb_to_gray(png_structrp png_ptr, int error_action, double red, + double green) +{ + png_set_rgb_to_gray_fixed(png_ptr, error_action, + png_fixed(png_ptr, red, "rgb to gray red coefficient"), + png_fixed(png_ptr, green, "rgb to gray green coefficient")); +} +#endif /* FLOATING POINT */ + +#endif /* RGB_TO_GRAY */ + +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ + defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) +void PNGAPI +png_set_read_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr + read_user_transform_fn) +{ + png_debug(1, "in png_set_read_user_transform_fn"); + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + png_ptr->transformations |= PNG_USER_TRANSFORM; + png_ptr->read_user_transform_fn = read_user_transform_fn; +#endif +} +#endif + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +#ifdef PNG_READ_GAMMA_SUPPORTED +/* In the case of gamma transformations only do transformations on images where + * the [file] gamma and screen_gamma are not close reciprocals, otherwise it + * slows things down slightly, and also needlessly introduces small errors. + */ +static int /* PRIVATE */ +png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma) +{ + /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma + * correction as a difference of the overall transform from 1.0 + * + * We want to compare the threshold with s*f - 1, if we get + * overflow here it is because of wacky gamma values so we + * turn on processing anyway. + */ + png_fixed_point gtest; + return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) || + png_gamma_significant(gtest); +} +#endif + +/* Initialize everything needed for the read. This includes modifying + * the palette. + */ + +/*For the moment 'png_init_palette_transformations' and + * 'png_init_rgb_transformations' only do some flag canceling optimizations. + * The intent is that these two routines should have palette or rgb operations + * extracted from 'png_init_read_transformations'. + */ +static void /* PRIVATE */ +png_init_palette_transformations(png_structrp png_ptr) +{ + /* Called to handle the (input) palette case. In png_do_read_transformations + * the first step is to expand the palette if requested, so this code must + * take care to only make changes that are invariant with respect to the + * palette expansion, or only do them if there is no expansion. + * + * STRIP_ALPHA has already been handled in the caller (by setting num_trans + * to 0.) + */ + int input_has_alpha = 0; + int input_has_transparency = 0; + + if (png_ptr->num_trans > 0) + { + int i; + + /* Ignore if all the entries are opaque (unlikely!) */ + for (i=0; i<png_ptr->num_trans; ++i) + { + if (png_ptr->trans_alpha[i] == 255) + continue; + else if (png_ptr->trans_alpha[i] == 0) + input_has_transparency = 1; + else + { + input_has_transparency = 1; + input_has_alpha = 1; + break; + } + } + } + + /* If no alpha we can optimize. */ + if (input_has_alpha == 0) + { + /* Any alpha means background and associative alpha processing is + * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA + * and ENCODE_ALPHA are irrelevant. + */ + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + + if (input_has_transparency == 0) + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND); + } + +#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) + /* png_set_background handling - deals with the complexity of whether the + * background color is in the file format or the screen format in the case + * where an 'expand' will happen. + */ + + /* The following code cannot be entered in the alpha pre-multiplication case + * because PNG_BACKGROUND_EXPAND is cancelled below. + */ + if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + (png_ptr->transformations & PNG_EXPAND)) + { + { + png_ptr->background.red = + png_ptr->palette[png_ptr->background.index].red; + png_ptr->background.green = + png_ptr->palette[png_ptr->background.index].green; + png_ptr->background.blue = + png_ptr->palette[png_ptr->background.index].blue; + +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_ALPHA) + { + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + /* Invert the alpha channel (in tRNS) unless the pixels are + * going to be expanded, in which case leave it for later + */ + int i, istop = png_ptr->num_trans; + + for (i=0; i<istop; i++) + png_ptr->trans_alpha[i] = (png_byte)(255 - + png_ptr->trans_alpha[i]); + } + } +#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */ + } + } /* background expand and (therefore) no alpha association. */ +#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */ +} + +static void /* PRIVATE */ +png_init_rgb_transformations(png_structrp png_ptr) +{ + /* Added to libpng-1.5.4: check the color type to determine whether there + * is any alpha or transparency in the image and simply cancel the + * background and alpha mode stuff if there isn't. + */ + int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0; + int input_has_transparency = png_ptr->num_trans > 0; + + /* If no alpha we can optimize. */ + if (input_has_alpha == 0) + { + /* Any alpha means background and associative alpha processing is + * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA + * and ENCODE_ALPHA are irrelevant. + */ +# ifdef PNG_READ_ALPHA_MODE_SUPPORTED + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; +# endif + + if (input_has_transparency == 0) + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND); + } + +#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) + /* png_set_background handling - deals with the complexity of whether the + * background color is in the file format or the screen format in the case + * where an 'expand' will happen. + */ + + /* The following code cannot be entered in the alpha pre-multiplication case + * because PNG_BACKGROUND_EXPAND is cancelled below. + */ + if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + (png_ptr->transformations & PNG_EXPAND) && + !(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) + /* i.e., GRAY or GRAY_ALPHA */ + { + { + /* Expand background and tRNS chunks */ + int gray = png_ptr->background.gray; + int trans_gray = png_ptr->trans_color.gray; + + switch (png_ptr->bit_depth) + { + case 1: + gray *= 0xff; + trans_gray *= 0xff; + break; + + case 2: + gray *= 0x55; + trans_gray *= 0x55; + break; + + case 4: + gray *= 0x11; + trans_gray *= 0x11; + break; + + default: + + case 8: + /* FALL THROUGH (Already 8 bits) */ + + case 16: + /* Already a full 16 bits */ + break; + } + + png_ptr->background.red = png_ptr->background.green = + png_ptr->background.blue = (png_uint_16)gray; + + if (!(png_ptr->transformations & PNG_EXPAND_tRNS)) + { + png_ptr->trans_color.red = png_ptr->trans_color.green = + png_ptr->trans_color.blue = (png_uint_16)trans_gray; + } + } + } /* background expand and (therefore) no alpha association. */ +#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */ +} + +void /* PRIVATE */ +png_init_read_transformations(png_structrp png_ptr) +{ + png_debug(1, "in png_init_read_transformations"); + + /* This internal function is called from png_read_start_row in pngrutil.c + * and it is called before the 'rowbytes' calculation is done, so the code + * in here can change or update the transformations flags. + * + * First do updates that do not depend on the details of the PNG image data + * being processed. + */ + +#ifdef PNG_READ_GAMMA_SUPPORTED + /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds + * png_set_alpha_mode and this is another source for a default file gamma so + * the test needs to be performed later - here. In addition prior to 1.5.4 + * the tests were repeated for the PALETTE color type here - this is no + * longer necessary (and doesn't seem to have been necessary before.) + */ + { + /* The following temporary indicates if overall gamma correction is + * required. + */ + int gamma_correction = 0; + + if (png_ptr->colorspace.gamma != 0) /* has been set */ + { + if (png_ptr->screen_gamma != 0) /* screen set too */ + gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma, + png_ptr->screen_gamma); + + else + /* Assume the output matches the input; a long time default behavior + * of libpng, although the standard has nothing to say about this. + */ + png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma); + } + + else if (png_ptr->screen_gamma != 0) + /* The converse - assume the file matches the screen, note that this + * perhaps undesireable default can (from 1.5.4) be changed by calling + * png_set_alpha_mode (even if the alpha handling mode isn't required + * or isn't changed from the default.) + */ + png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma); + + else /* neither are set */ + /* Just in case the following prevents any processing - file and screen + * are both assumed to be linear and there is no way to introduce a + * third gamma value other than png_set_background with 'UNIQUE', and, + * prior to 1.5.4 + */ + png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1; + + /* We have a gamma value now. */ + png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA; + + /* Now turn the gamma transformation on or off as appropriate. Notice + * that PNG_GAMMA just refers to the file->screen correction. Alpha + * composition may independently cause gamma correction because it needs + * linear data (e.g. if the file has a gAMA chunk but the screen gamma + * hasn't been specified.) In any case this flag may get turned off in + * the code immediately below if the transform can be handled outside the + * row loop. + */ + if (gamma_correction != 0) + png_ptr->transformations |= PNG_GAMMA; + + else + png_ptr->transformations &= ~PNG_GAMMA; + } +#endif + + /* Certain transformations have the effect of preventing other + * transformations that happen afterward in png_do_read_transformations, + * resolve the interdependencies here. From the code of + * png_do_read_transformations the order is: + * + * 1) PNG_EXPAND (including PNG_EXPAND_tRNS) + * 2) PNG_STRIP_ALPHA (if no compose) + * 3) PNG_RGB_TO_GRAY + * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY + * 5) PNG_COMPOSE + * 6) PNG_GAMMA + * 7) PNG_STRIP_ALPHA (if compose) + * 8) PNG_ENCODE_ALPHA + * 9) PNG_SCALE_16_TO_8 + * 10) PNG_16_TO_8 + * 11) PNG_QUANTIZE (converts to palette) + * 12) PNG_EXPAND_16 + * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY + * 14) PNG_INVERT_MONO + * 15) PNG_INVERT_ALPHA + * 16) PNG_SHIFT + * 17) PNG_PACK + * 18) PNG_BGR + * 19) PNG_PACKSWAP + * 20) PNG_FILLER (includes PNG_ADD_ALPHA) + * 21) PNG_SWAP_ALPHA + * 22) PNG_SWAP_BYTES + * 23) PNG_USER_TRANSFORM [must be last] + */ +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + !(png_ptr->transformations & PNG_COMPOSE)) + { + /* Stripping the alpha channel happens immediately after the 'expand' + * transformations, before all other transformation, so it cancels out + * the alpha handling. It has the side effect negating the effect of + * PNG_EXPAND_tRNS too: + */ + png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA | + PNG_EXPAND_tRNS); + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + + /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen + * so transparency information would remain just so long as it wasn't + * expanded. This produces unexpected API changes if the set of things + * that do PNG_EXPAND_tRNS changes (perfectly possible given the + * documentation - which says ask for what you want, accept what you + * get.) This makes the behavior consistent from 1.5.4: + */ + png_ptr->num_trans = 0; + } +#endif /* STRIP_ALPHA supported, no COMPOSE */ + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED + /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA + * settings will have no effect. + */ + if (!png_gamma_significant(png_ptr->screen_gamma)) + { + png_ptr->transformations &= ~PNG_ENCODE_ALPHA; + png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; + } +#endif + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + /* Make sure the coefficients for the rgb to gray conversion are set + * appropriately. + */ + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + png_colorspace_set_rgb_coefficients(png_ptr); +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED +#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED) + /* Detect gray background and attempt to enable optimization for + * gray --> RGB case. + * + * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or + * RGB_ALPHA (in which case need_expand is superfluous anyway), the + * background color might actually be gray yet not be flagged as such. + * This is not a problem for the current code, which uses + * PNG_BACKGROUND_IS_GRAY only to decide when to do the + * png_do_gray_to_rgb() transformation. + * + * TODO: this code needs to be revised to avoid the complexity and + * interdependencies. The color type of the background should be recorded in + * png_set_background, along with the bit depth, then the code has a record + * of exactly what color space the background is currently in. + */ + if (png_ptr->transformations & PNG_BACKGROUND_EXPAND) + { + /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if + * the file was grayscale the background value is gray. + */ + if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) + png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; + } + + else if (png_ptr->transformations & PNG_COMPOSE) + { + /* PNG_COMPOSE: png_set_background was called with need_expand false, + * so the color is in the color space of the output or png_set_alpha_mode + * was called and the color is black. Ignore RGB_TO_GRAY because that + * happens before GRAY_TO_RGB. + */ + if (png_ptr->transformations & PNG_GRAY_TO_RGB) + { + if (png_ptr->background.red == png_ptr->background.green && + png_ptr->background.red == png_ptr->background.blue) + { + png_ptr->mode |= PNG_BACKGROUND_IS_GRAY; + png_ptr->background.gray = png_ptr->background.red; + } + } + } +#endif /* PNG_READ_EXPAND_SUPPORTED && PNG_READ_BACKGROUND_SUPPORTED */ +#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */ + + /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations + * can be performed directly on the palette, and some (such as rgb to gray) + * can be optimized inside the palette. This is particularly true of the + * composite (background and alpha) stuff, which can be pretty much all done + * in the palette even if the result is expanded to RGB or gray afterward. + * + * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and + * earlier and the palette stuff is actually handled on the first row. This + * leads to the reported bug that the palette returned by png_get_PLTE is not + * updated. + */ + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + png_init_palette_transformations(png_ptr); + + else + png_init_rgb_transformations(png_ptr); + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + defined(PNG_READ_EXPAND_16_SUPPORTED) + if ((png_ptr->transformations & PNG_EXPAND_16) && + (png_ptr->transformations & PNG_COMPOSE) && + !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + png_ptr->bit_depth != 16) + { + /* TODO: fix this. Because the expand_16 operation is after the compose + * handling the background color must be 8, not 16, bits deep, but the + * application will supply a 16-bit value so reduce it here. + * + * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at + * present, so that case is ok (until do_expand_16 is moved.) + * + * NOTE: this discards the low 16 bits of the user supplied background + * color, but until expand_16 works properly there is no choice! + */ +# define CHOP(x) (x)=((png_uint_16)PNG_DIV257(x)) + CHOP(png_ptr->background.red); + CHOP(png_ptr->background.green); + CHOP(png_ptr->background.blue); + CHOP(png_ptr->background.gray); +# undef CHOP + } +#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */ + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \ + (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \ + defined(PNG_READ_STRIP_16_TO_8_SUPPORTED)) + if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) && + (png_ptr->transformations & PNG_COMPOSE) && + !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) && + png_ptr->bit_depth == 16) + { + /* On the other hand, if a 16-bit file is to be reduced to 8-bits per + * component this will also happen after PNG_COMPOSE and so the background + * color must be pre-expanded here. + * + * TODO: fix this too. + */ + png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257); + png_ptr->background.green = + (png_uint_16)(png_ptr->background.green * 257); + png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257); + png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257); + } +#endif + + /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the + * background support (see the comments in scripts/pnglibconf.dfa), this + * allows pre-multiplication of the alpha channel to be implemented as + * compositing on black. This is probably sub-optimal and has been done in + * 1.5.4 betas simply to enable external critique and testing (i.e. to + * implement the new API quickly, without lots of internal changes.) + */ + +#ifdef PNG_READ_GAMMA_SUPPORTED +# ifdef PNG_READ_BACKGROUND_SUPPORTED + /* Includes ALPHA_MODE */ + png_ptr->background_1 = png_ptr->background; +# endif + + /* This needs to change - in the palette image case a whole set of tables are + * built when it would be quicker to just calculate the correct value for + * each palette entry directly. Also, the test is too tricky - why check + * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that + * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the + * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction + * the gamma tables will not be built even if composition is required on a + * gamma encoded value. + * + * In 1.5.4 this is addressed below by an additional check on the individual + * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the + * tables. + */ + if ((png_ptr->transformations & PNG_GAMMA) + || ((png_ptr->transformations & PNG_RGB_TO_GRAY) + && (png_gamma_significant(png_ptr->colorspace.gamma) || + png_gamma_significant(png_ptr->screen_gamma))) + || ((png_ptr->transformations & PNG_COMPOSE) + && (png_gamma_significant(png_ptr->colorspace.gamma) + || png_gamma_significant(png_ptr->screen_gamma) +# ifdef PNG_READ_BACKGROUND_SUPPORTED + || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE + && png_gamma_significant(png_ptr->background_gamma)) +# endif + )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) + && png_gamma_significant(png_ptr->screen_gamma)) + ) + { + png_build_gamma_table(png_ptr, png_ptr->bit_depth); + +#ifdef PNG_READ_BACKGROUND_SUPPORTED + if (png_ptr->transformations & PNG_COMPOSE) + { + /* Issue a warning about this combination: because RGB_TO_GRAY is + * optimized to do the gamma transform if present yet do_background has + * to do the same thing if both options are set a + * double-gamma-correction happens. This is true in all versions of + * libpng to date. + */ + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + png_warning(png_ptr, + "libpng does not support gamma+background+rgb_to_gray"); + + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + /* We don't get to here unless there is a tRNS chunk with non-opaque + * entries - see the checking code at the start of this function. + */ + png_color back, back_1; + png_colorp palette = png_ptr->palette; + int num_palette = png_ptr->num_palette; + int i; + if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE) + { + + back.red = png_ptr->gamma_table[png_ptr->background.red]; + back.green = png_ptr->gamma_table[png_ptr->background.green]; + back.blue = png_ptr->gamma_table[png_ptr->background.blue]; + + back_1.red = png_ptr->gamma_to_1[png_ptr->background.red]; + back_1.green = png_ptr->gamma_to_1[png_ptr->background.green]; + back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue]; + } + else + { + png_fixed_point g, gs; + + switch (png_ptr->background_gamma_type) + { + case PNG_BACKGROUND_GAMMA_SCREEN: + g = (png_ptr->screen_gamma); + gs = PNG_FP_1; + break; + + case PNG_BACKGROUND_GAMMA_FILE: + g = png_reciprocal(png_ptr->colorspace.gamma); + gs = png_reciprocal2(png_ptr->colorspace.gamma, + png_ptr->screen_gamma); + break; + + case PNG_BACKGROUND_GAMMA_UNIQUE: + g = png_reciprocal(png_ptr->background_gamma); + gs = png_reciprocal2(png_ptr->background_gamma, + png_ptr->screen_gamma); + break; + default: + g = PNG_FP_1; /* back_1 */ + gs = PNG_FP_1; /* back */ + break; + } + + if (png_gamma_significant(gs)) + { + back.red = png_gamma_8bit_correct(png_ptr->background.red, + gs); + back.green = png_gamma_8bit_correct(png_ptr->background.green, + gs); + back.blue = png_gamma_8bit_correct(png_ptr->background.blue, + gs); + } + + else + { + back.red = (png_byte)png_ptr->background.red; + back.green = (png_byte)png_ptr->background.green; + back.blue = (png_byte)png_ptr->background.blue; + } + + if (png_gamma_significant(g)) + { + back_1.red = png_gamma_8bit_correct(png_ptr->background.red, + g); + back_1.green = png_gamma_8bit_correct( + png_ptr->background.green, g); + back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue, + g); + } + + else + { + back_1.red = (png_byte)png_ptr->background.red; + back_1.green = (png_byte)png_ptr->background.green; + back_1.blue = (png_byte)png_ptr->background.blue; + } + } + + for (i = 0; i < num_palette; i++) + { + if (i < (int)png_ptr->num_trans && + png_ptr->trans_alpha[i] != 0xff) + { + if (png_ptr->trans_alpha[i] == 0) + { + palette[i] = back; + } + else /* if (png_ptr->trans_alpha[i] != 0xff) */ + { + png_byte v, w; + + v = png_ptr->gamma_to_1[palette[i].red]; + png_composite(w, v, png_ptr->trans_alpha[i], back_1.red); + palette[i].red = png_ptr->gamma_from_1[w]; + + v = png_ptr->gamma_to_1[palette[i].green]; + png_composite(w, v, png_ptr->trans_alpha[i], back_1.green); + palette[i].green = png_ptr->gamma_from_1[w]; + + v = png_ptr->gamma_to_1[palette[i].blue]; + png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue); + palette[i].blue = png_ptr->gamma_from_1[w]; + } + } + else + { + palette[i].red = png_ptr->gamma_table[palette[i].red]; + palette[i].green = png_ptr->gamma_table[palette[i].green]; + palette[i].blue = png_ptr->gamma_table[palette[i].blue]; + } + } + + /* Prevent the transformations being done again. + * + * NOTE: this is highly dubious; it removes the transformations in + * place. This seems inconsistent with the general treatment of the + * transformations elsewhere. + */ + png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA); + } /* color_type == PNG_COLOR_TYPE_PALETTE */ + + /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */ + else /* color_type != PNG_COLOR_TYPE_PALETTE */ + { + int gs_sig, g_sig; + png_fixed_point g = PNG_FP_1; /* Correction to linear */ + png_fixed_point gs = PNG_FP_1; /* Correction to screen */ + + switch (png_ptr->background_gamma_type) + { + case PNG_BACKGROUND_GAMMA_SCREEN: + g = png_ptr->screen_gamma; + /* gs = PNG_FP_1; */ + break; + + case PNG_BACKGROUND_GAMMA_FILE: + g = png_reciprocal(png_ptr->colorspace.gamma); + gs = png_reciprocal2(png_ptr->colorspace.gamma, + png_ptr->screen_gamma); + break; + + case PNG_BACKGROUND_GAMMA_UNIQUE: + g = png_reciprocal(png_ptr->background_gamma); + gs = png_reciprocal2(png_ptr->background_gamma, + png_ptr->screen_gamma); + break; + + default: + png_error(png_ptr, "invalid background gamma type"); + } + + g_sig = png_gamma_significant(g); + gs_sig = png_gamma_significant(gs); + + if (g_sig != 0) + png_ptr->background_1.gray = png_gamma_correct(png_ptr, + png_ptr->background.gray, g); + + if (gs_sig != 0) + png_ptr->background.gray = png_gamma_correct(png_ptr, + png_ptr->background.gray, gs); + + if ((png_ptr->background.red != png_ptr->background.green) || + (png_ptr->background.red != png_ptr->background.blue) || + (png_ptr->background.red != png_ptr->background.gray)) + { + /* RGB or RGBA with color background */ + if (g_sig != 0) + { + png_ptr->background_1.red = png_gamma_correct(png_ptr, + png_ptr->background.red, g); + + png_ptr->background_1.green = png_gamma_correct(png_ptr, + png_ptr->background.green, g); + + png_ptr->background_1.blue = png_gamma_correct(png_ptr, + png_ptr->background.blue, g); + } + + if (gs_sig != 0) + { + png_ptr->background.red = png_gamma_correct(png_ptr, + png_ptr->background.red, gs); + + png_ptr->background.green = png_gamma_correct(png_ptr, + png_ptr->background.green, gs); + + png_ptr->background.blue = png_gamma_correct(png_ptr, + png_ptr->background.blue, gs); + } + } + + else + { + /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */ + png_ptr->background_1.red = png_ptr->background_1.green + = png_ptr->background_1.blue = png_ptr->background_1.gray; + + png_ptr->background.red = png_ptr->background.green + = png_ptr->background.blue = png_ptr->background.gray; + } + + /* The background is now in screen gamma: */ + png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN; + } /* color_type != PNG_COLOR_TYPE_PALETTE */ + }/* png_ptr->transformations & PNG_BACKGROUND */ + + else + /* Transformation does not include PNG_BACKGROUND */ +#endif /* PNG_READ_BACKGROUND_SUPPORTED */ + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + /* RGB_TO_GRAY needs to have non-gamma-corrected values! */ + && ((png_ptr->transformations & PNG_EXPAND) == 0 || + (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0) +#endif + ) + { + png_colorp palette = png_ptr->palette; + int num_palette = png_ptr->num_palette; + int i; + + /* NOTE: there are other transformations that should probably be in + * here too. + */ + for (i = 0; i < num_palette; i++) + { + palette[i].red = png_ptr->gamma_table[palette[i].red]; + palette[i].green = png_ptr->gamma_table[palette[i].green]; + palette[i].blue = png_ptr->gamma_table[palette[i].blue]; + } + + /* Done the gamma correction. */ + png_ptr->transformations &= ~PNG_GAMMA; + } /* color_type == PALETTE && !PNG_BACKGROUND transformation */ + } +#ifdef PNG_READ_BACKGROUND_SUPPORTED + else +#endif +#endif /* PNG_READ_GAMMA_SUPPORTED */ + +#ifdef PNG_READ_BACKGROUND_SUPPORTED + /* No GAMMA transformation (see the hanging else 4 lines above) */ + if ((png_ptr->transformations & PNG_COMPOSE) && + (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) + { + int i; + int istop = (int)png_ptr->num_trans; + png_color back; + png_colorp palette = png_ptr->palette; + + back.red = (png_byte)png_ptr->background.red; + back.green = (png_byte)png_ptr->background.green; + back.blue = (png_byte)png_ptr->background.blue; + + for (i = 0; i < istop; i++) + { + if (png_ptr->trans_alpha[i] == 0) + { + palette[i] = back; + } + + else if (png_ptr->trans_alpha[i] != 0xff) + { + /* The png_composite() macro is defined in png.h */ + png_composite(palette[i].red, palette[i].red, + png_ptr->trans_alpha[i], back.red); + + png_composite(palette[i].green, palette[i].green, + png_ptr->trans_alpha[i], back.green); + + png_composite(palette[i].blue, palette[i].blue, + png_ptr->trans_alpha[i], back.blue); + } + } + + png_ptr->transformations &= ~PNG_COMPOSE; + } +#endif /* PNG_READ_BACKGROUND_SUPPORTED */ + +#ifdef PNG_READ_SHIFT_SUPPORTED + if ((png_ptr->transformations & PNG_SHIFT) && + !(png_ptr->transformations & PNG_EXPAND) && + (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)) + { + int i; + int istop = png_ptr->num_palette; + int shift = 8 - png_ptr->sig_bit.red; + + png_ptr->transformations &= ~PNG_SHIFT; + + /* significant bits can be in the range 1 to 7 for a meaninful result, if + * the number of significant bits is 0 then no shift is done (this is an + * error condition which is silently ignored.) + */ + if (shift > 0 && shift < 8) + for (i=0; i<istop; ++i) + { + int component = png_ptr->palette[i].red; + + component >>= shift; + png_ptr->palette[i].red = (png_byte)component; + } + + shift = 8 - png_ptr->sig_bit.green; + if (shift > 0 && shift < 8) + for (i=0; i<istop; ++i) + { + int component = png_ptr->palette[i].green; + + component >>= shift; + png_ptr->palette[i].green = (png_byte)component; + } + + shift = 8 - png_ptr->sig_bit.blue; + if (shift > 0 && shift < 8) + for (i=0; i<istop; ++i) + { + int component = png_ptr->palette[i].blue; + + component >>= shift; + png_ptr->palette[i].blue = (png_byte)component; + } + } +#endif /* PNG_READ_SHIFT_SUPPORTED */ +} + +/* Modify the info structure to reflect the transformations. The + * info should be updated so a PNG file could be written with it, + * assuming the transformations result in valid PNG data. + */ +void /* PRIVATE */ +png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr) +{ + png_debug(1, "in png_read_transform_info"); + +#ifdef PNG_READ_EXPAND_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND) + { + if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + /* This check must match what actually happens in + * png_do_expand_palette; if it ever checks the tRNS chunk to see if + * it is all opaque we must do the same (at present it does not.) + */ + if (png_ptr->num_trans > 0) + info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA; + + else + info_ptr->color_type = PNG_COLOR_TYPE_RGB; + + info_ptr->bit_depth = 8; + info_ptr->num_trans = 0; + + if (png_ptr->palette == NULL) + png_error (png_ptr, "Palette is NULL in indexed image"); + } + else + { + if (png_ptr->num_trans) + { + if (png_ptr->transformations & PNG_EXPAND_tRNS) + info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; + } + if (info_ptr->bit_depth < 8) + info_ptr->bit_depth = 8; + + info_ptr->num_trans = 0; + } + } +#endif + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) + /* The following is almost certainly wrong unless the background value is in + * the screen space! + */ + if (png_ptr->transformations & PNG_COMPOSE) + info_ptr->background = png_ptr->background; +#endif + +#ifdef PNG_READ_GAMMA_SUPPORTED + /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4), + * however it seems that the code in png_init_read_transformations, which has + * been called before this from png_read_update_info->png_read_start_row + * sometimes does the gamma transform and cancels the flag. + * + * TODO: this looks wrong; the info_ptr should end up with a gamma equal to + * the screen_gamma value. The following probably results in weirdness if + * the info_ptr is used by the app after the rows have been read. + */ + info_ptr->colorspace.gamma = png_ptr->colorspace.gamma; +#endif + + if (info_ptr->bit_depth == 16) + { +# ifdef PNG_READ_16BIT_SUPPORTED +# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_SCALE_16_TO_8) + info_ptr->bit_depth = 8; +# endif + +# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_16_TO_8) + info_ptr->bit_depth = 8; +# endif + +# else + /* No 16 bit support: force chopping 16-bit input down to 8, in this case + * the app program can chose if both APIs are available by setting the + * correct scaling to use. + */ +# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + /* For compatibility with previous versions use the strip method by + * default. This code works because if PNG_SCALE_16_TO_8 is already + * set the code below will do that in preference to the chop. + */ + png_ptr->transformations |= PNG_16_TO_8; + info_ptr->bit_depth = 8; +# else + +# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + png_ptr->transformations |= PNG_SCALE_16_TO_8; + info_ptr->bit_depth = 8; +# else + + CONFIGURATION ERROR: you must enable at least one 16 to 8 method +# endif +# endif +#endif /* !READ_16BIT_SUPPORTED */ + } + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + if (png_ptr->transformations & PNG_GRAY_TO_RGB) + info_ptr->color_type = (png_byte)(info_ptr->color_type | + PNG_COLOR_MASK_COLOR); +#endif + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + info_ptr->color_type = (png_byte)(info_ptr->color_type & + ~PNG_COLOR_MASK_COLOR); +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED + if (png_ptr->transformations & PNG_QUANTIZE) + { + if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || + (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) && + png_ptr->palette_lookup && info_ptr->bit_depth == 8) + { + info_ptr->color_type = PNG_COLOR_TYPE_PALETTE; + } + } +#endif + +#ifdef PNG_READ_EXPAND_16_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND_16 && info_ptr->bit_depth == 8 && + info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) + { + info_ptr->bit_depth = 16; + } +#endif + +#ifdef PNG_READ_PACK_SUPPORTED + if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8)) + info_ptr->bit_depth = 8; +#endif + + if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + info_ptr->channels = 1; + + else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR) + info_ptr->channels = 3; + + else + info_ptr->channels = 1; + +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_STRIP_ALPHA) + { + info_ptr->color_type = (png_byte)(info_ptr->color_type & + ~PNG_COLOR_MASK_ALPHA); + info_ptr->num_trans = 0; + } +#endif + + if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA) + info_ptr->channels++; + +#ifdef PNG_READ_FILLER_SUPPORTED + /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */ + if ((png_ptr->transformations & PNG_FILLER) && + ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) || + (info_ptr->color_type == PNG_COLOR_TYPE_GRAY))) + { + info_ptr->channels++; + /* If adding a true alpha channel not just filler */ + if (png_ptr->transformations & PNG_ADD_ALPHA) + info_ptr->color_type |= PNG_COLOR_MASK_ALPHA; + } +#endif + +#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \ +defined(PNG_READ_USER_TRANSFORM_SUPPORTED) + if (png_ptr->transformations & PNG_USER_TRANSFORM) + { + if (info_ptr->bit_depth < png_ptr->user_transform_depth) + info_ptr->bit_depth = png_ptr->user_transform_depth; + + if (info_ptr->channels < png_ptr->user_transform_channels) + info_ptr->channels = png_ptr->user_transform_channels; + } +#endif + + info_ptr->pixel_depth = (png_byte)(info_ptr->channels * + info_ptr->bit_depth); + + info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width); + + /* Adding in 1.5.4: cache the above value in png_struct so that we can later + * check in png_rowbytes that the user buffer won't get overwritten. Note + * that the field is not always set - if png_read_update_info isn't called + * the application has to either not do any transforms or get the calculation + * right itself. + */ + png_ptr->info_rowbytes = info_ptr->rowbytes; + +#ifndef PNG_READ_EXPAND_SUPPORTED + if (png_ptr != NULL) + return; +#endif +} + +#ifdef PNG_READ_PACK_SUPPORTED +/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel, + * without changing the actual values. Thus, if you had a row with + * a bit depth of 1, you would end up with bytes that only contained + * the numbers 0 or 1. If you would rather they contain 0 and 255, use + * png_do_shift() after this. + */ +static void +png_do_unpack(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_unpack"); + + if (row_info->bit_depth < 8) + { + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + switch (row_info->bit_depth) + { + case 1: + { + png_bytep sp = row + (png_size_t)((row_width - 1) >> 3); + png_bytep dp = row + (png_size_t)row_width - 1; + png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07); + for (i = 0; i < row_width; i++) + { + *dp = (png_byte)((*sp >> shift) & 0x01); + + if (shift == 7) + { + shift = 0; + sp--; + } + + else + shift++; + + dp--; + } + break; + } + + case 2: + { + + png_bytep sp = row + (png_size_t)((row_width - 1) >> 2); + png_bytep dp = row + (png_size_t)row_width - 1; + png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1); + for (i = 0; i < row_width; i++) + { + *dp = (png_byte)((*sp >> shift) & 0x03); + + if (shift == 6) + { + shift = 0; + sp--; + } + + else + shift += 2; + + dp--; + } + break; + } + + case 4: + { + png_bytep sp = row + (png_size_t)((row_width - 1) >> 1); + png_bytep dp = row + (png_size_t)row_width - 1; + png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2); + for (i = 0; i < row_width; i++) + { + *dp = (png_byte)((*sp >> shift) & 0x0f); + + if (shift == 4) + { + shift = 0; + sp--; + } + + else + shift = 4; + + dp--; + } + break; + } + + default: + break; + } + row_info->bit_depth = 8; + row_info->pixel_depth = (png_byte)(8 * row_info->channels); + row_info->rowbytes = row_width * row_info->channels; + } +} +#endif + +#ifdef PNG_READ_SHIFT_SUPPORTED +/* Reverse the effects of png_do_shift. This routine merely shifts the + * pixels back to their significant bits values. Thus, if you have + * a row of bit depth 8, but only 5 are significant, this will shift + * the values back to 0 through 31. + */ +static void +png_do_unshift(png_row_infop row_info, png_bytep row, + png_const_color_8p sig_bits) +{ + int color_type; + + png_debug(1, "in png_do_unshift"); + + /* The palette case has already been handled in the _init routine. */ + color_type = row_info->color_type; + + if (color_type != PNG_COLOR_TYPE_PALETTE) + { + int shift[4]; + int channels = 0; + int bit_depth = row_info->bit_depth; + + if (color_type & PNG_COLOR_MASK_COLOR) + { + shift[channels++] = bit_depth - sig_bits->red; + shift[channels++] = bit_depth - sig_bits->green; + shift[channels++] = bit_depth - sig_bits->blue; + } + + else + { + shift[channels++] = bit_depth - sig_bits->gray; + } + + if (color_type & PNG_COLOR_MASK_ALPHA) + { + shift[channels++] = bit_depth - sig_bits->alpha; + } + + { + int c, have_shift; + + for (c = have_shift = 0; c < channels; ++c) + { + /* A shift of more than the bit depth is an error condition but it + * gets ignored here. + */ + if (shift[c] <= 0 || shift[c] >= bit_depth) + shift[c] = 0; + + else + have_shift = 1; + } + + if (have_shift == 0) + return; + } + + switch (bit_depth) + { + default: + /* Must be 1bpp gray: should not be here! */ + /* NOTREACHED */ + break; + + case 2: + /* Must be 2bpp gray */ + /* assert(channels == 1 && shift[0] == 1) */ + { + png_bytep bp = row; + png_bytep bp_end = bp + row_info->rowbytes; + + while (bp < bp_end) + { + int b = (*bp >> 1) & 0x55; + *bp++ = (png_byte)b; + } + break; + } + + case 4: + /* Must be 4bpp gray */ + /* assert(channels == 1) */ + { + png_bytep bp = row; + png_bytep bp_end = bp + row_info->rowbytes; + int gray_shift = shift[0]; + int mask = 0xf >> gray_shift; + + mask |= mask << 4; + + while (bp < bp_end) + { + int b = (*bp >> gray_shift) & mask; + *bp++ = (png_byte)b; + } + break; + } + + case 8: + /* Single byte components, G, GA, RGB, RGBA */ + { + png_bytep bp = row; + png_bytep bp_end = bp + row_info->rowbytes; + int channel = 0; + + while (bp < bp_end) + { + int b = *bp >> shift[channel]; + if (++channel >= channels) + channel = 0; + *bp++ = (png_byte)b; + } + break; + } + +#ifdef PNG_READ_16BIT_SUPPORTED + case 16: + /* Double byte components, G, GA, RGB, RGBA */ + { + png_bytep bp = row; + png_bytep bp_end = bp + row_info->rowbytes; + int channel = 0; + + while (bp < bp_end) + { + int value = (bp[0] << 8) + bp[1]; + + value >>= shift[channel]; + if (++channel >= channels) + channel = 0; + *bp++ = (png_byte)(value >> 8); + *bp++ = (png_byte)(value & 0xff); + } + break; + } +#endif + } + } +} +#endif + +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED +/* Scale rows of bit depth 16 down to 8 accurately */ +static void +png_do_scale_16_to_8(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_scale_16_to_8"); + + if (row_info->bit_depth == 16) + { + png_bytep sp = row; /* source */ + png_bytep dp = row; /* destination */ + png_bytep ep = sp + row_info->rowbytes; /* end+1 */ + + while (sp < ep) + { + /* The input is an array of 16 bit components, these must be scaled to + * 8 bits each. For a 16 bit value V the required value (from the PNG + * specification) is: + * + * (V * 255) / 65535 + * + * This reduces to round(V / 257), or floor((V + 128.5)/257) + * + * Represent V as the two byte value vhi.vlo. Make a guess that the + * result is the top byte of V, vhi, then the correction to this value + * is: + * + * error = floor(((V-vhi.vhi) + 128.5) / 257) + * = floor(((vlo-vhi) + 128.5) / 257) + * + * This can be approximated using integer arithmetic (and a signed + * shift): + * + * error = (vlo-vhi+128) >> 8; + * + * The approximate differs from the exact answer only when (vlo-vhi) is + * 128; it then gives a correction of +1 when the exact correction is + * 0. This gives 128 errors. The exact answer (correct for all 16 bit + * input values) is: + * + * error = (vlo-vhi+128)*65535 >> 24; + * + * An alternative arithmetic calculation which also gives no errors is: + * + * (V * 255 + 32895) >> 16 + */ + + png_int_32 tmp = *sp++; /* must be signed! */ + tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24; + *dp++ = (png_byte)tmp; + } + + row_info->bit_depth = 8; + row_info->pixel_depth = (png_byte)(8 * row_info->channels); + row_info->rowbytes = row_info->width * row_info->channels; + } +} +#endif + +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED +static void +/* Simply discard the low byte. This was the default behavior prior + * to libpng-1.5.4. + */ +png_do_chop(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_chop"); + + if (row_info->bit_depth == 16) + { + png_bytep sp = row; /* source */ + png_bytep dp = row; /* destination */ + png_bytep ep = sp + row_info->rowbytes; /* end+1 */ + + while (sp < ep) + { + *dp++ = *sp; + sp += 2; /* skip low byte */ + } + + row_info->bit_depth = 8; + row_info->pixel_depth = (png_byte)(8 * row_info->channels); + row_info->rowbytes = row_info->width * row_info->channels; + } +} +#endif + +#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED +static void +png_do_read_swap_alpha(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_read_swap_alpha"); + + { + png_uint_32 row_width = row_info->width; + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + /* This converts from RGBA to ARGB */ + if (row_info->bit_depth == 8) + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_byte save; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + save = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = save; + } + } + +#ifdef PNG_READ_16BIT_SUPPORTED + /* This converts from RRGGBBAA to AARRGGBB */ + else + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_byte save[2]; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + save[0] = *(--sp); + save[1] = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = save[0]; + *(--dp) = save[1]; + } + } +#endif + } + + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + /* This converts from GA to AG */ + if (row_info->bit_depth == 8) + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_byte save; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + save = *(--sp); + *(--dp) = *(--sp); + *(--dp) = save; + } + } + +#ifdef PNG_READ_16BIT_SUPPORTED + /* This converts from GGAA to AAGG */ + else + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_byte save[2]; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + save[0] = *(--sp); + save[1] = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = save[0]; + *(--dp) = save[1]; + } + } +#endif + } + } +} +#endif + +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED +static void +png_do_read_invert_alpha(png_row_infop row_info, png_bytep row) +{ + png_uint_32 row_width; + png_debug(1, "in png_do_read_invert_alpha"); + + row_width = row_info->width; + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + if (row_info->bit_depth == 8) + { + /* This inverts the alpha channel in RGBA */ + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + +/* This does nothing: + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + We can replace it with: +*/ + sp-=3; + dp=sp; + } + } + +#ifdef PNG_READ_16BIT_SUPPORTED + /* This inverts the alpha channel in RRGGBBAA */ + else + { + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + *(--dp) = (png_byte)(255 - *(--sp)); + +/* This does nothing: + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + We can replace it with: +*/ + sp-=6; + dp=sp; + } + } +#endif + } + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (row_info->bit_depth == 8) + { + /* This inverts the alpha channel in GA */ + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + *(--dp) = *(--sp); + } + } + +#ifdef PNG_READ_16BIT_SUPPORTED + else + { + /* This inverts the alpha channel in GGAA */ + png_bytep sp = row + row_info->rowbytes; + png_bytep dp = sp; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + *(--dp) = (png_byte)(255 - *(--sp)); + *(--dp) = (png_byte)(255 - *(--sp)); +/* + *(--dp) = *(--sp); + *(--dp) = *(--sp); +*/ + sp-=2; + dp=sp; + } + } +#endif + } +} +#endif + +#ifdef PNG_READ_FILLER_SUPPORTED +/* Add filler channel if we have RGB color */ +static void +png_do_read_filler(png_row_infop row_info, png_bytep row, + png_uint_32 filler, png_uint_32 flags) +{ + png_uint_32 i; + png_uint_32 row_width = row_info->width; + +#ifdef PNG_READ_16BIT_SUPPORTED + png_byte hi_filler = (png_byte)((filler>>8) & 0xff); +#endif + png_byte lo_filler = (png_byte)(filler & 0xff); + + png_debug(1, "in png_do_read_filler"); + + if ( + row_info->color_type == PNG_COLOR_TYPE_GRAY) + { + if (row_info->bit_depth == 8) + { + if (flags & PNG_FLAG_FILLER_AFTER) + { + /* This changes the data from G to GX */ + png_bytep sp = row + (png_size_t)row_width; + png_bytep dp = sp + (png_size_t)row_width; + for (i = 1; i < row_width; i++) + { + *(--dp) = lo_filler; + *(--dp) = *(--sp); + } + *(--dp) = lo_filler; + row_info->channels = 2; + row_info->pixel_depth = 16; + row_info->rowbytes = row_width * 2; + } + + else + { + /* This changes the data from G to XG */ + png_bytep sp = row + (png_size_t)row_width; + png_bytep dp = sp + (png_size_t)row_width; + for (i = 0; i < row_width; i++) + { + *(--dp) = *(--sp); + *(--dp) = lo_filler; + } + row_info->channels = 2; + row_info->pixel_depth = 16; + row_info->rowbytes = row_width * 2; + } + } + +#ifdef PNG_READ_16BIT_SUPPORTED + else if (row_info->bit_depth == 16) + { + if (flags & PNG_FLAG_FILLER_AFTER) + { + /* This changes the data from GG to GGXX */ + png_bytep sp = row + (png_size_t)row_width * 2; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 1; i < row_width; i++) + { + *(--dp) = hi_filler; + *(--dp) = lo_filler; + *(--dp) = *(--sp); + *(--dp) = *(--sp); + } + *(--dp) = hi_filler; + *(--dp) = lo_filler; + row_info->channels = 2; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + } + + else + { + /* This changes the data from GG to XXGG */ + png_bytep sp = row + (png_size_t)row_width * 2; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 0; i < row_width; i++) + { + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = hi_filler; + *(--dp) = lo_filler; + } + row_info->channels = 2; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + } + } +#endif + } /* COLOR_TYPE == GRAY */ + else if (row_info->color_type == PNG_COLOR_TYPE_RGB) + { + if (row_info->bit_depth == 8) + { + if (flags & PNG_FLAG_FILLER_AFTER) + { + /* This changes the data from RGB to RGBX */ + png_bytep sp = row + (png_size_t)row_width * 3; + png_bytep dp = sp + (png_size_t)row_width; + for (i = 1; i < row_width; i++) + { + *(--dp) = lo_filler; + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + } + *(--dp) = lo_filler; + row_info->channels = 4; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + } + + else + { + /* This changes the data from RGB to XRGB */ + png_bytep sp = row + (png_size_t)row_width * 3; + png_bytep dp = sp + (png_size_t)row_width; + for (i = 0; i < row_width; i++) + { + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = lo_filler; + } + row_info->channels = 4; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + } + } + +#ifdef PNG_READ_16BIT_SUPPORTED + else if (row_info->bit_depth == 16) + { + if (flags & PNG_FLAG_FILLER_AFTER) + { + /* This changes the data from RRGGBB to RRGGBBXX */ + png_bytep sp = row + (png_size_t)row_width * 6; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 1; i < row_width; i++) + { + *(--dp) = hi_filler; + *(--dp) = lo_filler; + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + } + *(--dp) = hi_filler; + *(--dp) = lo_filler; + row_info->channels = 4; + row_info->pixel_depth = 64; + row_info->rowbytes = row_width * 8; + } + + else + { + /* This changes the data from RRGGBB to XXRRGGBB */ + png_bytep sp = row + (png_size_t)row_width * 6; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 0; i < row_width; i++) + { + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = *(--sp); + *(--dp) = hi_filler; + *(--dp) = lo_filler; + } + + row_info->channels = 4; + row_info->pixel_depth = 64; + row_info->rowbytes = row_width * 8; + } + } +#endif + } /* COLOR_TYPE == RGB */ +} +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED +/* Expand grayscale files to RGB, with or without alpha */ +static void +png_do_gray_to_rgb(png_row_infop row_info, png_bytep row) +{ + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + png_debug(1, "in png_do_gray_to_rgb"); + + if (row_info->bit_depth >= 8 && + !(row_info->color_type & PNG_COLOR_MASK_COLOR)) + { + if (row_info->color_type == PNG_COLOR_TYPE_GRAY) + { + if (row_info->bit_depth == 8) + { + /* This changes G to RGB */ + png_bytep sp = row + (png_size_t)row_width - 1; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 0; i < row_width; i++) + { + *(dp--) = *sp; + *(dp--) = *sp; + *(dp--) = *(sp--); + } + } + + else + { + /* This changes GG to RRGGBB */ + png_bytep sp = row + (png_size_t)row_width * 2 - 1; + png_bytep dp = sp + (png_size_t)row_width * 4; + for (i = 0; i < row_width; i++) + { + *(dp--) = *sp; + *(dp--) = *(sp - 1); + *(dp--) = *sp; + *(dp--) = *(sp - 1); + *(dp--) = *(sp--); + *(dp--) = *(sp--); + } + } + } + + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (row_info->bit_depth == 8) + { + /* This changes GA to RGBA */ + png_bytep sp = row + (png_size_t)row_width * 2 - 1; + png_bytep dp = sp + (png_size_t)row_width * 2; + for (i = 0; i < row_width; i++) + { + *(dp--) = *(sp--); + *(dp--) = *sp; + *(dp--) = *sp; + *(dp--) = *(sp--); + } + } + + else + { + /* This changes GGAA to RRGGBBAA */ + png_bytep sp = row + (png_size_t)row_width * 4 - 1; + png_bytep dp = sp + (png_size_t)row_width * 4; + for (i = 0; i < row_width; i++) + { + *(dp--) = *(sp--); + *(dp--) = *(sp--); + *(dp--) = *sp; + *(dp--) = *(sp - 1); + *(dp--) = *sp; + *(dp--) = *(sp - 1); + *(dp--) = *(sp--); + *(dp--) = *(sp--); + } + } + } + row_info->channels = (png_byte)(row_info->channels + 2); + row_info->color_type |= PNG_COLOR_MASK_COLOR; + row_info->pixel_depth = (png_byte)(row_info->channels * + row_info->bit_depth); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); + } +} +#endif + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +/* Reduce RGB files to grayscale, with or without alpha + * using the equation given in Poynton's ColorFAQ of 1998-01-04 at + * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but + * versions dated 1998 through November 2002 have been archived at + * http://web.archive.org/web/20000816232553/http://www.inforamp.net/ + * ~poynton/notes/colour_and_gamma/ColorFAQ.txt ) + * Charles Poynton poynton at poynton.com + * + * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B + * + * which can be expressed with integers as + * + * Y = (6969 * R + 23434 * G + 2365 * B)/32768 + * + * Poynton's current link (as of January 2003 through July 2011): + * <http://www.poynton.com/notes/colour_and_gamma/> + * has changed the numbers slightly: + * + * Y = 0.2126*R + 0.7152*G + 0.0722*B + * + * which can be expressed with integers as + * + * Y = (6966 * R + 23436 * G + 2366 * B)/32768 + * + * Historically, however, libpng uses numbers derived from the ITU-R Rec 709 + * end point chromaticities and the D65 white point. Depending on the + * precision used for the D65 white point this produces a variety of different + * numbers, however if the four decimal place value used in ITU-R Rec 709 is + * used (0.3127,0.3290) the Y calculation would be: + * + * Y = (6968 * R + 23435 * G + 2366 * B)/32768 + * + * While this is correct the rounding results in an overflow for white, because + * the sum of the rounded coefficients is 32769, not 32768. Consequently + * libpng uses, instead, the closest non-overflowing approximation: + * + * Y = (6968 * R + 23434 * G + 2366 * B)/32768 + * + * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk + * (including an sRGB chunk) then the chromaticities are used to calculate the + * coefficients. See the chunk handling in pngrutil.c for more information. + * + * In all cases the calculation is to be done in a linear colorspace. If no + * gamma information is available to correct the encoding of the original RGB + * values this results in an implicit assumption that the original PNG RGB + * values were linear. + * + * Other integer coefficents can be used via png_set_rgb_to_gray(). Because + * the API takes just red and green coefficients the blue coefficient is + * calculated to make the sum 32768. This will result in different rounding + * to that used above. + */ +static int +png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row) + +{ + int rgb_error = 0; + + png_debug(1, "in png_do_rgb_to_gray"); + + if (!(row_info->color_type & PNG_COLOR_MASK_PALETTE) && + (row_info->color_type & PNG_COLOR_MASK_COLOR)) + { + PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff; + PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff; + PNG_CONST png_uint_32 bc = 32768 - rc - gc; + PNG_CONST png_uint_32 row_width = row_info->width; + PNG_CONST int have_alpha = + (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0; + + if (row_info->bit_depth == 8) + { +#ifdef PNG_READ_GAMMA_SUPPORTED + /* Notice that gamma to/from 1 are not necessarily inverses (if + * there is an overall gamma correction). Prior to 1.5.5 this code + * checked the linearized values for equality; this doesn't match + * the documentation, the original values must be checked. + */ + if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + png_byte red = *(sp++); + png_byte green = *(sp++); + png_byte blue = *(sp++); + + if (red != green || red != blue) + { + red = png_ptr->gamma_to_1[red]; + green = png_ptr->gamma_to_1[green]; + blue = png_ptr->gamma_to_1[blue]; + + rgb_error |= 1; + *(dp++) = png_ptr->gamma_from_1[ + (rc*red + gc*green + bc*blue + 16384)>>15]; + } + + else + { + /* If there is no overall correction the table will not be + * set. + */ + if (png_ptr->gamma_table != NULL) + red = png_ptr->gamma_table[red]; + + *(dp++) = red; + } + + if (have_alpha != 0) + *(dp++) = *(sp++); + } + } + else +#endif + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + png_byte red = *(sp++); + png_byte green = *(sp++); + png_byte blue = *(sp++); + + if (red != green || red != blue) + { + rgb_error |= 1; + /* NOTE: this is the historical approach which simply + * truncates the results. + */ + *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15); + } + + else + *(dp++) = red; + + if (have_alpha != 0) + *(dp++) = *(sp++); + } + } + } + + else /* RGB bit_depth == 16 */ + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL) + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + png_uint_16 red, green, blue, w; + + red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + + if (red == green && red == blue) + { + if (png_ptr->gamma_16_table != NULL) + w = png_ptr->gamma_16_table[(red&0xff) + >> png_ptr->gamma_shift][red>>8]; + + else + w = red; + } + + else + { + png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red&0xff) + >> png_ptr->gamma_shift][red>>8]; + png_uint_16 green_1 = + png_ptr->gamma_16_to_1[(green&0xff) >> + png_ptr->gamma_shift][green>>8]; + png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue&0xff) + >> png_ptr->gamma_shift][blue>>8]; + png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1 + + bc*blue_1 + 16384)>>15); + w = png_ptr->gamma_16_from_1[(gray16&0xff) >> + png_ptr->gamma_shift][gray16 >> 8]; + rgb_error |= 1; + } + + *(dp++) = (png_byte)((w>>8) & 0xff); + *(dp++) = (png_byte)(w & 0xff); + + if (have_alpha != 0) + { + *(dp++) = *(sp++); + *(dp++) = *(sp++); + } + } + } + else +#endif + { + png_bytep sp = row; + png_bytep dp = row; + png_uint_32 i; + + for (i = 0; i < row_width; i++) + { + png_uint_16 red, green, blue, gray16; + + red = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + green = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + blue = (png_uint_16)(((*(sp))<<8) | *(sp + 1)); sp += 2; + + if (red != green || red != blue) + rgb_error |= 1; + + /* From 1.5.5 in the 16 bit case do the accurate conversion even + * in the 'fast' case - this is because this is where the code + * ends up when handling linear 16 bit data. + */ + gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >> + 15); + *(dp++) = (png_byte)((gray16>>8) & 0xff); + *(dp++) = (png_byte)(gray16 & 0xff); + + if (have_alpha != 0) + { + *(dp++) = *(sp++); + *(dp++) = *(sp++); + } + } + } + } + + row_info->channels = (png_byte)(row_info->channels - 2); + row_info->color_type = (png_byte)(row_info->color_type & + ~PNG_COLOR_MASK_COLOR); + row_info->pixel_depth = (png_byte)(row_info->channels * + row_info->bit_depth); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); + } + return rgb_error; +} +#endif + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) +/* Replace any alpha or transparency with the supplied background color. + * "background" is already in the screen gamma, while "background_1" is + * at a gamma of 1.0. Paletted files have already been taken care of. + */ +static void +png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr) +{ +#ifdef PNG_READ_GAMMA_SUPPORTED + png_const_bytep gamma_table = png_ptr->gamma_table; + png_const_bytep gamma_from_1 = png_ptr->gamma_from_1; + png_const_bytep gamma_to_1 = png_ptr->gamma_to_1; + png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table; + png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1; + png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1; + int gamma_shift = png_ptr->gamma_shift; + int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0; +#endif + + png_bytep sp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + int shift; + + png_debug(1, "in png_do_compose"); + + { + switch (row_info->color_type) + { + case PNG_COLOR_TYPE_GRAY: + { + switch (row_info->bit_depth) + { + case 1: + { + sp = row; + shift = 7; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x01) + == png_ptr->trans_color.gray) + { + unsigned int tmp = *sp & (0x7f7f >> (7 - shift)); + tmp |= png_ptr->background.gray << shift; + *sp = (png_byte)(tmp & 0xff); + } + + if (shift == 0) + { + shift = 7; + sp++; + } + + else + shift--; + } + break; + } + + case 2: + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_table != NULL) + { + sp = row; + shift = 6; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x03) + == png_ptr->trans_color.gray) + { + unsigned int tmp = *sp & (0x3f3f >> (6 - shift)); + tmp |= png_ptr->background.gray << shift; + *sp = (png_byte)(tmp & 0xff); + } + + else + { + unsigned int p = (*sp >> shift) & 0x03; + unsigned int g = (gamma_table [p | (p << 2) | + (p << 4) | (p << 6)] >> 6) & 0x03; + unsigned int tmp = *sp & (0x3f3f >> (6 - shift)); + tmp |= g << shift; + *sp = (png_byte)(tmp & 0xff); + } + + if (shift == 0) + { + shift = 6; + sp++; + } + + else + shift -= 2; + } + } + + else +#endif + { + sp = row; + shift = 6; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x03) + == png_ptr->trans_color.gray) + { + unsigned int tmp = *sp & (0x3f3f >> (6 - shift)); + tmp |= png_ptr->background.gray << shift; + *sp = (png_byte)(tmp & 0xff); + } + + if (shift == 0) + { + shift = 6; + sp++; + } + + else + shift -= 2; + } + } + break; + } + + case 4: + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_table != NULL) + { + sp = row; + shift = 4; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x0f) + == png_ptr->trans_color.gray) + { + unsigned int tmp = *sp & (0xf0f >> (4 - shift)); + tmp |= png_ptr->background.gray << shift; + *sp = (png_byte)(tmp & 0xff); + } + + else + { + unsigned int p = (*sp >> shift) & 0x0f; + unsigned int g = (gamma_table[p | (p << 4)] >> 4) & + 0x0f; + unsigned int tmp = *sp & (0xf0f >> (4 - shift)); + tmp |= g << shift; + *sp = (png_byte)(tmp & 0xff); + } + + if (shift == 0) + { + shift = 4; + sp++; + } + + else + shift -= 4; + } + } + + else +#endif + { + sp = row; + shift = 4; + for (i = 0; i < row_width; i++) + { + if ((png_uint_16)((*sp >> shift) & 0x0f) + == png_ptr->trans_color.gray) + { + unsigned int tmp = *sp & (0xf0f >> (4 - shift)); + tmp |= png_ptr->background.gray << shift; + *sp = (png_byte)(tmp & 0xff); + } + + if (shift == 0) + { + shift = 4; + sp++; + } + + else + shift -= 4; + } + } + break; + } + + case 8: + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_table != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp++) + { + if (*sp == png_ptr->trans_color.gray) + *sp = (png_byte)png_ptr->background.gray; + + else + *sp = gamma_table[*sp]; + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp++) + { + if (*sp == png_ptr->trans_color.gray) + *sp = (png_byte)png_ptr->background.gray; + } + } + break; + } + + case 16: + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_16 != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 2) + { + png_uint_16 v; + + v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + + if (v == png_ptr->trans_color.gray) + { + /* Background is already in screen gamma */ + *sp = (png_byte)((png_ptr->background.gray >> 8) + & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray + & 0xff); + } + + else + { + v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 2) + { + png_uint_16 v; + + v = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + + if (v == png_ptr->trans_color.gray) + { + *sp = (png_byte)((png_ptr->background.gray >> 8) + & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray + & 0xff); + } + } + } + break; + } + + default: + break; + } + break; + } + + case PNG_COLOR_TYPE_RGB: + { + if (row_info->bit_depth == 8) + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_table != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 3) + { + if (*sp == png_ptr->trans_color.red && + *(sp + 1) == png_ptr->trans_color.green && + *(sp + 2) == png_ptr->trans_color.blue) + { + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; + } + + else + { + *sp = gamma_table[*sp]; + *(sp + 1) = gamma_table[*(sp + 1)]; + *(sp + 2) = gamma_table[*(sp + 2)]; + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 3) + { + if (*sp == png_ptr->trans_color.red && + *(sp + 1) == png_ptr->trans_color.green && + *(sp + 2) == png_ptr->trans_color.blue) + { + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; + } + } + } + } + else /* if (row_info->bit_depth == 16) */ + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_16 != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 6) + { + png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + + png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + + png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + + *(sp + 5)); + + if (r == png_ptr->trans_color.red && + g == png_ptr->trans_color.green && + b == png_ptr->trans_color.blue) + { + /* Background is already in screen gamma */ + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) + & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green + & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) + & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); + } + + else + { + png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + + v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)]; + *(sp + 2) = (png_byte)((v >> 8) & 0xff); + *(sp + 3) = (png_byte)(v & 0xff); + + v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)]; + *(sp + 4) = (png_byte)((v >> 8) & 0xff); + *(sp + 5) = (png_byte)(v & 0xff); + } + } + } + + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 6) + { + png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + + png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + + png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + + *(sp + 5)); + + if (r == png_ptr->trans_color.red && + g == png_ptr->trans_color.green && + b == png_ptr->trans_color.blue) + { + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) + & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green + & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) + & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); + } + } + } + } + break; + } + + case PNG_COLOR_TYPE_GRAY_ALPHA: + { + if (row_info->bit_depth == 8) + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_to_1 != NULL && gamma_from_1 != NULL && + gamma_table != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 2) + { + png_uint_16 a = *(sp + 1); + + if (a == 0xff) + *sp = gamma_table[*sp]; + + else if (a == 0) + { + /* Background is already in screen gamma */ + *sp = (png_byte)png_ptr->background.gray; + } + + else + { + png_byte v, w; + + v = gamma_to_1[*sp]; + png_composite(w, v, a, png_ptr->background_1.gray); + if (optimize == 0) + w = gamma_from_1[w]; + *sp = w; + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 2) + { + png_byte a = *(sp + 1); + + if (a == 0) + *sp = (png_byte)png_ptr->background.gray; + + else if (a < 0xff) + png_composite(*sp, *sp, a, png_ptr->background.gray); + } + } + } + else /* if (png_ptr->bit_depth == 16) */ + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_16 != NULL && gamma_16_from_1 != NULL && + gamma_16_to_1 != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 4) + { + png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + + if (a == (png_uint_16)0xffff) + { + png_uint_16 v; + + v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + } + + else if (a == 0) + { + /* Background is already in screen gamma */ + *sp = (png_byte)((png_ptr->background.gray >> 8) + & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); + } + + else + { + png_uint_16 g, v, w; + + g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp]; + png_composite_16(v, g, a, png_ptr->background_1.gray); + if (optimize != 0) + w = v; + else + w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8]; + *sp = (png_byte)((w >> 8) & 0xff); + *(sp + 1) = (png_byte)(w & 0xff); + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 4) + { + png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + + if (a == 0) + { + *sp = (png_byte)((png_ptr->background.gray >> 8) + & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff); + } + + else if (a < 0xffff) + { + png_uint_16 g, v; + + g = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + png_composite_16(v, g, a, png_ptr->background.gray); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + } + } + } + } + break; + } + + case PNG_COLOR_TYPE_RGB_ALPHA: + { + if (row_info->bit_depth == 8) + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_to_1 != NULL && gamma_from_1 != NULL && + gamma_table != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 4) + { + png_byte a = *(sp + 3); + + if (a == 0xff) + { + *sp = gamma_table[*sp]; + *(sp + 1) = gamma_table[*(sp + 1)]; + *(sp + 2) = gamma_table[*(sp + 2)]; + } + + else if (a == 0) + { + /* Background is already in screen gamma */ + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; + } + + else + { + png_byte v, w; + + v = gamma_to_1[*sp]; + png_composite(w, v, a, png_ptr->background_1.red); + if (optimize == 0) w = gamma_from_1[w]; + *sp = w; + + v = gamma_to_1[*(sp + 1)]; + png_composite(w, v, a, png_ptr->background_1.green); + if (optimize == 0) w = gamma_from_1[w]; + *(sp + 1) = w; + + v = gamma_to_1[*(sp + 2)]; + png_composite(w, v, a, png_ptr->background_1.blue); + if (optimize == 0) w = gamma_from_1[w]; + *(sp + 2) = w; + } + } + } + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 4) + { + png_byte a = *(sp + 3); + + if (a == 0) + { + *sp = (png_byte)png_ptr->background.red; + *(sp + 1) = (png_byte)png_ptr->background.green; + *(sp + 2) = (png_byte)png_ptr->background.blue; + } + + else if (a < 0xff) + { + png_composite(*sp, *sp, a, png_ptr->background.red); + + png_composite(*(sp + 1), *(sp + 1), a, + png_ptr->background.green); + + png_composite(*(sp + 2), *(sp + 2), a, + png_ptr->background.blue); + } + } + } + } + else /* if (row_info->bit_depth == 16) */ + { +#ifdef PNG_READ_GAMMA_SUPPORTED + if (gamma_16 != NULL && gamma_16_from_1 != NULL && + gamma_16_to_1 != NULL) + { + sp = row; + for (i = 0; i < row_width; i++, sp += 8) + { + png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6)) + << 8) + (png_uint_16)(*(sp + 7))); + + if (a == (png_uint_16)0xffff) + { + png_uint_16 v; + + v = gamma_16[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + + v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)]; + *(sp + 2) = (png_byte)((v >> 8) & 0xff); + *(sp + 3) = (png_byte)(v & 0xff); + + v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)]; + *(sp + 4) = (png_byte)((v >> 8) & 0xff); + *(sp + 5) = (png_byte)(v & 0xff); + } + + else if (a == 0) + { + /* Background is already in screen gamma */ + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) + & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green + & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) + & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); + } + + else + { + png_uint_16 v, w; + + v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp]; + png_composite_16(w, v, a, png_ptr->background_1.red); + if (optimize == 0) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> + 8]; + *sp = (png_byte)((w >> 8) & 0xff); + *(sp + 1) = (png_byte)(w & 0xff); + + v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)]; + png_composite_16(w, v, a, png_ptr->background_1.green); + if (optimize == 0) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> + 8]; + + *(sp + 2) = (png_byte)((w >> 8) & 0xff); + *(sp + 3) = (png_byte)(w & 0xff); + + v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)]; + png_composite_16(w, v, a, png_ptr->background_1.blue); + if (optimize == 0) + w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> + 8]; + + *(sp + 4) = (png_byte)((w >> 8) & 0xff); + *(sp + 5) = (png_byte)(w & 0xff); + } + } + } + + else +#endif + { + sp = row; + for (i = 0; i < row_width; i++, sp += 8) + { + png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6)) + << 8) + (png_uint_16)(*(sp + 7))); + + if (a == 0) + { + *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff); + *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff); + *(sp + 2) = (png_byte)((png_ptr->background.green >> 8) + & 0xff); + *(sp + 3) = (png_byte)(png_ptr->background.green + & 0xff); + *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8) + & 0xff); + *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff); + } + + else if (a < 0xffff) + { + png_uint_16 v; + + png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1)); + png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8) + + *(sp + 3)); + png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8) + + *(sp + 5)); + + png_composite_16(v, r, a, png_ptr->background.red); + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + + png_composite_16(v, g, a, png_ptr->background.green); + *(sp + 2) = (png_byte)((v >> 8) & 0xff); + *(sp + 3) = (png_byte)(v & 0xff); + + png_composite_16(v, b, a, png_ptr->background.blue); + *(sp + 4) = (png_byte)((v >> 8) & 0xff); + *(sp + 5) = (png_byte)(v & 0xff); + } + } + } + } + break; + } + + default: + break; + } + } +} +#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_READ_ALPHA_MODE_SUPPORTED */ + +#ifdef PNG_READ_GAMMA_SUPPORTED +/* Gamma correct the image, avoiding the alpha channel. Make sure + * you do this after you deal with the transparency issue on grayscale + * or RGB images. If your bit depth is 8, use gamma_table, if it + * is 16, use gamma_16_table and gamma_shift. Build these with + * build_gamma_table(). + */ +static void +png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr) +{ + png_const_bytep gamma_table = png_ptr->gamma_table; + png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table; + int gamma_shift = png_ptr->gamma_shift; + + png_bytep sp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + png_debug(1, "in png_do_gamma"); + + if (((row_info->bit_depth <= 8 && gamma_table != NULL) || + (row_info->bit_depth == 16 && gamma_16_table != NULL))) + { + switch (row_info->color_type) + { + case PNG_COLOR_TYPE_RGB: + { + if (row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++) + { + *sp = gamma_table[*sp]; + sp++; + *sp = gamma_table[*sp]; + sp++; + *sp = gamma_table[*sp]; + sp++; + } + } + + else /* if (row_info->bit_depth == 16) */ + { + sp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 v; + + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + } + } + break; + } + + case PNG_COLOR_TYPE_RGB_ALPHA: + { + if (row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++) + { + *sp = gamma_table[*sp]; + sp++; + + *sp = gamma_table[*sp]; + sp++; + + *sp = gamma_table[*sp]; + sp++; + + sp++; + } + } + + else /* if (row_info->bit_depth == 16) */ + { + sp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + + v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 4; + } + } + break; + } + + case PNG_COLOR_TYPE_GRAY_ALPHA: + { + if (row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++) + { + *sp = gamma_table[*sp]; + sp += 2; + } + } + + else /* if (row_info->bit_depth == 16) */ + { + sp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 4; + } + } + break; + } + + case PNG_COLOR_TYPE_GRAY: + { + if (row_info->bit_depth == 2) + { + sp = row; + for (i = 0; i < row_width; i += 4) + { + int a = *sp & 0xc0; + int b = *sp & 0x30; + int c = *sp & 0x0c; + int d = *sp & 0x03; + + *sp = (png_byte)( + ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)| + ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)| + ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)| + ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) )); + sp++; + } + } + + if (row_info->bit_depth == 4) + { + sp = row; + for (i = 0; i < row_width; i += 2) + { + int msb = *sp & 0xf0; + int lsb = *sp & 0x0f; + + *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0) + | (((int)gamma_table[(lsb << 4) | lsb]) >> 4)); + sp++; + } + } + + else if (row_info->bit_depth == 8) + { + sp = row; + for (i = 0; i < row_width; i++) + { + *sp = gamma_table[*sp]; + sp++; + } + } + + else if (row_info->bit_depth == 16) + { + sp = row; + for (i = 0; i < row_width; i++) + { + png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp]; + *sp = (png_byte)((v >> 8) & 0xff); + *(sp + 1) = (png_byte)(v & 0xff); + sp += 2; + } + } + break; + } + + default: + break; + } + } +} +#endif + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED +/* Encode the alpha channel to the output gamma (the input channel is always + * linear.) Called only with color types that have an alpha channel. Needs the + * from_1 tables. + */ +static void +png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr) +{ + png_uint_32 row_width = row_info->width; + + png_debug(1, "in png_do_encode_alpha"); + + if (row_info->color_type & PNG_COLOR_MASK_ALPHA) + { + if (row_info->bit_depth == 8) + { + PNG_CONST png_bytep table = png_ptr->gamma_from_1; + + if (table != NULL) + { + PNG_CONST int step = + (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2; + + /* The alpha channel is the last component: */ + row += step - 1; + + for (; row_width > 0; --row_width, row += step) + *row = table[*row]; + + return; + } + } + + else if (row_info->bit_depth == 16) + { + PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1; + PNG_CONST int gamma_shift = png_ptr->gamma_shift; + + if (table != NULL) + { + PNG_CONST int step = + (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4; + + /* The alpha channel is the last component: */ + row += step - 2; + + for (; row_width > 0; --row_width, row += step) + { + png_uint_16 v; + + v = table[*(row + 1) >> gamma_shift][*row]; + *row = (png_byte)((v >> 8) & 0xff); + *(row + 1) = (png_byte)(v & 0xff); + } + + return; + } + } + } + + /* Only get to here if called with a weird row_info; no harm has been done, + * so just issue a warning. + */ + png_warning(png_ptr, "png_do_encode_alpha: unexpected call"); +} +#endif + +#ifdef PNG_READ_EXPAND_SUPPORTED +/* Expands a palette row to an RGB or RGBA row depending + * upon whether you supply trans and num_trans. + */ +static void +png_do_expand_palette(png_row_infop row_info, png_bytep row, + png_const_colorp palette, png_const_bytep trans_alpha, int num_trans) +{ + int shift, value; + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + png_debug(1, "in png_do_expand_palette"); + + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (row_info->bit_depth < 8) + { + switch (row_info->bit_depth) + { + case 1: + { + sp = row + (png_size_t)((row_width - 1) >> 3); + dp = row + (png_size_t)row_width - 1; + shift = 7 - (int)((row_width + 7) & 0x07); + for (i = 0; i < row_width; i++) + { + if ((*sp >> shift) & 0x01) + *dp = 1; + + else + *dp = 0; + + if (shift == 7) + { + shift = 0; + sp--; + } + + else + shift++; + + dp--; + } + break; + } + + case 2: + { + sp = row + (png_size_t)((row_width - 1) >> 2); + dp = row + (png_size_t)row_width - 1; + shift = (int)((3 - ((row_width + 3) & 0x03)) << 1); + for (i = 0; i < row_width; i++) + { + value = (*sp >> shift) & 0x03; + *dp = (png_byte)value; + if (shift == 6) + { + shift = 0; + sp--; + } + + else + shift += 2; + + dp--; + } + break; + } + + case 4: + { + sp = row + (png_size_t)((row_width - 1) >> 1); + dp = row + (png_size_t)row_width - 1; + shift = (int)((row_width & 0x01) << 2); + for (i = 0; i < row_width; i++) + { + value = (*sp >> shift) & 0x0f; + *dp = (png_byte)value; + if (shift == 4) + { + shift = 0; + sp--; + } + + else + shift += 4; + + dp--; + } + break; + } + + default: + break; + } + row_info->bit_depth = 8; + row_info->pixel_depth = 8; + row_info->rowbytes = row_width; + } + + if (row_info->bit_depth == 8) + { + { + if (num_trans > 0) + { + sp = row + (png_size_t)row_width - 1; + dp = row + (png_size_t)(row_width << 2) - 1; + + for (i = 0; i < row_width; i++) + { + if ((int)(*sp) >= num_trans) + *dp-- = 0xff; + + else + *dp-- = trans_alpha[*sp]; + + *dp-- = palette[*sp].blue; + *dp-- = palette[*sp].green; + *dp-- = palette[*sp].red; + sp--; + } + row_info->bit_depth = 8; + row_info->pixel_depth = 32; + row_info->rowbytes = row_width * 4; + row_info->color_type = 6; + row_info->channels = 4; + } + + else + { + sp = row + (png_size_t)row_width - 1; + dp = row + (png_size_t)(row_width * 3) - 1; + + for (i = 0; i < row_width; i++) + { + *dp-- = palette[*sp].blue; + *dp-- = palette[*sp].green; + *dp-- = palette[*sp].red; + sp--; + } + + row_info->bit_depth = 8; + row_info->pixel_depth = 24; + row_info->rowbytes = row_width * 3; + row_info->color_type = 2; + row_info->channels = 3; + } + } + } + } +} + +/* If the bit depth < 8, it is expanded to 8. Also, if the already + * expanded transparency value is supplied, an alpha channel is built. + */ +static void +png_do_expand(png_row_infop row_info, png_bytep row, + png_const_color_16p trans_color) +{ + int shift, value; + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + png_debug(1, "in png_do_expand"); + + { + if (row_info->color_type == PNG_COLOR_TYPE_GRAY) + { + unsigned int gray = trans_color ? trans_color->gray : 0; + + if (row_info->bit_depth < 8) + { + switch (row_info->bit_depth) + { + case 1: + { + gray = (gray & 0x01) * 0xff; + sp = row + (png_size_t)((row_width - 1) >> 3); + dp = row + (png_size_t)row_width - 1; + shift = 7 - (int)((row_width + 7) & 0x07); + for (i = 0; i < row_width; i++) + { + if ((*sp >> shift) & 0x01) + *dp = 0xff; + + else + *dp = 0; + + if (shift == 7) + { + shift = 0; + sp--; + } + + else + shift++; + + dp--; + } + break; + } + + case 2: + { + gray = (gray & 0x03) * 0x55; + sp = row + (png_size_t)((row_width - 1) >> 2); + dp = row + (png_size_t)row_width - 1; + shift = (int)((3 - ((row_width + 3) & 0x03)) << 1); + for (i = 0; i < row_width; i++) + { + value = (*sp >> shift) & 0x03; + *dp = (png_byte)(value | (value << 2) | (value << 4) | + (value << 6)); + if (shift == 6) + { + shift = 0; + sp--; + } + + else + shift += 2; + + dp--; + } + break; + } + + case 4: + { + gray = (gray & 0x0f) * 0x11; + sp = row + (png_size_t)((row_width - 1) >> 1); + dp = row + (png_size_t)row_width - 1; + shift = (int)((1 - ((row_width + 1) & 0x01)) << 2); + for (i = 0; i < row_width; i++) + { + value = (*sp >> shift) & 0x0f; + *dp = (png_byte)(value | (value << 4)); + if (shift == 4) + { + shift = 0; + sp--; + } + + else + shift = 4; + + dp--; + } + break; + } + + default: + break; + } + + row_info->bit_depth = 8; + row_info->pixel_depth = 8; + row_info->rowbytes = row_width; + } + + if (trans_color != NULL) + { + if (row_info->bit_depth == 8) + { + gray = gray & 0xff; + sp = row + (png_size_t)row_width - 1; + dp = row + (png_size_t)(row_width << 1) - 1; + + for (i = 0; i < row_width; i++) + { + if (*sp == gray) + *dp-- = 0; + + else + *dp-- = 0xff; + + *dp-- = *sp--; + } + } + + else if (row_info->bit_depth == 16) + { + unsigned int gray_high = (gray >> 8) & 0xff; + unsigned int gray_low = gray & 0xff; + sp = row + row_info->rowbytes - 1; + dp = row + (row_info->rowbytes << 1) - 1; + for (i = 0; i < row_width; i++) + { + if (*(sp - 1) == gray_high && *(sp) == gray_low) + { + *dp-- = 0; + *dp-- = 0; + } + + else + { + *dp-- = 0xff; + *dp-- = 0xff; + } + + *dp-- = *sp--; + *dp-- = *sp--; + } + } + + row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA; + row_info->channels = 2; + row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, + row_width); + } + } + else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_color) + { + if (row_info->bit_depth == 8) + { + png_byte red = (png_byte)(trans_color->red & 0xff); + png_byte green = (png_byte)(trans_color->green & 0xff); + png_byte blue = (png_byte)(trans_color->blue & 0xff); + sp = row + (png_size_t)row_info->rowbytes - 1; + dp = row + (png_size_t)(row_width << 2) - 1; + for (i = 0; i < row_width; i++) + { + if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue) + *dp-- = 0; + + else + *dp-- = 0xff; + + *dp-- = *sp--; + *dp-- = *sp--; + *dp-- = *sp--; + } + } + else if (row_info->bit_depth == 16) + { + png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff); + png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff); + png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff); + png_byte red_low = (png_byte)(trans_color->red & 0xff); + png_byte green_low = (png_byte)(trans_color->green & 0xff); + png_byte blue_low = (png_byte)(trans_color->blue & 0xff); + sp = row + row_info->rowbytes - 1; + dp = row + (png_size_t)(row_width << 3) - 1; + for (i = 0; i < row_width; i++) + { + if (*(sp - 5) == red_high && + *(sp - 4) == red_low && + *(sp - 3) == green_high && + *(sp - 2) == green_low && + *(sp - 1) == blue_high && + *(sp ) == blue_low) + { + *dp-- = 0; + *dp-- = 0; + } + + else + { + *dp-- = 0xff; + *dp-- = 0xff; + } + + *dp-- = *sp--; + *dp-- = *sp--; + *dp-- = *sp--; + *dp-- = *sp--; + *dp-- = *sp--; + *dp-- = *sp--; + } + } + row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA; + row_info->channels = 4; + row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); + } + } +} +#endif + +#ifdef PNG_READ_EXPAND_16_SUPPORTED +/* If the bit depth is 8 and the color type is not a palette type expand the + * whole row to 16 bits. Has no effect otherwise. + */ +static void +png_do_expand_16(png_row_infop row_info, png_bytep row) +{ + if (row_info->bit_depth == 8 && + row_info->color_type != PNG_COLOR_TYPE_PALETTE) + { + /* The row have a sequence of bytes containing [0..255] and we need + * to turn it into another row containing [0..65535], to do this we + * calculate: + * + * (input / 255) * 65535 + * + * Which happens to be exactly input * 257 and this can be achieved + * simply by byte replication in place (copying backwards). + */ + png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */ + png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */ + while (dp > sp) + dp[-2] = dp[-1] = *--sp, dp -= 2; + + row_info->rowbytes *= 2; + row_info->bit_depth = 16; + row_info->pixel_depth = (png_byte)(row_info->channels * 16); + } +} +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED +static void +png_do_quantize(png_row_infop row_info, png_bytep row, + png_const_bytep palette_lookup, png_const_bytep quantize_lookup) +{ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width=row_info->width; + + png_debug(1, "in png_do_quantize"); + + if (row_info->bit_depth == 8) + { + if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup) + { + int r, g, b, p; + sp = row; + dp = row; + for (i = 0; i < row_width; i++) + { + r = *sp++; + g = *sp++; + b = *sp++; + + /* This looks real messy, but the compiler will reduce + * it down to a reasonable formula. For example, with + * 5 bits per color, we get: + * p = (((r >> 3) & 0x1f) << 10) | + * (((g >> 3) & 0x1f) << 5) | + * ((b >> 3) & 0x1f); + */ + p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) & + ((1 << PNG_QUANTIZE_RED_BITS) - 1)) << + (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) | + (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) & + ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) << + (PNG_QUANTIZE_BLUE_BITS)) | + ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) & + ((1 << PNG_QUANTIZE_BLUE_BITS) - 1)); + + *dp++ = palette_lookup[p]; + } + + row_info->color_type = PNG_COLOR_TYPE_PALETTE; + row_info->channels = 1; + row_info->pixel_depth = row_info->bit_depth; + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); + } + + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA && + palette_lookup != NULL) + { + int r, g, b, p; + sp = row; + dp = row; + for (i = 0; i < row_width; i++) + { + r = *sp++; + g = *sp++; + b = *sp++; + sp++; + + p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) & + ((1 << PNG_QUANTIZE_RED_BITS) - 1)) << + (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) | + (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) & + ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) << + (PNG_QUANTIZE_BLUE_BITS)) | + ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) & + ((1 << PNG_QUANTIZE_BLUE_BITS) - 1)); + + *dp++ = palette_lookup[p]; + } + + row_info->color_type = PNG_COLOR_TYPE_PALETTE; + row_info->channels = 1; + row_info->pixel_depth = row_info->bit_depth; + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width); + } + + else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE && + quantize_lookup) + { + sp = row; + + for (i = 0; i < row_width; i++, sp++) + { + *sp = quantize_lookup[*sp]; + } + } + } +} +#endif /* PNG_READ_QUANTIZE_SUPPORTED */ + +/* Transform the row. The order of transformations is significant, + * and is very touchy. If you add a transformation, take care to + * decide how it fits in with the other transformations here. + */ +void /* PRIVATE */ +png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info) +{ + png_debug(1, "in png_do_read_transformations"); + + if (png_ptr->row_buf == NULL) + { + /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this + * error is incredibly rare and incredibly easy to debug without this + * information. + */ + png_error(png_ptr, "NULL row buffer"); + } + + /* The following is debugging; prior to 1.5.4 the code was never compiled in; + * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro + * PNG_WARN_UNINITIALIZED_ROW removed. In 1.6 the new flag is set only for + * all transformations, however in practice the ROW_INIT always gets done on + * demand, if necessary. + */ + if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 && + !(png_ptr->flags & PNG_FLAG_ROW_INIT)) + { + /* Application has failed to call either png_read_start_image() or + * png_read_update_info() after setting transforms that expand pixels. + * This check added to libpng-1.2.19 (but not enabled until 1.5.4). + */ + png_error(png_ptr, "Uninitialized row"); + } + +#ifdef PNG_READ_EXPAND_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND) + { + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE) + { + png_do_expand_palette(row_info, png_ptr->row_buf + 1, + png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans); + } + + else + { + if (png_ptr->num_trans && + (png_ptr->transformations & PNG_EXPAND_tRNS)) + png_do_expand(row_info, png_ptr->row_buf + 1, + &(png_ptr->trans_color)); + + else + png_do_expand(row_info, png_ptr->row_buf + 1, + NULL); + } + } +#endif + +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + !(png_ptr->transformations & PNG_COMPOSE) && + (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + png_do_strip_channel(row_info, png_ptr->row_buf + 1, + 0 /* at_start == false, because SWAP_ALPHA happens later */); +#endif + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + if (png_ptr->transformations & PNG_RGB_TO_GRAY) + { + int rgb_error = + png_do_rgb_to_gray(png_ptr, row_info, + png_ptr->row_buf + 1); + + if (rgb_error != 0) + { + png_ptr->rgb_to_gray_status=1; + if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == + PNG_RGB_TO_GRAY_WARN) + png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel"); + + if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == + PNG_RGB_TO_GRAY_ERR) + png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel"); + } + } +#endif + +/* From Andreas Dilger e-mail to png-implement, 26 March 1998: + * + * In most cases, the "simple transparency" should be done prior to doing + * gray-to-RGB, or you will have to test 3x as many bytes to check if a + * pixel is transparent. You would also need to make sure that the + * transparency information is upgraded to RGB. + * + * To summarize, the current flow is: + * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite + * with background "in place" if transparent, + * convert to RGB if necessary + * - Gray + alpha -> composite with gray background and remove alpha bytes, + * convert to RGB if necessary + * + * To support RGB backgrounds for gray images we need: + * - Gray + simple transparency -> convert to RGB + simple transparency, + * compare 3 or 6 bytes and composite with + * background "in place" if transparent + * (3x compare/pixel compared to doing + * composite with gray bkgrnd) + * - Gray + alpha -> convert to RGB + alpha, composite with background and + * remove alpha bytes (3x float + * operations/pixel compared with composite + * on gray background) + * + * Greg's change will do this. The reason it wasn't done before is for + * performance, as this increases the per-pixel operations. If we would check + * in advance if the background was gray or RGB, and position the gray-to-RGB + * transform appropriately, then it would save a lot of work/time. + */ + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + /* If gray -> RGB, do so now only if background is non-gray; else do later + * for performance reasons + */ + if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && + !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) + png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1); +#endif + +#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) + if (png_ptr->transformations & PNG_COMPOSE) + png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr); +#endif + +#ifdef PNG_READ_GAMMA_SUPPORTED + if ((png_ptr->transformations & PNG_GAMMA) && +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + /* Because RGB_TO_GRAY does the gamma transform. */ + !(png_ptr->transformations & PNG_RGB_TO_GRAY) && +#endif +#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) + /* Because PNG_COMPOSE does the gamma transform if there is something to + * do (if there is an alpha channel or transparency.) + */ + !((png_ptr->transformations & PNG_COMPOSE) && + ((png_ptr->num_trans != 0) || + (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) && +#endif + /* Because png_init_read_transformations transforms the palette, unless + * RGB_TO_GRAY will do the transform. + */ + (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)) + png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr); +#endif + +#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED + if ((png_ptr->transformations & PNG_STRIP_ALPHA) && + (png_ptr->transformations & PNG_COMPOSE) && + (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA || + row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)) + png_do_strip_channel(row_info, png_ptr->row_buf + 1, + 0 /* at_start == false, because SWAP_ALPHA happens later */); +#endif + +#ifdef PNG_READ_ALPHA_MODE_SUPPORTED + if ((png_ptr->transformations & PNG_ENCODE_ALPHA) && + (row_info->color_type & PNG_COLOR_MASK_ALPHA)) + png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr); +#endif + +#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED + if (png_ptr->transformations & PNG_SCALE_16_TO_8) + png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED + /* There is no harm in doing both of these because only one has any effect, + * by putting the 'scale' option first if the app asks for scale (either by + * calling the API or in a TRANSFORM flag) this is what happens. + */ + if (png_ptr->transformations & PNG_16_TO_8) + png_do_chop(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED + if (png_ptr->transformations & PNG_QUANTIZE) + { + png_do_quantize(row_info, png_ptr->row_buf + 1, + png_ptr->palette_lookup, png_ptr->quantize_index); + + if (row_info->rowbytes == 0) + png_error(png_ptr, "png_do_quantize returned rowbytes=0"); + } +#endif /* PNG_READ_QUANTIZE_SUPPORTED */ + +#ifdef PNG_READ_EXPAND_16_SUPPORTED + /* Do the expansion now, after all the arithmetic has been done. Notice + * that previous transformations can handle the PNG_EXPAND_16 flag if this + * is efficient (particularly true in the case of gamma correction, where + * better accuracy results faster!) + */ + if (png_ptr->transformations & PNG_EXPAND_16) + png_do_expand_16(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + /* NOTE: moved here in 1.5.4 (from much later in this list.) */ + if ((png_ptr->transformations & PNG_GRAY_TO_RGB) && + (png_ptr->mode & PNG_BACKGROUND_IS_GRAY)) + png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_INVERT_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_MONO) + png_do_invert(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_ALPHA) + png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_SHIFT_SUPPORTED + if (png_ptr->transformations & PNG_SHIFT) + png_do_unshift(row_info, png_ptr->row_buf + 1, + &(png_ptr->shift)); +#endif + +#ifdef PNG_READ_PACK_SUPPORTED + if (png_ptr->transformations & PNG_PACK) + png_do_unpack(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED + /* Added at libpng-1.5.10 */ + if (row_info->color_type == PNG_COLOR_TYPE_PALETTE && + png_ptr->num_palette_max >= 0) + png_do_check_palette_indexes(png_ptr, row_info); +#endif + +#ifdef PNG_READ_BGR_SUPPORTED + if (png_ptr->transformations & PNG_BGR) + png_do_bgr(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if (png_ptr->transformations & PNG_PACKSWAP) + png_do_packswap(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_FILLER_SUPPORTED + if (png_ptr->transformations & PNG_FILLER) + png_do_read_filler(row_info, png_ptr->row_buf + 1, + (png_uint_32)png_ptr->filler, png_ptr->flags); +#endif + +#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_SWAP_ALPHA) + png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_READ_16BIT_SUPPORTED +#ifdef PNG_READ_SWAP_SUPPORTED + if (png_ptr->transformations & PNG_SWAP_BYTES) + png_do_swap(row_info, png_ptr->row_buf + 1); +#endif +#endif + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + if (png_ptr->transformations & PNG_USER_TRANSFORM) + { + if (png_ptr->read_user_transform_fn != NULL) + (*(png_ptr->read_user_transform_fn)) /* User read transform function */ + (png_ptr, /* png_ptr */ + row_info, /* row_info: */ + /* png_uint_32 width; width of row */ + /* png_size_t rowbytes; number of bytes in row */ + /* png_byte color_type; color type of pixels */ + /* png_byte bit_depth; bit depth of samples */ + /* png_byte channels; number of channels (1-4) */ + /* png_byte pixel_depth; bits per pixel (depth*channels) */ + png_ptr->row_buf + 1); /* start of pixel data for row */ +#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED + if (png_ptr->user_transform_depth) + row_info->bit_depth = png_ptr->user_transform_depth; + + if (png_ptr->user_transform_channels) + row_info->channels = png_ptr->user_transform_channels; +#endif + row_info->pixel_depth = (png_byte)(row_info->bit_depth * + row_info->channels); + + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width); + } +#endif +} + +#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ +#endif /* PNG_READ_SUPPORTED */ diff --git a/png/pngrutil.c b/png/pngrutil.c new file mode 100755 index 0000000..cc52202 --- /dev/null +++ b/png/pngrutil.c @@ -0,0 +1,4469 @@ + +/* pngrutil.c - utilities to read a PNG file + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * This file contains routines that are only called from within + * libpng itself during the course of reading an image. + */ + +#include "pngpriv.h" + +#ifdef PNG_READ_SUPPORTED + +png_uint_32 PNGAPI +png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf) +{ + png_uint_32 uval = png_get_uint_32(buf); + + if (uval > PNG_UINT_31_MAX) + png_error(png_ptr, "PNG unsigned integer out of range"); + + return (uval); +} + +#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED) +/* The following is a variation on the above for use with the fixed + * point values used for gAMA and cHRM. Instead of png_error it + * issues a warning and returns (-1) - an invalid value because both + * gAMA and cHRM use *unsigned* integers for fixed point values. + */ +#define PNG_FIXED_ERROR (-1) + +static png_fixed_point /* PRIVATE */ +png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf) +{ + png_uint_32 uval = png_get_uint_32(buf); + + if (uval <= PNG_UINT_31_MAX) + return (png_fixed_point)uval; /* known to be in range */ + + /* The caller can turn off the warning by passing NULL. */ + if (png_ptr != NULL) + png_warning(png_ptr, "PNG fixed point integer out of range"); + + return PNG_FIXED_ERROR; +} +#endif + +#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED +/* NOTE: the read macros will obscure these definitions, so that if + * PNG_USE_READ_MACROS is set the library will not use them internally, + * but the APIs will still be available externally. + * + * The parentheses around "PNGAPI function_name" in the following three + * functions are necessary because they allow the macros to co-exist with + * these (unused but exported) functions. + */ + +/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */ +png_uint_32 (PNGAPI +png_get_uint_32)(png_const_bytep buf) +{ + png_uint_32 uval = + ((png_uint_32)(*(buf )) << 24) + + ((png_uint_32)(*(buf + 1)) << 16) + + ((png_uint_32)(*(buf + 2)) << 8) + + ((png_uint_32)(*(buf + 3)) ) ; + + return uval; +} + +/* Grab a signed 32-bit integer from a buffer in big-endian format. The + * data is stored in the PNG file in two's complement format and there + * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore + * the following code does a two's complement to native conversion. + */ +png_int_32 (PNGAPI +png_get_int_32)(png_const_bytep buf) +{ + png_uint_32 uval = png_get_uint_32(buf); + if ((uval & 0x80000000) == 0) /* non-negative */ + return uval; + + uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */ + return -(png_int_32)uval; +} + +/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */ +png_uint_16 (PNGAPI +png_get_uint_16)(png_const_bytep buf) +{ + /* ANSI-C requires an int value to accomodate at least 16 bits so this + * works and allows the compiler not to worry about possible narrowing + * on 32 bit systems. (Pre-ANSI systems did not make integers smaller + * than 16 bits either.) + */ + unsigned int val = + ((unsigned int)(*buf) << 8) + + ((unsigned int)(*(buf + 1))); + + return (png_uint_16)val; +} + +#endif /* PNG_READ_INT_FUNCTIONS_SUPPORTED */ + +/* Read and check the PNG file signature */ +void /* PRIVATE */ +png_read_sig(png_structrp png_ptr, png_inforp info_ptr) +{ + png_size_t num_checked, num_to_check; + + /* Exit if the user application does not expect a signature. */ + if (png_ptr->sig_bytes >= 8) + return; + + num_checked = png_ptr->sig_bytes; + num_to_check = 8 - num_checked; + +#ifdef PNG_IO_STATE_SUPPORTED + png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE; +#endif + + /* The signature must be serialized in a single I/O call. */ + png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check); + png_ptr->sig_bytes = 8; + + if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) + { + if (num_checked < 4 && + png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) + png_error(png_ptr, "Not a PNG file"); + else + png_error(png_ptr, "PNG file corrupted by ASCII conversion"); + } + if (num_checked < 3) + png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; +} + +/* Read the chunk header (length + type name). + * Put the type name into png_ptr->chunk_name, and return the length. + */ +png_uint_32 /* PRIVATE */ +png_read_chunk_header(png_structrp png_ptr) +{ + png_byte buf[8]; + png_uint_32 length; + +#ifdef PNG_IO_STATE_SUPPORTED + png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR; +#endif + + /* Read the length and the chunk name. + * This must be performed in a single I/O call. + */ + png_read_data(png_ptr, buf, 8); + length = png_get_uint_31(png_ptr, buf); + + /* Put the chunk name into png_ptr->chunk_name. */ + png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4); + + png_debug2(0, "Reading %lx chunk, length = %lu", + (unsigned long)png_ptr->chunk_name, (unsigned long)length); + + /* Reset the crc and run it over the chunk name. */ + png_reset_crc(png_ptr); + png_calculate_crc(png_ptr, buf + 4, 4); + + /* Check to see if chunk name is valid. */ + png_check_chunk_name(png_ptr, png_ptr->chunk_name); + +#ifdef PNG_IO_STATE_SUPPORTED + png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA; +#endif + + return length; +} + +/* Read data, and (optionally) run it through the CRC. */ +void /* PRIVATE */ +png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length) +{ + if (png_ptr == NULL) + return; + + png_read_data(png_ptr, buf, length); + png_calculate_crc(png_ptr, buf, length); +} + +/* Optionally skip data and then check the CRC. Depending on whether we + * are reading an ancillary or critical chunk, and how the program has set + * things up, we may calculate the CRC on the data and print a message. + * Returns '1' if there was a CRC error, '0' otherwise. + */ +int /* PRIVATE */ +png_crc_finish(png_structrp png_ptr, png_uint_32 skip) +{ + /* The size of the local buffer for inflate is a good guess as to a + * reasonable size to use for buffering reads from the application. + */ + while (skip > 0) + { + png_uint_32 len; + png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; + + len = (sizeof tmpbuf); + if (len > skip) + len = skip; + skip -= len; + + png_crc_read(png_ptr, tmpbuf, len); + } + + if (png_crc_error(png_ptr)) + { + if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) ? + !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) : + (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE)) + { + png_chunk_warning(png_ptr, "CRC error"); + } + + else + png_chunk_error(png_ptr, "CRC error"); + + return (1); + } + + return (0); +} + +/* Compare the CRC stored in the PNG file with that calculated by libpng from + * the data it has read thus far. + */ +int /* PRIVATE */ +png_crc_error(png_structrp png_ptr) +{ + png_byte crc_bytes[4]; + png_uint_32 crc; + int need_crc = 1; + + if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)) + { + if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == + (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) + need_crc = 0; + } + + else /* critical */ + { + if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) + need_crc = 0; + } + +#ifdef PNG_IO_STATE_SUPPORTED + png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC; +#endif + + /* The chunk CRC must be serialized in a single I/O call. */ + png_read_data(png_ptr, crc_bytes, 4); + + if (need_crc != 0) + { + crc = png_get_uint_32(crc_bytes); + return ((int)(crc != png_ptr->crc)); + } + + else + return (0); +} + +#if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\ + defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\ + defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\ + defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED) +/* Manage the read buffer; this simply reallocates the buffer if it is not small + * enough (or if it is not allocated). The routine returns a pointer to the + * buffer; if an error occurs and 'warn' is set the routine returns NULL, else + * it will call png_error (via png_malloc) on failure. (warn == 2 means + * 'silent'). + */ +static png_bytep +png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn) +{ + png_bytep buffer = png_ptr->read_buffer; + + if (buffer != NULL && new_size > png_ptr->read_buffer_size) + { + png_ptr->read_buffer = NULL; + png_ptr->read_buffer = NULL; + png_ptr->read_buffer_size = 0; + png_free(png_ptr, buffer); + buffer = NULL; + } + + if (buffer == NULL) + { + buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size)); + + if (buffer != NULL) + { + png_ptr->read_buffer = buffer; + png_ptr->read_buffer_size = new_size; + } + + else if (warn < 2) /* else silent */ + { + if (warn != 0) + png_chunk_warning(png_ptr, "insufficient memory to read chunk"); + + else + png_chunk_error(png_ptr, "insufficient memory to read chunk"); + } + } + + return buffer; +} +#endif /* PNG_READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */ + +/* png_inflate_claim: claim the zstream for some nefarious purpose that involves + * decompression. Returns Z_OK on success, else a zlib error code. It checks + * the owner but, in final release builds, just issues a warning if some other + * chunk apparently owns the stream. Prior to release it does a png_error. + */ +static int +png_inflate_claim(png_structrp png_ptr, png_uint_32 owner) +{ + if (png_ptr->zowner != 0) + { + char msg[64]; + + PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner); + /* So the message that results is "<chunk> using zstream"; this is an + * internal error, but is very useful for debugging. i18n requirements + * are minimal. + */ + (void)png_safecat(msg, (sizeof msg), 4, " using zstream"); +# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC + png_chunk_warning(png_ptr, msg); + png_ptr->zowner = 0; +# else + png_chunk_error(png_ptr, msg); +# endif + } + + /* Implementation note: unlike 'png_deflate_claim' this internal function + * does not take the size of the data as an argument. Some efficiency could + * be gained by using this when it is known *if* the zlib stream itself does + * not record the number; however, this is an illusion: the original writer + * of the PNG may have selected a lower window size, and we really must + * follow that because, for systems with with limited capabilities, we + * would otherwise reject the application's attempts to use a smaller window + * size (zlib doesn't have an interface to say "this or lower"!). + * + * inflateReset2 was added to zlib 1.2.4; before this the window could not be + * reset, therefore it is necessary to always allocate the maximum window + * size with earlier zlibs just in case later compressed chunks need it. + */ + { + int ret; /* zlib return code */ +# if PNG_ZLIB_VERNUM >= 0x1240 + +# if defined(PNG_SET_OPTION_SUPPORTED) && \ + defined(PNG_MAXIMUM_INFLATE_WINDOW) + int window_bits; + + if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) == + PNG_OPTION_ON) + window_bits = 15; + + else + window_bits = 0; +# else +# define window_bits 0 +# endif +# endif + + /* Set this for safety, just in case the previous owner left pointers to + * memory allocations. + */ + png_ptr->zstream.next_in = NULL; + png_ptr->zstream.avail_in = 0; + png_ptr->zstream.next_out = NULL; + png_ptr->zstream.avail_out = 0; + + if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) + { +# if PNG_ZLIB_VERNUM < 0x1240 + ret = inflateReset(&png_ptr->zstream); +# else + ret = inflateReset2(&png_ptr->zstream, window_bits); +# endif + } + + else + { +# if PNG_ZLIB_VERNUM < 0x1240 + ret = inflateInit(&png_ptr->zstream); +# else + ret = inflateInit2(&png_ptr->zstream, window_bits); +# endif + + if (ret == Z_OK) + png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; + } + + if (ret == Z_OK) + png_ptr->zowner = owner; + + else + png_zstream_error(png_ptr, ret); + + return ret; + } + +# ifdef window_bits +# undef window_bits +# endif +} + +#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED +/* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to + * allow the caller to do multiple calls if required. If the 'finish' flag is + * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must + * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and + * Z_OK or Z_STREAM_END will be returned on success. + * + * The input and output sizes are updated to the actual amounts of data consumed + * or written, not the amount available (as in a z_stream). The data pointers + * are not changed, so the next input is (data+input_size) and the next + * available output is (output+output_size). + */ +static int +png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish, + /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr, + /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr) +{ + if (png_ptr->zowner == owner) /* Else not claimed */ + { + int ret; + png_alloc_size_t avail_out = *output_size_ptr; + png_uint_32 avail_in = *input_size_ptr; + + /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it + * can't even necessarily handle 65536 bytes) because the type uInt is + * "16 bits or more". Consequently it is necessary to chunk the input to + * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the + * maximum value that can be stored in a uInt.) It is possible to set + * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have + * a performance advantage, because it reduces the amount of data accessed + * at each step and that may give the OS more time to page it in. + */ + png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); + /* avail_in and avail_out are set below from 'size' */ + png_ptr->zstream.avail_in = 0; + png_ptr->zstream.avail_out = 0; + + /* Read directly into the output if it is available (this is set to + * a local buffer below if output is NULL). + */ + if (output != NULL) + png_ptr->zstream.next_out = output; + + do + { + uInt avail; + Byte local_buffer[PNG_INFLATE_BUF_SIZE]; + + /* zlib INPUT BUFFER */ + /* The setting of 'avail_in' used to be outside the loop; by setting it + * inside it is possible to chunk the input to zlib and simply rely on + * zlib to advance the 'next_in' pointer. This allows arbitrary + * amounts of data to be passed through zlib at the unavoidable cost of + * requiring a window save (memcpy of up to 32768 output bytes) + * every ZLIB_IO_MAX input bytes. + */ + avail_in += png_ptr->zstream.avail_in; /* not consumed last time */ + + avail = ZLIB_IO_MAX; + + if (avail_in < avail) + avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */ + + avail_in -= avail; + png_ptr->zstream.avail_in = avail; + + /* zlib OUTPUT BUFFER */ + avail_out += png_ptr->zstream.avail_out; /* not written last time */ + + avail = ZLIB_IO_MAX; /* maximum zlib can process */ + + if (output == NULL) + { + /* Reset the output buffer each time round if output is NULL and + * make available the full buffer, up to 'remaining_space' + */ + png_ptr->zstream.next_out = local_buffer; + if ((sizeof local_buffer) < avail) + avail = (sizeof local_buffer); + } + + if (avail_out < avail) + avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */ + + png_ptr->zstream.avail_out = avail; + avail_out -= avail; + + /* zlib inflate call */ + /* In fact 'avail_out' may be 0 at this point, that happens at the end + * of the read when the final LZ end code was not passed at the end of + * the previous chunk of input data. Tell zlib if we have reached the + * end of the output buffer. + */ + ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH : + (finish ? Z_FINISH : Z_SYNC_FLUSH)); + } while (ret == Z_OK); + + /* For safety kill the local buffer pointer now */ + if (output == NULL) + png_ptr->zstream.next_out = NULL; + + /* Claw back the 'size' and 'remaining_space' byte counts. */ + avail_in += png_ptr->zstream.avail_in; + avail_out += png_ptr->zstream.avail_out; + + /* Update the input and output sizes; the updated values are the amount + * consumed or written, effectively the inverse of what zlib uses. + */ + if (avail_out > 0) + *output_size_ptr -= avail_out; + + if (avail_in > 0) + *input_size_ptr -= avail_in; + + /* Ensure png_ptr->zstream.msg is set (even in the success case!) */ + png_zstream_error(png_ptr, ret); + return ret; + } + + else + { + /* This is a bad internal error. The recovery assigns to the zstream msg + * pointer, which is not owned by the caller, but this is safe; it's only + * used on errors! + */ + png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); + return Z_STREAM_ERROR; + } +} + +/* + * Decompress trailing data in a chunk. The assumption is that read_buffer + * points at an allocated area holding the contents of a chunk with a + * trailing compressed part. What we get back is an allocated area + * holding the original prefix part and an uncompressed version of the + * trailing part (the malloc area passed in is freed). + */ +static int +png_decompress_chunk(png_structrp png_ptr, + png_uint_32 chunklength, png_uint_32 prefix_size, + png_alloc_size_t *newlength /* must be initialized to the maximum! */, + int terminate /*add a '\0' to the end of the uncompressed data*/) +{ + /* TODO: implement different limits for different types of chunk. + * + * The caller supplies *newlength set to the maximum length of the + * uncompressed data, but this routine allocates space for the prefix and + * maybe a '\0' terminator too. We have to assume that 'prefix_size' is + * limited only by the maximum chunk size. + */ + png_alloc_size_t limit = PNG_SIZE_MAX; + +# ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED + if (png_ptr->user_chunk_malloc_max > 0 && + png_ptr->user_chunk_malloc_max < limit) + limit = png_ptr->user_chunk_malloc_max; +# elif PNG_USER_CHUNK_MALLOC_MAX > 0 + if (PNG_USER_CHUNK_MALLOC_MAX < limit) + limit = PNG_USER_CHUNK_MALLOC_MAX; +# endif + + if (limit >= prefix_size + (terminate != 0)) + { + int ret; + + limit -= prefix_size + (terminate != 0); + + if (limit < *newlength) + *newlength = limit; + + /* Now try to claim the stream. */ + ret = png_inflate_claim(png_ptr, png_ptr->chunk_name); + + if (ret == Z_OK) + { + png_uint_32 lzsize = chunklength - prefix_size; + + ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, + /* input: */ png_ptr->read_buffer + prefix_size, &lzsize, + /* output: */ NULL, newlength); + + if (ret == Z_STREAM_END) + { + /* Use 'inflateReset' here, not 'inflateReset2' because this + * preserves the previously decided window size (otherwise it would + * be necessary to store the previous window size.) In practice + * this doesn't matter anyway, because png_inflate will call inflate + * with Z_FINISH in almost all cases, so the window will not be + * maintained. + */ + if (inflateReset(&png_ptr->zstream) == Z_OK) + { + /* Because of the limit checks above we know that the new, + * expanded, size will fit in a size_t (let alone an + * png_alloc_size_t). Use png_malloc_base here to avoid an + * extra OOM message. + */ + png_alloc_size_t new_size = *newlength; + png_alloc_size_t buffer_size = prefix_size + new_size + + (terminate != 0); + png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr, + buffer_size)); + + if (text != NULL) + { + ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, + png_ptr->read_buffer + prefix_size, &lzsize, + text + prefix_size, newlength); + + if (ret == Z_STREAM_END) + { + if (new_size == *newlength) + { + if (terminate != 0) + text[prefix_size + *newlength] = 0; + + if (prefix_size > 0) + memcpy(text, png_ptr->read_buffer, prefix_size); + + { + png_bytep old_ptr = png_ptr->read_buffer; + + png_ptr->read_buffer = text; + png_ptr->read_buffer_size = buffer_size; + text = old_ptr; /* freed below */ + } + } + + else + { + /* The size changed on the second read, there can be no + * guarantee that anything is correct at this point. + * The 'msg' pointer has been set to "unexpected end of + * LZ stream", which is fine, but return an error code + * that the caller won't accept. + */ + ret = PNG_UNEXPECTED_ZLIB_RETURN; + } + } + + else if (ret == Z_OK) + ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */ + + /* Free the text pointer (this is the old read_buffer on + * success) + */ + png_free(png_ptr, text); + + /* This really is very benign, but it's still an error because + * the extra space may otherwise be used as a Trojan Horse. + */ + if (ret == Z_STREAM_END && + chunklength - prefix_size != lzsize) + png_chunk_benign_error(png_ptr, "extra compressed data"); + } + + else + { + /* Out of memory allocating the buffer */ + ret = Z_MEM_ERROR; + png_zstream_error(png_ptr, Z_MEM_ERROR); + } + } + + else + { + /* inflateReset failed, store the error message */ + png_zstream_error(png_ptr, ret); + + if (ret == Z_STREAM_END) + ret = PNG_UNEXPECTED_ZLIB_RETURN; + } + } + + else if (ret == Z_OK) + ret = PNG_UNEXPECTED_ZLIB_RETURN; + + /* Release the claimed stream */ + png_ptr->zowner = 0; + } + + else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */ + ret = PNG_UNEXPECTED_ZLIB_RETURN; + + return ret; + } + + else + { + /* Application/configuration limits exceeded */ + png_zstream_error(png_ptr, Z_MEM_ERROR); + return Z_MEM_ERROR; + } +} +#endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */ + +#ifdef PNG_READ_iCCP_SUPPORTED +/* Perform a partial read and decompress, producing 'avail_out' bytes and + * reading from the current chunk as required. + */ +static int +png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size, + png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size, + int finish) +{ + if (png_ptr->zowner == png_ptr->chunk_name) + { + int ret; + + /* next_in and avail_in must have been initialized by the caller. */ + png_ptr->zstream.next_out = next_out; + png_ptr->zstream.avail_out = 0; /* set in the loop */ + + do + { + if (png_ptr->zstream.avail_in == 0) + { + if (read_size > *chunk_bytes) + read_size = (uInt)*chunk_bytes; + *chunk_bytes -= read_size; + + if (read_size > 0) + png_crc_read(png_ptr, read_buffer, read_size); + + png_ptr->zstream.next_in = read_buffer; + png_ptr->zstream.avail_in = read_size; + } + + if (png_ptr->zstream.avail_out == 0) + { + uInt avail = ZLIB_IO_MAX; + if (avail > *out_size) + avail = (uInt)*out_size; + *out_size -= avail; + + png_ptr->zstream.avail_out = avail; + } + + /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all + * the available output is produced; this allows reading of truncated + * streams. + */ + ret = inflate(&png_ptr->zstream, + *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH)); + } + while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0)); + + *out_size += png_ptr->zstream.avail_out; + png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */ + + /* Ensure the error message pointer is always set: */ + png_zstream_error(png_ptr, ret); + return ret; + } + + else + { + png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); + return Z_STREAM_ERROR; + } +} +#endif + +/* Read and check the IDHR chunk */ +void /* PRIVATE */ +png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_byte buf[13]; + png_uint_32 width, height; + int bit_depth, color_type, compression_type, filter_type; + int interlace_type; + + png_debug(1, "in png_handle_IHDR"); + + if (png_ptr->mode & PNG_HAVE_IHDR) + png_chunk_error(png_ptr, "out of place"); + + /* Check the length */ + if (length != 13) + png_chunk_error(png_ptr, "invalid"); + + png_ptr->mode |= PNG_HAVE_IHDR; + + png_crc_read(png_ptr, buf, 13); + png_crc_finish(png_ptr, 0); + + width = png_get_uint_31(png_ptr, buf); + height = png_get_uint_31(png_ptr, buf + 4); + bit_depth = buf[8]; + color_type = buf[9]; + compression_type = buf[10]; + filter_type = buf[11]; + interlace_type = buf[12]; + + /* Set internal variables */ + png_ptr->width = width; + png_ptr->height = height; + png_ptr->bit_depth = (png_byte)bit_depth; + png_ptr->interlaced = (png_byte)interlace_type; + png_ptr->color_type = (png_byte)color_type; +#ifdef PNG_MNG_FEATURES_SUPPORTED + png_ptr->filter_type = (png_byte)filter_type; +#endif + png_ptr->compression_type = (png_byte)compression_type; + + /* Find number of channels */ + switch (png_ptr->color_type) + { + default: /* invalid, png_set_IHDR calls png_error */ + case PNG_COLOR_TYPE_GRAY: + case PNG_COLOR_TYPE_PALETTE: + png_ptr->channels = 1; + break; + + case PNG_COLOR_TYPE_RGB: + png_ptr->channels = 3; + break; + + case PNG_COLOR_TYPE_GRAY_ALPHA: + png_ptr->channels = 2; + break; + + case PNG_COLOR_TYPE_RGB_ALPHA: + png_ptr->channels = 4; + break; + } + + /* Set up other useful info */ + png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * + png_ptr->channels); + png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width); + png_debug1(3, "bit_depth = %d", png_ptr->bit_depth); + png_debug1(3, "channels = %d", png_ptr->channels); + png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes); + png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, + color_type, interlace_type, compression_type, filter_type); +} + +/* Read and check the palette */ +void /* PRIVATE */ +png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_color palette[PNG_MAX_PALETTE_LENGTH]; + int num, i; +#ifdef PNG_POINTER_INDEXING_SUPPORTED + png_colorp pal_ptr; +#endif + + png_debug(1, "in png_handle_PLTE"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + /* Moved to before the 'after IDAT' check below because otherwise duplicate + * PLTE chunks are potentially ignored (the spec says there shall not be more + * than one PLTE, the error is not treated as benign, so this check trumps + * the requirement that PLTE appears before IDAT.) + */ + else if (png_ptr->mode & PNG_HAVE_PLTE) + png_chunk_error(png_ptr, "duplicate"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + /* This is benign because the non-benign error happened before, when an + * IDAT was encountered in a color-mapped image with no PLTE. + */ + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + png_ptr->mode |= PNG_HAVE_PLTE; + + if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "ignored in grayscale PNG"); + return; + } + +#ifndef PNG_READ_OPT_PLTE_SUPPORTED + if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) + { + png_crc_finish(png_ptr, length); + return; + } +#endif + + if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3) + { + png_crc_finish(png_ptr, length); + + if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) + png_chunk_benign_error(png_ptr, "invalid"); + + else + png_chunk_error(png_ptr, "invalid"); + + return; + } + + /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */ + num = (int)length / 3; + +#ifdef PNG_POINTER_INDEXING_SUPPORTED + for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++) + { + png_byte buf[3]; + + png_crc_read(png_ptr, buf, 3); + pal_ptr->red = buf[0]; + pal_ptr->green = buf[1]; + pal_ptr->blue = buf[2]; + } +#else + for (i = 0; i < num; i++) + { + png_byte buf[3]; + + png_crc_read(png_ptr, buf, 3); + /* Don't depend upon png_color being any order */ + palette[i].red = buf[0]; + palette[i].green = buf[1]; + palette[i].blue = buf[2]; + } +#endif + + /* If we actually need the PLTE chunk (ie for a paletted image), we do + * whatever the normal CRC configuration tells us. However, if we + * have an RGB image, the PLTE can be considered ancillary, so + * we will act as though it is. + */ +#ifndef PNG_READ_OPT_PLTE_SUPPORTED + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) +#endif + { + png_crc_finish(png_ptr, 0); + } + +#ifndef PNG_READ_OPT_PLTE_SUPPORTED + else if (png_crc_error(png_ptr)) /* Only if we have a CRC error */ + { + /* If we don't want to use the data from an ancillary chunk, + * we have two options: an error abort, or a warning and we + * ignore the data in this chunk (which should be OK, since + * it's considered ancillary for a RGB or RGBA image). + * + * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the + * chunk type to determine whether to check the ancillary or the critical + * flags. + */ + if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE)) + { + if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) + return; + + else + png_chunk_error(png_ptr, "CRC error"); + } + + /* Otherwise, we (optionally) emit a warning and use the chunk. */ + else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)) + png_chunk_warning(png_ptr, "CRC error"); + } +#endif + + /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its + * own copy of the palette. This has the side effect that when png_start_row + * is called (this happens after any call to png_read_update_info) the + * info_ptr palette gets changed. This is extremely unexpected and + * confusing. + * + * Fix this by not sharing the palette in this way. + */ + png_set_PLTE(png_ptr, info_ptr, palette, num); + + /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before + * IDAT. Prior to 1.6.0 this was not checked; instead the code merely + * checked the apparent validity of a tRNS chunk inserted before PLTE on a + * palette PNG. 1.6.0 attempts to rigorously follow the standard and + * therefore does a benign error if the erroneous condition is detected *and* + * cancels the tRNS if the benign error returns. The alternative is to + * amend the standard since it would be rather hypocritical of the standards + * maintainers to ignore it. + */ +#ifdef PNG_READ_tRNS_SUPPORTED + if (png_ptr->num_trans > 0 || + (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)) + { + /* Cancel this because otherwise it would be used if the transforms + * require it. Don't cancel the 'valid' flag because this would prevent + * detection of duplicate chunks. + */ + png_ptr->num_trans = 0; + + if (info_ptr != NULL) + info_ptr->num_trans = 0; + + png_chunk_benign_error(png_ptr, "tRNS must be after"); + } +#endif + +#ifdef PNG_READ_hIST_SUPPORTED + if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) + png_chunk_benign_error(png_ptr, "hIST must be after"); +#endif + +#ifdef PNG_READ_bKGD_SUPPORTED + if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) + png_chunk_benign_error(png_ptr, "bKGD must be after"); +#endif +} + +void /* PRIVATE */ +png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_debug(1, "in png_handle_IEND"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT)) + png_chunk_error(png_ptr, "out of place"); + + png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND); + + png_crc_finish(png_ptr, length); + + if (length != 0) + png_chunk_benign_error(png_ptr, "invalid"); + + PNG_UNUSED(info_ptr) +} + +#ifdef PNG_READ_gAMA_SUPPORTED +void /* PRIVATE */ +png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_fixed_point igamma; + png_byte buf[4]; + + png_debug(1, "in png_handle_gAMA"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + if (length != 4) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, buf, 4); + + if (png_crc_finish(png_ptr, 0)) + return; + + igamma = png_get_fixed_point(NULL, buf); + + png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma); + png_colorspace_sync(png_ptr, info_ptr); +} +#endif + +#ifdef PNG_READ_sBIT_SUPPORTED +void /* PRIVATE */ +png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + unsigned int truelen, i; + png_byte sample_depth; + png_byte buf[4]; + + png_debug(1, "in png_handle_sBIT"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + truelen = 3; + sample_depth = 8; + } + + else + { + truelen = png_ptr->channels; + sample_depth = png_ptr->bit_depth; + } + + if (length != truelen || length > 4) + { + png_chunk_benign_error(png_ptr, "invalid"); + png_crc_finish(png_ptr, length); + return; + } + + buf[0] = buf[1] = buf[2] = buf[3] = sample_depth; + png_crc_read(png_ptr, buf, truelen); + + if (png_crc_finish(png_ptr, 0)) + return; + + for (i=0; i<truelen; ++i) + if (buf[i] == 0 || buf[i] > sample_depth) + { + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) + { + png_ptr->sig_bit.red = buf[0]; + png_ptr->sig_bit.green = buf[1]; + png_ptr->sig_bit.blue = buf[2]; + png_ptr->sig_bit.alpha = buf[3]; + } + + else + { + png_ptr->sig_bit.gray = buf[0]; + png_ptr->sig_bit.red = buf[0]; + png_ptr->sig_bit.green = buf[0]; + png_ptr->sig_bit.blue = buf[0]; + png_ptr->sig_bit.alpha = buf[1]; + } + + png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit)); +} +#endif + +#ifdef PNG_READ_cHRM_SUPPORTED +void /* PRIVATE */ +png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_byte buf[32]; + png_xy xy; + + png_debug(1, "in png_handle_cHRM"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + if (length != 32) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, buf, 32); + + if (png_crc_finish(png_ptr, 0)) + return; + + xy.whitex = png_get_fixed_point(NULL, buf); + xy.whitey = png_get_fixed_point(NULL, buf + 4); + xy.redx = png_get_fixed_point(NULL, buf + 8); + xy.redy = png_get_fixed_point(NULL, buf + 12); + xy.greenx = png_get_fixed_point(NULL, buf + 16); + xy.greeny = png_get_fixed_point(NULL, buf + 20); + xy.bluex = png_get_fixed_point(NULL, buf + 24); + xy.bluey = png_get_fixed_point(NULL, buf + 28); + + if (xy.whitex == PNG_FIXED_ERROR || + xy.whitey == PNG_FIXED_ERROR || + xy.redx == PNG_FIXED_ERROR || + xy.redy == PNG_FIXED_ERROR || + xy.greenx == PNG_FIXED_ERROR || + xy.greeny == PNG_FIXED_ERROR || + xy.bluex == PNG_FIXED_ERROR || + xy.bluey == PNG_FIXED_ERROR) + { + png_chunk_benign_error(png_ptr, "invalid values"); + return; + } + + /* If a colorspace error has already been output skip this chunk */ + if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) + return; + + if (png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) + { + png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; + png_colorspace_sync(png_ptr, info_ptr); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; + (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy, + 1/*prefer cHRM values*/); + png_colorspace_sync(png_ptr, info_ptr); +} +#endif + +#ifdef PNG_READ_sRGB_SUPPORTED +void /* PRIVATE */ +png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_byte intent; + + png_debug(1, "in png_handle_sRGB"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + if (length != 1) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, &intent, 1); + + if (png_crc_finish(png_ptr, 0)) + return; + + /* If a colorspace error has already been output skip this chunk */ + if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) + return; + + /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect + * this. + */ + if (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) + { + png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; + png_colorspace_sync(png_ptr, info_ptr); + png_chunk_benign_error(png_ptr, "too many profiles"); + return; + } + + (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent); + png_colorspace_sync(png_ptr, info_ptr); +} +#endif /* PNG_READ_sRGB_SUPPORTED */ + +#ifdef PNG_READ_iCCP_SUPPORTED +void /* PRIVATE */ +png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +/* Note: this does not properly handle profiles that are > 64K under DOS */ +{ + png_const_charp errmsg = NULL; /* error message output, or no error */ + int finished = 0; /* crc checked */ + + png_debug(1, "in png_handle_iCCP"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + /* Consistent with all the above colorspace handling an obviously *invalid* + * chunk is just ignored, so does not invalidate the color space. An + * alternative is to set the 'invalid' flags at the start of this routine + * and only clear them in they were not set before and all the tests pass. + * The minimum 'deflate' stream is assumed to be just the 2 byte header and 4 + * byte checksum. The keyword must be one character and there is a + * terminator (0) byte and the compression method. + */ + if (length < 9) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "too short"); + return; + } + + /* If a colorspace error has already been output skip this chunk */ + if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) + { + png_crc_finish(png_ptr, length); + return; + } + + /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect + * this. + */ + if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0) + { + uInt read_length, keyword_length; + char keyword[81]; + + /* Find the keyword; the keyword plus separator and compression method + * bytes can be at most 81 characters long. + */ + read_length = 81; /* maximum */ + if (read_length > length) + read_length = (uInt)length; + + png_crc_read(png_ptr, (png_bytep)keyword, read_length); + length -= read_length; + + keyword_length = 0; + while (keyword_length < 80 && keyword_length < read_length && + keyword[keyword_length] != 0) + ++keyword_length; + + /* TODO: make the keyword checking common */ + if (keyword_length >= 1 && keyword_length <= 79) + { + /* We only understand '0' compression - deflate - so if we get a + * different value we can't safely decode the chunk. + */ + if (keyword_length+1 < read_length && + keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE) + { + read_length -= keyword_length+2; + + if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK) + { + Byte profile_header[132]; + Byte local_buffer[PNG_INFLATE_BUF_SIZE]; + png_alloc_size_t size = (sizeof profile_header); + + png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2); + png_ptr->zstream.avail_in = read_length; + (void)png_inflate_read(png_ptr, local_buffer, + (sizeof local_buffer), &length, profile_header, &size, + 0/*finish: don't, because the output is too small*/); + + if (size == 0) + { + /* We have the ICC profile header; do the basic header checks. + */ + const png_uint_32 profile_length = + png_get_uint_32(profile_header); + + if (png_icc_check_length(png_ptr, &png_ptr->colorspace, + keyword, profile_length)) + { + /* The length is apparently ok, so we can check the 132 + * byte header. + */ + if (png_icc_check_header(png_ptr, &png_ptr->colorspace, + keyword, profile_length, profile_header, + png_ptr->color_type)) + { + /* Now read the tag table; a variable size buffer is + * needed at this point, allocate one for the whole + * profile. The header check has already validated + * that none of these stuff will overflow. + */ + const png_uint_32 tag_count = png_get_uint_32( + profile_header+128); + png_bytep profile = png_read_buffer(png_ptr, + profile_length, 2/*silent*/); + + if (profile != NULL) + { + memcpy(profile, profile_header, + (sizeof profile_header)); + + size = 12 * tag_count; + + (void)png_inflate_read(png_ptr, local_buffer, + (sizeof local_buffer), &length, + profile + (sizeof profile_header), &size, 0); + + /* Still expect a buffer error because we expect + * there to be some tag data! + */ + if (size == 0) + { + if (png_icc_check_tag_table(png_ptr, + &png_ptr->colorspace, keyword, profile_length, + profile)) + { + /* The profile has been validated for basic + * security issues, so read the whole thing in. + */ + size = profile_length - (sizeof profile_header) + - 12 * tag_count; + + (void)png_inflate_read(png_ptr, local_buffer, + (sizeof local_buffer), &length, + profile + (sizeof profile_header) + + 12 * tag_count, &size, 1/*finish*/); + + if (length > 0 && !(png_ptr->flags & + PNG_FLAG_BENIGN_ERRORS_WARN)) + errmsg = "extra compressed data"; + + /* But otherwise allow extra data: */ + else if (size == 0) + { + if (length > 0) + { + /* This can be handled completely, so + * keep going. + */ + png_chunk_warning(png_ptr, + "extra compressed data"); + } + + png_crc_finish(png_ptr, length); + finished = 1; + +# ifdef PNG_sRGB_SUPPORTED + /* Check for a match against sRGB */ + png_icc_set_sRGB(png_ptr, + &png_ptr->colorspace, profile, + png_ptr->zstream.adler); +# endif + + /* Steal the profile for info_ptr. */ + if (info_ptr != NULL) + { + png_free_data(png_ptr, info_ptr, + PNG_FREE_ICCP, 0); + + info_ptr->iccp_name = png_voidcast(char*, + png_malloc_base(png_ptr, + keyword_length+1)); + if (info_ptr->iccp_name != NULL) + { + memcpy(info_ptr->iccp_name, keyword, + keyword_length+1); + info_ptr->iccp_proflen = + profile_length; + info_ptr->iccp_profile = profile; + png_ptr->read_buffer = NULL; /*steal*/ + info_ptr->free_me |= PNG_FREE_ICCP; + info_ptr->valid |= PNG_INFO_iCCP; + } + + else + { + png_ptr->colorspace.flags |= + PNG_COLORSPACE_INVALID; + errmsg = "out of memory"; + } + } + + /* else the profile remains in the read + * buffer which gets reused for subsequent + * chunks. + */ + + if (info_ptr != NULL) + png_colorspace_sync(png_ptr, info_ptr); + + if (errmsg == NULL) + { + png_ptr->zowner = 0; + return; + } + } + + else if (size > 0) + errmsg = "truncated"; + + else + errmsg = png_ptr->zstream.msg; + } + + /* else png_icc_check_tag_table output an error */ + } + + else /* profile truncated */ + errmsg = png_ptr->zstream.msg; + } + + else + errmsg = "out of memory"; + } + + /* else png_icc_check_header output an error */ + } + + /* else png_icc_check_length output an error */ + } + + else /* profile truncated */ + errmsg = png_ptr->zstream.msg; + + /* Release the stream */ + png_ptr->zowner = 0; + } + + else /* png_inflate_claim failed */ + errmsg = png_ptr->zstream.msg; + } + + else + errmsg = "bad compression method"; /* or missing */ + } + + else + errmsg = "bad keyword"; + } + + else + errmsg = "too many profiles"; + + /* Failure: the reason is in 'errmsg' */ + if (finished == 0) + png_crc_finish(png_ptr, length); + + png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; + png_colorspace_sync(png_ptr, info_ptr); + if (errmsg != NULL) /* else already output */ + png_chunk_benign_error(png_ptr, errmsg); +} +#endif /* PNG_READ_iCCP_SUPPORTED */ + +#ifdef PNG_READ_sPLT_SUPPORTED +void /* PRIVATE */ +png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +/* Note: this does not properly handle chunks that are > 64K under DOS */ +{ + png_bytep entry_start, buffer; + png_sPLT_t new_palette; + png_sPLT_entryp pp; + png_uint_32 data_length; + int entry_size, i; + png_uint_32 skip = 0; + png_uint_32 dl; + png_size_t max_dl; + + png_debug(1, "in png_handle_sPLT"); + +#ifdef PNG_USER_LIMITS_SUPPORTED + if (png_ptr->user_chunk_cache_max != 0) + { + if (png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + return; + } + + if (--png_ptr->user_chunk_cache_max == 1) + { + png_warning(png_ptr, "No space in chunk cache for sPLT"); + png_crc_finish(png_ptr, length); + return; + } + } +#endif + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + +#ifdef PNG_MAX_MALLOC_64K + if (length > 65535U) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "too large to fit in memory"); + return; + } +#endif + + buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); + if (buffer == NULL) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of memory"); + return; + } + + + /* WARNING: this may break if size_t is less than 32 bits; it is assumed + * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a + * potential breakage point if the types in pngconf.h aren't exactly right. + */ + png_crc_read(png_ptr, buffer, length); + + if (png_crc_finish(png_ptr, skip)) + return; + + buffer[length] = 0; + + for (entry_start = buffer; *entry_start; entry_start++) + /* Empty loop to find end of name */ ; + + ++entry_start; + + /* A sample depth should follow the separator, and we should be on it */ + if (entry_start > buffer + length - 2) + { + png_warning(png_ptr, "malformed sPLT chunk"); + return; + } + + new_palette.depth = *entry_start++; + entry_size = (new_palette.depth == 8 ? 6 : 10); + /* This must fit in a png_uint_32 because it is derived from the original + * chunk data length. + */ + data_length = length - (png_uint_32)(entry_start - buffer); + + /* Integrity-check the data length */ + if (data_length % entry_size) + { + png_warning(png_ptr, "sPLT chunk has bad length"); + return; + } + + dl = (png_int_32)(data_length / entry_size); + max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry)); + + if (dl > max_dl) + { + png_warning(png_ptr, "sPLT chunk too long"); + return; + } + + new_palette.nentries = (png_int_32)(data_length / entry_size); + + new_palette.entries = (png_sPLT_entryp)png_malloc_warn( + png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry))); + + if (new_palette.entries == NULL) + { + png_warning(png_ptr, "sPLT chunk requires too much memory"); + return; + } + +#ifdef PNG_POINTER_INDEXING_SUPPORTED + for (i = 0; i < new_palette.nentries; i++) + { + pp = new_palette.entries + i; + + if (new_palette.depth == 8) + { + pp->red = *entry_start++; + pp->green = *entry_start++; + pp->blue = *entry_start++; + pp->alpha = *entry_start++; + } + + else + { + pp->red = png_get_uint_16(entry_start); entry_start += 2; + pp->green = png_get_uint_16(entry_start); entry_start += 2; + pp->blue = png_get_uint_16(entry_start); entry_start += 2; + pp->alpha = png_get_uint_16(entry_start); entry_start += 2; + } + + pp->frequency = png_get_uint_16(entry_start); entry_start += 2; + } +#else + pp = new_palette.entries; + + for (i = 0; i < new_palette.nentries; i++) + { + + if (new_palette.depth == 8) + { + pp[i].red = *entry_start++; + pp[i].green = *entry_start++; + pp[i].blue = *entry_start++; + pp[i].alpha = *entry_start++; + } + + else + { + pp[i].red = png_get_uint_16(entry_start); entry_start += 2; + pp[i].green = png_get_uint_16(entry_start); entry_start += 2; + pp[i].blue = png_get_uint_16(entry_start); entry_start += 2; + pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2; + } + + pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2; + } +#endif + + /* Discard all chunk data except the name and stash that */ + new_palette.name = (png_charp)buffer; + + png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); + + png_free(png_ptr, new_palette.entries); +} +#endif /* PNG_READ_sPLT_SUPPORTED */ + +#ifdef PNG_READ_tRNS_SUPPORTED +void /* PRIVATE */ +png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_byte readbuf[PNG_MAX_PALETTE_LENGTH]; + + png_debug(1, "in png_handle_tRNS"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) + { + png_byte buf[2]; + + if (length != 2) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, buf, 2); + png_ptr->num_trans = 1; + png_ptr->trans_color.gray = png_get_uint_16(buf); + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) + { + png_byte buf[6]; + + if (length != 6) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, buf, length); + png_ptr->num_trans = 1; + png_ptr->trans_color.red = png_get_uint_16(buf); + png_ptr->trans_color.green = png_get_uint_16(buf + 2); + png_ptr->trans_color.blue = png_get_uint_16(buf + 4); + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (!(png_ptr->mode & PNG_HAVE_PLTE)) + { + /* TODO: is this actually an error in the ISO spec? */ + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + if (length > png_ptr->num_palette || length > PNG_MAX_PALETTE_LENGTH || + length == 0) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, readbuf, length); + png_ptr->num_trans = (png_uint_16)length; + } + + else + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid with alpha channel"); + return; + } + + if (png_crc_finish(png_ptr, 0)) + { + png_ptr->num_trans = 0; + return; + } + + /* TODO: this is a horrible side effect in the palette case because the + * png_struct ends up with a pointer to the tRNS buffer owned by the + * png_info. Fix this. + */ + png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans, + &(png_ptr->trans_color)); +} +#endif + +#ifdef PNG_READ_bKGD_SUPPORTED +void /* PRIVATE */ +png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + unsigned int truelen; + png_byte buf[6]; + png_color_16 background; + + png_debug(1, "in png_handle_bKGD"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if ((png_ptr->mode & PNG_HAVE_IDAT) || + (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && + !(png_ptr->mode & PNG_HAVE_PLTE))) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + truelen = 1; + + else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR) + truelen = 6; + + else + truelen = 2; + + if (length != truelen) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, buf, truelen); + + if (png_crc_finish(png_ptr, 0)) + return; + + /* We convert the index value into RGB components so that we can allow + * arbitrary RGB values for background when we have transparency, and + * so it is easy to determine the RGB values of the background color + * from the info_ptr struct. + */ + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + background.index = buf[0]; + + if (info_ptr && info_ptr->num_palette) + { + if (buf[0] >= info_ptr->num_palette) + { + png_chunk_benign_error(png_ptr, "invalid index"); + return; + } + + background.red = (png_uint_16)png_ptr->palette[buf[0]].red; + background.green = (png_uint_16)png_ptr->palette[buf[0]].green; + background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue; + } + + else + background.red = background.green = background.blue = 0; + + background.gray = 0; + } + + else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */ + { + background.index = 0; + background.red = + background.green = + background.blue = + background.gray = png_get_uint_16(buf); + } + + else + { + background.index = 0; + background.red = png_get_uint_16(buf); + background.green = png_get_uint_16(buf + 2); + background.blue = png_get_uint_16(buf + 4); + background.gray = 0; + } + + png_set_bKGD(png_ptr, info_ptr, &background); +} +#endif + +#ifdef PNG_READ_hIST_SUPPORTED +void /* PRIVATE */ +png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + unsigned int num, i; + png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH]; + + png_debug(1, "in png_handle_hIST"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if ((png_ptr->mode & PNG_HAVE_IDAT) || !(png_ptr->mode & PNG_HAVE_PLTE)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + num = length / 2 ; + + if (num != png_ptr->num_palette || num > PNG_MAX_PALETTE_LENGTH) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + for (i = 0; i < num; i++) + { + png_byte buf[2]; + + png_crc_read(png_ptr, buf, 2); + readbuf[i] = png_get_uint_16(buf); + } + + if (png_crc_finish(png_ptr, 0)) + return; + + png_set_hIST(png_ptr, info_ptr, readbuf); +} +#endif + +#ifdef PNG_READ_pHYs_SUPPORTED +void /* PRIVATE */ +png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_byte buf[9]; + png_uint_32 res_x, res_y; + int unit_type; + + png_debug(1, "in png_handle_pHYs"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + if (length != 9) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, buf, 9); + + if (png_crc_finish(png_ptr, 0)) + return; + + res_x = png_get_uint_32(buf); + res_y = png_get_uint_32(buf + 4); + unit_type = buf[8]; + png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type); +} +#endif + +#ifdef PNG_READ_oFFs_SUPPORTED +void /* PRIVATE */ +png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_byte buf[9]; + png_int_32 offset_x, offset_y; + int unit_type; + + png_debug(1, "in png_handle_oFFs"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + if (length != 9) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, buf, 9); + + if (png_crc_finish(png_ptr, 0)) + return; + + offset_x = png_get_int_32(buf); + offset_y = png_get_int_32(buf + 4); + unit_type = buf[8]; + png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type); +} +#endif + +#ifdef PNG_READ_pCAL_SUPPORTED +/* Read the pCAL chunk (described in the PNG Extensions document) */ +void /* PRIVATE */ +png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_int_32 X0, X1; + png_byte type, nparams; + png_bytep buffer, buf, units, endptr; + png_charpp params; + int i; + + png_debug(1, "in png_handle_pCAL"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", + length + 1); + + buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); + + if (buffer == NULL) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of memory"); + return; + } + + png_crc_read(png_ptr, buffer, length); + + if (png_crc_finish(png_ptr, 0)) + return; + + buffer[length] = 0; /* Null terminate the last string */ + + png_debug(3, "Finding end of pCAL purpose string"); + for (buf = buffer; *buf; buf++) + /* Empty loop */ ; + + endptr = buffer + length; + + /* We need to have at least 12 bytes after the purpose string + * in order to get the parameter information. + */ + if (endptr <= buf + 12) + { + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_debug(3, "Reading pCAL X0, X1, type, nparams, and units"); + X0 = png_get_int_32((png_bytep)buf+1); + X1 = png_get_int_32((png_bytep)buf+5); + type = buf[9]; + nparams = buf[10]; + units = buf + 11; + + png_debug(3, "Checking pCAL equation type and number of parameters"); + /* Check that we have the right number of parameters for known + * equation types. + */ + if ((type == PNG_EQUATION_LINEAR && nparams != 2) || + (type == PNG_EQUATION_BASE_E && nparams != 3) || + (type == PNG_EQUATION_ARBITRARY && nparams != 3) || + (type == PNG_EQUATION_HYPERBOLIC && nparams != 4)) + { + png_chunk_benign_error(png_ptr, "invalid parameter count"); + return; + } + + else if (type >= PNG_EQUATION_LAST) + { + png_chunk_benign_error(png_ptr, "unrecognized equation type"); + } + + for (buf = units; *buf; buf++) + /* Empty loop to move past the units string. */ ; + + png_debug(3, "Allocating pCAL parameters array"); + + params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, + nparams * (sizeof (png_charp)))); + + if (params == NULL) + { + png_chunk_benign_error(png_ptr, "out of memory"); + return; + } + + /* Get pointers to the start of each parameter string. */ + for (i = 0; i < nparams; i++) + { + buf++; /* Skip the null string terminator from previous parameter. */ + + png_debug1(3, "Reading pCAL parameter %d", i); + + for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++) + /* Empty loop to move past each parameter string */ ; + + /* Make sure we haven't run out of data yet */ + if (buf > endptr) + { + png_free(png_ptr, params); + png_chunk_benign_error(png_ptr, "invalid data"); + return; + } + } + + png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams, + (png_charp)units, params); + + png_free(png_ptr, params); +} +#endif + +#ifdef PNG_READ_sCAL_SUPPORTED +/* Read the sCAL chunk */ +void /* PRIVATE */ +png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_bytep buffer; + png_size_t i; + int state; + + png_debug(1, "in png_handle_sCAL"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (png_ptr->mode & PNG_HAVE_IDAT) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of place"); + return; + } + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + /* Need unit type, width, \0, height: minimum 4 bytes */ + else if (length < 4) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", + length + 1); + + buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); + + if (buffer == NULL) + { + png_chunk_benign_error(png_ptr, "out of memory"); + png_crc_finish(png_ptr, length); + return; + } + + png_crc_read(png_ptr, buffer, length); + buffer[length] = 0; /* Null terminate the last string */ + + if (png_crc_finish(png_ptr, 0)) + return; + + /* Validate the unit. */ + if (buffer[0] != 1 && buffer[0] != 2) + { + png_chunk_benign_error(png_ptr, "invalid unit"); + return; + } + + /* Validate the ASCII numbers, need two ASCII numbers separated by + * a '\0' and they need to fit exactly in the chunk data. + */ + i = 1; + state = 0; + + if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) || + i >= length || buffer[i++] != 0) + png_chunk_benign_error(png_ptr, "bad width format"); + + else if (!PNG_FP_IS_POSITIVE(state)) + png_chunk_benign_error(png_ptr, "non-positive width"); + + else + { + png_size_t heighti = i; + + state = 0; + if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) || + i != length) + png_chunk_benign_error(png_ptr, "bad height format"); + + else if (!PNG_FP_IS_POSITIVE(state)) + png_chunk_benign_error(png_ptr, "non-positive height"); + + else + /* This is the (only) success case. */ + png_set_sCAL_s(png_ptr, info_ptr, buffer[0], + (png_charp)buffer+1, (png_charp)buffer+heighti); + } +} +#endif + +#ifdef PNG_READ_tIME_SUPPORTED +void /* PRIVATE */ +png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_byte buf[7]; + png_time mod_time; + + png_debug(1, "in png_handle_tIME"); + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "duplicate"); + return; + } + + if (png_ptr->mode & PNG_HAVE_IDAT) + png_ptr->mode |= PNG_AFTER_IDAT; + + if (length != 7) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "invalid"); + return; + } + + png_crc_read(png_ptr, buf, 7); + + if (png_crc_finish(png_ptr, 0)) + return; + + mod_time.second = buf[6]; + mod_time.minute = buf[5]; + mod_time.hour = buf[4]; + mod_time.day = buf[3]; + mod_time.month = buf[2]; + mod_time.year = png_get_uint_16(buf); + + png_set_tIME(png_ptr, info_ptr, &mod_time); +} +#endif + +#ifdef PNG_READ_tEXt_SUPPORTED +/* Note: this does not properly handle chunks that are > 64K under DOS */ +void /* PRIVATE */ +png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_text text_info; + png_bytep buffer; + png_charp key; + png_charp text; + png_uint_32 skip = 0; + + png_debug(1, "in png_handle_tEXt"); + +#ifdef PNG_USER_LIMITS_SUPPORTED + if (png_ptr->user_chunk_cache_max != 0) + { + if (png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + return; + } + + if (--png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "no space in chunk cache"); + return; + } + } +#endif + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + if (png_ptr->mode & PNG_HAVE_IDAT) + png_ptr->mode |= PNG_AFTER_IDAT; + +#ifdef PNG_MAX_MALLOC_64K + if (length > 65535U) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "too large to fit in memory"); + return; + } +#endif + + buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); + + if (buffer == NULL) + { + png_chunk_benign_error(png_ptr, "out of memory"); + return; + } + + png_crc_read(png_ptr, buffer, length); + + if (png_crc_finish(png_ptr, skip)) + return; + + key = (png_charp)buffer; + key[length] = 0; + + for (text = key; *text; text++) + /* Empty loop to find end of key */ ; + + if (text != key + length) + text++; + + text_info.compression = PNG_TEXT_COMPRESSION_NONE; + text_info.key = key; + text_info.lang = NULL; + text_info.lang_key = NULL; + text_info.itxt_length = 0; + text_info.text = text; + text_info.text_length = strlen(text); + + if (png_set_text_2(png_ptr, info_ptr, &text_info, 1)) + png_warning(png_ptr, "Insufficient memory to process text chunk"); +} +#endif + +#ifdef PNG_READ_zTXt_SUPPORTED +/* Note: this does not correctly handle chunks that are > 64K under DOS */ +void /* PRIVATE */ +png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_const_charp errmsg = NULL; + png_bytep buffer; + png_uint_32 keyword_length; + + png_debug(1, "in png_handle_zTXt"); + +#ifdef PNG_USER_LIMITS_SUPPORTED + if (png_ptr->user_chunk_cache_max != 0) + { + if (png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + return; + } + + if (--png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "no space in chunk cache"); + return; + } + } +#endif + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + if (png_ptr->mode & PNG_HAVE_IDAT) + png_ptr->mode |= PNG_AFTER_IDAT; + + buffer = png_read_buffer(png_ptr, length, 2/*silent*/); + + if (buffer == NULL) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of memory"); + return; + } + + png_crc_read(png_ptr, buffer, length); + + if (png_crc_finish(png_ptr, 0)) + return; + + /* TODO: also check that the keyword contents match the spec! */ + for (keyword_length = 0; + keyword_length < length && buffer[keyword_length] != 0; + ++keyword_length) + /* Empty loop to find end of name */ ; + + if (keyword_length > 79 || keyword_length < 1) + errmsg = "bad keyword"; + + /* zTXt must have some LZ data after the keyword, although it may expand to + * zero bytes; we need a '\0' at the end of the keyword, the compression type + * then the LZ data: + */ + else if (keyword_length + 3 > length) + errmsg = "truncated"; + + else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE) + errmsg = "unknown compression type"; + + else + { + png_alloc_size_t uncompressed_length = PNG_SIZE_MAX; + + /* TODO: at present png_decompress_chunk imposes a single application + * level memory limit, this should be split to different values for iCCP + * and text chunks. + */ + if (png_decompress_chunk(png_ptr, length, keyword_length+2, + &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) + { + png_text text; + + /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except + * for the extra compression type byte and the fact that it isn't + * necessarily '\0' terminated. + */ + buffer = png_ptr->read_buffer; + buffer[uncompressed_length+(keyword_length+2)] = 0; + + text.compression = PNG_TEXT_COMPRESSION_zTXt; + text.key = (png_charp)buffer; + text.text = (png_charp)(buffer + keyword_length+2); + text.text_length = uncompressed_length; + text.itxt_length = 0; + text.lang = NULL; + text.lang_key = NULL; + + if (png_set_text_2(png_ptr, info_ptr, &text, 1)) + errmsg = "insufficient memory"; + } + + else + errmsg = png_ptr->zstream.msg; + } + + if (errmsg != NULL) + png_chunk_benign_error(png_ptr, errmsg); +} +#endif + +#ifdef PNG_READ_iTXt_SUPPORTED +/* Note: this does not correctly handle chunks that are > 64K under DOS */ +void /* PRIVATE */ +png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) +{ + png_const_charp errmsg = NULL; + png_bytep buffer; + png_uint_32 prefix_length; + + png_debug(1, "in png_handle_iTXt"); + +#ifdef PNG_USER_LIMITS_SUPPORTED + if (png_ptr->user_chunk_cache_max != 0) + { + if (png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + return; + } + + if (--png_ptr->user_chunk_cache_max == 1) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "no space in chunk cache"); + return; + } + } +#endif + + if (!(png_ptr->mode & PNG_HAVE_IHDR)) + png_chunk_error(png_ptr, "missing IHDR"); + + if (png_ptr->mode & PNG_HAVE_IDAT) + png_ptr->mode |= PNG_AFTER_IDAT; + + buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); + + if (buffer == NULL) + { + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "out of memory"); + return; + } + + png_crc_read(png_ptr, buffer, length); + + if (png_crc_finish(png_ptr, 0)) + return; + + /* First the keyword. */ + for (prefix_length=0; + prefix_length < length && buffer[prefix_length] != 0; + ++prefix_length) + /* Empty loop */ ; + + /* Perform a basic check on the keyword length here. */ + if (prefix_length > 79 || prefix_length < 1) + errmsg = "bad keyword"; + + /* Expect keyword, compression flag, compression type, language, translated + * keyword (both may be empty but are 0 terminated) then the text, which may + * be empty. + */ + else if (prefix_length + 5 > length) + errmsg = "truncated"; + + else if (buffer[prefix_length+1] == 0 || + (buffer[prefix_length+1] == 1 && + buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE)) + { + int compressed = buffer[prefix_length+1] != 0; + png_uint_32 language_offset, translated_keyword_offset; + png_alloc_size_t uncompressed_length = 0; + + /* Now the language tag */ + prefix_length += 3; + language_offset = prefix_length; + + for (; prefix_length < length && buffer[prefix_length] != 0; + ++prefix_length) + /* Empty loop */ ; + + /* WARNING: the length may be invalid here, this is checked below. */ + translated_keyword_offset = ++prefix_length; + + for (; prefix_length < length && buffer[prefix_length] != 0; + ++prefix_length) + /* Empty loop */ ; + + /* prefix_length should now be at the trailing '\0' of the translated + * keyword, but it may already be over the end. None of this arithmetic + * can overflow because chunks are at most 2^31 bytes long, but on 16-bit + * systems the available allocaton may overflow. + */ + ++prefix_length; + + if (!compressed && prefix_length <= length) + uncompressed_length = length - prefix_length; + + else if (compressed && prefix_length < length) + { + uncompressed_length = PNG_SIZE_MAX; + + /* TODO: at present png_decompress_chunk imposes a single application + * level memory limit, this should be split to different values for + * iCCP and text chunks. + */ + if (png_decompress_chunk(png_ptr, length, prefix_length, + &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) + buffer = png_ptr->read_buffer; + + else + errmsg = png_ptr->zstream.msg; + } + + else + errmsg = "truncated"; + + if (errmsg == NULL) + { + png_text text; + + buffer[uncompressed_length+prefix_length] = 0; + + if (compressed != 0) + text.compression = PNG_ITXT_COMPRESSION_NONE; + + else + text.compression = PNG_ITXT_COMPRESSION_zTXt; + + text.key = (png_charp)buffer; + text.lang = (png_charp)buffer + language_offset; + text.lang_key = (png_charp)buffer + translated_keyword_offset; + text.text = (png_charp)buffer + prefix_length; + text.text_length = 0; + text.itxt_length = uncompressed_length; + + if (png_set_text_2(png_ptr, info_ptr, &text, 1)) + errmsg = "insufficient memory"; + } + } + + else + errmsg = "bad compression info"; + + if (errmsg != NULL) + png_chunk_benign_error(png_ptr, errmsg); +} +#endif + +#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED +/* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */ +static int +png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length) +{ + png_alloc_size_t limit = PNG_SIZE_MAX; + + if (png_ptr->unknown_chunk.data != NULL) + { + png_free(png_ptr, png_ptr->unknown_chunk.data); + png_ptr->unknown_chunk.data = NULL; + } + +# ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED + if (png_ptr->user_chunk_malloc_max > 0 && + png_ptr->user_chunk_malloc_max < limit) + limit = png_ptr->user_chunk_malloc_max; + +# elif PNG_USER_CHUNK_MALLOC_MAX > 0 + if (PNG_USER_CHUNK_MALLOC_MAX < limit) + limit = PNG_USER_CHUNK_MALLOC_MAX; +# endif + + if (length <= limit) + { + PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); + /* The following is safe because of the PNG_SIZE_MAX init above */ + png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/; + /* 'mode' is a flag array, only the bottom four bits matter here */ + png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/; + + if (length == 0) + png_ptr->unknown_chunk.data = NULL; + + else + { + /* Do a 'warn' here - it is handled below. */ + png_ptr->unknown_chunk.data = png_voidcast(png_bytep, + png_malloc_warn(png_ptr, length)); + } + } + + if (png_ptr->unknown_chunk.data == NULL && length > 0) + { + /* This is benign because we clean up correctly */ + png_crc_finish(png_ptr, length); + png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits"); + return 0; + } + + else + { + if (length > 0) + png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); + png_crc_finish(png_ptr, 0); + return 1; + } +} +#endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ + +/* Handle an unknown, or known but disabled, chunk */ +void /* PRIVATE */ +png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr, + png_uint_32 length, int keep) +{ + int handled = 0; /* the chunk was handled */ + + png_debug(1, "in png_handle_unknown"); + +#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED + /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing + * the bug which meant that setting a non-default behavior for a specific + * chunk would be ignored (the default was always used unless a user + * callback was installed). + * + * 'keep' is the value from the png_chunk_unknown_handling, the setting for + * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it + * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here. + * This is just an optimization to avoid multiple calls to the lookup + * function. + */ +# ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED +# ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED + keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name); +# endif +# endif + + /* One of the following methods will read the chunk or skip it (at least one + * of these is always defined because this is the only way to switch on + * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) + */ +# ifdef PNG_READ_USER_CHUNKS_SUPPORTED + /* The user callback takes precedence over the chunk keep value, but the + * keep value is still required to validate a save of a critical chunk. + */ + if (png_ptr->read_user_chunk_fn != NULL) + { + if (png_cache_unknown_chunk(png_ptr, length)) + { + /* Callback to user unknown chunk handler */ + int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr, + &png_ptr->unknown_chunk); + + /* ret is: + * negative: An error occured, png_chunk_error will be called. + * zero: The chunk was not handled, the chunk will be discarded + * unless png_set_keep_unknown_chunks has been used to set + * a 'keep' behavior for this particular chunk, in which + * case that will be used. A critical chunk will cause an + * error at this point unless it is to be saved. + * positive: The chunk was handled, libpng will ignore/discard it. + */ + if (ret < 0) + png_chunk_error(png_ptr, "error in user chunk"); + + else if (ret == 0) + { + /* If the keep value is 'default' or 'never' override it, but + * still error out on critical chunks unless the keep value is + * 'always' While this is weird it is the behavior in 1.4.12. + * A possible improvement would be to obey the value set for the + * chunk, but this would be an API change that would probably + * damage some applications. + * + * The png_app_warning below catches the case that matters, where + * the application has not set specific save or ignore for this + * chunk or global save or ignore. + */ + if (keep < PNG_HANDLE_CHUNK_IF_SAFE) + { +# ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED + if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE) + { + png_chunk_warning(png_ptr, "Saving unknown chunk:"); + png_app_warning(png_ptr, + "forcing save of an unhandled chunk;" + " please call png_set_keep_unknown_chunks"); + /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */ + } +# endif + keep = PNG_HANDLE_CHUNK_IF_SAFE; + } + } + + else /* chunk was handled */ + { + handled = 1; + /* Critical chunks can be safely discarded at this point. */ + keep = PNG_HANDLE_CHUNK_NEVER; + } + } + + else + keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */ + } + + else + /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */ +# endif /* PNG_READ_USER_CHUNKS_SUPPORTED */ + +# ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED + { + /* keep is currently just the per-chunk setting, if there was no + * setting change it to the global default now (not that this may + * still be AS_DEFAULT) then obtain the cache of the chunk if required, + * if not simply skip the chunk. + */ + if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) + keep = png_ptr->unknown_default; + + if (keep == PNG_HANDLE_CHUNK_ALWAYS || + (keep == PNG_HANDLE_CHUNK_IF_SAFE && + PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) + { + if (!png_cache_unknown_chunk(png_ptr, length)) + keep = PNG_HANDLE_CHUNK_NEVER; + } + + else + png_crc_finish(png_ptr, length); + } +# else +# ifndef PNG_READ_USER_CHUNKS_SUPPORTED +# error no method to support READ_UNKNOWN_CHUNKS +# endif + + { + /* If here there is no read callback pointer set and no support is + * compiled in to just save the unknown chunks, so simply skip this + * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then + * the app has erroneously asked for unknown chunk saving when there + * is no support. + */ + if (keep > PNG_HANDLE_CHUNK_NEVER) + png_app_error(png_ptr, "no unknown chunk support available"); + + png_crc_finish(png_ptr, length); + } +# endif + +# ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED + /* Now store the chunk in the chunk list if appropriate, and if the limits + * permit it. + */ + if (keep == PNG_HANDLE_CHUNK_ALWAYS || + (keep == PNG_HANDLE_CHUNK_IF_SAFE && + PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) + { +# ifdef PNG_USER_LIMITS_SUPPORTED + switch (png_ptr->user_chunk_cache_max) + { + case 2: + png_ptr->user_chunk_cache_max = 1; + png_chunk_benign_error(png_ptr, "no space in chunk cache"); + /* FALL THROUGH */ + case 1: + /* NOTE: prior to 1.6.0 this case resulted in an unknown critical + * chunk being skipped, now there will be a hard error below. + */ + break; + + default: /* not at limit */ + --(png_ptr->user_chunk_cache_max); + /* FALL THROUGH */ + case 0: /* no limit */ +# endif /* PNG_USER_LIMITS_SUPPORTED */ + /* Here when the limit isn't reached or when limits are compiled + * out; store the chunk. + */ + png_set_unknown_chunks(png_ptr, info_ptr, + &png_ptr->unknown_chunk, 1); + handled = 1; +# ifdef PNG_USER_LIMITS_SUPPORTED + break; + } +# endif + } +# else /* no store support: the chunk must be handled by the user callback */ + PNG_UNUSED(info_ptr) +# endif + + /* Regardless of the error handling below the cached data (if any) can be + * freed now. Notice that the data is not freed if there is a png_error, but + * it will be freed by destroy_read_struct. + */ + if (png_ptr->unknown_chunk.data != NULL) + png_free(png_ptr, png_ptr->unknown_chunk.data); + png_ptr->unknown_chunk.data = NULL; + +#else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ + /* There is no support to read an unknown chunk, so just skip it. */ + png_crc_finish(png_ptr, length); + PNG_UNUSED(info_ptr) + PNG_UNUSED(keep) +#endif /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ + + /* Check for unhandled critical chunks */ + if (!handled && PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) + png_chunk_error(png_ptr, "unhandled critical chunk"); +} + +/* This function is called to verify that a chunk name is valid. + * This function can't have the "critical chunk check" incorporated + * into it, since in the future we will need to be able to call user + * functions to handle unknown critical chunks after we check that + * the chunk name itself is valid. + */ + +/* Bit hacking: the test for an invalid byte in the 4 byte chunk name is: + * + * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) + */ + +void /* PRIVATE */ +png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name) +{ + int i; + + png_debug(1, "in png_check_chunk_name"); + + for (i=1; i<=4; ++i) + { + int c = chunk_name & 0xff; + + if (c < 65 || c > 122 || (c > 90 && c < 97)) + png_chunk_error(png_ptr, "invalid chunk type"); + + chunk_name >>= 8; + } +} + +/* Combines the row recently read in with the existing pixels in the row. This + * routine takes care of alpha and transparency if requested. This routine also + * handles the two methods of progressive display of interlaced images, + * depending on the 'display' value; if 'display' is true then the whole row + * (dp) is filled from the start by replicating the available pixels. If + * 'display' is false only those pixels present in the pass are filled in. + */ +void /* PRIVATE */ +png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display) +{ + unsigned int pixel_depth = png_ptr->transformed_pixel_depth; + png_const_bytep sp = png_ptr->row_buf + 1; + png_uint_32 row_width = png_ptr->width; + unsigned int pass = png_ptr->pass; + png_bytep end_ptr = 0; + png_byte end_byte = 0; + unsigned int end_mask; + + png_debug(1, "in png_combine_row"); + + /* Added in 1.5.6: it should not be possible to enter this routine until at + * least one row has been read from the PNG data and transformed. + */ + if (pixel_depth == 0) + png_error(png_ptr, "internal row logic error"); + + /* Added in 1.5.4: the pixel depth should match the information returned by + * any call to png_read_update_info at this point. Do not continue if we got + * this wrong. + */ + if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes != + PNG_ROWBYTES(pixel_depth, row_width)) + png_error(png_ptr, "internal row size calculation error"); + + /* Don't expect this to ever happen: */ + if (row_width == 0) + png_error(png_ptr, "internal row width error"); + + /* Preserve the last byte in cases where only part of it will be overwritten, + * the multiply below may overflow, we don't care because ANSI-C guarantees + * we get the low bits. + */ + end_mask = (pixel_depth * row_width) & 7; + if (end_mask != 0) + { + /* end_ptr == NULL is a flag to say do nothing */ + end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1; + end_byte = *end_ptr; +# ifdef PNG_READ_PACKSWAP_SUPPORTED + if (png_ptr->transformations & PNG_PACKSWAP) /* little-endian byte */ + end_mask = 0xff << end_mask; + + else /* big-endian byte */ +# endif + end_mask = 0xff >> end_mask; + /* end_mask is now the bits to *keep* from the destination row */ + } + + /* For non-interlaced images this reduces to a memcpy(). A memcpy() + * will also happen if interlacing isn't supported or if the application + * does not call png_set_interlace_handling(). In the latter cases the + * caller just gets a sequence of the unexpanded rows from each interlace + * pass. + */ +#ifdef PNG_READ_INTERLACING_SUPPORTED + if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) && + pass < 6 && (display == 0 || + /* The following copies everything for 'display' on passes 0, 2 and 4. */ + (display == 1 && (pass & 1) != 0))) + { + /* Narrow images may have no bits in a pass; the caller should handle + * this, but this test is cheap: + */ + if (row_width <= PNG_PASS_START_COL(pass)) + return; + + if (pixel_depth < 8) + { + /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit + * into 32 bits, then a single loop over the bytes using the four byte + * values in the 32-bit mask can be used. For the 'display' option the + * expanded mask may also not require any masking within a byte. To + * make this work the PACKSWAP option must be taken into account - it + * simply requires the pixels to be reversed in each byte. + * + * The 'regular' case requires a mask for each of the first 6 passes, + * the 'display' case does a copy for the even passes in the range + * 0..6. This has already been handled in the test above. + * + * The masks are arranged as four bytes with the first byte to use in + * the lowest bits (little-endian) regardless of the order (PACKSWAP or + * not) of the pixels in each byte. + * + * NOTE: the whole of this logic depends on the caller of this function + * only calling it on rows appropriate to the pass. This function only + * understands the 'x' logic; the 'y' logic is handled by the caller. + * + * The following defines allow generation of compile time constant bit + * masks for each pixel depth and each possibility of swapped or not + * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, + * is in the range 0..7; and the result is 1 if the pixel is to be + * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' + * for the block method. + * + * With some compilers a compile time expression of the general form: + * + * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) + * + * Produces warnings with values of 'shift' in the range 33 to 63 + * because the right hand side of the ?: expression is evaluated by + * the compiler even though it isn't used. Microsoft Visual C (various + * versions) and the Intel C compiler are known to do this. To avoid + * this the following macros are used in 1.5.6. This is a temporary + * solution to avoid destabilizing the code during the release process. + */ +# if PNG_USE_COMPILE_TIME_MASKS +# define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) +# define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) +# else +# define PNG_LSR(x,s) ((x)>>(s)) +# define PNG_LSL(x,s) ((x)<<(s)) +# endif +# define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ + PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) +# define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ + PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) + + /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is + * little endian - the first pixel is at bit 0 - however the extra + * parameter 's' can be set to cause the mask position to be swapped + * within each byte, to match the PNG format. This is done by XOR of + * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. + */ +# define PIXEL_MASK(p,x,d,s) \ + (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) + + /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. + */ +# define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) +# define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) + + /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp + * cases the result needs replicating, for the 4-bpp case the above + * generates a full 32 bits. + */ +# define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) + +# define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ + S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ + S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) + +# define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ + B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ + B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) + +#if PNG_USE_COMPILE_TIME_MASKS + /* Utility macros to construct all the masks for a depth/swap + * combination. The 's' parameter says whether the format is PNG + * (big endian bytes) or not. Only the three odd-numbered passes are + * required for the display/block algorithm. + */ +# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ + S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } + +# define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) } + +# define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) + + /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and + * then pass: + */ + static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = + { + /* Little-endian byte masks for PACKSWAP */ + { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, + /* Normal (big-endian byte) masks - PNG format */ + { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } + }; + + /* display_mask has only three entries for the odd passes, so index by + * pass>>1. + */ + static PNG_CONST png_uint_32 display_mask[2][3][3] = + { + /* Little-endian byte masks for PACKSWAP */ + { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, + /* Normal (big-endian byte) masks - PNG format */ + { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } + }; + +# define MASK(pass,depth,display,png)\ + ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ + row_mask[png][DEPTH_INDEX(depth)][pass]) + +#else /* !PNG_USE_COMPILE_TIME_MASKS */ + /* This is the runtime alternative: it seems unlikely that this will + * ever be either smaller or faster than the compile time approach. + */ +# define MASK(pass,depth,display,png)\ + ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) +#endif /* !PNG_USE_COMPILE_TIME_MASKS */ + + /* Use the appropriate mask to copy the required bits. In some cases + * the byte mask will be 0 or 0xff; optimize these cases. row_width is + * the number of pixels, but the code copies bytes, so it is necessary + * to special case the end. + */ + png_uint_32 pixels_per_byte = 8 / pixel_depth; + png_uint_32 mask; + +# ifdef PNG_READ_PACKSWAP_SUPPORTED + if (png_ptr->transformations & PNG_PACKSWAP) + mask = MASK(pass, pixel_depth, display, 0); + + else +# endif + mask = MASK(pass, pixel_depth, display, 1); + + for (;;) + { + png_uint_32 m; + + /* It doesn't matter in the following if png_uint_32 has more than + * 32 bits because the high bits always match those in m<<24; it is, + * however, essential to use OR here, not +, because of this. + */ + m = mask; + mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ + m &= 0xff; + + if (m != 0) /* something to copy */ + { + if (m != 0xff) + *dp = (png_byte)((*dp & ~m) | (*sp & m)); + else + *dp = *sp; + } + + /* NOTE: this may overwrite the last byte with garbage if the image + * is not an exact number of bytes wide; libpng has always done + * this. + */ + if (row_width <= pixels_per_byte) + break; /* May need to restore part of the last byte */ + + row_width -= pixels_per_byte; + ++dp; + ++sp; + } + } + + else /* pixel_depth >= 8 */ + { + unsigned int bytes_to_copy, bytes_to_jump; + + /* Validate the depth - it must be a multiple of 8 */ + if (pixel_depth & 7) + png_error(png_ptr, "invalid user transform pixel depth"); + + pixel_depth >>= 3; /* now in bytes */ + row_width *= pixel_depth; + + /* Regardless of pass number the Adam 7 interlace always results in a + * fixed number of pixels to copy then to skip. There may be a + * different number of pixels to skip at the start though. + */ + { + unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; + + row_width -= offset; + dp += offset; + sp += offset; + } + + /* Work out the bytes to copy. */ + if (display != 0) + { + /* When doing the 'block' algorithm the pixel in the pass gets + * replicated to adjacent pixels. This is why the even (0,2,4,6) + * passes are skipped above - the entire expanded row is copied. + */ + bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; + + /* But don't allow this number to exceed the actual row width. */ + if (bytes_to_copy > row_width) + bytes_to_copy = row_width; + } + + else /* normal row; Adam7 only ever gives us one pixel to copy. */ + bytes_to_copy = pixel_depth; + + /* In Adam7 there is a constant offset between where the pixels go. */ + bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth; + + /* And simply copy these bytes. Some optimization is possible here, + * depending on the value of 'bytes_to_copy'. Special case the low + * byte counts, which we know to be frequent. + * + * Notice that these cases all 'return' rather than 'break' - this + * avoids an unnecessary test on whether to restore the last byte + * below. + */ + switch (bytes_to_copy) + { + case 1: + for (;;) + { + *dp = *sp; + + if (row_width <= bytes_to_jump) + return; + + dp += bytes_to_jump; + sp += bytes_to_jump; + row_width -= bytes_to_jump; + } + + case 2: + /* There is a possibility of a partial copy at the end here; this + * slows the code down somewhat. + */ + do + { + dp[0] = sp[0], dp[1] = sp[1]; + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + } + while (row_width > 1); + + /* And there can only be one byte left at this point: */ + *dp = *sp; + return; + + case 3: + /* This can only be the RGB case, so each copy is exactly one + * pixel and it is not necessary to check for a partial copy. + */ + for(;;) + { + dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2]; + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + } + + default: +#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE + /* Check for double byte alignment and, if possible, use a + * 16-bit copy. Don't attempt this for narrow images - ones that + * are less than an interlace panel wide. Don't attempt it for + * wide bytes_to_copy either - use the memcpy there. + */ + if (bytes_to_copy < 16 /*else use memcpy*/ && + png_isaligned(dp, png_uint_16) && + png_isaligned(sp, png_uint_16) && + bytes_to_copy % (sizeof (png_uint_16)) == 0 && + bytes_to_jump % (sizeof (png_uint_16)) == 0) + { + /* Everything is aligned for png_uint_16 copies, but try for + * png_uint_32 first. + */ + if (png_isaligned(dp, png_uint_32) && + png_isaligned(sp, png_uint_32) && + bytes_to_copy % (sizeof (png_uint_32)) == 0 && + bytes_to_jump % (sizeof (png_uint_32)) == 0) + { + png_uint_32p dp32 = png_aligncast(png_uint_32p,dp); + png_const_uint_32p sp32 = png_aligncastconst( + png_const_uint_32p, sp); + size_t skip = (bytes_to_jump-bytes_to_copy) / + (sizeof (png_uint_32)); + + do + { + size_t c = bytes_to_copy; + do + { + *dp32++ = *sp32++; + c -= (sizeof (png_uint_32)); + } + while (c > 0); + + if (row_width <= bytes_to_jump) + return; + + dp32 += skip; + sp32 += skip; + row_width -= bytes_to_jump; + } + while (bytes_to_copy <= row_width); + + /* Get to here when the row_width truncates the final copy. + * There will be 1-3 bytes left to copy, so don't try the + * 16-bit loop below. + */ + dp = (png_bytep)dp32; + sp = (png_const_bytep)sp32; + do + *dp++ = *sp++; + while (--row_width > 0); + return; + } + + /* Else do it in 16-bit quantities, but only if the size is + * not too large. + */ + else + { + png_uint_16p dp16 = png_aligncast(png_uint_16p, dp); + png_const_uint_16p sp16 = png_aligncastconst( + png_const_uint_16p, sp); + size_t skip = (bytes_to_jump-bytes_to_copy) / + (sizeof (png_uint_16)); + + do + { + size_t c = bytes_to_copy; + do + { + *dp16++ = *sp16++; + c -= (sizeof (png_uint_16)); + } + while (c > 0); + + if (row_width <= bytes_to_jump) + return; + + dp16 += skip; + sp16 += skip; + row_width -= bytes_to_jump; + } + while (bytes_to_copy <= row_width); + + /* End of row - 1 byte left, bytes_to_copy > row_width: */ + dp = (png_bytep)dp16; + sp = (png_const_bytep)sp16; + do + *dp++ = *sp++; + while (--row_width > 0); + return; + } + } +#endif /* PNG_ALIGN_ code */ + + /* The true default - use a memcpy: */ + for (;;) + { + memcpy(dp, sp, bytes_to_copy); + + if (row_width <= bytes_to_jump) + return; + + sp += bytes_to_jump; + dp += bytes_to_jump; + row_width -= bytes_to_jump; + if (bytes_to_copy > row_width) + bytes_to_copy = row_width; + } + } + + /* NOT REACHED*/ + } /* pixel_depth >= 8 */ + + /* Here if pixel_depth < 8 to check 'end_ptr' below. */ + } + else +#endif /* PNG_READ_INTERLACING_SUPPORTED */ + + /* If here then the switch above wasn't used so just memcpy the whole row + * from the temporary row buffer (notice that this overwrites the end of the + * destination row if it is a partial byte.) + */ + memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width)); + + /* Restore the overwritten bits from the last byte if necessary. */ + if (end_ptr != NULL) + *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask)); +} + +#ifdef PNG_READ_INTERLACING_SUPPORTED +void /* PRIVATE */ +png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass, + png_uint_32 transformations /* Because these may affect the byte layout */) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + /* Offset to next interlace block */ + static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + png_debug(1, "in png_do_read_interlace"); + if (row != NULL && row_info != NULL) + { + png_uint_32 final_width; + + final_width = row_info->width * png_pass_inc[pass]; + + switch (row_info->pixel_depth) + { + case 1: + { + png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3); + png_bytep dp = row + (png_size_t)((final_width - 1) >> 3); + int sshift, dshift; + int s_start, s_end, s_inc; + int jstop = png_pass_inc[pass]; + png_byte v; + png_uint_32 i; + int j; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if (transformations & PNG_PACKSWAP) + { + sshift = (int)((row_info->width + 7) & 0x07); + dshift = (int)((final_width + 7) & 0x07); + s_start = 7; + s_end = 0; + s_inc = -1; + } + + else +#endif + { + sshift = 7 - (int)((row_info->width + 7) & 0x07); + dshift = 7 - (int)((final_width + 7) & 0x07); + s_start = 0; + s_end = 7; + s_inc = 1; + } + + for (i = 0; i < row_info->width; i++) + { + v = (png_byte)((*sp >> sshift) & 0x01); + for (j = 0; j < jstop; j++) + { + unsigned int tmp = *dp & (0x7f7f >> (7 - dshift)); + tmp |= v << dshift; + *dp = (png_byte)(tmp & 0xff); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + case 2: + { + png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2); + png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2); + int sshift, dshift; + int s_start, s_end, s_inc; + int jstop = png_pass_inc[pass]; + png_uint_32 i; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if (transformations & PNG_PACKSWAP) + { + sshift = (int)(((row_info->width + 3) & 0x03) << 1); + dshift = (int)(((final_width + 3) & 0x03) << 1); + s_start = 6; + s_end = 0; + s_inc = -2; + } + + else +#endif + { + sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1); + dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1); + s_start = 0; + s_end = 6; + s_inc = 2; + } + + for (i = 0; i < row_info->width; i++) + { + png_byte v; + int j; + + v = (png_byte)((*sp >> sshift) & 0x03); + for (j = 0; j < jstop; j++) + { + unsigned int tmp = *dp & (0x3f3f >> (6 - dshift)); + tmp |= v << dshift; + *dp = (png_byte)(tmp & 0xff); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + case 4: + { + png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1); + png_bytep dp = row + (png_size_t)((final_width - 1) >> 1); + int sshift, dshift; + int s_start, s_end, s_inc; + png_uint_32 i; + int jstop = png_pass_inc[pass]; + +#ifdef PNG_READ_PACKSWAP_SUPPORTED + if (transformations & PNG_PACKSWAP) + { + sshift = (int)(((row_info->width + 1) & 0x01) << 2); + dshift = (int)(((final_width + 1) & 0x01) << 2); + s_start = 4; + s_end = 0; + s_inc = -4; + } + + else +#endif + { + sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2); + dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2); + s_start = 0; + s_end = 4; + s_inc = 4; + } + + for (i = 0; i < row_info->width; i++) + { + png_byte v = (png_byte)((*sp >> sshift) & 0x0f); + int j; + + for (j = 0; j < jstop; j++) + { + unsigned int tmp = *dp & (0xf0f >> (4 - dshift)); + tmp |= v << dshift; + *dp = (png_byte)(tmp & 0xff); + + if (dshift == s_end) + { + dshift = s_start; + dp--; + } + + else + dshift += s_inc; + } + + if (sshift == s_end) + { + sshift = s_start; + sp--; + } + + else + sshift += s_inc; + } + break; + } + + default: + { + png_size_t pixel_bytes = (row_info->pixel_depth >> 3); + + png_bytep sp = row + (png_size_t)(row_info->width - 1) + * pixel_bytes; + + png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes; + + int jstop = png_pass_inc[pass]; + png_uint_32 i; + + for (i = 0; i < row_info->width; i++) + { + png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */ + int j; + + memcpy(v, sp, pixel_bytes); + + for (j = 0; j < jstop; j++) + { + memcpy(dp, v, pixel_bytes); + dp -= pixel_bytes; + } + + sp -= pixel_bytes; + } + break; + } + } + + row_info->width = final_width; + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width); + } +#ifndef PNG_READ_PACKSWAP_SUPPORTED + PNG_UNUSED(transformations) /* Silence compiler warning */ +#endif +} +#endif /* PNG_READ_INTERLACING_SUPPORTED */ + +static void +png_read_filter_row_sub(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_size_t istop = row_info->rowbytes; + unsigned int bpp = (row_info->pixel_depth + 7) >> 3; + png_bytep rp = row + bpp; + + PNG_UNUSED(prev_row) + + for (i = bpp; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff); + rp++; + } +} + +static void +png_read_filter_row_up(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_size_t istop = row_info->rowbytes; + png_bytep rp = row; + png_const_bytep pp = prev_row; + + for (i = 0; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff); + rp++; + } +} + +static void +png_read_filter_row_avg(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_size_t i; + png_bytep rp = row; + png_const_bytep pp = prev_row; + unsigned int bpp = (row_info->pixel_depth + 7) >> 3; + png_size_t istop = row_info->rowbytes - bpp; + + for (i = 0; i < bpp; i++) + { + *rp = (png_byte)(((int)(*rp) + + ((int)(*pp++) / 2 )) & 0xff); + + rp++; + } + + for (i = 0; i < istop; i++) + { + *rp = (png_byte)(((int)(*rp) + + (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff); + + rp++; + } +} + +static void +png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + png_bytep rp_end = row + row_info->rowbytes; + int a, c; + + /* First pixel/byte */ + c = *prev_row++; + a = *row + c; + *row++ = (png_byte)a; + + /* Remainder */ + while (row < rp_end) + { + int b, pa, pb, pc, p; + + a &= 0xff; /* From previous iteration or start */ + b = *prev_row++; + + p = b - c; + pc = a - c; + +# ifdef PNG_USE_ABS + pa = abs(p); + pb = abs(pc); + pc = abs(p + pc); +# else + pa = p < 0 ? -p : p; + pb = pc < 0 ? -pc : pc; + pc = (p + pc) < 0 ? -(p + pc) : p + pc; +# endif + + /* Find the best predictor, the least of pa, pb, pc favoring the earlier + * ones in the case of a tie. + */ + if (pb < pa) pa = pb, a = b; + if (pc < pa) a = c; + + /* Calculate the current pixel in a, and move the previous row pixel to c + * for the next time round the loop + */ + c = b; + a += *row; + *row++ = (png_byte)a; + } +} + +static void +png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row, + png_const_bytep prev_row) +{ + int bpp = (row_info->pixel_depth + 7) >> 3; + png_bytep rp_end = row + bpp; + + /* Process the first pixel in the row completely (this is the same as 'up' + * because there is only one candidate predictor for the first row). + */ + while (row < rp_end) + { + int a = *row + *prev_row++; + *row++ = (png_byte)a; + } + + /* Remainder */ + rp_end += row_info->rowbytes - bpp; + + while (row < rp_end) + { + int a, b, c, pa, pb, pc, p; + + c = *(prev_row - bpp); + a = *(row - bpp); + b = *prev_row++; + + p = b - c; + pc = a - c; + +# ifdef PNG_USE_ABS + pa = abs(p); + pb = abs(pc); + pc = abs(p + pc); +# else + pa = p < 0 ? -p : p; + pb = pc < 0 ? -pc : pc; + pc = (p + pc) < 0 ? -(p + pc) : p + pc; +# endif + + if (pb < pa) pa = pb, a = b; + if (pc < pa) a = c; + + a += *row; + *row++ = (png_byte)a; + } +} + +static void +png_init_filter_functions(png_structrp pp) + /* This function is called once for every PNG image (except for PNG images + * that only use PNG_FILTER_VALUE_NONE for all rows) to set the + * implementations required to reverse the filtering of PNG rows. Reversing + * the filter is the first transformation performed on the row data. It is + * performed in place, therefore an implementation can be selected based on + * the image pixel format. If the implementation depends on image width then + * take care to ensure that it works correctly if the image is interlaced - + * interlacing causes the actual row width to vary. + */ +{ + unsigned int bpp = (pp->pixel_depth + 7) >> 3; + + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; + pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; + if (bpp == 1) + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth_1byte_pixel; + else + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth_multibyte_pixel; + +#ifdef PNG_FILTER_OPTIMIZATIONS + /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to + * call to install hardware optimizations for the above functions; simply + * replace whatever elements of the pp->read_filter[] array with a hardware + * specific (or, for that matter, generic) optimization. + * + * To see an example of this examine what configure.ac does when + * --enable-arm-neon is specified on the command line. + */ + PNG_FILTER_OPTIMIZATIONS(pp, bpp); +#endif +} + +void /* PRIVATE */ +png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row, + png_const_bytep prev_row, int filter) +{ + /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define + * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic + * implementations. See png_init_filter_functions above. + */ + if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) + { + if (pp->read_filter[0] == NULL) + png_init_filter_functions(pp); + + pp->read_filter[filter-1](row_info, row, prev_row); + } +} + +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED +void /* PRIVATE */ +png_read_IDAT_data(png_structrp png_ptr, png_bytep output, + png_alloc_size_t avail_out) +{ + /* Loop reading IDATs and decompressing the result into output[avail_out] */ + png_ptr->zstream.next_out = output; + png_ptr->zstream.avail_out = 0; /* safety: set below */ + + if (output == NULL) + avail_out = 0; + + do + { + int ret; + png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; + + if (png_ptr->zstream.avail_in == 0) + { + uInt avail_in; + png_bytep buffer; + + while (png_ptr->idat_size == 0) + { + png_crc_finish(png_ptr, 0); + + png_ptr->idat_size = png_read_chunk_header(png_ptr); + /* This is an error even in the 'check' case because the code just + * consumed a non-IDAT header. + */ + if (png_ptr->chunk_name != png_IDAT) + png_error(png_ptr, "Not enough image data"); + } + + avail_in = png_ptr->IDAT_read_size; + + if (avail_in > png_ptr->idat_size) + avail_in = (uInt)png_ptr->idat_size; + + /* A PNG with a gradually increasing IDAT size will defeat this attempt + * to minimize memory usage by causing lots of re-allocs, but + * realistically doing IDAT_read_size re-allocs is not likely to be a + * big problem. + */ + buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/); + + png_crc_read(png_ptr, buffer, avail_in); + png_ptr->idat_size -= avail_in; + + png_ptr->zstream.next_in = buffer; + png_ptr->zstream.avail_in = avail_in; + } + + /* And set up the output side. */ + if (output != NULL) /* standard read */ + { + uInt out = ZLIB_IO_MAX; + + if (out > avail_out) + out = (uInt)avail_out; + + avail_out -= out; + png_ptr->zstream.avail_out = out; + } + + else /* after last row, checking for end */ + { + png_ptr->zstream.next_out = tmpbuf; + png_ptr->zstream.avail_out = (sizeof tmpbuf); + } + + /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the + * process. If the LZ stream is truncated the sequential reader will + * terminally damage the stream, above, by reading the chunk header of the + * following chunk (it then exits with png_error). + * + * TODO: deal more elegantly with truncated IDAT lists. + */ + ret = inflate(&png_ptr->zstream, Z_NO_FLUSH); + + /* Take the unconsumed output back. */ + if (output != NULL) + avail_out += png_ptr->zstream.avail_out; + + else /* avail_out counts the extra bytes */ + avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out; + + png_ptr->zstream.avail_out = 0; + + if (ret == Z_STREAM_END) + { + /* Do this for safety; we won't read any more into this row. */ + png_ptr->zstream.next_out = NULL; + + png_ptr->mode |= PNG_AFTER_IDAT; + png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; + + if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0) + png_chunk_benign_error(png_ptr, "Extra compressed data"); + break; + } + + if (ret != Z_OK) + { + png_zstream_error(png_ptr, ret); + + if (output != NULL) + png_chunk_error(png_ptr, png_ptr->zstream.msg); + + else /* checking */ + { + png_chunk_benign_error(png_ptr, png_ptr->zstream.msg); + return; + } + } + } while (avail_out > 0); + + if (avail_out > 0) + { + /* The stream ended before the image; this is the same as too few IDATs so + * should be handled the same way. + */ + if (output != NULL) + png_error(png_ptr, "Not enough image data"); + + else /* the deflate stream contained extra data */ + png_chunk_benign_error(png_ptr, "Too much image data"); + } +} + +void /* PRIVATE */ +png_read_finish_IDAT(png_structrp png_ptr) +{ + /* We don't need any more data and the stream should have ended, however the + * LZ end code may actually not have been processed. In this case we must + * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk + * may still remain to be consumed. + */ + if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) + { + /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in + * the compressed stream, but the stream may be damaged too, so even after + * this call we may need to terminate the zstream ownership. + */ + png_read_IDAT_data(png_ptr, NULL, 0); + png_ptr->zstream.next_out = NULL; /* safety */ + + /* Now clear everything out for safety; the following may not have been + * done. + */ + if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) + { + png_ptr->mode |= PNG_AFTER_IDAT; + png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; + } + } + + /* If the zstream has not been released do it now *and* terminate the reading + * of the final IDAT chunk. + */ + if (png_ptr->zowner == png_IDAT) + { + /* Always do this; the pointers otherwise point into the read buffer. */ + png_ptr->zstream.next_in = NULL; + png_ptr->zstream.avail_in = 0; + + /* Now we no longer own the zstream. */ + png_ptr->zowner = 0; + + /* The slightly weird semantics of the sequential IDAT reading is that we + * are always in or at the end of an IDAT chunk, so we always need to do a + * crc_finish here. If idat_size is non-zero we also need to read the + * spurious bytes at the end of the chunk now. + */ + (void)png_crc_finish(png_ptr, png_ptr->idat_size); + } +} + +void /* PRIVATE */ +png_read_finish_row(png_structrp png_ptr) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; + + png_debug(1, "in png_read_finish_row"); + png_ptr->row_number++; + if (png_ptr->row_number < png_ptr->num_rows) + return; + + if (png_ptr->interlaced) + { + png_ptr->row_number = 0; + + /* TO DO: don't do this if prev_row isn't needed (requires + * read-ahead of the next row's filter byte. + */ + memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); + + do + { + png_ptr->pass++; + + if (png_ptr->pass >= 7) + break; + + png_ptr->iwidth = (png_ptr->width + + png_pass_inc[png_ptr->pass] - 1 - + png_pass_start[png_ptr->pass]) / + png_pass_inc[png_ptr->pass]; + + if (!(png_ptr->transformations & PNG_INTERLACE)) + { + png_ptr->num_rows = (png_ptr->height + + png_pass_yinc[png_ptr->pass] - 1 - + png_pass_ystart[png_ptr->pass]) / + png_pass_yinc[png_ptr->pass]; + } + + else /* if (png_ptr->transformations & PNG_INTERLACE) */ + break; /* libpng deinterlacing sees every row */ + + } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0); + + if (png_ptr->pass < 7) + return; + } + + /* Here after at the end of the last row of the last pass. */ + png_read_finish_IDAT(png_ptr); +} +#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ + +void /* PRIVATE */ +png_read_start_row(png_structrp png_ptr) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; + + int max_pixel_depth; + png_size_t row_bytes; + + png_debug(1, "in png_read_start_row"); + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED + png_init_read_transformations(png_ptr); +#endif + if (png_ptr->interlaced) + { + if (!(png_ptr->transformations & PNG_INTERLACE)) + png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - + png_pass_ystart[0]) / png_pass_yinc[0]; + + else + png_ptr->num_rows = png_ptr->height; + + png_ptr->iwidth = (png_ptr->width + + png_pass_inc[png_ptr->pass] - 1 - + png_pass_start[png_ptr->pass]) / + png_pass_inc[png_ptr->pass]; + } + + else + { + png_ptr->num_rows = png_ptr->height; + png_ptr->iwidth = png_ptr->width; + } + + max_pixel_depth = png_ptr->pixel_depth; + + /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of + * calculations to calculate the final pixel depth, then + * png_do_read_transforms actually does the transforms. This means that the + * code which effectively calculates this value is actually repeated in three + * separate places. They must all match. Innocent changes to the order of + * transformations can and will break libpng in a way that causes memory + * overwrites. + * + * TODO: fix this. + */ +#ifdef PNG_READ_PACK_SUPPORTED + if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8) + max_pixel_depth = 8; +#endif + +#ifdef PNG_READ_EXPAND_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (png_ptr->num_trans) + max_pixel_depth = 32; + + else + max_pixel_depth = 24; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) + { + if (max_pixel_depth < 8) + max_pixel_depth = 8; + + if (png_ptr->num_trans) + max_pixel_depth *= 2; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB) + { + if (png_ptr->num_trans) + { + max_pixel_depth *= 4; + max_pixel_depth /= 3; + } + } + } +#endif + +#ifdef PNG_READ_EXPAND_16_SUPPORTED + if (png_ptr->transformations & PNG_EXPAND_16) + { +# ifdef PNG_READ_EXPAND_SUPPORTED + /* In fact it is an error if it isn't supported, but checking is + * the safe way. + */ + if (png_ptr->transformations & PNG_EXPAND) + { + if (png_ptr->bit_depth < 16) + max_pixel_depth *= 2; + } + else +# endif + png_ptr->transformations &= ~PNG_EXPAND_16; + } +#endif + +#ifdef PNG_READ_FILLER_SUPPORTED + if (png_ptr->transformations & (PNG_FILLER)) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) + { + if (max_pixel_depth <= 8) + max_pixel_depth = 16; + + else + max_pixel_depth = 32; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB || + png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + if (max_pixel_depth <= 32) + max_pixel_depth = 32; + + else + max_pixel_depth = 64; + } + } +#endif + +#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED + if (png_ptr->transformations & PNG_GRAY_TO_RGB) + { + if ( +#ifdef PNG_READ_EXPAND_SUPPORTED + (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) || +#endif +#ifdef PNG_READ_FILLER_SUPPORTED + (png_ptr->transformations & (PNG_FILLER)) || +#endif + png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (max_pixel_depth <= 16) + max_pixel_depth = 32; + + else + max_pixel_depth = 64; + } + + else + { + if (max_pixel_depth <= 8) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + max_pixel_depth = 32; + + else + max_pixel_depth = 24; + } + + else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + max_pixel_depth = 64; + + else + max_pixel_depth = 48; + } + } +#endif + +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \ +defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) + if (png_ptr->transformations & PNG_USER_TRANSFORM) + { + int user_pixel_depth = png_ptr->user_transform_depth * + png_ptr->user_transform_channels; + + if (user_pixel_depth > max_pixel_depth) + max_pixel_depth = user_pixel_depth; + } +#endif + + /* This value is stored in png_struct and double checked in the row read + * code. + */ + png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth; + png_ptr->transformed_pixel_depth = 0; /* calculated on demand */ + + /* Align the width on the next larger 8 pixels. Mainly used + * for interlacing + */ + row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7)); + /* Calculate the maximum bytes needed, adding a byte and a pixel + * for safety's sake + */ + row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) + + 1 + ((max_pixel_depth + 7) >> 3); + +#ifdef PNG_MAX_MALLOC_64K + if (row_bytes > (png_uint_32)65536L) + png_error(png_ptr, "This image requires a row greater than 64KB"); +#endif + + if (row_bytes + 48 > png_ptr->old_big_row_buf_size) + { + png_free(png_ptr, png_ptr->big_row_buf); + png_free(png_ptr, png_ptr->big_prev_row); + + if (png_ptr->interlaced) + png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr, + row_bytes + 48); + + else + png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48); + + png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48); + +#ifdef PNG_ALIGNED_MEMORY_SUPPORTED + /* Use 16-byte aligned memory for row_buf with at least 16 bytes + * of padding before and after row_buf; treat prev_row similarly. + * NOTE: the alignment is to the start of the pixels, one beyond the start + * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this + * was incorrect; the filter byte was aligned, which had the exact + * opposite effect of that intended. + */ + { + png_bytep temp = png_ptr->big_row_buf + 32; + int extra = (int)((temp - (png_bytep)0) & 0x0f); + png_ptr->row_buf = temp - extra - 1/*filter byte*/; + + temp = png_ptr->big_prev_row + 32; + extra = (int)((temp - (png_bytep)0) & 0x0f); + png_ptr->prev_row = temp - extra - 1/*filter byte*/; + } + +#else + /* Use 31 bytes of padding before and 17 bytes after row_buf. */ + png_ptr->row_buf = png_ptr->big_row_buf + 31; + png_ptr->prev_row = png_ptr->big_prev_row + 31; +#endif + png_ptr->old_big_row_buf_size = row_bytes + 48; + } + +#ifdef PNG_MAX_MALLOC_64K + if (png_ptr->rowbytes > 65535) + png_error(png_ptr, "This image requires a row greater than 64KB"); + +#endif + if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1)) + png_error(png_ptr, "Row has too many bytes to allocate in memory"); + + memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); + + png_debug1(3, "width = %u,", png_ptr->width); + png_debug1(3, "height = %u,", png_ptr->height); + png_debug1(3, "iwidth = %u,", png_ptr->iwidth); + png_debug1(3, "num_rows = %u,", png_ptr->num_rows); + png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes); + png_debug1(3, "irowbytes = %lu", + (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1); + + /* The sequential reader needs a buffer for IDAT, but the progressive reader + * does not, so free the read buffer now regardless; the sequential reader + * reallocates it on demand. + */ + if (png_ptr->read_buffer) + { + png_bytep buffer = png_ptr->read_buffer; + + png_ptr->read_buffer_size = 0; + png_ptr->read_buffer = NULL; + png_free(png_ptr, buffer); + } + + /* Finally claim the zstream for the inflate of the IDAT data, use the bits + * value from the stream (note that this will result in a fatal error if the + * IDAT stream has a bogus deflate header window_bits value, but this should + * not be happening any longer!) + */ + if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK) + png_error(png_ptr, png_ptr->zstream.msg); + + png_ptr->flags |= PNG_FLAG_ROW_INIT; +} +#endif /* PNG_READ_SUPPORTED */ diff --git a/png/pngset.c b/png/pngset.c new file mode 100755 index 0000000..0c827d3 --- /dev/null +++ b/png/pngset.c @@ -0,0 +1,1597 @@ + +/* pngset.c - storage of image information into info struct + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * The functions here are used during reads to store data from the file + * into the info struct, and during writes to store application data + * into the info struct for writing into the file. This abstracts the + * info struct and allows us to change the structure in the future. + */ + +#include "pngpriv.h" + +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) + +#ifdef PNG_bKGD_SUPPORTED +void PNGAPI +png_set_bKGD(png_const_structrp png_ptr, png_inforp info_ptr, + png_const_color_16p background) +{ + png_debug1(1, "in %s storage function", "bKGD"); + + if (png_ptr == NULL || info_ptr == NULL || background == NULL) + return; + + info_ptr->background = *background; + info_ptr->valid |= PNG_INFO_bKGD; +} +#endif + +#ifdef PNG_cHRM_SUPPORTED +void PNGFAPI +png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr, + png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x, + png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y, + png_fixed_point blue_x, png_fixed_point blue_y) +{ + png_xy xy; + + png_debug1(1, "in %s storage function", "cHRM fixed"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + xy.redx = red_x; + xy.redy = red_y; + xy.greenx = green_x; + xy.greeny = green_y; + xy.bluex = blue_x; + xy.bluey = blue_y; + xy.whitex = white_x; + xy.whitey = white_y; + + if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy, + 2/* override with app values*/)) + info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; + + png_colorspace_sync_info(png_ptr, info_ptr); +} + +void PNGFAPI +png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr, + png_fixed_point int_red_X, png_fixed_point int_red_Y, + png_fixed_point int_red_Z, png_fixed_point int_green_X, + png_fixed_point int_green_Y, png_fixed_point int_green_Z, + png_fixed_point int_blue_X, png_fixed_point int_blue_Y, + png_fixed_point int_blue_Z) +{ + png_XYZ XYZ; + + png_debug1(1, "in %s storage function", "cHRM XYZ fixed"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + XYZ.red_X = int_red_X; + XYZ.red_Y = int_red_Y; + XYZ.red_Z = int_red_Z; + XYZ.green_X = int_green_X; + XYZ.green_Y = int_green_Y; + XYZ.green_Z = int_green_Z; + XYZ.blue_X = int_blue_X; + XYZ.blue_Y = int_blue_Y; + XYZ.blue_Z = int_blue_Z; + + if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace, &XYZ, 2)) + info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; + + png_colorspace_sync_info(png_ptr, info_ptr); +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_cHRM(png_const_structrp png_ptr, png_inforp info_ptr, + double white_x, double white_y, double red_x, double red_y, + double green_x, double green_y, double blue_x, double blue_y) +{ + png_set_cHRM_fixed(png_ptr, info_ptr, + png_fixed(png_ptr, white_x, "cHRM White X"), + png_fixed(png_ptr, white_y, "cHRM White Y"), + png_fixed(png_ptr, red_x, "cHRM Red X"), + png_fixed(png_ptr, red_y, "cHRM Red Y"), + png_fixed(png_ptr, green_x, "cHRM Green X"), + png_fixed(png_ptr, green_y, "cHRM Green Y"), + png_fixed(png_ptr, blue_x, "cHRM Blue X"), + png_fixed(png_ptr, blue_y, "cHRM Blue Y")); +} + +void PNGAPI +png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X, + double red_Y, double red_Z, double green_X, double green_Y, double green_Z, + double blue_X, double blue_Y, double blue_Z) +{ + png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, + png_fixed(png_ptr, red_X, "cHRM Red X"), + png_fixed(png_ptr, red_Y, "cHRM Red Y"), + png_fixed(png_ptr, red_Z, "cHRM Red Z"), + png_fixed(png_ptr, green_X, "cHRM Red X"), + png_fixed(png_ptr, green_Y, "cHRM Red Y"), + png_fixed(png_ptr, green_Z, "cHRM Red Z"), + png_fixed(png_ptr, blue_X, "cHRM Red X"), + png_fixed(png_ptr, blue_Y, "cHRM Red Y"), + png_fixed(png_ptr, blue_Z, "cHRM Red Z")); +} +# endif /* PNG_FLOATING_POINT_SUPPORTED */ + +#endif /* PNG_cHRM_SUPPORTED */ + +#ifdef PNG_gAMA_SUPPORTED +void PNGFAPI +png_set_gAMA_fixed(png_const_structrp png_ptr, png_inforp info_ptr, + png_fixed_point file_gamma) +{ + png_debug1(1, "in %s storage function", "gAMA"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + png_colorspace_set_gamma(png_ptr, &info_ptr->colorspace, file_gamma); + png_colorspace_sync_info(png_ptr, info_ptr); +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_gAMA(png_const_structrp png_ptr, png_inforp info_ptr, double file_gamma) +{ + png_set_gAMA_fixed(png_ptr, info_ptr, png_fixed(png_ptr, file_gamma, + "png_set_gAMA")); +} +# endif +#endif + +#ifdef PNG_hIST_SUPPORTED +void PNGAPI +png_set_hIST(png_const_structrp png_ptr, png_inforp info_ptr, + png_const_uint_16p hist) +{ + int i; + + png_debug1(1, "in %s storage function", "hIST"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + if (info_ptr->num_palette == 0 || info_ptr->num_palette + > PNG_MAX_PALETTE_LENGTH) + { + png_warning(png_ptr, + "Invalid palette size, hIST allocation skipped"); + + return; + } + + png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0); + + /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in + * version 1.2.1 + */ + info_ptr->hist = png_voidcast(png_uint_16p, png_malloc_warn(png_ptr, + PNG_MAX_PALETTE_LENGTH * (sizeof (png_uint_16)))); + + if (info_ptr->hist == NULL) + { + png_warning(png_ptr, "Insufficient memory for hIST chunk data"); + return; + } + + info_ptr->free_me |= PNG_FREE_HIST; + + for (i = 0; i < info_ptr->num_palette; i++) + info_ptr->hist[i] = hist[i]; + + info_ptr->valid |= PNG_INFO_hIST; +} +#endif + +void PNGAPI +png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr, + png_uint_32 width, png_uint_32 height, int bit_depth, + int color_type, int interlace_type, int compression_type, + int filter_type) +{ + png_debug1(1, "in %s storage function", "IHDR"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + info_ptr->width = width; + info_ptr->height = height; + info_ptr->bit_depth = (png_byte)bit_depth; + info_ptr->color_type = (png_byte)color_type; + info_ptr->compression_type = (png_byte)compression_type; + info_ptr->filter_type = (png_byte)filter_type; + info_ptr->interlace_type = (png_byte)interlace_type; + + png_check_IHDR (png_ptr, info_ptr->width, info_ptr->height, + info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type, + info_ptr->compression_type, info_ptr->filter_type); + + if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + info_ptr->channels = 1; + + else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR) + info_ptr->channels = 3; + + else + info_ptr->channels = 1; + + if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA) + info_ptr->channels++; + + info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth); + + info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width); +} + +#ifdef PNG_oFFs_SUPPORTED +void PNGAPI +png_set_oFFs(png_const_structrp png_ptr, png_inforp info_ptr, + png_int_32 offset_x, png_int_32 offset_y, int unit_type) +{ + png_debug1(1, "in %s storage function", "oFFs"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + info_ptr->x_offset = offset_x; + info_ptr->y_offset = offset_y; + info_ptr->offset_unit_type = (png_byte)unit_type; + info_ptr->valid |= PNG_INFO_oFFs; +} +#endif + +#ifdef PNG_pCAL_SUPPORTED +void PNGAPI +png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr, + png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type, + int nparams, png_const_charp units, png_charpp params) +{ + png_size_t length; + int i; + + png_debug1(1, "in %s storage function", "pCAL"); + + if (png_ptr == NULL || info_ptr == NULL || purpose == NULL || units == NULL + || (nparams > 0 && params == NULL)) + return; + + length = strlen(purpose) + 1; + png_debug1(3, "allocating purpose for info (%lu bytes)", + (unsigned long)length); + + /* TODO: validate format of calibration name and unit name */ + + /* Check that the type matches the specification. */ + if (type < 0 || type > 3) + png_error(png_ptr, "Invalid pCAL equation type"); + + if (nparams < 0 || nparams > 255) + png_error(png_ptr, "Invalid pCAL parameter count"); + + /* Validate params[nparams] */ + for (i=0; i<nparams; ++i) + if (params[i] == NULL || + !png_check_fp_string(params[i], strlen(params[i]))) + png_error(png_ptr, "Invalid format for pCAL parameter"); + + info_ptr->pcal_purpose = png_voidcast(png_charp, + png_malloc_warn(png_ptr, length)); + + if (info_ptr->pcal_purpose == NULL) + { + png_warning(png_ptr, "Insufficient memory for pCAL purpose"); + return; + } + + memcpy(info_ptr->pcal_purpose, purpose, length); + + png_debug(3, "storing X0, X1, type, and nparams in info"); + info_ptr->pcal_X0 = X0; + info_ptr->pcal_X1 = X1; + info_ptr->pcal_type = (png_byte)type; + info_ptr->pcal_nparams = (png_byte)nparams; + + length = strlen(units) + 1; + png_debug1(3, "allocating units for info (%lu bytes)", + (unsigned long)length); + + info_ptr->pcal_units = png_voidcast(png_charp, + png_malloc_warn(png_ptr, length)); + + if (info_ptr->pcal_units == NULL) + { + png_warning(png_ptr, "Insufficient memory for pCAL units"); + return; + } + + memcpy(info_ptr->pcal_units, units, length); + + info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, + (png_size_t)((nparams + 1) * (sizeof (png_charp))))); + + if (info_ptr->pcal_params == NULL) + { + png_warning(png_ptr, "Insufficient memory for pCAL params"); + return; + } + + memset(info_ptr->pcal_params, 0, (nparams + 1) * (sizeof (png_charp))); + + for (i = 0; i < nparams; i++) + { + length = strlen(params[i]) + 1; + png_debug2(3, "allocating parameter %d for info (%lu bytes)", i, + (unsigned long)length); + + info_ptr->pcal_params[i] = (png_charp)png_malloc_warn(png_ptr, length); + + if (info_ptr->pcal_params[i] == NULL) + { + png_warning(png_ptr, "Insufficient memory for pCAL parameter"); + return; + } + + memcpy(info_ptr->pcal_params[i], params[i], length); + } + + info_ptr->valid |= PNG_INFO_pCAL; + info_ptr->free_me |= PNG_FREE_PCAL; +} +#endif + +#ifdef PNG_sCAL_SUPPORTED +void PNGAPI +png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr, + int unit, png_const_charp swidth, png_const_charp sheight) +{ + png_size_t lengthw = 0, lengthh = 0; + + png_debug1(1, "in %s storage function", "sCAL"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + /* Double check the unit (should never get here with an invalid + * unit unless this is an API call.) + */ + if (unit != 1 && unit != 2) + png_error(png_ptr, "Invalid sCAL unit"); + + if (swidth == NULL || (lengthw = strlen(swidth)) == 0 || + swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw)) + png_error(png_ptr, "Invalid sCAL width"); + + if (sheight == NULL || (lengthh = strlen(sheight)) == 0 || + sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh)) + png_error(png_ptr, "Invalid sCAL height"); + + info_ptr->scal_unit = (png_byte)unit; + + ++lengthw; + + png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthw); + + info_ptr->scal_s_width = png_voidcast(png_charp, + png_malloc_warn(png_ptr, lengthw)); + + if (info_ptr->scal_s_width == NULL) + { + png_warning(png_ptr, "Memory allocation failed while processing sCAL"); + return; + } + + memcpy(info_ptr->scal_s_width, swidth, lengthw); + + ++lengthh; + + png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthh); + + info_ptr->scal_s_height = png_voidcast(png_charp, + png_malloc_warn(png_ptr, lengthh)); + + if (info_ptr->scal_s_height == NULL) + { + png_free (png_ptr, info_ptr->scal_s_width); + info_ptr->scal_s_width = NULL; + + png_warning(png_ptr, "Memory allocation failed while processing sCAL"); + return; + } + + memcpy(info_ptr->scal_s_height, sheight, lengthh); + + info_ptr->valid |= PNG_INFO_sCAL; + info_ptr->free_me |= PNG_FREE_SCAL; +} + +# ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit, + double width, double height) +{ + png_debug1(1, "in %s storage function", "sCAL"); + + /* Check the arguments. */ + if (width <= 0) + png_warning(png_ptr, "Invalid sCAL width ignored"); + + else if (height <= 0) + png_warning(png_ptr, "Invalid sCAL height ignored"); + + else + { + /* Convert 'width' and 'height' to ASCII. */ + char swidth[PNG_sCAL_MAX_DIGITS+1]; + char sheight[PNG_sCAL_MAX_DIGITS+1]; + + png_ascii_from_fp(png_ptr, swidth, (sizeof swidth), width, + PNG_sCAL_PRECISION); + png_ascii_from_fp(png_ptr, sheight, (sizeof sheight), height, + PNG_sCAL_PRECISION); + + png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight); + } +} +# endif + +# ifdef PNG_FIXED_POINT_SUPPORTED +void PNGAPI +png_set_sCAL_fixed(png_const_structrp png_ptr, png_inforp info_ptr, int unit, + png_fixed_point width, png_fixed_point height) +{ + png_debug1(1, "in %s storage function", "sCAL"); + + /* Check the arguments. */ + if (width <= 0) + png_warning(png_ptr, "Invalid sCAL width ignored"); + + else if (height <= 0) + png_warning(png_ptr, "Invalid sCAL height ignored"); + + else + { + /* Convert 'width' and 'height' to ASCII. */ + char swidth[PNG_sCAL_MAX_DIGITS+1]; + char sheight[PNG_sCAL_MAX_DIGITS+1]; + + png_ascii_from_fixed(png_ptr, swidth, (sizeof swidth), width); + png_ascii_from_fixed(png_ptr, sheight, (sizeof sheight), height); + + png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight); + } +} +# endif +#endif + +#ifdef PNG_pHYs_SUPPORTED +void PNGAPI +png_set_pHYs(png_const_structrp png_ptr, png_inforp info_ptr, + png_uint_32 res_x, png_uint_32 res_y, int unit_type) +{ + png_debug1(1, "in %s storage function", "pHYs"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + info_ptr->x_pixels_per_unit = res_x; + info_ptr->y_pixels_per_unit = res_y; + info_ptr->phys_unit_type = (png_byte)unit_type; + info_ptr->valid |= PNG_INFO_pHYs; +} +#endif + +void PNGAPI +png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr, + png_const_colorp palette, int num_palette) +{ + + png_debug1(1, "in %s storage function", "PLTE"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH) + { + if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + png_error(png_ptr, "Invalid palette length"); + + else + { + png_warning(png_ptr, "Invalid palette length"); + return; + } + } + + if ((num_palette > 0 && palette == NULL) || + (num_palette == 0 +# ifdef PNG_MNG_FEATURES_SUPPORTED + && (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 +# endif + )) + { + png_error(png_ptr, "Invalid palette"); + return; + } + + /* It may not actually be necessary to set png_ptr->palette here; + * we do it for backward compatibility with the way the png_handle_tRNS + * function used to do the allocation. + * + * 1.6.0: the above statement appears to be incorrect; something has to set + * the palette inside png_struct on read. + */ + png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0); + + /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead + * of num_palette entries, in case of an invalid PNG file that has + * too-large sample values. + */ + png_ptr->palette = png_voidcast(png_colorp, png_calloc(png_ptr, + PNG_MAX_PALETTE_LENGTH * (sizeof (png_color)))); + + if (num_palette > 0) + memcpy(png_ptr->palette, palette, num_palette * (sizeof (png_color))); + info_ptr->palette = png_ptr->palette; + info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette; + + info_ptr->free_me |= PNG_FREE_PLTE; + + info_ptr->valid |= PNG_INFO_PLTE; +} + +#ifdef PNG_sBIT_SUPPORTED +void PNGAPI +png_set_sBIT(png_const_structrp png_ptr, png_inforp info_ptr, + png_const_color_8p sig_bit) +{ + png_debug1(1, "in %s storage function", "sBIT"); + + if (png_ptr == NULL || info_ptr == NULL || sig_bit == NULL) + return; + + info_ptr->sig_bit = *sig_bit; + info_ptr->valid |= PNG_INFO_sBIT; +} +#endif + +#ifdef PNG_sRGB_SUPPORTED +void PNGAPI +png_set_sRGB(png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent) +{ + png_debug1(1, "in %s storage function", "sRGB"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + (void)png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent); + png_colorspace_sync_info(png_ptr, info_ptr); +} + +void PNGAPI +png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr, + int srgb_intent) +{ + png_debug1(1, "in %s storage function", "sRGB_gAMA_and_cHRM"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent)) + { + /* This causes the gAMA and cHRM to be written too */ + info_ptr->colorspace.flags |= + PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM; + } + + png_colorspace_sync_info(png_ptr, info_ptr); +} +#endif /* sRGB */ + + +#ifdef PNG_iCCP_SUPPORTED +void PNGAPI +png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr, + png_const_charp name, int compression_type, + png_const_bytep profile, png_uint_32 proflen) +{ + png_charp new_iccp_name; + png_bytep new_iccp_profile; + png_size_t length; + + png_debug1(1, "in %s storage function", "iCCP"); + + if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL) + return; + + if (compression_type != PNG_COMPRESSION_TYPE_BASE) + png_app_error(png_ptr, "Invalid iCCP compression method"); + + /* Set the colorspace first because this validates the profile; do not + * override previously set app cHRM or gAMA here (because likely as not the + * application knows better than libpng what the correct values are.) Pass + * the info_ptr color_type field to png_colorspace_set_ICC because in the + * write case it has not yet been stored in png_ptr. + */ + { + int result = png_colorspace_set_ICC(png_ptr, &info_ptr->colorspace, name, + proflen, profile, info_ptr->color_type); + + png_colorspace_sync_info(png_ptr, info_ptr); + + /* Don't do any of the copying if the profile was bad, or inconsistent. */ + if (result == 0) + return; + + /* But do write the gAMA and cHRM chunks from the profile. */ + info_ptr->colorspace.flags |= + PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM; + } + + length = strlen(name)+1; + new_iccp_name = png_voidcast(png_charp, png_malloc_warn(png_ptr, length)); + + if (new_iccp_name == NULL) + { + png_benign_error(png_ptr, "Insufficient memory to process iCCP chunk"); + return; + } + + memcpy(new_iccp_name, name, length); + new_iccp_profile = png_voidcast(png_bytep, + png_malloc_warn(png_ptr, proflen)); + + if (new_iccp_profile == NULL) + { + png_free(png_ptr, new_iccp_name); + png_benign_error(png_ptr, + "Insufficient memory to process iCCP profile"); + return; + } + + memcpy(new_iccp_profile, profile, proflen); + + png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0); + + info_ptr->iccp_proflen = proflen; + info_ptr->iccp_name = new_iccp_name; + info_ptr->iccp_profile = new_iccp_profile; + info_ptr->free_me |= PNG_FREE_ICCP; + info_ptr->valid |= PNG_INFO_iCCP; +} +#endif + +#ifdef PNG_TEXT_SUPPORTED +void PNGAPI +png_set_text(png_const_structrp png_ptr, png_inforp info_ptr, + png_const_textp text_ptr, int num_text) +{ + int ret; + ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text); + + if (ret != 0) + png_error(png_ptr, "Insufficient memory to store text"); +} + +int /* PRIVATE */ +png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr, + png_const_textp text_ptr, int num_text) +{ + int i; + + png_debug1(1, "in %lx storage function", png_ptr == NULL ? "unexpected" : + (unsigned long)png_ptr->chunk_name); + + if (png_ptr == NULL || info_ptr == NULL || num_text <= 0 || text_ptr == NULL) + return(0); + + /* Make sure we have enough space in the "text" array in info_struct + * to hold all of the incoming text_ptr objects. This compare can't overflow + * because max_text >= num_text (anyway, subtract of two positive integers + * can't overflow in any case.) + */ + if (num_text > info_ptr->max_text - info_ptr->num_text) + { + int old_num_text = info_ptr->num_text; + int max_text; + png_textp new_text = NULL; + + /* Calculate an appropriate max_text, checking for overflow. */ + max_text = old_num_text; + if (num_text <= INT_MAX - max_text) + { + max_text += num_text; + + /* Round up to a multiple of 8 */ + if (max_text < INT_MAX-8) + max_text = (max_text + 8) & ~0x7; + + else + max_text = INT_MAX; + + /* Now allocate a new array and copy the old members in, this does all + * the overflow checks. + */ + new_text = png_voidcast(png_textp,png_realloc_array(png_ptr, + info_ptr->text, old_num_text, max_text-old_num_text, + sizeof *new_text)); + } + + if (new_text == NULL) + { + png_chunk_report(png_ptr, "too many text chunks", + PNG_CHUNK_WRITE_ERROR); + return 1; + } + + png_free(png_ptr, info_ptr->text); + + info_ptr->text = new_text; + info_ptr->free_me |= PNG_FREE_TEXT; + info_ptr->max_text = max_text; + /* num_text is adjusted below as the entries are copied in */ + + png_debug1(3, "allocated %d entries for info_ptr->text", max_text); + } + + for (i = 0; i < num_text; i++) + { + size_t text_length, key_len; + size_t lang_len, lang_key_len; + png_textp textp = &(info_ptr->text[info_ptr->num_text]); + + if (text_ptr[i].key == NULL) + continue; + + if (text_ptr[i].compression < PNG_TEXT_COMPRESSION_NONE || + text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST) + { + png_chunk_report(png_ptr, "text compression mode is out of range", + PNG_CHUNK_WRITE_ERROR); + continue; + } + + key_len = strlen(text_ptr[i].key); + + if (text_ptr[i].compression <= 0) + { + lang_len = 0; + lang_key_len = 0; + } + + else +# ifdef PNG_iTXt_SUPPORTED + { + /* Set iTXt data */ + + if (text_ptr[i].lang != NULL) + lang_len = strlen(text_ptr[i].lang); + + else + lang_len = 0; + + if (text_ptr[i].lang_key != NULL) + lang_key_len = strlen(text_ptr[i].lang_key); + + else + lang_key_len = 0; + } +# else /* PNG_iTXt_SUPPORTED */ + { + png_chunk_report(png_ptr, "iTXt chunk not supported", + PNG_CHUNK_WRITE_ERROR); + continue; + } +# endif + + if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0') + { + text_length = 0; +# ifdef PNG_iTXt_SUPPORTED + if (text_ptr[i].compression > 0) + textp->compression = PNG_ITXT_COMPRESSION_NONE; + + else +# endif + textp->compression = PNG_TEXT_COMPRESSION_NONE; + } + + else + { + text_length = strlen(text_ptr[i].text); + textp->compression = text_ptr[i].compression; + } + + textp->key = png_voidcast(png_charp,png_malloc_base(png_ptr, + key_len + text_length + lang_len + lang_key_len + 4)); + + if (textp->key == NULL) + { + png_chunk_report(png_ptr, "text chunk: out of memory", + PNG_CHUNK_WRITE_ERROR); + return 1; + } + + png_debug2(2, "Allocated %lu bytes at %p in png_set_text", + (unsigned long)(png_uint_32) + (key_len + lang_len + lang_key_len + text_length + 4), + textp->key); + + memcpy(textp->key, text_ptr[i].key, key_len); + *(textp->key + key_len) = '\0'; + + if (text_ptr[i].compression > 0) + { + textp->lang = textp->key + key_len + 1; + memcpy(textp->lang, text_ptr[i].lang, lang_len); + *(textp->lang + lang_len) = '\0'; + textp->lang_key = textp->lang + lang_len + 1; + memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len); + *(textp->lang_key + lang_key_len) = '\0'; + textp->text = textp->lang_key + lang_key_len + 1; + } + + else + { + textp->lang=NULL; + textp->lang_key=NULL; + textp->text = textp->key + key_len + 1; + } + + if (text_length != 0) + memcpy(textp->text, text_ptr[i].text, text_length); + + *(textp->text + text_length) = '\0'; + +# ifdef PNG_iTXt_SUPPORTED + if (textp->compression > 0) + { + textp->text_length = 0; + textp->itxt_length = text_length; + } + + else +# endif + { + textp->text_length = text_length; + textp->itxt_length = 0; + } + + info_ptr->num_text++; + png_debug1(3, "transferred text chunk %d", info_ptr->num_text); + } + + return(0); +} +#endif + +#ifdef PNG_tIME_SUPPORTED +void PNGAPI +png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr, + png_const_timep mod_time) +{ + png_debug1(1, "in %s storage function", "tIME"); + + if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL || + (png_ptr->mode & PNG_WROTE_tIME)) + return; + + if (mod_time->month == 0 || mod_time->month > 12 || + mod_time->day == 0 || mod_time->day > 31 || + mod_time->hour > 23 || mod_time->minute > 59 || + mod_time->second > 60) + { + png_warning(png_ptr, "Ignoring invalid time value"); + return; + } + + info_ptr->mod_time = *mod_time; + info_ptr->valid |= PNG_INFO_tIME; +} +#endif + +#ifdef PNG_tRNS_SUPPORTED +void PNGAPI +png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr, + png_const_bytep trans_alpha, int num_trans, png_const_color_16p trans_color) +{ + png_debug1(1, "in %s storage function", "tRNS"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + if (trans_alpha != NULL) + { + /* It may not actually be necessary to set png_ptr->trans_alpha here; + * we do it for backward compatibility with the way the png_handle_tRNS + * function used to do the allocation. + * + * 1.6.0: The above statement is incorrect; png_handle_tRNS effectively + * relies on png_set_tRNS storing the information in png_struct + * (otherwise it won't be there for the code in pngrtran.c). + */ + + png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0); + + /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */ + png_ptr->trans_alpha = info_ptr->trans_alpha = png_voidcast(png_bytep, + png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH)); + + if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH) + memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans); + } + + if (trans_color != NULL) + { + int sample_max = (1 << info_ptr->bit_depth); + + if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY && + trans_color->gray > sample_max) || + (info_ptr->color_type == PNG_COLOR_TYPE_RGB && + (trans_color->red > sample_max || + trans_color->green > sample_max || + trans_color->blue > sample_max))) + png_warning(png_ptr, + "tRNS chunk has out-of-range samples for bit_depth"); + + info_ptr->trans_color = *trans_color; + + if (num_trans == 0) + num_trans = 1; + } + + info_ptr->num_trans = (png_uint_16)num_trans; + + if (num_trans != 0) + { + info_ptr->valid |= PNG_INFO_tRNS; + info_ptr->free_me |= PNG_FREE_TRNS; + } +} +#endif + +#ifdef PNG_sPLT_SUPPORTED +void PNGAPI +png_set_sPLT(png_const_structrp png_ptr, + png_inforp info_ptr, png_const_sPLT_tp entries, int nentries) +/* + * entries - array of png_sPLT_t structures + * to be added to the list of palettes + * in the info structure. + * + * nentries - number of palette structures to be + * added. + */ +{ + png_sPLT_tp np; + + if (png_ptr == NULL || info_ptr == NULL || nentries <= 0 || entries == NULL) + return; + + /* Use the internal realloc function, which checks for all the possible + * overflows. Notice that the parameters are (int) and (size_t) + */ + np = png_voidcast(png_sPLT_tp,png_realloc_array(png_ptr, + info_ptr->splt_palettes, info_ptr->splt_palettes_num, nentries, + sizeof *np)); + + if (np == NULL) + { + /* Out of memory or too many chunks */ + png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR); + return; + } + + png_free(png_ptr, info_ptr->splt_palettes); + info_ptr->splt_palettes = np; + info_ptr->free_me |= PNG_FREE_SPLT; + + np += info_ptr->splt_palettes_num; + + do + { + png_size_t length; + + /* Skip invalid input entries */ + if (entries->name == NULL || entries->entries == NULL) + { + /* png_handle_sPLT doesn't do this, so this is an app error */ + png_app_error(png_ptr, "png_set_sPLT: invalid sPLT"); + /* Just skip the invalid entry */ + continue; + } + + np->depth = entries->depth; + + /* In the even of out-of-memory just return - there's no point keeping on + * trying to add sPLT chunks. + */ + length = strlen(entries->name) + 1; + np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length)); + + if (np->name == NULL) + break; + + memcpy(np->name, entries->name, length); + + /* IMPORTANT: we have memory now that won't get freed if something else + * goes wrong, this code must free it. png_malloc_array produces no + * warnings, use a png_chunk_report (below) if there is an error. + */ + np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr, + entries->nentries, sizeof (png_sPLT_entry))); + + if (np->entries == NULL) + { + png_free(png_ptr, np->name); + break; + } + + np->nentries = entries->nentries; + /* This multiply can't overflow because png_malloc_array has already + * checked it when doing the allocation. + */ + memcpy(np->entries, entries->entries, + entries->nentries * sizeof (png_sPLT_entry)); + + /* Note that 'continue' skips the advance of the out pointer and out + * count, so an invalid entry is not added. + */ + info_ptr->valid |= PNG_INFO_sPLT; + ++(info_ptr->splt_palettes_num); + ++np; + } + while (++entries, --nentries); + + if (nentries > 0) + png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR); +} +#endif /* PNG_sPLT_SUPPORTED */ + +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED +static png_byte +check_location(png_const_structrp png_ptr, int location) +{ + location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT); + + /* New in 1.6.0; copy the location and check it. This is an API + * change, previously the app had to use the + * png_set_unknown_chunk_location API below for each chunk. + */ + if (location == 0 && !(png_ptr->mode & PNG_IS_READ_STRUCT)) + { + /* Write struct, so unknown chunks come from the app */ + png_app_warning(png_ptr, + "png_set_unknown_chunks now expects a valid location"); + /* Use the old behavior */ + location = (png_byte)(png_ptr->mode & + (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT)); + } + + /* This need not be an internal error - if the app calls + * png_set_unknown_chunks on a read pointer it must get the location right. + */ + if (location == 0) + png_error(png_ptr, "invalid location in png_set_unknown_chunks"); + + /* Now reduce the location to the top-most set bit by removing each least + * significant bit in turn. + */ + while (location != (location & -location)) + location &= ~(location & -location); + + /* The cast is safe because 'location' is a bit mask and only the low four + * bits are significant. + */ + return (png_byte)location; +} + +void PNGAPI +png_set_unknown_chunks(png_const_structrp png_ptr, + png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns) +{ + png_unknown_chunkp np; + + if (png_ptr == NULL || info_ptr == NULL || num_unknowns <= 0 || + unknowns == NULL) + return; + + /* Check for the failure cases where support has been disabled at compile + * time. This code is hardly ever compiled - it's here because + * STORE_UNKNOWN_CHUNKS is set by both read and write code (compiling in this + * code) but may be meaningless if the read or write handling of unknown + * chunks is not compiled in. + */ +# if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \ + defined(PNG_READ_SUPPORTED) + if (png_ptr->mode & PNG_IS_READ_STRUCT) + { + png_app_error(png_ptr, "no unknown chunk support on read"); + return; + } +# endif +# if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \ + defined(PNG_WRITE_SUPPORTED) + if (!(png_ptr->mode & PNG_IS_READ_STRUCT)) + { + png_app_error(png_ptr, "no unknown chunk support on write"); + return; + } +# endif + + /* Prior to 1.6.0 this code used png_malloc_warn; however, this meant that + * unknown critical chunks could be lost with just a warning resulting in + * undefined behavior. Now png_chunk_report is used to provide behavior + * appropriate to read or write. + */ + np = png_voidcast(png_unknown_chunkp, png_realloc_array(png_ptr, + info_ptr->unknown_chunks, info_ptr->unknown_chunks_num, num_unknowns, + sizeof *np)); + + if (np == NULL) + { + png_chunk_report(png_ptr, "too many unknown chunks", + PNG_CHUNK_WRITE_ERROR); + return; + } + + png_free(png_ptr, info_ptr->unknown_chunks); + info_ptr->unknown_chunks = np; /* safe because it is initialized */ + info_ptr->free_me |= PNG_FREE_UNKN; + + np += info_ptr->unknown_chunks_num; + + /* Increment unknown_chunks_num each time round the loop to protect the + * just-allocated chunk data. + */ + for (; num_unknowns > 0; --num_unknowns, ++unknowns) + { + memcpy(np->name, unknowns->name, (sizeof np->name)); + np->name[(sizeof np->name)-1] = '\0'; + np->location = check_location(png_ptr, unknowns->location); + + if (unknowns->size == 0) + { + np->data = NULL; + np->size = 0; + } + + else + { + np->data = png_voidcast(png_bytep, + png_malloc_base(png_ptr, unknowns->size)); + + if (np->data == NULL) + { + png_chunk_report(png_ptr, "unknown chunk: out of memory", + PNG_CHUNK_WRITE_ERROR); + /* But just skip storing the unknown chunk */ + continue; + } + + memcpy(np->data, unknowns->data, unknowns->size); + np->size = unknowns->size; + } + + /* These increments are skipped on out-of-memory for the data - the + * unknown chunk entry gets overwritten if the png_chunk_report returns. + * This is correct in the read case (the chunk is just dropped.) + */ + ++np; + ++(info_ptr->unknown_chunks_num); + } +} + +void PNGAPI +png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr, + int chunk, int location) +{ + /* This API is pretty pointless in 1.6.0 because the location can be set + * before the call to png_set_unknown_chunks. + * + * TODO: add a png_app_warning in 1.7 + */ + if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 && + chunk < info_ptr->unknown_chunks_num) + { + if ((location & (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT)) == 0) + { + png_app_error(png_ptr, "invalid unknown chunk location"); + /* Fake out the pre 1.6.0 behavior: */ + if ((location & PNG_HAVE_IDAT)) /* undocumented! */ + location = PNG_AFTER_IDAT; + + else + location = PNG_HAVE_IHDR; /* also undocumented */ + } + + info_ptr->unknown_chunks[chunk].location = + check_location(png_ptr, location); + } +} +#endif + + +#ifdef PNG_MNG_FEATURES_SUPPORTED +png_uint_32 PNGAPI +png_permit_mng_features (png_structrp png_ptr, png_uint_32 mng_features) +{ + png_debug(1, "in png_permit_mng_features"); + + if (png_ptr == NULL) + return 0; + + png_ptr->mng_features_permitted = mng_features & PNG_ALL_MNG_FEATURES; + + return png_ptr->mng_features_permitted; +} +#endif + +#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED +static unsigned int +add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep) +{ + unsigned int i; + + /* Utility function: update the 'keep' state of a chunk if it is already in + * the list, otherwise add it to the list. + */ + for (i=0; i<count; ++i, list += 5) if (memcmp(list, add, 4) == 0) + { + list[4] = (png_byte)keep; + return count; + } + + if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT) + { + ++count; + memcpy(list, add, 4); + list[4] = (png_byte)keep; + } + + return count; +} + +void PNGAPI +png_set_keep_unknown_chunks(png_structrp png_ptr, int keep, + png_const_bytep chunk_list, int num_chunks_in) +{ + png_bytep new_list; + unsigned int num_chunks, old_num_chunks; + + if (png_ptr == NULL) + return; + + if (keep < 0 || keep >= PNG_HANDLE_CHUNK_LAST) + { + png_app_error(png_ptr, "png_set_keep_unknown_chunks: invalid keep"); + return; + } + + if (num_chunks_in <= 0) + { + png_ptr->unknown_default = keep; + + /* '0' means just set the flags, so stop here */ + if (num_chunks_in == 0) + return; + } + + if (num_chunks_in < 0) + { + /* Ignore all unknown chunks and all chunks recognized by + * libpng except for IHDR, PLTE, tRNS, IDAT, and IEND + */ + static PNG_CONST png_byte chunks_to_ignore[] = { + 98, 75, 71, 68, '\0', /* bKGD */ + 99, 72, 82, 77, '\0', /* cHRM */ + 103, 65, 77, 65, '\0', /* gAMA */ + 104, 73, 83, 84, '\0', /* hIST */ + 105, 67, 67, 80, '\0', /* iCCP */ + 105, 84, 88, 116, '\0', /* iTXt */ + 111, 70, 70, 115, '\0', /* oFFs */ + 112, 67, 65, 76, '\0', /* pCAL */ + 112, 72, 89, 115, '\0', /* pHYs */ + 115, 66, 73, 84, '\0', /* sBIT */ + 115, 67, 65, 76, '\0', /* sCAL */ + 115, 80, 76, 84, '\0', /* sPLT */ + 115, 84, 69, 82, '\0', /* sTER */ + 115, 82, 71, 66, '\0', /* sRGB */ + 116, 69, 88, 116, '\0', /* tEXt */ + 116, 73, 77, 69, '\0', /* tIME */ + 122, 84, 88, 116, '\0' /* zTXt */ + }; + + chunk_list = chunks_to_ignore; + num_chunks = (sizeof chunks_to_ignore)/5; + } + + else /* num_chunks_in > 0 */ + { + if (chunk_list == NULL) + { + /* Prior to 1.6.0 this was silently ignored, now it is an app_error + * which can be switched off. + */ + png_app_error(png_ptr, "png_set_keep_unknown_chunks: no chunk list"); + return; + } + + num_chunks = num_chunks_in; + } + + old_num_chunks = png_ptr->num_chunk_list; + if (png_ptr->chunk_list == NULL) + old_num_chunks = 0; + + /* Since num_chunks is always restricted to UINT_MAX/5 this can't overflow. + */ + if (num_chunks + old_num_chunks > UINT_MAX/5) + { + png_app_error(png_ptr, "png_set_keep_unknown_chunks: too many chunks"); + return; + } + + /* If these chunks are being reset to the default then no more memory is + * required because add_one_chunk above doesn't extend the list if the 'keep' + * parameter is the default. + */ + if (keep != 0) + { + new_list = png_voidcast(png_bytep, png_malloc(png_ptr, + 5 * (num_chunks + old_num_chunks))); + + if (old_num_chunks > 0) + memcpy(new_list, png_ptr->chunk_list, 5*old_num_chunks); + } + + else if (old_num_chunks > 0) + new_list = png_ptr->chunk_list; + + else + new_list = NULL; + + /* Add the new chunks together with each one's handling code. If the chunk + * already exists the code is updated, otherwise the chunk is added to the + * end. (In libpng 1.6.0 order no longer matters because this code enforces + * the earlier convention that the last setting is the one that is used.) + */ + if (new_list != NULL) + { + png_const_bytep inlist; + png_bytep outlist; + unsigned int i; + + for (i=0; i<num_chunks; ++i) + old_num_chunks = add_one_chunk(new_list, old_num_chunks, + chunk_list+5*i, keep); + + /* Now remove any spurious 'default' entries. */ + num_chunks = 0; + for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5) + if (inlist[4]) + { + if (outlist != inlist) + memcpy(outlist, inlist, 5); + outlist += 5; + ++num_chunks; + } + + /* This means the application has removed all the specialized handling. */ + if (num_chunks == 0) + { + if (png_ptr->chunk_list != new_list) + png_free(png_ptr, new_list); + + new_list = NULL; + } + } + + else + num_chunks = 0; + + png_ptr->num_chunk_list = num_chunks; + + if (png_ptr->chunk_list != new_list) + { + if (png_ptr->chunk_list != NULL) + png_free(png_ptr, png_ptr->chunk_list); + + png_ptr->chunk_list = new_list; + } +} +#endif + +#ifdef PNG_READ_USER_CHUNKS_SUPPORTED +void PNGAPI +png_set_read_user_chunk_fn(png_structrp png_ptr, png_voidp user_chunk_ptr, + png_user_chunk_ptr read_user_chunk_fn) +{ + png_debug(1, "in png_set_read_user_chunk_fn"); + + if (png_ptr == NULL) + return; + + png_ptr->read_user_chunk_fn = read_user_chunk_fn; + png_ptr->user_chunk_ptr = user_chunk_ptr; +} +#endif + +#ifdef PNG_INFO_IMAGE_SUPPORTED +void PNGAPI +png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr, + png_bytepp row_pointers) +{ + png_debug1(1, "in %s storage function", "rows"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + if (info_ptr->row_pointers && (info_ptr->row_pointers != row_pointers)) + png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0); + + info_ptr->row_pointers = row_pointers; + + if (row_pointers != NULL) + info_ptr->valid |= PNG_INFO_IDAT; +} +#endif + +void PNGAPI +png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size) +{ + if (png_ptr == NULL) + return; + + if (size == 0 || size > PNG_UINT_31_MAX) + png_error(png_ptr, "invalid compression buffer size"); + +# ifdef PNG_SEQUENTIAL_READ_SUPPORTED + if (png_ptr->mode & PNG_IS_READ_STRUCT) + { + png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */ + return; + } +# endif + +# ifdef PNG_WRITE_SUPPORTED + if (!(png_ptr->mode & PNG_IS_READ_STRUCT)) + { + if (png_ptr->zowner != 0) + { + png_warning(png_ptr, + "Compression buffer size cannot be changed because it is in use"); + return; + } + + if (size > ZLIB_IO_MAX) + { + png_warning(png_ptr, + "Compression buffer size limited to system maximum"); + size = ZLIB_IO_MAX; /* must fit */ + } + + else if (size < 6) + { + /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH + * if this is permitted. + */ + png_warning(png_ptr, + "Compression buffer size cannot be reduced below 6"); + return; + } + + if (png_ptr->zbuffer_size != size) + { + png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list); + png_ptr->zbuffer_size = (uInt)size; + } + } +# endif +} + +void PNGAPI +png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask) +{ + if (png_ptr && info_ptr) + info_ptr->valid &= ~mask; +} + + +#ifdef PNG_SET_USER_LIMITS_SUPPORTED +/* This function was added to libpng 1.2.6 */ +void PNGAPI +png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max, + png_uint_32 user_height_max) +{ + /* Images with dimensions larger than these limits will be + * rejected by png_set_IHDR(). To accept any PNG datastream + * regardless of dimensions, set both limits to 0x7ffffffL. + */ + if (png_ptr == NULL) + return; + + png_ptr->user_width_max = user_width_max; + png_ptr->user_height_max = user_height_max; +} + +/* This function was added to libpng 1.4.0 */ +void PNGAPI +png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max) +{ + if (png_ptr != NULL) + png_ptr->user_chunk_cache_max = user_chunk_cache_max; +} + +/* This function was added to libpng 1.4.1 */ +void PNGAPI +png_set_chunk_malloc_max (png_structrp png_ptr, + png_alloc_size_t user_chunk_malloc_max) +{ + if (png_ptr != NULL) + png_ptr->user_chunk_malloc_max = user_chunk_malloc_max; +} +#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */ + + +#ifdef PNG_BENIGN_ERRORS_SUPPORTED +void PNGAPI +png_set_benign_errors(png_structrp png_ptr, int allowed) +{ + png_debug(1, "in png_set_benign_errors"); + + /* If allowed is 1, png_benign_error() is treated as a warning. + * + * If allowed is 0, png_benign_error() is treated as an error (which + * is the default behavior if png_set_benign_errors() is not called). + */ + + if (allowed != 0) + png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN | + PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN; + + else + png_ptr->flags &= ~(PNG_FLAG_BENIGN_ERRORS_WARN | + PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN); +} +#endif /* PNG_BENIGN_ERRORS_SUPPORTED */ + +#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED + /* Whether to report invalid palette index; added at libng-1.5.10. + * It is possible for an indexed (color-type==3) PNG file to contain + * pixels with invalid (out-of-range) indexes if the PLTE chunk has + * fewer entries than the image's bit-depth would allow. We recover + * from this gracefully by filling any incomplete palette with zeroes + * (opaque black). By default, when this occurs libpng will issue + * a benign error. This API can be used to override that behavior. + */ +void PNGAPI +png_set_check_for_invalid_index(png_structrp png_ptr, int allowed) +{ + png_debug(1, "in png_set_check_for_invalid_index"); + + if (allowed > 0) + png_ptr->num_palette_max = 0; + + else + png_ptr->num_palette_max = -1; +} +#endif +#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ diff --git a/png/pngstruct.h b/png/pngstruct.h new file mode 100755 index 0000000..d58c028 --- /dev/null +++ b/png/pngstruct.h @@ -0,0 +1,489 @@ + +/* pngstruct.h - header file for PNG reference library + * + * Copyright (c) 1998-2013 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * Last changed in libpng 1.6.1 [March 28, 2013] + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +/* The structure that holds the information to read and write PNG files. + * The only people who need to care about what is inside of this are the + * people who will be modifying the library for their own special needs. + * It should NOT be accessed directly by an application. + */ + +#ifndef PNGSTRUCT_H +#define PNGSTRUCT_H +/* zlib.h defines the structure z_stream, an instance of which is included + * in this structure and is required for decompressing the LZ compressed + * data in PNG files. + */ +#ifndef ZLIB_CONST + /* We must ensure that zlib uses 'const' in declarations. */ +# define ZLIB_CONST +#endif +#include "zlib.h" +#ifdef const + /* zlib.h sometimes #defines const to nothing, undo this. */ +# undef const +#endif + +/* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility + * with older builds. + */ +#if ZLIB_VERNUM < 0x1260 +# define PNGZ_MSG_CAST(s) png_constcast(char*,s) +# define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b) +#else +# define PNGZ_MSG_CAST(s) (s) +# define PNGZ_INPUT_CAST(b) (b) +#endif + +/* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib + * can handle at once. This type need be no larger than 16 bits (so maximum of + * 65535), this define allows us to discover how big it is, but limited by the + * maximuum for png_size_t. The value can be overriden in a library build + * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably + * lower value (e.g. 255 works). A lower value may help memory usage (slightly) + * and may even improve performance on some systems (and degrade it on others.) + */ +#ifndef ZLIB_IO_MAX +# define ZLIB_IO_MAX ((uInt)-1) +#endif + +#ifdef PNG_WRITE_SUPPORTED +/* The type of a compression buffer list used by the write code. */ +typedef struct png_compression_buffer +{ + struct png_compression_buffer *next; + png_byte output[1]; /* actually zbuf_size */ +} png_compression_buffer, *png_compression_bufferp; + +#define PNG_COMPRESSION_BUFFER_SIZE(pp)\ + (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size) +#endif + +/* Colorspace support; structures used in png_struct, png_info and in internal + * functions to hold and communicate information about the color space. + * + * PNG_COLORSPACE_SUPPORTED is only required if the application will perform + * colorspace corrections, otherwise all the colorspace information can be + * skipped and the size of libpng can be reduced (significantly) by compiling + * out the colorspace support. + */ +#ifdef PNG_COLORSPACE_SUPPORTED +/* The chromaticities of the red, green and blue colorants and the chromaticity + * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)). + */ +typedef struct png_xy +{ + png_fixed_point redx, redy; + png_fixed_point greenx, greeny; + png_fixed_point bluex, bluey; + png_fixed_point whitex, whitey; +} png_xy; + +/* The same data as above but encoded as CIE XYZ values. When this data comes + * from chromaticities the sum of the Y values is assumed to be 1.0 + */ +typedef struct png_XYZ +{ + png_fixed_point red_X, red_Y, red_Z; + png_fixed_point green_X, green_Y, green_Z; + png_fixed_point blue_X, blue_Y, blue_Z; +} png_XYZ; +#endif /* COLORSPACE */ + +#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED) +/* A colorspace is all the above plus, potentially, profile information, + * however at present libpng does not use the profile internally so it is only + * stored in the png_info struct (if iCCP is supported.) The rendering intent + * is retained here and is checked. + * + * The file gamma encoding information is also stored here and gamma correction + * is done by libpng, whereas color correction must currently be done by the + * application. + */ +typedef struct png_colorspace +{ +#ifdef PNG_GAMMA_SUPPORTED + png_fixed_point gamma; /* File gamma */ +#endif + +#ifdef PNG_COLORSPACE_SUPPORTED + png_xy end_points_xy; /* End points as chromaticities */ + png_XYZ end_points_XYZ; /* End points as CIE XYZ colorant values */ + png_uint_16 rendering_intent; /* Rendering intent of a profile */ +#endif + + /* Flags are always defined to simplify the code. */ + png_uint_16 flags; /* As defined below */ +} png_colorspace, * PNG_RESTRICT png_colorspacerp; + +typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp; + +/* General flags for the 'flags' field */ +#define PNG_COLORSPACE_HAVE_GAMMA 0x0001 +#define PNG_COLORSPACE_HAVE_ENDPOINTS 0x0002 +#define PNG_COLORSPACE_HAVE_INTENT 0x0004 +#define PNG_COLORSPACE_FROM_gAMA 0x0008 +#define PNG_COLORSPACE_FROM_cHRM 0x0010 +#define PNG_COLORSPACE_FROM_sRGB 0x0020 +#define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040 +#define PNG_COLORSPACE_MATCHES_sRGB 0x0080 /* exact match on profile */ +#define PNG_COLORSPACE_INVALID 0x8000 +#define PNG_COLORSPACE_CANCEL(flags) (0xffff ^ (flags)) +#endif /* COLORSPACE || GAMMA */ + +struct png_struct_def +{ +#ifdef PNG_SETJMP_SUPPORTED + jmp_buf jmp_buf_local; /* New name in 1.6.0 for jmp_buf in png_struct */ + png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */ + jmp_buf *jmp_buf_ptr; /* passed to longjmp_fn */ + size_t jmp_buf_size; /* size of the above, if allocated */ +#endif + png_error_ptr error_fn; /* function for printing errors and aborting */ +#ifdef PNG_WARNINGS_SUPPORTED + png_error_ptr warning_fn; /* function for printing warnings */ +#endif + png_voidp error_ptr; /* user supplied struct for error functions */ + png_rw_ptr write_data_fn; /* function for writing output data */ + png_rw_ptr read_data_fn; /* function for reading input data */ + png_voidp io_ptr; /* ptr to application struct for I/O functions */ + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + png_user_transform_ptr read_user_transform_fn; /* user read transform */ +#endif + +#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED + png_user_transform_ptr write_user_transform_fn; /* user write transform */ +#endif + +/* These were added in libpng-1.0.2 */ +#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ + defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) + png_voidp user_transform_ptr; /* user supplied struct for user transform */ + png_byte user_transform_depth; /* bit depth of user transformed pixels */ + png_byte user_transform_channels; /* channels in user transformed pixels */ +#endif +#endif + + png_uint_32 mode; /* tells us where we are in the PNG file */ + png_uint_32 flags; /* flags indicating various things to libpng */ + png_uint_32 transformations; /* which transformations to perform */ + + png_uint_32 zowner; /* ID (chunk type) of zstream owner, 0 if none */ + z_stream zstream; /* decompression structure */ + +#ifdef PNG_WRITE_SUPPORTED + png_compression_bufferp zbuffer_list; /* Created on demand during write */ + uInt zbuffer_size; /* size of the actual buffer */ + + int zlib_level; /* holds zlib compression level */ + int zlib_method; /* holds zlib compression method */ + int zlib_window_bits; /* holds zlib compression window bits */ + int zlib_mem_level; /* holds zlib compression memory level */ + int zlib_strategy; /* holds zlib compression strategy */ +#endif +/* Added at libpng 1.5.4 */ +#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED + int zlib_text_level; /* holds zlib compression level */ + int zlib_text_method; /* holds zlib compression method */ + int zlib_text_window_bits; /* holds zlib compression window bits */ + int zlib_text_mem_level; /* holds zlib compression memory level */ + int zlib_text_strategy; /* holds zlib compression strategy */ +#endif +/* End of material added at libpng 1.5.4 */ +/* Added at libpng 1.6.0 */ +#ifdef PNG_WRITE_SUPPORTED + int zlib_set_level; /* Actual values set into the zstream on write */ + int zlib_set_method; + int zlib_set_window_bits; + int zlib_set_mem_level; + int zlib_set_strategy; +#endif + + png_uint_32 width; /* width of image in pixels */ + png_uint_32 height; /* height of image in pixels */ + png_uint_32 num_rows; /* number of rows in current pass */ + png_uint_32 usr_width; /* width of row at start of write */ + png_size_t rowbytes; /* size of row in bytes */ + png_uint_32 iwidth; /* width of current interlaced row in pixels */ + png_uint_32 row_number; /* current row in interlace pass */ + png_uint_32 chunk_name; /* PNG_CHUNK() id of current chunk */ + png_bytep prev_row; /* buffer to save previous (unfiltered) row. + * This is a pointer into big_prev_row + */ + png_bytep row_buf; /* buffer to save current (unfiltered) row. + * This is a pointer into big_row_buf + */ +#ifdef PNG_WRITE_SUPPORTED + png_bytep sub_row; /* buffer to save "sub" row when filtering */ + png_bytep up_row; /* buffer to save "up" row when filtering */ + png_bytep avg_row; /* buffer to save "avg" row when filtering */ + png_bytep paeth_row; /* buffer to save "Paeth" row when filtering */ +#endif + png_size_t info_rowbytes; /* Added in 1.5.4: cache of updated row bytes */ + + png_uint_32 idat_size; /* current IDAT size for read */ + png_uint_32 crc; /* current chunk CRC value */ + png_colorp palette; /* palette from the input file */ + png_uint_16 num_palette; /* number of color entries in palette */ + +/* Added at libpng-1.5.10 */ +#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED + int num_palette_max; /* maximum palette index found in IDAT */ +#endif + + png_uint_16 num_trans; /* number of transparency values */ + png_byte compression; /* file compression type (always 0) */ + png_byte filter; /* file filter type (always 0) */ + png_byte interlaced; /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */ + png_byte pass; /* current interlace pass (0 - 6) */ + png_byte do_filter; /* row filter flags (see PNG_FILTER_ below ) */ + png_byte color_type; /* color type of file */ + png_byte bit_depth; /* bit depth of file */ + png_byte usr_bit_depth; /* bit depth of users row: write only */ + png_byte pixel_depth; /* number of bits per pixel */ + png_byte channels; /* number of channels in file */ +#ifdef PNG_WRITE_SUPPORTED + png_byte usr_channels; /* channels at start of write: write only */ +#endif + png_byte sig_bytes; /* magic bytes read/written from start of file */ + png_byte maximum_pixel_depth; + /* pixel depth used for the row buffers */ + png_byte transformed_pixel_depth; + /* pixel depth after read/write transforms */ +#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) + png_uint_16 filler; /* filler bytes for pixel expansion */ +#endif + +#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) + png_byte background_gamma_type; + png_fixed_point background_gamma; + png_color_16 background; /* background color in screen gamma space */ +#ifdef PNG_READ_GAMMA_SUPPORTED + png_color_16 background_1; /* background normalized to gamma 1.0 */ +#endif +#endif /* PNG_bKGD_SUPPORTED */ + +#ifdef PNG_WRITE_FLUSH_SUPPORTED + png_flush_ptr output_flush_fn; /* Function for flushing output */ + png_uint_32 flush_dist; /* how many rows apart to flush, 0 - no flush */ + png_uint_32 flush_rows; /* number of rows written since last flush */ +#endif + +#ifdef PNG_READ_GAMMA_SUPPORTED + int gamma_shift; /* number of "insignificant" bits in 16-bit gamma */ + png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */ + + png_bytep gamma_table; /* gamma table for 8-bit depth files */ + png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */ +#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \ + defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \ + defined(PNG_READ_RGB_TO_GRAY_SUPPORTED) + png_bytep gamma_from_1; /* converts from 1.0 to screen */ + png_bytep gamma_to_1; /* converts from file to 1.0 */ + png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */ + png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */ +#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */ +#endif + +#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED) + png_color_8 sig_bit; /* significant bits in each available channel */ +#endif + +#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) + png_color_8 shift; /* shift for significant bit tranformation */ +#endif + +#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \ + || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) + png_bytep trans_alpha; /* alpha values for paletted files */ + png_color_16 trans_color; /* transparent color for non-paletted files */ +#endif + + png_read_status_ptr read_row_fn; /* called after each row is decoded */ + png_write_status_ptr write_row_fn; /* called after each row is encoded */ +#ifdef PNG_PROGRESSIVE_READ_SUPPORTED + png_progressive_info_ptr info_fn; /* called after header data fully read */ + png_progressive_row_ptr row_fn; /* called after a prog. row is decoded */ + png_progressive_end_ptr end_fn; /* called after image is complete */ + png_bytep save_buffer_ptr; /* current location in save_buffer */ + png_bytep save_buffer; /* buffer for previously read data */ + png_bytep current_buffer_ptr; /* current location in current_buffer */ + png_bytep current_buffer; /* buffer for recently used data */ + png_uint_32 push_length; /* size of current input chunk */ + png_uint_32 skip_length; /* bytes to skip in input data */ + png_size_t save_buffer_size; /* amount of data now in save_buffer */ + png_size_t save_buffer_max; /* total size of save_buffer */ + png_size_t buffer_size; /* total amount of available input data */ + png_size_t current_buffer_size; /* amount of data now in current_buffer */ + int process_mode; /* what push library is currently doing */ + int cur_palette; /* current push library palette index */ + +#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ + +#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__) +/* For the Borland special 64K segment handler */ + png_bytepp offset_table_ptr; + png_bytep offset_table; + png_uint_16 offset_table_number; + png_uint_16 offset_table_count; + png_uint_16 offset_table_count_free; +#endif + +#ifdef PNG_READ_QUANTIZE_SUPPORTED + png_bytep palette_lookup; /* lookup table for quantizing */ + png_bytep quantize_index; /* index translation for palette files */ +#endif + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + png_byte heuristic_method; /* heuristic for row filter selection */ + png_byte num_prev_filters; /* number of weights for previous rows */ + png_bytep prev_filters; /* filter type(s) of previous row(s) */ + png_uint_16p filter_weights; /* weight(s) for previous line(s) */ + png_uint_16p inv_filter_weights; /* 1/weight(s) for previous line(s) */ + png_uint_16p filter_costs; /* relative filter calculation cost */ + png_uint_16p inv_filter_costs; /* 1/relative filter calculation cost */ +#endif + + /* Options */ +#ifdef PNG_SET_OPTION_SUPPORTED + png_byte options; /* On/off state (up to 4 options) */ +#endif + +#if PNG_LIBPNG_VER < 10700 +/* To do: remove this from libpng-1.7 */ +#ifdef PNG_TIME_RFC1123_SUPPORTED + char time_buffer[29]; /* String to hold RFC 1123 time text */ +#endif +#endif + +/* New members added in libpng-1.0.6 */ + + png_uint_32 free_me; /* flags items libpng is responsible for freeing */ + +#ifdef PNG_USER_CHUNKS_SUPPORTED + png_voidp user_chunk_ptr; +#ifdef PNG_READ_USER_CHUNKS_SUPPORTED + png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */ +#endif +#endif + +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED + int unknown_default; /* As PNG_HANDLE_* */ + unsigned int num_chunk_list; /* Number of entries in the list */ + png_bytep chunk_list; /* List of png_byte[5]; the textual chunk name + * followed by a PNG_HANDLE_* byte */ +#endif + +/* New members added in libpng-1.0.3 */ +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED + png_byte rgb_to_gray_status; + /* Added in libpng 1.5.5 to record setting of coefficients: */ + png_byte rgb_to_gray_coefficients_set; + /* These were changed from png_byte in libpng-1.0.6 */ + png_uint_16 rgb_to_gray_red_coeff; + png_uint_16 rgb_to_gray_green_coeff; + /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */ +#endif + +/* New member added in libpng-1.0.4 (renamed in 1.0.9) */ +#if defined(PNG_MNG_FEATURES_SUPPORTED) +/* Changed from png_byte to png_uint_32 at version 1.2.0 */ + png_uint_32 mng_features_permitted; +#endif + +/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */ +#ifdef PNG_MNG_FEATURES_SUPPORTED + png_byte filter_type; +#endif + +/* New members added in libpng-1.2.0 */ + +/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */ +#ifdef PNG_USER_MEM_SUPPORTED + png_voidp mem_ptr; /* user supplied struct for mem functions */ + png_malloc_ptr malloc_fn; /* function for allocating memory */ + png_free_ptr free_fn; /* function for freeing memory */ +#endif + +/* New member added in libpng-1.0.13 and 1.2.0 */ + png_bytep big_row_buf; /* buffer to save current (unfiltered) row */ + +#ifdef PNG_READ_QUANTIZE_SUPPORTED +/* The following three members were added at version 1.0.14 and 1.2.4 */ + png_bytep quantize_sort; /* working sort array */ + png_bytep index_to_palette; /* where the original index currently is + in the palette */ + png_bytep palette_to_index; /* which original index points to this + palette color */ +#endif + +/* New members added in libpng-1.0.16 and 1.2.6 */ + png_byte compression_type; + +#ifdef PNG_USER_LIMITS_SUPPORTED + png_uint_32 user_width_max; + png_uint_32 user_height_max; + + /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown + * chunks that can be stored (0 means unlimited). + */ + png_uint_32 user_chunk_cache_max; + + /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk + * can occupy when decompressed. 0 means unlimited. + */ + png_alloc_size_t user_chunk_malloc_max; +#endif + +/* New member added in libpng-1.0.25 and 1.2.17 */ +#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED + /* Temporary storage for unknown chunk that the library doesn't recognize, + * used while reading the chunk. + */ + png_unknown_chunk unknown_chunk; +#endif + +/* New member added in libpng-1.2.26 */ + png_size_t old_big_row_buf_size; + +#ifdef PNG_READ_SUPPORTED +/* New member added in libpng-1.2.30 */ + png_bytep read_buffer; /* buffer for reading chunk data */ + png_alloc_size_t read_buffer_size; /* current size of the buffer */ +#endif +#ifdef PNG_SEQUENTIAL_READ_SUPPORTED + uInt IDAT_read_size; /* limit on read buffer size for IDAT */ +#endif + +#ifdef PNG_IO_STATE_SUPPORTED +/* New member added in libpng-1.4.0 */ + png_uint_32 io_state; +#endif + +/* New member added in libpng-1.5.6 */ + png_bytep big_prev_row; + +/* New member added in libpng-1.5.7 */ + void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info, + png_bytep row, png_const_bytep prev_row); + +#ifdef PNG_READ_SUPPORTED +#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED) + png_colorspace colorspace; +#endif +#endif +}; +#endif /* PNGSTRUCT_H */ diff --git a/png/pngtest.c b/png/pngtest.c new file mode 100755 index 0000000..ffac74e --- /dev/null +++ b/png/pngtest.c @@ -0,0 +1,1994 @@ + +/* pngtest.c - a simple test program to test libpng + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * This program reads in a PNG image, writes it out again, and then + * compares the two files. If the files are identical, this shows that + * the basic chunk handling, filtering, and (de)compression code is working + * properly. It does not currently test all of the transforms, although + * it probably should. + * + * The program will report "FAIL" in certain legitimate cases: + * 1) when the compression level or filter selection method is changed. + * 2) when the maximum IDAT size (PNG_ZBUF_SIZE in pngconf.h) is not 8192. + * 3) unknown unsafe-to-copy ancillary chunks or unknown critical chunks + * exist in the input file. + * 4) others not listed here... + * In these cases, it is best to check with another tool such as "pngcheck" + * to see what the differences between the two files are. + * + * If a filename is given on the command-line, then this file is used + * for the input, rather than the default "pngtest.png". This allows + * testing a wide variety of files easily. You can also test a number + * of files at once by typing "pngtest -m file1.png file2.png ..." + */ + +#define _POSIX_SOURCE 1 + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +/* Defined so I can write to a file on gui/windowing platforms */ +/* #define STDERR stderr */ +#define STDERR stdout /* For DOS */ + +#include "png.h" + +/* Known chunks that exist in pngtest.png must be supported or pngtest will fail + * simply as a result of re-ordering them. This may be fixed in 1.7 + * + * pngtest allocates a single row buffer for each row and overwrites it, + * therefore if the write side doesn't support the writing of interlaced images + * nothing can be done for an interlaced image (and the code below will fail + * horribly trying to write extra data after writing garbage). + */ +#if defined PNG_READ_SUPPORTED && /* else nothing can be done */\ + defined PNG_READ_bKGD_SUPPORTED &&\ + defined PNG_READ_cHRM_SUPPORTED &&\ + defined PNG_READ_gAMA_SUPPORTED &&\ + defined PNG_READ_oFFs_SUPPORTED &&\ + defined PNG_READ_pCAL_SUPPORTED &&\ + defined PNG_READ_pHYs_SUPPORTED &&\ + defined PNG_READ_sBIT_SUPPORTED &&\ + defined PNG_READ_sCAL_SUPPORTED &&\ + defined PNG_READ_sRGB_SUPPORTED &&\ + defined PNG_READ_tEXt_SUPPORTED &&\ + defined PNG_READ_tIME_SUPPORTED &&\ + defined PNG_READ_zTXt_SUPPORTED &&\ + defined PNG_WRITE_INTERLACING_SUPPORTED + +#ifdef PNG_ZLIB_HEADER +# include PNG_ZLIB_HEADER /* defined by pnglibconf.h from 1.7 */ +#else +# include "zlib.h" +#endif + +/* Copied from pngpriv.h but only used in error messages below. */ +#ifndef PNG_ZBUF_SIZE +# define PNG_ZBUF_SIZE 8192 +#endif +#define FCLOSE(file) fclose(file) + +#ifndef PNG_STDIO_SUPPORTED +typedef FILE * png_FILE_p; +#endif + +/* Makes pngtest verbose so we can find problems. */ +#ifndef PNG_DEBUG +# define PNG_DEBUG 0 +#endif + +#if PNG_DEBUG > 1 +# define pngtest_debug(m) ((void)fprintf(stderr, m "\n")) +# define pngtest_debug1(m,p1) ((void)fprintf(stderr, m "\n", p1)) +# define pngtest_debug2(m,p1,p2) ((void)fprintf(stderr, m "\n", p1, p2)) +#else +# define pngtest_debug(m) ((void)0) +# define pngtest_debug1(m,p1) ((void)0) +# define pngtest_debug2(m,p1,p2) ((void)0) +#endif + +#if !PNG_DEBUG +# define SINGLE_ROWBUF_ALLOC /* Makes buffer overruns easier to nail */ +#endif + +/* Turn on CPU timing +#define PNGTEST_TIMING +*/ + +#ifndef PNG_FLOATING_POINT_SUPPORTED +#undef PNGTEST_TIMING +#endif + +#ifdef PNGTEST_TIMING +static float t_start, t_stop, t_decode, t_encode, t_misc; +#include <time.h> +#endif + +#ifdef PNG_TIME_RFC1123_SUPPORTED +#define PNG_tIME_STRING_LENGTH 29 +static int tIME_chunk_present = 0; +static char tIME_string[PNG_tIME_STRING_LENGTH] = "tIME chunk is not present"; +#endif + +static int verbose = 0; +static int strict = 0; +static int relaxed = 0; +static int unsupported_chunks = 0; /* chunk unsupported by libpng in input */ +static int error_count = 0; /* count calls to png_error */ +static int warning_count = 0; /* count calls to png_warning */ + +/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */ +#ifndef png_jmpbuf +# define png_jmpbuf(png_ptr) png_ptr->jmpbuf +#endif + +/* Defines for unknown chunk handling if required. */ +#ifndef PNG_HANDLE_CHUNK_ALWAYS +# define PNG_HANDLE_CHUNK_ALWAYS 3 +#endif +#ifndef PNG_HANDLE_CHUNK_IF_SAFE +# define PNG_HANDLE_CHUNK_IF_SAFE 2 +#endif + +/* Utility to save typing/errors, the argument must be a name */ +#define MEMZERO(var) ((void)memset(&var, 0, sizeof var)) + +/* Example of using row callbacks to make a simple progress meter */ +static int status_pass = 1; +static int status_dots_requested = 0; +static int status_dots = 1; + +static void PNGCBAPI +read_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass) +{ + if (png_ptr == NULL || row_number > PNG_UINT_31_MAX) + return; + + if (status_pass != pass) + { + fprintf(stdout, "\n Pass %d: ", pass); + status_pass = pass; + status_dots = 31; + } + + status_dots--; + + if (status_dots == 0) + { + fprintf(stdout, "\n "); + status_dots=30; + } + + fprintf(stdout, "r"); +} + +#ifdef PNG_WRITE_SUPPORTED +static void PNGCBAPI +write_row_callback(png_structp png_ptr, png_uint_32 row_number, int pass) +{ + if (png_ptr == NULL || row_number > PNG_UINT_31_MAX || pass > 7) + return; + + fprintf(stdout, "w"); +} +#endif + + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED +/* Example of using user transform callback (we don't transform anything, + * but merely examine the row filters. We set this to 256 rather than + * 5 in case illegal filter values are present.) + */ +static png_uint_32 filters_used[256]; +static void PNGCBAPI +count_filters(png_structp png_ptr, png_row_infop row_info, png_bytep data) +{ + if (png_ptr != NULL && row_info != NULL) + ++filters_used[*(data - 1)]; +} +#endif + +#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED +/* Example of using user transform callback (we don't transform anything, + * but merely count the zero samples) + */ + +static png_uint_32 zero_samples; + +static void PNGCBAPI +count_zero_samples(png_structp png_ptr, png_row_infop row_info, png_bytep data) +{ + png_bytep dp = data; + if (png_ptr == NULL) + return; + + /* Contents of row_info: + * png_uint_32 width width of row + * png_uint_32 rowbytes number of bytes in row + * png_byte color_type color type of pixels + * png_byte bit_depth bit depth of samples + * png_byte channels number of channels (1-4) + * png_byte pixel_depth bits per pixel (depth*channels) + */ + + /* Counts the number of zero samples (or zero pixels if color_type is 3 */ + + if (row_info->color_type == 0 || row_info->color_type == 3) + { + int pos = 0; + png_uint_32 n, nstop; + + for (n = 0, nstop=row_info->width; n<nstop; n++) + { + if (row_info->bit_depth == 1) + { + if (((*dp << pos++ ) & 0x80) == 0) + zero_samples++; + + if (pos == 8) + { + pos = 0; + dp++; + } + } + + if (row_info->bit_depth == 2) + { + if (((*dp << (pos+=2)) & 0xc0) == 0) + zero_samples++; + + if (pos == 8) + { + pos = 0; + dp++; + } + } + + if (row_info->bit_depth == 4) + { + if (((*dp << (pos+=4)) & 0xf0) == 0) + zero_samples++; + + if (pos == 8) + { + pos = 0; + dp++; + } + } + + if (row_info->bit_depth == 8) + if (*dp++ == 0) + zero_samples++; + + if (row_info->bit_depth == 16) + { + if ((*dp | *(dp+1)) == 0) + zero_samples++; + dp+=2; + } + } + } + else /* Other color types */ + { + png_uint_32 n, nstop; + int channel; + int color_channels = row_info->channels; + if (row_info->color_type > 3)color_channels--; + + for (n = 0, nstop=row_info->width; n<nstop; n++) + { + for (channel = 0; channel < color_channels; channel++) + { + if (row_info->bit_depth == 8) + if (*dp++ == 0) + zero_samples++; + + if (row_info->bit_depth == 16) + { + if ((*dp | *(dp+1)) == 0) + zero_samples++; + + dp+=2; + } + } + if (row_info->color_type > 3) + { + dp++; + if (row_info->bit_depth == 16) + dp++; + } + } + } +} +#endif /* PNG_WRITE_USER_TRANSFORM_SUPPORTED */ + +#ifndef PNG_STDIO_SUPPORTED +/* START of code to validate stdio-free compilation */ +/* These copies of the default read/write functions come from pngrio.c and + * pngwio.c. They allow "don't include stdio" testing of the library. + * This is the function that does the actual reading of data. If you are + * not reading from a standard C stream, you should create a replacement + * read_data function and use it at run time with png_set_read_fn(), rather + * than changing the library. + */ + +#ifdef PNG_IO_STATE_SUPPORTED +void +pngtest_check_io_state(png_structp png_ptr, png_size_t data_length, + png_uint_32 io_op); +void +pngtest_check_io_state(png_structp png_ptr, png_size_t data_length, + png_uint_32 io_op) +{ + png_uint_32 io_state = png_get_io_state(png_ptr); + int err = 0; + + /* Check if the current operation (reading / writing) is as expected. */ + if ((io_state & PNG_IO_MASK_OP) != io_op) + png_error(png_ptr, "Incorrect operation in I/O state"); + + /* Check if the buffer size specific to the current location + * (file signature / header / data / crc) is as expected. + */ + switch (io_state & PNG_IO_MASK_LOC) + { + case PNG_IO_SIGNATURE: + if (data_length > 8) + err = 1; + break; + case PNG_IO_CHUNK_HDR: + if (data_length != 8) + err = 1; + break; + case PNG_IO_CHUNK_DATA: + break; /* no restrictions here */ + case PNG_IO_CHUNK_CRC: + if (data_length != 4) + err = 1; + break; + default: + err = 1; /* uninitialized */ + } + if (err != 0) + png_error(png_ptr, "Bad I/O state or buffer size"); +} +#endif + +static void PNGCBAPI +pngtest_read_data(png_structp png_ptr, png_bytep data, png_size_t length) +{ + png_size_t check = 0; + png_voidp io_ptr; + + /* fread() returns 0 on error, so it is OK to store this in a png_size_t + * instead of an int, which is what fread() actually returns. + */ + io_ptr = png_get_io_ptr(png_ptr); + if (io_ptr != NULL) + { + check = fread(data, 1, length, (png_FILE_p)io_ptr); + } + + if (check != length) + { + png_error(png_ptr, "Read Error"); + } + +#ifdef PNG_IO_STATE_SUPPORTED + pngtest_check_io_state(png_ptr, length, PNG_IO_READING); +#endif +} + +#ifdef PNG_WRITE_FLUSH_SUPPORTED +static void PNGCBAPI +pngtest_flush(png_structp png_ptr) +{ + /* Do nothing; fflush() is said to be just a waste of energy. */ + PNG_UNUSED(png_ptr) /* Stifle compiler warning */ +} +#endif + +/* This is the function that does the actual writing of data. If you are + * not writing to a standard C stream, you should create a replacement + * write_data function and use it at run time with png_set_write_fn(), rather + * than changing the library. + */ +static void PNGCBAPI +pngtest_write_data(png_structp png_ptr, png_bytep data, png_size_t length) +{ + png_size_t check; + + check = fwrite(data, 1, length, (png_FILE_p)png_get_io_ptr(png_ptr)); + + if (check != length) + { + png_error(png_ptr, "Write Error"); + } + +#ifdef PNG_IO_STATE_SUPPORTED + pngtest_check_io_state(png_ptr, length, PNG_IO_WRITING); +#endif +} +#endif /* !PNG_STDIO_SUPPORTED */ + +/* This function is called when there is a warning, but the library thinks + * it can continue anyway. Replacement functions don't have to do anything + * here if you don't want to. In the default configuration, png_ptr is + * not used, but it is passed in case it may be useful. + */ +typedef struct +{ + PNG_CONST char *file_name; +} pngtest_error_parameters; + +static void PNGCBAPI +pngtest_warning(png_structp png_ptr, png_const_charp message) +{ + PNG_CONST char *name = "UNKNOWN (ERROR!)"; + pngtest_error_parameters *test = + (pngtest_error_parameters*)png_get_error_ptr(png_ptr); + + ++warning_count; + + if (test != NULL && test->file_name != NULL) + name = test->file_name; + + fprintf(STDERR, "%s: libpng warning: %s\n", name, message); +} + +/* This is the default error handling function. Note that replacements for + * this function MUST NOT RETURN, or the program will likely crash. This + * function is used by default, or if the program supplies NULL for the + * error function pointer in png_set_error_fn(). + */ +static void PNGCBAPI +pngtest_error(png_structp png_ptr, png_const_charp message) +{ + ++error_count; + + pngtest_warning(png_ptr, message); + /* We can return because png_error calls the default handler, which is + * actually OK in this case. + */ +} + +/* END of code to validate stdio-free compilation */ + +/* START of code to validate memory allocation and deallocation */ +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + +/* Allocate memory. For reasonable files, size should never exceed + * 64K. However, zlib may allocate more then 64K if you don't tell + * it not to. See zconf.h and png.h for more information. zlib does + * need to allocate exactly 64K, so whatever you call here must + * have the ability to do that. + * + * This piece of code can be compiled to validate max 64K allocations + * by setting MAXSEG_64K in zlib zconf.h *or* PNG_MAX_MALLOC_64K. + */ +typedef struct memory_information +{ + png_alloc_size_t size; + png_voidp pointer; + struct memory_information *next; +} memory_information; +typedef memory_information *memory_infop; + +static memory_infop pinformation = NULL; +static int current_allocation = 0; +static int maximum_allocation = 0; +static int total_allocation = 0; +static int num_allocations = 0; + +png_voidp PNGCBAPI png_debug_malloc PNGARG((png_structp png_ptr, + png_alloc_size_t size)); +void PNGCBAPI png_debug_free PNGARG((png_structp png_ptr, png_voidp ptr)); + +png_voidp +PNGCBAPI png_debug_malloc(png_structp png_ptr, png_alloc_size_t size) +{ + + /* png_malloc has already tested for NULL; png_create_struct calls + * png_debug_malloc directly, with png_ptr == NULL which is OK + */ + + if (size == 0) + return (NULL); + + /* This calls the library allocator twice, once to get the requested + buffer and once to get a new free list entry. */ + { + /* Disable malloc_fn and free_fn */ + memory_infop pinfo; + png_set_mem_fn(png_ptr, NULL, NULL, NULL); + pinfo = (memory_infop)png_malloc(png_ptr, + (sizeof *pinfo)); + pinfo->size = size; + current_allocation += size; + total_allocation += size; + num_allocations ++; + + if (current_allocation > maximum_allocation) + maximum_allocation = current_allocation; + + pinfo->pointer = png_malloc(png_ptr, size); + /* Restore malloc_fn and free_fn */ + + png_set_mem_fn(png_ptr, + NULL, png_debug_malloc, png_debug_free); + + if (size != 0 && pinfo->pointer == NULL) + { + current_allocation -= size; + total_allocation -= size; + png_error(png_ptr, + "out of memory in pngtest->png_debug_malloc"); + } + + pinfo->next = pinformation; + pinformation = pinfo; + /* Make sure the caller isn't assuming zeroed memory. */ + memset(pinfo->pointer, 0xdd, pinfo->size); + + if (verbose != 0) + printf("png_malloc %lu bytes at %p\n", (unsigned long)size, + pinfo->pointer); + + return (png_voidp)(pinfo->pointer); + } +} + +/* Free a pointer. It is removed from the list at the same time. */ +void PNGCBAPI +png_debug_free(png_structp png_ptr, png_voidp ptr) +{ + if (png_ptr == NULL) + fprintf(STDERR, "NULL pointer to png_debug_free.\n"); + + if (ptr == 0) + { +#if 0 /* This happens all the time. */ + fprintf(STDERR, "WARNING: freeing NULL pointer\n"); +#endif + return; + } + + /* Unlink the element from the list. */ + { + memory_infop *ppinfo = &pinformation; + + for (;;) + { + memory_infop pinfo = *ppinfo; + + if (pinfo->pointer == ptr) + { + *ppinfo = pinfo->next; + current_allocation -= pinfo->size; + if (current_allocation < 0) + fprintf(STDERR, "Duplicate free of memory\n"); + /* We must free the list element too, but first kill + the memory that is to be freed. */ + memset(ptr, 0x55, pinfo->size); + if (pinfo != NULL) + free(pinfo); + pinfo = NULL; + break; + } + + if (pinfo->next == NULL) + { + fprintf(STDERR, "Pointer %x not found\n", (unsigned int)ptr); + break; + } + + ppinfo = &pinfo->next; + } + } + + /* Finally free the data. */ + if (verbose != 0) + printf("Freeing %p\n", ptr); + + if (ptr != NULL) + free(ptr); + ptr = NULL; +} +#endif /* PNG_USER_MEM_SUPPORTED && PNG_DEBUG */ +/* END of code to test memory allocation/deallocation */ + + +#ifdef PNG_READ_USER_CHUNKS_SUPPORTED +/* Demonstration of user chunk support of the sTER and vpAg chunks */ + +/* (sTER is a public chunk not yet known by libpng. vpAg is a private +chunk used in ImageMagick to store "virtual page" size). */ + +static struct user_chunk_data +{ + png_const_infop info_ptr; + png_uint_32 vpAg_width, vpAg_height; + png_byte vpAg_units; + png_byte sTER_mode; + int location[2]; +} +user_chunk_data; + +/* Used for location and order; zero means nothing. */ +#define have_sTER 0x01 +#define have_vpAg 0x02 +#define before_PLTE 0x10 +#define before_IDAT 0x20 +#define after_IDAT 0x40 + +static void +init_callback_info(png_const_infop info_ptr) +{ + MEMZERO(user_chunk_data); + user_chunk_data.info_ptr = info_ptr; +} + +static int +set_location(png_structp png_ptr, struct user_chunk_data *data, int what) +{ + int location; + + if ((data->location[0] & what) || (data->location[1] & what)) + return 0; /* already have one of these */ + + /* Find where we are (the code below zeros info_ptr to indicate that the + * chunks before the first IDAT have been read.) + */ + if (data->info_ptr == NULL) /* after IDAT */ + location = what | after_IDAT; + + else if (png_get_valid(png_ptr, data->info_ptr, PNG_INFO_PLTE)) + location = what | before_IDAT; + + else + location = what | before_PLTE; + + if (data->location[0] == 0) + data->location[0] = location; + + else + data->location[1] = location; + + return 1; /* handled */ +} + +static int PNGCBAPI +read_user_chunk_callback(png_struct *png_ptr, png_unknown_chunkp chunk) +{ + struct user_chunk_data *my_user_chunk_data = + (struct user_chunk_data*)png_get_user_chunk_ptr(png_ptr); + + if (my_user_chunk_data == NULL) + png_error(png_ptr, "lost user chunk pointer"); + + /* Return one of the following: + * return (-n); chunk had an error + * return (0); did not recognize + * return (n); success + * + * The unknown chunk structure contains the chunk data: + * png_byte name[5]; + * png_byte *data; + * png_size_t size; + * + * Note that libpng has already taken care of the CRC handling. + */ + + if (chunk->name[0] == 115 && chunk->name[1] == 84 && /* s T */ + chunk->name[2] == 69 && chunk->name[3] == 82) /* E R */ + { + /* Found sTER chunk */ + if (chunk->size != 1) + return (-1); /* Error return */ + + if (chunk->data[0] != 0 && chunk->data[0] != 1) + return (-1); /* Invalid mode */ + + if (set_location(png_ptr, my_user_chunk_data, have_sTER)) + { + my_user_chunk_data->sTER_mode=chunk->data[0]; + return (1); + } + + else + return (0); /* duplicate sTER - give it to libpng */ + } + + if (chunk->name[0] != 118 || chunk->name[1] != 112 || /* v p */ + chunk->name[2] != 65 || chunk->name[3] != 103) /* A g */ + return (0); /* Did not recognize */ + + /* Found ImageMagick vpAg chunk */ + + if (chunk->size != 9) + return (-1); /* Error return */ + + if (!set_location(png_ptr, my_user_chunk_data, have_vpAg)) + return (0); /* duplicate vpAg */ + + my_user_chunk_data->vpAg_width = png_get_uint_31(png_ptr, chunk->data); + my_user_chunk_data->vpAg_height = png_get_uint_31(png_ptr, chunk->data + 4); + my_user_chunk_data->vpAg_units = chunk->data[8]; + + return (1); +} + +#ifdef PNG_WRITE_SUPPORTED +static void +write_sTER_chunk(png_structp write_ptr) +{ + png_byte sTER[5] = {115, 84, 69, 82, '\0'}; + + if (verbose != 0) + fprintf(STDERR, "\n stereo mode = %d\n", user_chunk_data.sTER_mode); + + png_write_chunk(write_ptr, sTER, &user_chunk_data.sTER_mode, 1); +} + +static void +write_vpAg_chunk(png_structp write_ptr) +{ + png_byte vpAg[5] = {118, 112, 65, 103, '\0'}; + + png_byte vpag_chunk_data[9]; + + if (verbose != 0) + fprintf(STDERR, " vpAg = %lu x %lu, units = %d\n", + (unsigned long)user_chunk_data.vpAg_width, + (unsigned long)user_chunk_data.vpAg_height, + user_chunk_data.vpAg_units); + + png_save_uint_32(vpag_chunk_data, user_chunk_data.vpAg_width); + png_save_uint_32(vpag_chunk_data + 4, user_chunk_data.vpAg_height); + vpag_chunk_data[8] = user_chunk_data.vpAg_units; + png_write_chunk(write_ptr, vpAg, vpag_chunk_data, 9); +} + +static void +write_chunks(png_structp write_ptr, int location) +{ + int i; + + /* Notice that this preserves the original chunk order, however chunks + * intercepted by the callback will be written *after* chunks passed to + * libpng. This will actually reverse a pair of sTER chunks or a pair of + * vpAg chunks, resulting in an error later. This is not worth worrying + * about - the chunks should not be duplicated! + */ + for (i=0; i<2; ++i) + { + if (user_chunk_data.location[i] == (location | have_sTER)) + write_sTER_chunk(write_ptr); + + else if (user_chunk_data.location[i] == (location | have_vpAg)) + write_vpAg_chunk(write_ptr); + } +} +#endif /* PNG_WRITE_SUPPORTED */ +#else /* !PNG_READ_USER_CHUNKS_SUPPORTED */ +# define write_chunks(pp,loc) ((void)0) +#endif +/* END of code to demonstrate user chunk support */ + +/* START of code to check that libpng has the required text support; this only + * checks for the write support because if read support is missing the chunk + * will simply not be reported back to pngtest. + */ +#ifdef PNG_TEXT_SUPPORTED +static void +pngtest_check_text_support(png_const_structp png_ptr, png_textp text_ptr, + int num_text) +{ + while (num_text > 0) + { + switch (text_ptr[--num_text].compression) + { + case PNG_TEXT_COMPRESSION_NONE: + break; + + case PNG_TEXT_COMPRESSION_zTXt: +# ifndef PNG_WRITE_zTXt_SUPPORTED + ++unsupported_chunks; +# endif + break; + + case PNG_ITXT_COMPRESSION_NONE: + case PNG_ITXT_COMPRESSION_zTXt: +# ifndef PNG_WRITE_iTXt_SUPPORTED + ++unsupported_chunks; +# endif + break; + + default: + /* This is an error */ + png_error(png_ptr, "invalid text chunk compression field"); + break; + } + } +} +#endif +/* END of code to check that libpng has the required text support */ + +/* Test one file */ +static int +test_one_file(PNG_CONST char *inname, PNG_CONST char *outname) +{ + static png_FILE_p fpin; + static png_FILE_p fpout; /* "static" prevents setjmp corruption */ + pngtest_error_parameters error_parameters; + png_structp read_ptr; + png_infop read_info_ptr, end_info_ptr; +#ifdef PNG_WRITE_SUPPORTED + png_structp write_ptr; + png_infop write_info_ptr; + png_infop write_end_info_ptr; + int interlace_preserved = 1; +#else + png_structp write_ptr = NULL; + png_infop write_info_ptr = NULL; + png_infop write_end_info_ptr = NULL; +#endif + png_bytep row_buf; + png_uint_32 y; + png_uint_32 width, height; + int num_pass = 1, pass; + int bit_depth, color_type; + + row_buf = NULL; + error_parameters.file_name = inname; + + if ((fpin = fopen(inname, "rb")) == NULL) + { + fprintf(STDERR, "Could not find input file %s\n", inname); + return (1); + } + + if ((fpout = fopen(outname, "wb")) == NULL) + { + fprintf(STDERR, "Could not open output file %s\n", outname); + FCLOSE(fpin); + return (1); + } + + pngtest_debug("Allocating read and write structures"); +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + read_ptr = + png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL, + NULL, NULL, NULL, png_debug_malloc, png_debug_free); +#else + read_ptr = + png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); +#endif + png_set_error_fn(read_ptr, &error_parameters, pngtest_error, + pngtest_warning); + +#ifdef PNG_WRITE_SUPPORTED +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + write_ptr = + png_create_write_struct_2(PNG_LIBPNG_VER_STRING, NULL, + NULL, NULL, NULL, png_debug_malloc, png_debug_free); +#else + write_ptr = + png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); +#endif + png_set_error_fn(write_ptr, &error_parameters, pngtest_error, + pngtest_warning); +#endif + pngtest_debug("Allocating read_info, write_info and end_info structures"); + read_info_ptr = png_create_info_struct(read_ptr); + end_info_ptr = png_create_info_struct(read_ptr); +#ifdef PNG_WRITE_SUPPORTED + write_info_ptr = png_create_info_struct(write_ptr); + write_end_info_ptr = png_create_info_struct(write_ptr); +#endif + +#ifdef PNG_READ_USER_CHUNKS_SUPPORTED + init_callback_info(read_info_ptr); + png_set_read_user_chunk_fn(read_ptr, &user_chunk_data, + read_user_chunk_callback); +#endif + +#ifdef PNG_SETJMP_SUPPORTED + pngtest_debug("Setting jmpbuf for read struct"); + if (setjmp(png_jmpbuf(read_ptr))) + { + fprintf(STDERR, "%s -> %s: libpng read error\n", inname, outname); + png_free(read_ptr, row_buf); + row_buf = NULL; + png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr); +#ifdef PNG_WRITE_SUPPORTED + png_destroy_info_struct(write_ptr, &write_end_info_ptr); + png_destroy_write_struct(&write_ptr, &write_info_ptr); +#endif + FCLOSE(fpin); + FCLOSE(fpout); + return (1); + } + +#ifdef PNG_WRITE_SUPPORTED + pngtest_debug("Setting jmpbuf for write struct"); + + if (setjmp(png_jmpbuf(write_ptr))) + { + fprintf(STDERR, "%s -> %s: libpng write error\n", inname, outname); + png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr); + png_destroy_info_struct(write_ptr, &write_end_info_ptr); +#ifdef PNG_WRITE_SUPPORTED + png_destroy_write_struct(&write_ptr, &write_info_ptr); +#endif + FCLOSE(fpin); + FCLOSE(fpout); + return (1); + } +#endif +#endif + + if (strict != 0) + { + /* Treat png_benign_error() as errors on read */ + png_set_benign_errors(read_ptr, 0); + +#ifdef PNG_WRITE_SUPPORTED + /* Treat them as errors on write */ + png_set_benign_errors(write_ptr, 0); +#endif + + /* if strict is not set, then app warnings and errors are treated as + * warnings in release builds, but not in unstable builds; this can be + * changed with '--relaxed'. + */ + } + + else if (relaxed != 0) + { + /* Allow application (pngtest) errors and warnings to pass */ + png_set_benign_errors(read_ptr, 1); + +#ifdef PNG_WRITE_SUPPORTED + png_set_benign_errors(write_ptr, 1); +#endif + } + + pngtest_debug("Initializing input and output streams"); +#ifdef PNG_STDIO_SUPPORTED + png_init_io(read_ptr, fpin); +# ifdef PNG_WRITE_SUPPORTED + png_init_io(write_ptr, fpout); +# endif +#else + png_set_read_fn(read_ptr, (png_voidp)fpin, pngtest_read_data); +# ifdef PNG_WRITE_SUPPORTED + png_set_write_fn(write_ptr, (png_voidp)fpout, pngtest_write_data, +# ifdef PNG_WRITE_FLUSH_SUPPORTED + pngtest_flush); +# else + NULL); +# endif +# endif +#endif + + if (status_dots_requested == 1) + { +#ifdef PNG_WRITE_SUPPORTED + png_set_write_status_fn(write_ptr, write_row_callback); +#endif + png_set_read_status_fn(read_ptr, read_row_callback); + } + + else + { +#ifdef PNG_WRITE_SUPPORTED + png_set_write_status_fn(write_ptr, NULL); +#endif + png_set_read_status_fn(read_ptr, NULL); + } + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + { + int i; + + for (i = 0; i<256; i++) + filters_used[i] = 0; + + png_set_read_user_transform_fn(read_ptr, count_filters); + } +#endif +#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED + zero_samples = 0; + png_set_write_user_transform_fn(write_ptr, count_zero_samples); +#endif + +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED + /* Preserve all the unknown chunks, if possible. If this is disabled then, + * even if the png_{get,set}_unknown_chunks stuff is enabled, we can't use + * libpng to *save* the unknown chunks on read (because we can't switch the + * save option on!) + * + * Notice that if SET_UNKNOWN_CHUNKS is *not* supported read will discard all + * unknown chunks and write will write them all. + */ +#ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED + png_set_keep_unknown_chunks(read_ptr, PNG_HANDLE_CHUNK_ALWAYS, + NULL, 0); +#endif +#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + png_set_keep_unknown_chunks(write_ptr, PNG_HANDLE_CHUNK_ALWAYS, + NULL, 0); +#endif +#endif + + pngtest_debug("Reading info struct"); + png_read_info(read_ptr, read_info_ptr); + +#ifdef PNG_READ_USER_CHUNKS_SUPPORTED + /* This is a bit of a hack; there is no obvious way in the callback function + * to determine that the chunks before the first IDAT have been read, so + * remove the info_ptr (which is only used to determine position relative to + * PLTE) here to indicate that we are after the IDAT. + */ + user_chunk_data.info_ptr = NULL; +#endif + + pngtest_debug("Transferring info struct"); + { + int interlace_type, compression_type, filter_type; + + if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth, + &color_type, &interlace_type, &compression_type, &filter_type)) + { + png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth, + color_type, interlace_type, compression_type, filter_type); +#ifndef PNG_READ_INTERLACING_SUPPORTED + /* num_pass will not be set below, set it here if the image is + * interlaced: what happens is that write interlacing is *not* turned + * on an the partial interlaced rows are written directly. + */ + switch (interlace_type) + { + case PNG_INTERLACE_NONE: + num_pass = 1; + break; + + case PNG_INTERLACE_ADAM7: + num_pass = 7; + break; + + default: + png_error(read_ptr, "invalid interlace type"); + /*NOT REACHED*/ + } +#endif + } + } +#ifdef PNG_FIXED_POINT_SUPPORTED +#ifdef PNG_cHRM_SUPPORTED + { + png_fixed_point white_x, white_y, red_x, red_y, green_x, green_y, blue_x, + blue_y; + + if (png_get_cHRM_fixed(read_ptr, read_info_ptr, &white_x, &white_y, + &red_x, &red_y, &green_x, &green_y, &blue_x, &blue_y)) + { + png_set_cHRM_fixed(write_ptr, write_info_ptr, white_x, white_y, red_x, + red_y, green_x, green_y, blue_x, blue_y); + } + } +#endif +#ifdef PNG_gAMA_SUPPORTED + { + png_fixed_point gamma; + + if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma)) + png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma); + } +#endif +#else /* Use floating point versions */ +#ifdef PNG_FLOATING_POINT_SUPPORTED +#ifdef PNG_cHRM_SUPPORTED + { + double white_x, white_y, red_x, red_y, green_x, green_y, blue_x, + blue_y; + + if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x, + &red_y, &green_x, &green_y, &blue_x, &blue_y)) + { + png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x, + red_y, green_x, green_y, blue_x, blue_y); + } + } +#endif +#ifdef PNG_gAMA_SUPPORTED + { + double gamma; + + if (png_get_gAMA(read_ptr, read_info_ptr, &gamma)) + png_set_gAMA(write_ptr, write_info_ptr, gamma); + } +#endif +#endif /* Floating point */ +#endif /* Fixed point */ +#ifdef PNG_iCCP_SUPPORTED + { + png_charp name; + png_bytep profile; + png_uint_32 proflen; + int compression_type; + + if (png_get_iCCP(read_ptr, read_info_ptr, &name, &compression_type, + &profile, &proflen)) + { + png_set_iCCP(write_ptr, write_info_ptr, name, compression_type, + profile, proflen); + } + } +#endif +#ifdef PNG_sRGB_SUPPORTED + { + int intent; + + if (png_get_sRGB(read_ptr, read_info_ptr, &intent)) + png_set_sRGB(write_ptr, write_info_ptr, intent); + } +#endif + { + png_colorp palette; + int num_palette; + + if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette)) + png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette); + } +#ifdef PNG_bKGD_SUPPORTED + { + png_color_16p background; + + if (png_get_bKGD(read_ptr, read_info_ptr, &background)) + { + png_set_bKGD(write_ptr, write_info_ptr, background); + } + } +#endif +#ifdef PNG_hIST_SUPPORTED + { + png_uint_16p hist; + + if (png_get_hIST(read_ptr, read_info_ptr, &hist)) + png_set_hIST(write_ptr, write_info_ptr, hist); + } +#endif +#ifdef PNG_oFFs_SUPPORTED + { + png_int_32 offset_x, offset_y; + int unit_type; + + if (png_get_oFFs(read_ptr, read_info_ptr, &offset_x, &offset_y, + &unit_type)) + { + png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type); + } + } +#endif +#ifdef PNG_pCAL_SUPPORTED + { + png_charp purpose, units; + png_charpp params; + png_int_32 X0, X1; + int type, nparams; + + if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type, + &nparams, &units, ¶ms)) + { + png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type, + nparams, units, params); + } + } +#endif +#ifdef PNG_pHYs_SUPPORTED + { + png_uint_32 res_x, res_y; + int unit_type; + + if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y, &unit_type)) + png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type); + } +#endif +#ifdef PNG_sBIT_SUPPORTED + { + png_color_8p sig_bit; + + if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit)) + png_set_sBIT(write_ptr, write_info_ptr, sig_bit); + } +#endif +#ifdef PNG_sCAL_SUPPORTED +#if defined(PNG_FLOATING_POINT_SUPPORTED) && \ + defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) + { + int unit; + double scal_width, scal_height; + + if (png_get_sCAL(read_ptr, read_info_ptr, &unit, &scal_width, + &scal_height)) + { + png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height); + } + } +#else +#ifdef PNG_FIXED_POINT_SUPPORTED + { + int unit; + png_charp scal_width, scal_height; + + if (png_get_sCAL_s(read_ptr, read_info_ptr, &unit, &scal_width, + &scal_height)) + { + png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width, + scal_height); + } + } +#endif +#endif +#endif +#ifdef PNG_TEXT_SUPPORTED + { + png_textp text_ptr; + int num_text; + + if (png_get_text(read_ptr, read_info_ptr, &text_ptr, &num_text) > 0) + { + pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text); + + pngtest_check_text_support(read_ptr, text_ptr, num_text); + + if (verbose != 0) + { + int i; + + printf("\n"); + for (i=0; i<num_text; i++) + { + printf(" Text compression[%d]=%d\n", + i, text_ptr[i].compression); + } + } + + png_set_text(write_ptr, write_info_ptr, text_ptr, num_text); + } + } +#endif +#ifdef PNG_tIME_SUPPORTED + { + png_timep mod_time; + + if (png_get_tIME(read_ptr, read_info_ptr, &mod_time)) + { + png_set_tIME(write_ptr, write_info_ptr, mod_time); +#ifdef PNG_TIME_RFC1123_SUPPORTED + if (png_convert_to_rfc1123_buffer(tIME_string, mod_time)) + tIME_string[(sizeof tIME_string) - 1] = '\0'; + + else + { + strncpy(tIME_string, "*** invalid time ***", (sizeof tIME_string)); + tIME_string[(sizeof tIME_string) - 1] = '\0'; + } + + tIME_chunk_present++; +#endif /* PNG_TIME_RFC1123_SUPPORTED */ + } + } +#endif +#ifdef PNG_tRNS_SUPPORTED + { + png_bytep trans_alpha; + int num_trans; + png_color_16p trans_color; + + if (png_get_tRNS(read_ptr, read_info_ptr, &trans_alpha, &num_trans, + &trans_color)) + { + int sample_max = (1 << bit_depth); + /* libpng doesn't reject a tRNS chunk with out-of-range samples */ + if (!((color_type == PNG_COLOR_TYPE_GRAY && + (int)trans_color->gray > sample_max) || + (color_type == PNG_COLOR_TYPE_RGB && + ((int)trans_color->red > sample_max || + (int)trans_color->green > sample_max || + (int)trans_color->blue > sample_max)))) + png_set_tRNS(write_ptr, write_info_ptr, trans_alpha, num_trans, + trans_color); + } + } +#endif +#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + { + png_unknown_chunkp unknowns; + int num_unknowns = png_get_unknown_chunks(read_ptr, read_info_ptr, + &unknowns); + + if (num_unknowns != 0) + { + png_set_unknown_chunks(write_ptr, write_info_ptr, unknowns, + num_unknowns); +#if PNG_LIBPNG_VER < 10600 + /* Copy the locations from the read_info_ptr. The automatically + * generated locations in write_end_info_ptr are wrong prior to 1.6.0 + * because they are reset from the write pointer (removed in 1.6.0). + */ + { + int i; + for (i = 0; i < num_unknowns; i++) + png_set_unknown_chunk_location(write_ptr, write_info_ptr, i, + unknowns[i].location); + } +#endif + } + } +#endif + +#ifdef PNG_WRITE_SUPPORTED + pngtest_debug("Writing info struct"); + + /* Write the info in two steps so that if we write the 'unknown' chunks here + * they go to the correct place. + */ + png_write_info_before_PLTE(write_ptr, write_info_ptr); + + write_chunks(write_ptr, before_PLTE); /* before PLTE */ + + png_write_info(write_ptr, write_info_ptr); + + write_chunks(write_ptr, before_IDAT); /* after PLTE */ +#endif + +#ifdef SINGLE_ROWBUF_ALLOC + pngtest_debug("Allocating row buffer..."); + row_buf = (png_bytep)png_malloc(read_ptr, + png_get_rowbytes(read_ptr, read_info_ptr)); + + pngtest_debug1("\t0x%08lx", (unsigned long)row_buf); +#endif /* SINGLE_ROWBUF_ALLOC */ + pngtest_debug("Writing row data"); + +#ifdef PNG_READ_INTERLACING_SUPPORTED + num_pass = png_set_interlace_handling(read_ptr); + if (png_set_interlace_handling(write_ptr) != num_pass) + png_error(write_ptr, "png_set_interlace_handling: inconsistent num_pass"); +#endif + +#ifdef PNGTEST_TIMING + t_stop = (float)clock(); + t_misc += (t_stop - t_start); + t_start = t_stop; +#endif + for (pass = 0; pass < num_pass; pass++) + { + pngtest_debug1("Writing row data for pass %d", pass); + for (y = 0; y < height; y++) + { +#ifndef SINGLE_ROWBUF_ALLOC + pngtest_debug2("Allocating row buffer (pass %d, y = %u)...", pass, y); + row_buf = (png_bytep)png_malloc(read_ptr, + png_get_rowbytes(read_ptr, read_info_ptr)); + + pngtest_debug2("\t0x%08lx (%u bytes)", (unsigned long)row_buf, + png_get_rowbytes(read_ptr, read_info_ptr)); + +#endif /* !SINGLE_ROWBUF_ALLOC */ + png_read_rows(read_ptr, (png_bytepp)&row_buf, NULL, 1); + +#ifdef PNG_WRITE_SUPPORTED +#ifdef PNGTEST_TIMING + t_stop = (float)clock(); + t_decode += (t_stop - t_start); + t_start = t_stop; +#endif + png_write_rows(write_ptr, (png_bytepp)&row_buf, 1); +#ifdef PNGTEST_TIMING + t_stop = (float)clock(); + t_encode += (t_stop - t_start); + t_start = t_stop; +#endif +#endif /* PNG_WRITE_SUPPORTED */ + +#ifndef SINGLE_ROWBUF_ALLOC + pngtest_debug2("Freeing row buffer (pass %d, y = %u)", pass, y); + png_free(read_ptr, row_buf); + row_buf = NULL; +#endif /* !SINGLE_ROWBUF_ALLOC */ + } + } + +#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED +# ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED + png_free_data(read_ptr, read_info_ptr, PNG_FREE_UNKN, -1); +# endif +# ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + png_free_data(write_ptr, write_info_ptr, PNG_FREE_UNKN, -1); +# endif +#endif + + pngtest_debug("Reading and writing end_info data"); + + png_read_end(read_ptr, end_info_ptr); +#ifdef PNG_TEXT_SUPPORTED + { + png_textp text_ptr; + int num_text; + + if (png_get_text(read_ptr, end_info_ptr, &text_ptr, &num_text) > 0) + { + pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text); + + pngtest_check_text_support(read_ptr, text_ptr, num_text); + + if (verbose != 0) + { + int i; + + printf("\n"); + for (i=0; i<num_text; i++) + { + printf(" Text compression[%d]=%d\n", + i, text_ptr[i].compression); + } + } + + png_set_text(write_ptr, write_end_info_ptr, text_ptr, num_text); + } + } +#endif +#ifdef PNG_tIME_SUPPORTED + { + png_timep mod_time; + + if (png_get_tIME(read_ptr, end_info_ptr, &mod_time)) + { + png_set_tIME(write_ptr, write_end_info_ptr, mod_time); +#ifdef PNG_TIME_RFC1123_SUPPORTED + if (png_convert_to_rfc1123_buffer(tIME_string, mod_time)) + tIME_string[(sizeof tIME_string) - 1] = '\0'; + + else + { + strncpy(tIME_string, "*** invalid time ***", sizeof tIME_string); + tIME_string[(sizeof tIME_string)-1] = '\0'; + } + + tIME_chunk_present++; +#endif /* PNG_TIME_RFC1123_SUPPORTED */ + } + } +#endif +#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + { + png_unknown_chunkp unknowns; + int num_unknowns = png_get_unknown_chunks(read_ptr, end_info_ptr, + &unknowns); + + if (num_unknowns != 0) + { + png_set_unknown_chunks(write_ptr, write_end_info_ptr, unknowns, + num_unknowns); +#if PNG_LIBPNG_VER < 10600 + /* Copy the locations from the read_info_ptr. The automatically + * generated locations in write_end_info_ptr are wrong prior to 1.6.0 + * because they are reset from the write pointer (removed in 1.6.0). + */ + { + int i; + for (i = 0; i < num_unknowns; i++) + png_set_unknown_chunk_location(write_ptr, write_end_info_ptr, i, + unknowns[i].location); + } +#endif + } + } +#endif + +#ifdef PNG_WRITE_SUPPORTED +#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED + /* Normally one would use Z_DEFAULT_STRATEGY for text compression. + * This is here just to make pngtest replicate the results from libpng + * versions prior to 1.5.4, and to test this new API. + */ + png_set_text_compression_strategy(write_ptr, Z_FILTERED); +#endif + + /* When the unknown vpAg/sTER chunks are written by pngtest the only way to + * do it is to write them *before* calling png_write_end. When unknown + * chunks are written by libpng, however, they are written just before IEND. + * There seems to be no way round this, however vpAg/sTER are not expected + * after IDAT. + */ + write_chunks(write_ptr, after_IDAT); + + png_write_end(write_ptr, write_end_info_ptr); +#endif + +#ifdef PNG_EASY_ACCESS_SUPPORTED + if (verbose != 0) + { + png_uint_32 iwidth, iheight; + iwidth = png_get_image_width(write_ptr, write_info_ptr); + iheight = png_get_image_height(write_ptr, write_info_ptr); + fprintf(STDERR, "\n Image width = %lu, height = %lu\n", + (unsigned long)iwidth, (unsigned long)iheight); + } +#endif + + pngtest_debug("Destroying data structs"); +#ifdef SINGLE_ROWBUF_ALLOC + pngtest_debug("destroying row_buf for read_ptr"); + png_free(read_ptr, row_buf); + row_buf = NULL; +#endif /* SINGLE_ROWBUF_ALLOC */ + pngtest_debug("destroying read_ptr, read_info_ptr, end_info_ptr"); + png_destroy_read_struct(&read_ptr, &read_info_ptr, &end_info_ptr); +#ifdef PNG_WRITE_SUPPORTED + pngtest_debug("destroying write_end_info_ptr"); + png_destroy_info_struct(write_ptr, &write_end_info_ptr); + pngtest_debug("destroying write_ptr, write_info_ptr"); + png_destroy_write_struct(&write_ptr, &write_info_ptr); +#endif + pngtest_debug("Destruction complete."); + + FCLOSE(fpin); + FCLOSE(fpout); + + /* Summarize any warnings or errors and in 'strict' mode fail the test. + * Unsupported chunks can result in warnings, in that case ignore the strict + * setting, otherwise fail the test on warnings as well as errors. + */ + if (error_count > 0) + { + /* We don't really expect to get here because of the setjmp handling + * above, but this is safe. + */ + fprintf(STDERR, "\n %s: %d libpng errors found (%d warnings)", + inname, error_count, warning_count); + + if (strict != 0) + return (1); + } + +# ifdef PNG_WRITE_SUPPORTED + /* If there we no write support nothing was written! */ + else if (unsupported_chunks > 0) + { + fprintf(STDERR, "\n %s: unsupported chunks (%d)%s", + inname, unsupported_chunks, strict ? ": IGNORED --strict!" : ""); + } +# endif + + else if (warning_count > 0) + { + fprintf(STDERR, "\n %s: %d libpng warnings found", + inname, warning_count); + + if (strict != 0) + return (1); + } + + pngtest_debug("Opening files for comparison"); + if ((fpin = fopen(inname, "rb")) == NULL) + { + fprintf(STDERR, "Could not find file %s\n", inname); + return (1); + } + + if ((fpout = fopen(outname, "rb")) == NULL) + { + fprintf(STDERR, "Could not find file %s\n", outname); + FCLOSE(fpin); + return (1); + } + +#ifdef PNG_WRITE_SUPPORTED /* else nothing was written */ + if (interlace_preserved != 0) /* else the files will be changed */ + { + for (;;) + { + static int wrote_question = 0; + png_size_t num_in, num_out; + char inbuf[256], outbuf[256]; + + num_in = fread(inbuf, 1, sizeof inbuf, fpin); + num_out = fread(outbuf, 1, sizeof outbuf, fpout); + + if (num_in != num_out) + { + fprintf(STDERR, "\nFiles %s and %s are of a different size\n", + inname, outname); + + if (wrote_question == 0 && unsupported_chunks == 0) + { + fprintf(STDERR, + " Was %s written with the same maximum IDAT chunk size (%d bytes),", + inname, PNG_ZBUF_SIZE); + fprintf(STDERR, + "\n filtering heuristic (libpng default), compression"); + fprintf(STDERR, + " level (zlib default),\n and zlib version (%s)?\n\n", + ZLIB_VERSION); + wrote_question = 1; + } + + FCLOSE(fpin); + FCLOSE(fpout); + + if (strict != 0 && unsupported_chunks == 0) + return (1); + + else + return (0); + } + + if (num_in == 0) + break; + + if (memcmp(inbuf, outbuf, num_in)) + { + fprintf(STDERR, "\nFiles %s and %s are different\n", inname, + outname); + + if (wrote_question == 0 && unsupported_chunks == 0) + { + fprintf(STDERR, + " Was %s written with the same maximum IDAT chunk size (%d bytes),", + inname, PNG_ZBUF_SIZE); + fprintf(STDERR, + "\n filtering heuristic (libpng default), compression"); + fprintf(STDERR, + " level (zlib default),\n and zlib version (%s)?\n\n", + ZLIB_VERSION); + wrote_question = 1; + } + + FCLOSE(fpin); + FCLOSE(fpout); + + /* NOTE: the unsupported_chunks escape is permitted here because + * unsupported text chunk compression will result in the compression + * mode being changed (to NONE) yet, in the test case, the result + * can be exactly the same size! + */ + if (strict != 0 && unsupported_chunks == 0) + return (1); + + else + return (0); + } + } + } +#endif /* PNG_WRITE_SUPPORTED */ + + FCLOSE(fpin); + FCLOSE(fpout); + + return (0); +} + +/* Input and output filenames */ +#ifdef RISCOS +static PNG_CONST char *inname = "pngtest/png"; +static PNG_CONST char *outname = "pngout/png"; +#else +static PNG_CONST char *inname = "pngtest.png"; +static PNG_CONST char *outname = "pngout.png"; +#endif + +int +main(int argc, char *argv[]) +{ + int multiple = 0; + int ierror = 0; + + fprintf(STDERR, "\n Testing libpng version %s\n", PNG_LIBPNG_VER_STRING); + fprintf(STDERR, " with zlib version %s\n", ZLIB_VERSION); + fprintf(STDERR, "%s", png_get_copyright(NULL)); + /* Show the version of libpng used in building the library */ + fprintf(STDERR, " library (%lu):%s", + (unsigned long)png_access_version_number(), + png_get_header_version(NULL)); + + /* Show the version of libpng used in building the application */ + fprintf(STDERR, " pngtest (%lu):%s", (unsigned long)PNG_LIBPNG_VER, + PNG_HEADER_VERSION_STRING); + + /* Do some consistency checking on the memory allocation settings, I'm + * not sure this matters, but it is nice to know, the first of these + * tests should be impossible because of the way the macros are set + * in pngconf.h + */ +#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K) + fprintf(STDERR, " NOTE: Zlib compiled for max 64k, libpng not\n"); +#endif + /* I think the following can happen. */ +#if !defined(MAXSEG_64K) && defined(PNG_MAX_MALLOC_64K) + fprintf(STDERR, " NOTE: libpng compiled for max 64k, zlib not\n"); +#endif + + if (strcmp(png_libpng_ver, PNG_LIBPNG_VER_STRING)) + { + fprintf(STDERR, + "Warning: versions are different between png.h and png.c\n"); + fprintf(STDERR, " png.h version: %s\n", PNG_LIBPNG_VER_STRING); + fprintf(STDERR, " png.c version: %s\n\n", png_libpng_ver); + ++ierror; + } + + if (argc > 1) + { + if (strcmp(argv[1], "-m") == 0) + { + multiple = 1; + status_dots_requested = 0; + } + + else if (strcmp(argv[1], "-mv") == 0 || + strcmp(argv[1], "-vm") == 0 ) + { + multiple = 1; + verbose = 1; + status_dots_requested = 1; + } + + else if (strcmp(argv[1], "-v") == 0) + { + verbose = 1; + status_dots_requested = 1; + inname = argv[2]; + } + + else if (strcmp(argv[1], "--strict") == 0) + { + status_dots_requested = 0; + verbose = 1; + inname = argv[2]; + strict++; + relaxed = 0; + } + + else if (strcmp(argv[1], "--relaxed") == 0) + { + status_dots_requested = 0; + verbose = 1; + inname = argv[2]; + strict = 0; + relaxed++; + } + + else + { + inname = argv[1]; + status_dots_requested = 0; + } + } + + if (!multiple && argc == 3 + verbose) + outname = argv[2 + verbose]; + + if ((!multiple && argc > 3 + verbose) || (multiple && argc < 2)) + { + fprintf(STDERR, + "usage: %s [infile.png] [outfile.png]\n\t%s -m {infile.png}\n", + argv[0], argv[0]); + fprintf(STDERR, + " reads/writes one PNG file (without -m) or multiple files (-m)\n"); + fprintf(STDERR, + " with -m %s is used as a temporary file\n", outname); + exit(1); + } + + if (multiple != 0) + { + int i; +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + int allocation_now = current_allocation; +#endif + for (i=2; i<argc; ++i) + { + int kerror; + fprintf(STDERR, "\n Testing %s:", argv[i]); + kerror = test_one_file(argv[i], outname); + if (kerror == 0) + { +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + int k; +#endif +#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED + fprintf(STDERR, "\n PASS (%lu zero samples)\n", + (unsigned long)zero_samples); +#else + fprintf(STDERR, " PASS\n"); +#endif +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + for (k = 0; k<256; k++) + if (filters_used[k]) + fprintf(STDERR, " Filter %d was used %lu times\n", + k, (unsigned long)filters_used[k]); +#endif +#ifdef PNG_TIME_RFC1123_SUPPORTED + if (tIME_chunk_present != 0) + fprintf(STDERR, " tIME = %s\n", tIME_string); + + tIME_chunk_present = 0; +#endif /* PNG_TIME_RFC1123_SUPPORTED */ + } + + else + { + fprintf(STDERR, " FAIL\n"); + ierror += kerror; + } +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + if (allocation_now != current_allocation) + fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n", + current_allocation - allocation_now); + + if (current_allocation != 0) + { + memory_infop pinfo = pinformation; + + fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n", + current_allocation); + + while (pinfo != NULL) + { + fprintf(STDERR, " %lu bytes at %x\n", + (unsigned long)pinfo->size, + (unsigned int)pinfo->pointer); + pinfo = pinfo->next; + } + } +#endif + } +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + fprintf(STDERR, " Current memory allocation: %10d bytes\n", + current_allocation); + fprintf(STDERR, " Maximum memory allocation: %10d bytes\n", + maximum_allocation); + fprintf(STDERR, " Total memory allocation: %10d bytes\n", + total_allocation); + fprintf(STDERR, " Number of allocations: %10d\n", + num_allocations); +#endif + } + + else + { + int i; + for (i = 0; i<3; ++i) + { + int kerror; +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + int allocation_now = current_allocation; +#endif + if (i == 1) + status_dots_requested = 1; + + else if (verbose == 0) + status_dots_requested = 0; + + if (i == 0 || verbose == 1 || ierror != 0) + fprintf(STDERR, "\n Testing %s:", inname); + + kerror = test_one_file(inname, outname); + + if (kerror == 0) + { + if (verbose == 1 || i == 2) + { +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + int k; +#endif +#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED + fprintf(STDERR, "\n PASS (%lu zero samples)\n", + (unsigned long)zero_samples); +#else + fprintf(STDERR, " PASS\n"); +#endif +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + for (k = 0; k<256; k++) + if (filters_used[k]) + fprintf(STDERR, " Filter %d was used %lu times\n", + k, (unsigned long)filters_used[k]); +#endif +#ifdef PNG_TIME_RFC1123_SUPPORTED + if (tIME_chunk_present != 0) + fprintf(STDERR, " tIME = %s\n", tIME_string); +#endif /* PNG_TIME_RFC1123_SUPPORTED */ + } + } + + else + { + if (verbose == 0 && i != 2) + fprintf(STDERR, "\n Testing %s:", inname); + + fprintf(STDERR, " FAIL\n"); + ierror += kerror; + } +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + if (allocation_now != current_allocation) + fprintf(STDERR, "MEMORY ERROR: %d bytes lost\n", + current_allocation - allocation_now); + + if (current_allocation != 0) + { + memory_infop pinfo = pinformation; + + fprintf(STDERR, "MEMORY ERROR: %d bytes still allocated\n", + current_allocation); + + while (pinfo != NULL) + { + fprintf(STDERR, " %lu bytes at %x\n", + (unsigned long)pinfo->size, (unsigned int)pinfo->pointer); + pinfo = pinfo->next; + } + } +#endif + } +#if defined(PNG_USER_MEM_SUPPORTED) && PNG_DEBUG + fprintf(STDERR, " Current memory allocation: %10d bytes\n", + current_allocation); + fprintf(STDERR, " Maximum memory allocation: %10d bytes\n", + maximum_allocation); + fprintf(STDERR, " Total memory allocation: %10d bytes\n", + total_allocation); + fprintf(STDERR, " Number of allocations: %10d\n", + num_allocations); +#endif + } + +#ifdef PNGTEST_TIMING + t_stop = (float)clock(); + t_misc += (t_stop - t_start); + t_start = t_stop; + fprintf(STDERR, " CPU time used = %.3f seconds", + (t_misc+t_decode+t_encode)/(float)CLOCKS_PER_SEC); + fprintf(STDERR, " (decoding %.3f,\n", + t_decode/(float)CLOCKS_PER_SEC); + fprintf(STDERR, " encoding %.3f ,", + t_encode/(float)CLOCKS_PER_SEC); + fprintf(STDERR, " other %.3f seconds)\n\n", + t_misc/(float)CLOCKS_PER_SEC); +#endif + + if (ierror == 0) + fprintf(STDERR, " libpng passes test\n"); + + else + fprintf(STDERR, " libpng FAILS test\n"); + + return (int)(ierror != 0); +} +#else +int +main(void) +{ + fprintf(STDERR, + " test ignored because libpng was not built with read support\n"); + /* And skip this test */ + return PNG_LIBPNG_VER < 10600 ? 0 : 77; +} +#endif + +/* Generate a compiler error if there is an old png.h in the search path. */ +typedef png_libpng_version_1_6_12 Your_png_h_is_not_version_1_6_12; diff --git a/png/pngtest.png b/png/pngtest.png Binary files differnew file mode 100755 index 0000000..cb3fef4 --- /dev/null +++ b/png/pngtest.png diff --git a/png/pngtrans.c b/png/pngtrans.c new file mode 100755 index 0000000..792e13a --- /dev/null +++ b/png/pngtrans.c @@ -0,0 +1,850 @@ + +/* pngtrans.c - transforms the data in a row (used by both readers and writers) + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +#include "pngpriv.h" + +#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) + +#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) +/* Turn on BGR-to-RGB mapping */ +void PNGAPI +png_set_bgr(png_structrp png_ptr) +{ + png_debug(1, "in png_set_bgr"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_BGR; +} +#endif + +#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) +/* Turn on 16 bit byte swapping */ +void PNGAPI +png_set_swap(png_structrp png_ptr) +{ + png_debug(1, "in png_set_swap"); + + if (png_ptr == NULL) + return; + + if (png_ptr->bit_depth == 16) + png_ptr->transformations |= PNG_SWAP_BYTES; +} +#endif + +#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) +/* Turn on pixel packing */ +void PNGAPI +png_set_packing(png_structrp png_ptr) +{ + png_debug(1, "in png_set_packing"); + + if (png_ptr == NULL) + return; + + if (png_ptr->bit_depth < 8) + { + png_ptr->transformations |= PNG_PACK; +# ifdef PNG_WRITE_SUPPORTED + png_ptr->usr_bit_depth = 8; +# endif + } +} +#endif + +#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) +/* Turn on packed pixel swapping */ +void PNGAPI +png_set_packswap(png_structrp png_ptr) +{ + png_debug(1, "in png_set_packswap"); + + if (png_ptr == NULL) + return; + + if (png_ptr->bit_depth < 8) + png_ptr->transformations |= PNG_PACKSWAP; +} +#endif + +#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) +void PNGAPI +png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits) +{ + png_debug(1, "in png_set_shift"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_SHIFT; + png_ptr->shift = *true_bits; +} +#endif + +#if defined(PNG_READ_INTERLACING_SUPPORTED) || \ + defined(PNG_WRITE_INTERLACING_SUPPORTED) +int PNGAPI +png_set_interlace_handling(png_structrp png_ptr) +{ + png_debug(1, "in png_set_interlace handling"); + + if (png_ptr && png_ptr->interlaced) + { + png_ptr->transformations |= PNG_INTERLACE; + return (7); + } + + return (1); +} +#endif + +#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) +/* Add a filler byte on read, or remove a filler or alpha byte on write. + * The filler type has changed in v0.95 to allow future 2-byte fillers + * for 48-bit input data, as well as to avoid problems with some compilers + * that don't like bytes as parameters. + */ +void PNGAPI +png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc) +{ + png_debug(1, "in png_set_filler"); + + if (png_ptr == NULL) + return; + + /* In libpng 1.6 it is possible to determine whether this is a read or write + * operation and therefore to do more checking here for a valid call. + */ + if (png_ptr->mode & PNG_IS_READ_STRUCT) + { +# ifdef PNG_READ_FILLER_SUPPORTED + /* On read png_set_filler is always valid, regardless of the base PNG + * format, because other transformations can give a format where the + * filler code can execute (basically an 8 or 16-bit component RGB or G + * format.) + * + * NOTE: usr_channels is not used by the read code! (This has led to + * confusion in the past.) The filler is only used in the read code. + */ + png_ptr->filler = (png_uint_16)filler; +# else + png_app_error(png_ptr, "png_set_filler not supported on read"); + PNG_UNUSED(filler) /* not used in the write case */ + return; +# endif + } + + else /* write */ + { +# ifdef PNG_WRITE_FILLER_SUPPORTED + /* On write the usr_channels parameter must be set correctly at the + * start to record the number of channels in the app-supplied data. + */ + switch (png_ptr->color_type) + { + case PNG_COLOR_TYPE_RGB: + png_ptr->usr_channels = 4; + break; + + case PNG_COLOR_TYPE_GRAY: + if (png_ptr->bit_depth >= 8) + { + png_ptr->usr_channels = 2; + break; + } + + else + { + /* There simply isn't any code in libpng to strip out bits + * from bytes when the components are less than a byte in + * size! + */ + png_app_error(png_ptr, + "png_set_filler is invalid for low bit depth gray output"); + return; + } + + default: + png_app_error(png_ptr, + "png_set_filler: inappropriate color type"); + return; + } +# else + png_app_error(png_ptr, "png_set_filler not supported on write"); + return; +# endif + } + + /* Here on success - libpng supports the operation, set the transformation + * and the flag to say where the filler channel is. + */ + png_ptr->transformations |= PNG_FILLER; + + if (filler_loc == PNG_FILLER_AFTER) + png_ptr->flags |= PNG_FLAG_FILLER_AFTER; + + else + png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER; +} + +/* Added to libpng-1.2.7 */ +void PNGAPI +png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc) +{ + png_debug(1, "in png_set_add_alpha"); + + if (png_ptr == NULL) + return; + + png_set_filler(png_ptr, filler, filler_loc); + /* The above may fail to do anything. */ + if (png_ptr->transformations & PNG_FILLER) + png_ptr->transformations |= PNG_ADD_ALPHA; +} + +#endif + +#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ + defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) +void PNGAPI +png_set_swap_alpha(png_structrp png_ptr) +{ + png_debug(1, "in png_set_swap_alpha"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_SWAP_ALPHA; +} +#endif + +#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ + defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) +void PNGAPI +png_set_invert_alpha(png_structrp png_ptr) +{ + png_debug(1, "in png_set_invert_alpha"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_INVERT_ALPHA; +} +#endif + +#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) +void PNGAPI +png_set_invert_mono(png_structrp png_ptr) +{ + png_debug(1, "in png_set_invert_mono"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_INVERT_MONO; +} + +/* Invert monochrome grayscale data */ +void /* PRIVATE */ +png_do_invert(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_invert"); + + /* This test removed from libpng version 1.0.13 and 1.2.0: + * if (row_info->bit_depth == 1 && + */ + if (row_info->color_type == PNG_COLOR_TYPE_GRAY) + { + png_bytep rp = row; + png_size_t i; + png_size_t istop = row_info->rowbytes; + + for (i = 0; i < istop; i++) + { + *rp = (png_byte)(~(*rp)); + rp++; + } + } + + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && + row_info->bit_depth == 8) + { + png_bytep rp = row; + png_size_t i; + png_size_t istop = row_info->rowbytes; + + for (i = 0; i < istop; i += 2) + { + *rp = (png_byte)(~(*rp)); + rp += 2; + } + } + +#ifdef PNG_16BIT_SUPPORTED + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && + row_info->bit_depth == 16) + { + png_bytep rp = row; + png_size_t i; + png_size_t istop = row_info->rowbytes; + + for (i = 0; i < istop; i += 4) + { + *rp = (png_byte)(~(*rp)); + *(rp + 1) = (png_byte)(~(*(rp + 1))); + rp += 4; + } + } +#endif +} +#endif + +#ifdef PNG_16BIT_SUPPORTED +#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) +/* Swaps byte order on 16 bit depth images */ +void /* PRIVATE */ +png_do_swap(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_swap"); + + if (row_info->bit_depth == 16) + { + png_bytep rp = row; + png_uint_32 i; + png_uint_32 istop= row_info->width * row_info->channels; + + for (i = 0; i < istop; i++, rp += 2) + { +#ifdef PNG_BUILTIN_BSWAP16_SUPPORTED + /* Feature added to libpng-1.6.11 for testing purposes, not + * enabled by default. + */ + *(png_uint_16*)rp = __builtin_bswap16(*(png_uint_16*)rp); +#else + png_byte t = *rp; + *rp = *(rp + 1); + *(rp + 1) = t; +#endif + } + } +} +#endif +#endif + +#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) +static PNG_CONST png_byte onebppswaptable[256] = { + 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, + 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0, + 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, + 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, + 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, + 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4, + 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, + 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC, + 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, + 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2, + 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, + 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA, + 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, + 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6, + 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, + 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, + 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, + 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1, + 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, + 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9, + 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, + 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, + 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, + 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD, + 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, + 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3, + 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, + 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, + 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, + 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7, + 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, + 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF +}; + +static PNG_CONST png_byte twobppswaptable[256] = { + 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0, + 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0, + 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4, + 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4, + 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8, + 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8, + 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC, + 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC, + 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1, + 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1, + 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5, + 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5, + 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9, + 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9, + 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD, + 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD, + 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2, + 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2, + 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6, + 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6, + 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA, + 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA, + 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE, + 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE, + 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3, + 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3, + 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7, + 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7, + 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB, + 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB, + 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF, + 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF +}; + +static PNG_CONST png_byte fourbppswaptable[256] = { + 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, + 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0, + 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71, + 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1, + 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72, + 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2, + 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73, + 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3, + 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74, + 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4, + 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75, + 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5, + 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76, + 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6, + 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77, + 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7, + 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78, + 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8, + 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79, + 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9, + 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A, + 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA, + 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B, + 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB, + 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C, + 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC, + 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D, + 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD, + 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E, + 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE, + 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F, + 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF +}; + +/* Swaps pixel packing order within bytes */ +void /* PRIVATE */ +png_do_packswap(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_packswap"); + + if (row_info->bit_depth < 8) + { + png_bytep rp; + png_const_bytep end, table; + + end = row + row_info->rowbytes; + + if (row_info->bit_depth == 1) + table = onebppswaptable; + + else if (row_info->bit_depth == 2) + table = twobppswaptable; + + else if (row_info->bit_depth == 4) + table = fourbppswaptable; + + else + return; + + for (rp = row; rp < end; rp++) + *rp = table[*rp]; + } +} +#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */ + +#if defined(PNG_WRITE_FILLER_SUPPORTED) || \ + defined(PNG_READ_STRIP_ALPHA_SUPPORTED) +/* Remove a channel - this used to be 'png_do_strip_filler' but it used a + * somewhat weird combination of flags to determine what to do. All the calls + * to png_do_strip_filler are changed in 1.5.2 to call this instead with the + * correct arguments. + * + * The routine isn't general - the channel must be the channel at the start or + * end (not in the middle) of each pixel. + */ +void /* PRIVATE */ +png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start) +{ + png_bytep sp = row; /* source pointer */ + png_bytep dp = row; /* destination pointer */ + png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */ + + /* At the start sp will point to the first byte to copy and dp to where + * it is copied to. ep always points just beyond the end of the row, so + * the loop simply copies (channels-1) channels until sp reaches ep. + * + * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc. + * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc. + */ + + /* GA, GX, XG cases */ + if (row_info->channels == 2) + { + if (row_info->bit_depth == 8) + { + if (at_start != 0) /* Skip initial filler */ + ++sp; + else /* Skip initial channel and, for sp, the filler */ + sp += 2, ++dp; + + /* For a 1 pixel wide image there is nothing to do */ + while (sp < ep) + *dp++ = *sp, sp += 2; + + row_info->pixel_depth = 8; + } + + else if (row_info->bit_depth == 16) + { + if (at_start != 0) /* Skip initial filler */ + sp += 2; + else /* Skip initial channel and, for sp, the filler */ + sp += 4, dp += 2; + + while (sp < ep) + *dp++ = *sp++, *dp++ = *sp, sp += 3; + + row_info->pixel_depth = 16; + } + + else + return; /* bad bit depth */ + + row_info->channels = 1; + + /* Finally fix the color type if it records an alpha channel */ + if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + row_info->color_type = PNG_COLOR_TYPE_GRAY; + } + + /* RGBA, RGBX, XRGB cases */ + else if (row_info->channels == 4) + { + if (row_info->bit_depth == 8) + { + if (at_start != 0) /* Skip initial filler */ + ++sp; + else /* Skip initial channels and, for sp, the filler */ + sp += 4, dp += 3; + + /* Note that the loop adds 3 to dp and 4 to sp each time. */ + while (sp < ep) + *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2; + + row_info->pixel_depth = 24; + } + + else if (row_info->bit_depth == 16) + { + if (at_start != 0) /* Skip initial filler */ + sp += 2; + else /* Skip initial channels and, for sp, the filler */ + sp += 8, dp += 6; + + while (sp < ep) + { + /* Copy 6 bytes, skip 2 */ + *dp++ = *sp++, *dp++ = *sp++; + *dp++ = *sp++, *dp++ = *sp++; + *dp++ = *sp++, *dp++ = *sp, sp += 3; + } + + row_info->pixel_depth = 48; + } + + else + return; /* bad bit depth */ + + row_info->channels = 3; + + /* Finally fix the color type if it records an alpha channel */ + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + row_info->color_type = PNG_COLOR_TYPE_RGB; + } + + else + return; /* The filler channel has gone already */ + + /* Fix the rowbytes value. */ + row_info->rowbytes = dp-row; +} +#endif + +#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) +/* Swaps red and blue bytes within a pixel */ +void /* PRIVATE */ +png_do_bgr(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_bgr"); + + if ((row_info->color_type & PNG_COLOR_MASK_COLOR)) + { + png_uint_32 row_width = row_info->width; + if (row_info->bit_depth == 8) + { + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + { + png_bytep rp; + png_uint_32 i; + + for (i = 0, rp = row; i < row_width; i++, rp += 3) + { + png_byte save = *rp; + *rp = *(rp + 2); + *(rp + 2) = save; + } + } + + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + png_bytep rp; + png_uint_32 i; + + for (i = 0, rp = row; i < row_width; i++, rp += 4) + { + png_byte save = *rp; + *rp = *(rp + 2); + *(rp + 2) = save; + } + } + } + +#ifdef PNG_16BIT_SUPPORTED + else if (row_info->bit_depth == 16) + { + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + { + png_bytep rp; + png_uint_32 i; + + for (i = 0, rp = row; i < row_width; i++, rp += 6) + { + png_byte save = *rp; + *rp = *(rp + 4); + *(rp + 4) = save; + save = *(rp + 1); + *(rp + 1) = *(rp + 5); + *(rp + 5) = save; + } + } + + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + png_bytep rp; + png_uint_32 i; + + for (i = 0, rp = row; i < row_width; i++, rp += 8) + { + png_byte save = *rp; + *rp = *(rp + 4); + *(rp + 4) = save; + save = *(rp + 1); + *(rp + 1) = *(rp + 5); + *(rp + 5) = save; + } + } + } +#endif + } +} +#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */ + +#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \ + defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED) +/* Added at libpng-1.5.10 */ +void /* PRIVATE */ +png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info) +{ + if (png_ptr->num_palette < (1 << row_info->bit_depth) && + png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */ + { + /* Calculations moved outside switch in an attempt to stop different + * compiler warnings. 'padding' is in *bits* within the last byte, it is + * an 'int' because pixel_depth becomes an 'int' in the expression below, + * and this calculation is used because it avoids warnings that other + * forms produced on either GCC or MSVC. + */ + int padding = (-row_info->pixel_depth * row_info->width) & 7; + png_bytep rp = png_ptr->row_buf + row_info->rowbytes; + + switch (row_info->bit_depth) + { + case 1: + { + /* in this case, all bytes must be 0 so we don't need + * to unpack the pixels except for the rightmost one. + */ + for (; rp > png_ptr->row_buf; rp--) + { + if (*rp >> padding != 0) + png_ptr->num_palette_max = 1; + padding = 0; + } + + break; + } + + case 2: + { + for (; rp > png_ptr->row_buf; rp--) + { + int i = ((*rp >> padding) & 0x03); + + if (i > png_ptr->num_palette_max) + png_ptr->num_palette_max = i; + + i = (((*rp >> padding) >> 2) & 0x03); + + if (i > png_ptr->num_palette_max) + png_ptr->num_palette_max = i; + + i = (((*rp >> padding) >> 4) & 0x03); + + if (i > png_ptr->num_palette_max) + png_ptr->num_palette_max = i; + + i = (((*rp >> padding) >> 6) & 0x03); + + if (i > png_ptr->num_palette_max) + png_ptr->num_palette_max = i; + + padding = 0; + } + + break; + } + + case 4: + { + for (; rp > png_ptr->row_buf; rp--) + { + int i = ((*rp >> padding) & 0x0f); + + if (i > png_ptr->num_palette_max) + png_ptr->num_palette_max = i; + + i = (((*rp >> padding) >> 4) & 0x0f); + + if (i > png_ptr->num_palette_max) + png_ptr->num_palette_max = i; + + padding = 0; + } + + break; + } + + case 8: + { + for (; rp > png_ptr->row_buf; rp--) + { + if (*rp > png_ptr->num_palette_max) + png_ptr->num_palette_max = (int) *rp; + } + + break; + } + + default: + break; + } + } +} +#endif /* PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED */ + +#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ + defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) +#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED +void PNGAPI +png_set_user_transform_info(png_structrp png_ptr, png_voidp + user_transform_ptr, int user_transform_depth, int user_transform_channels) +{ + png_debug(1, "in png_set_user_transform_info"); + + if (png_ptr == NULL) + return; + +#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED + if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && + (png_ptr->flags & PNG_FLAG_ROW_INIT) != 0) + { + png_app_error(png_ptr, + "info change after png_start_read_image or png_read_update_info"); + return; + } +#endif + + png_ptr->user_transform_ptr = user_transform_ptr; + png_ptr->user_transform_depth = (png_byte)user_transform_depth; + png_ptr->user_transform_channels = (png_byte)user_transform_channels; +} +#endif + +/* This function returns a pointer to the user_transform_ptr associated with + * the user transform functions. The application should free any memory + * associated with this pointer before png_write_destroy and png_read_destroy + * are called. + */ +#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED +png_voidp PNGAPI +png_get_user_transform_ptr(png_const_structrp png_ptr) +{ + if (png_ptr == NULL) + return (NULL); + + return png_ptr->user_transform_ptr; +} +#endif + +#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED +png_uint_32 PNGAPI +png_get_current_row_number(png_const_structrp png_ptr) +{ + /* See the comments in png.h - this is the sub-image row when reading and + * interlaced image. + */ + if (png_ptr != NULL) + return png_ptr->row_number; + + return PNG_UINT_32_MAX; /* help the app not to fail silently */ +} + +png_byte PNGAPI +png_get_current_pass_number(png_const_structrp png_ptr) +{ + if (png_ptr != NULL) + return png_ptr->pass; + return 8; /* invalid */ +} +#endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */ +#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED || + PNG_WRITE_USER_TRANSFORM_SUPPORTED */ +#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ diff --git a/png/pngwio.c b/png/pngwio.c new file mode 100755 index 0000000..1b525f9 --- /dev/null +++ b/png/pngwio.c @@ -0,0 +1,168 @@ + +/* pngwio.c - functions for data output + * + * Last changed in libpng 1.6.9 [February 6, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + * + * This file provides a location for all output. Users who need + * special handling are expected to write functions that have the same + * arguments as these and perform similar functions, but that possibly + * use different output methods. Note that you shouldn't change these + * functions, but rather write replacement functions and then change + * them at run time with png_set_write_fn(...). + */ + +#include "pngpriv.h" + +#ifdef PNG_WRITE_SUPPORTED + +/* Write the data to whatever output you are using. The default routine + * writes to a file pointer. Note that this routine sometimes gets called + * with very small lengths, so you should implement some kind of simple + * buffering if you are using unbuffered writes. This should never be asked + * to write more than 64K on a 16 bit machine. + */ + +void /* PRIVATE */ +png_write_data(png_structrp png_ptr, png_const_bytep data, png_size_t length) +{ + /* NOTE: write_data_fn must not change the buffer! */ + if (png_ptr->write_data_fn != NULL ) + (*(png_ptr->write_data_fn))(png_ptr, png_constcast(png_bytep,data), + length); + + else + png_error(png_ptr, "Call to NULL write function"); +} + +#ifdef PNG_STDIO_SUPPORTED +/* This is the function that does the actual writing of data. If you are + * not writing to a standard C stream, you should create a replacement + * write_data function and use it at run time with png_set_write_fn(), rather + * than changing the library. + */ +void PNGCBAPI +png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length) +{ + png_size_t check; + + if (png_ptr == NULL) + return; + + check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr)); + + if (check != length) + png_error(png_ptr, "Write Error"); +} +#endif + +/* This function is called to output any data pending writing (normally + * to disk). After png_flush is called, there should be no data pending + * writing in any buffers. + */ +#ifdef PNG_WRITE_FLUSH_SUPPORTED +void /* PRIVATE */ +png_flush(png_structrp png_ptr) +{ + if (png_ptr->output_flush_fn != NULL) + (*(png_ptr->output_flush_fn))(png_ptr); +} + +# ifdef PNG_STDIO_SUPPORTED +void PNGCBAPI +png_default_flush(png_structp png_ptr) +{ + png_FILE_p io_ptr; + + if (png_ptr == NULL) + return; + + io_ptr = png_voidcast(png_FILE_p, (png_ptr->io_ptr)); + fflush(io_ptr); +} +# endif +#endif + +/* This function allows the application to supply new output functions for + * libpng if standard C streams aren't being used. + * + * This function takes as its arguments: + * png_ptr - pointer to a png output data structure + * io_ptr - pointer to user supplied structure containing info about + * the output functions. May be NULL. + * write_data_fn - pointer to a new output function that takes as its + * arguments a pointer to a png_struct, a pointer to + * data to be written, and a 32-bit unsigned int that is + * the number of bytes to be written. The new write + * function should call png_error(png_ptr, "Error msg") + * to exit and output any fatal error messages. May be + * NULL, in which case libpng's default function will + * be used. + * flush_data_fn - pointer to a new flush function that takes as its + * arguments a pointer to a png_struct. After a call to + * the flush function, there should be no data in any buffers + * or pending transmission. If the output method doesn't do + * any buffering of output, a function prototype must still be + * supplied although it doesn't have to do anything. If + * PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile + * time, output_flush_fn will be ignored, although it must be + * supplied for compatibility. May be NULL, in which case + * libpng's default function will be used, if + * PNG_WRITE_FLUSH_SUPPORTED is defined. This is not + * a good idea if io_ptr does not point to a standard + * *FILE structure. + */ +void PNGAPI +png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr, + png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn) +{ + if (png_ptr == NULL) + return; + + png_ptr->io_ptr = io_ptr; + +#ifdef PNG_STDIO_SUPPORTED + if (write_data_fn != NULL) + png_ptr->write_data_fn = write_data_fn; + + else + png_ptr->write_data_fn = png_default_write_data; +#else + png_ptr->write_data_fn = write_data_fn; +#endif + +#ifdef PNG_WRITE_FLUSH_SUPPORTED +# ifdef PNG_STDIO_SUPPORTED + + if (output_flush_fn != NULL) + png_ptr->output_flush_fn = output_flush_fn; + + else + png_ptr->output_flush_fn = png_default_flush; + +# else + png_ptr->output_flush_fn = output_flush_fn; +# endif +#else + PNG_UNUSED(output_flush_fn) +#endif /* PNG_WRITE_FLUSH_SUPPORTED */ + +#ifdef PNG_READ_SUPPORTED + /* It is an error to read while writing a png file */ + if (png_ptr->read_data_fn != NULL) + { + png_ptr->read_data_fn = NULL; + + png_warning(png_ptr, + "Can't set both read_data_fn and write_data_fn in the" + " same structure"); + } +#endif +} +#endif /* PNG_WRITE_SUPPORTED */ diff --git a/png/pngwrite.c b/png/pngwrite.c new file mode 100755 index 0000000..7087d08 --- /dev/null +++ b/png/pngwrite.c @@ -0,0 +1,2437 @@ + +/* pngwrite.c - general routines to write a PNG file + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +#include "pngpriv.h" +#if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) +# include <errno.h> +#endif + +#ifdef PNG_WRITE_SUPPORTED + +#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED +/* Write out all the unknown chunks for the current given location */ +static void +write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr, + unsigned int where) +{ + if (info_ptr->unknown_chunks_num) + { + png_const_unknown_chunkp up; + + png_debug(5, "writing extra chunks"); + + for (up = info_ptr->unknown_chunks; + up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num; + ++up) + if (up->location & where) + { + /* If per-chunk unknown chunk handling is enabled use it, otherwise + * just write the chunks the application has set. + */ +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED + int keep = png_handle_as_unknown(png_ptr, up->name); + + /* NOTE: this code is radically different from the read side in the + * matter of handling an ancillary unknown chunk. In the read side + * the default behavior is to discard it, in the code below the default + * behavior is to write it. Critical chunks are, however, only + * written if explicitly listed or if the default is set to write all + * unknown chunks. + * + * The default handling is also slightly weird - it is not possible to + * stop the writing of all unsafe-to-copy chunks! + * + * TODO: REVIEW: this would seem to be a bug. + */ + if (keep != PNG_HANDLE_CHUNK_NEVER && + ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ || + keep == PNG_HANDLE_CHUNK_ALWAYS || + (keep == PNG_HANDLE_CHUNK_AS_DEFAULT && + png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS))) +#endif + { + /* TODO: review, what is wrong with a zero length unknown chunk? */ + if (up->size == 0) + png_warning(png_ptr, "Writing zero-length unknown chunk"); + + png_write_chunk(png_ptr, up->name, up->data, up->size); + } + } + } +} +#endif /* PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED */ + +/* Writes all the PNG information. This is the suggested way to use the + * library. If you have a new chunk to add, make a function to write it, + * and put it in the correct location here. If you want the chunk written + * after the image data, put it in png_write_end(). I strongly encourage + * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing + * the chunk, as that will keep the code from breaking if you want to just + * write a plain PNG file. If you have long comments, I suggest writing + * them in png_write_end(), and compressing them. + */ +void PNGAPI +png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr) +{ + png_debug(1, "in png_write_info_before_PLTE"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE)) + { + /* Write PNG signature */ + png_write_sig(png_ptr); + +#ifdef PNG_MNG_FEATURES_SUPPORTED + if ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) && \ + (png_ptr->mng_features_permitted)) + { + png_warning(png_ptr, "MNG features are not allowed in a PNG datastream"); + png_ptr->mng_features_permitted = 0; + } +#endif + + /* Write IHDR information. */ + png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height, + info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type, + info_ptr->filter_type, +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + info_ptr->interlace_type +#else + 0 +#endif + ); + + /* The rest of these check to see if the valid field has the appropriate + * flag set, and if it does, writes the chunk. + * + * 1.6.0: COLORSPACE support controls the writing of these chunks too, and + * the chunks will be written if the WRITE routine is there and information + * is available in the COLORSPACE. (See png_colorspace_sync_info in png.c + * for where the valid flags get set.) + * + * Under certain circumstances the colorspace can be invalidated without + * syncing the info_struct 'valid' flags; this happens if libpng detects and + * error and calls png_error while the color space is being set, yet the + * application continues writing the PNG. So check the 'invalid' flag here + * too. + */ +#ifdef PNG_GAMMA_SUPPORTED +# ifdef PNG_WRITE_gAMA_SUPPORTED + if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) && + (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) && + (info_ptr->valid & PNG_INFO_gAMA)) + png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma); +# endif +#endif + +#ifdef PNG_COLORSPACE_SUPPORTED + /* Write only one of sRGB or an ICC profile. If a profile was supplied + * and it matches one of the known sRGB ones issue a warning. + */ +# ifdef PNG_WRITE_iCCP_SUPPORTED + if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) && + (info_ptr->valid & PNG_INFO_iCCP)) + { +# ifdef PNG_WRITE_sRGB_SUPPORTED + if (info_ptr->valid & PNG_INFO_sRGB) + png_app_warning(png_ptr, + "profile matches sRGB but writing iCCP instead"); +# endif + + png_write_iCCP(png_ptr, info_ptr->iccp_name, + info_ptr->iccp_profile); + } +# ifdef PNG_WRITE_sRGB_SUPPORTED + else +# endif +# endif + +# ifdef PNG_WRITE_sRGB_SUPPORTED + if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) && + (info_ptr->valid & PNG_INFO_sRGB)) + png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent); +# endif /* WRITE_sRGB */ +#endif /* COLORSPACE */ + +#ifdef PNG_WRITE_sBIT_SUPPORTED + if (info_ptr->valid & PNG_INFO_sBIT) + png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type); +#endif + +#ifdef PNG_COLORSPACE_SUPPORTED +# ifdef PNG_WRITE_cHRM_SUPPORTED + if (!(info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) && + (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) && + (info_ptr->valid & PNG_INFO_cHRM)) + png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy); +# endif +#endif + +#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR); +#endif + + png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE; + } +} + +void PNGAPI +png_write_info(png_structrp png_ptr, png_const_inforp info_ptr) +{ +#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED) + int i; +#endif + + png_debug(1, "in png_write_info"); + + if (png_ptr == NULL || info_ptr == NULL) + return; + + png_write_info_before_PLTE(png_ptr, info_ptr); + + if (info_ptr->valid & PNG_INFO_PLTE) + png_write_PLTE(png_ptr, info_ptr->palette, + (png_uint_32)info_ptr->num_palette); + + else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + png_error(png_ptr, "Valid palette required for paletted images"); + +#ifdef PNG_WRITE_tRNS_SUPPORTED + if (info_ptr->valid & PNG_INFO_tRNS) + { +#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED + /* Invert the alpha channel (in tRNS) */ + if ((png_ptr->transformations & PNG_INVERT_ALPHA) && + info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + int j; + for (j = 0; j<(int)info_ptr->num_trans; j++) + info_ptr->trans_alpha[j] = + (png_byte)(255 - info_ptr->trans_alpha[j]); + } +#endif + png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color), + info_ptr->num_trans, info_ptr->color_type); + } +#endif +#ifdef PNG_WRITE_bKGD_SUPPORTED + if (info_ptr->valid & PNG_INFO_bKGD) + png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type); +#endif + +#ifdef PNG_WRITE_hIST_SUPPORTED + if (info_ptr->valid & PNG_INFO_hIST) + png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette); +#endif + +#ifdef PNG_WRITE_oFFs_SUPPORTED + if (info_ptr->valid & PNG_INFO_oFFs) + png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset, + info_ptr->offset_unit_type); +#endif + +#ifdef PNG_WRITE_pCAL_SUPPORTED + if (info_ptr->valid & PNG_INFO_pCAL) + png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0, + info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams, + info_ptr->pcal_units, info_ptr->pcal_params); +#endif + +#ifdef PNG_WRITE_sCAL_SUPPORTED + if (info_ptr->valid & PNG_INFO_sCAL) + png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit, + info_ptr->scal_s_width, info_ptr->scal_s_height); +#endif /* sCAL */ + +#ifdef PNG_WRITE_pHYs_SUPPORTED + if (info_ptr->valid & PNG_INFO_pHYs) + png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit, + info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type); +#endif /* pHYs */ + +#ifdef PNG_WRITE_tIME_SUPPORTED + if (info_ptr->valid & PNG_INFO_tIME) + { + png_write_tIME(png_ptr, &(info_ptr->mod_time)); + png_ptr->mode |= PNG_WROTE_tIME; + } +#endif /* tIME */ + +#ifdef PNG_WRITE_sPLT_SUPPORTED + if (info_ptr->valid & PNG_INFO_sPLT) + for (i = 0; i < (int)info_ptr->splt_palettes_num; i++) + png_write_sPLT(png_ptr, info_ptr->splt_palettes + i); +#endif /* sPLT */ + +#ifdef PNG_WRITE_TEXT_SUPPORTED + /* Check to see if we need to write text chunks */ + for (i = 0; i < info_ptr->num_text; i++) + { + png_debug2(2, "Writing header text chunk %d, type %d", i, + info_ptr->text[i].compression); + /* An internationalized chunk? */ + if (info_ptr->text[i].compression > 0) + { +#ifdef PNG_WRITE_iTXt_SUPPORTED + /* Write international chunk */ + png_write_iTXt(png_ptr, + info_ptr->text[i].compression, + info_ptr->text[i].key, + info_ptr->text[i].lang, + info_ptr->text[i].lang_key, + info_ptr->text[i].text); +#else + png_warning(png_ptr, "Unable to write international text"); +#endif + /* Mark this chunk as written */ + info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; + } + + /* If we want a compressed text chunk */ + else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt) + { +#ifdef PNG_WRITE_zTXt_SUPPORTED + /* Write compressed chunk */ + png_write_zTXt(png_ptr, info_ptr->text[i].key, + info_ptr->text[i].text, 0, + info_ptr->text[i].compression); +#else + png_warning(png_ptr, "Unable to write compressed text"); +#endif + /* Mark this chunk as written */ + info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR; + } + + else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE) + { +#ifdef PNG_WRITE_tEXt_SUPPORTED + /* Write uncompressed chunk */ + png_write_tEXt(png_ptr, info_ptr->text[i].key, + info_ptr->text[i].text, + 0); + /* Mark this chunk as written */ + info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; +#else + /* Can't get here */ + png_warning(png_ptr, "Unable to write uncompressed text"); +#endif + } + } +#endif /* tEXt */ + +#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE); +#endif +} + +/* Writes the end of the PNG file. If you don't want to write comments or + * time information, you can pass NULL for info. If you already wrote these + * in png_write_info(), do not write them again here. If you have long + * comments, I suggest writing them here, and compressing them. + */ +void PNGAPI +png_write_end(png_structrp png_ptr, png_inforp info_ptr) +{ + png_debug(1, "in png_write_end"); + + if (png_ptr == NULL) + return; + + if (!(png_ptr->mode & PNG_HAVE_IDAT)) + png_error(png_ptr, "No IDATs written into file"); + +#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED + if (png_ptr->num_palette_max > png_ptr->num_palette) + png_benign_error(png_ptr, "Wrote palette index exceeding num_palette"); +#endif + + /* See if user wants us to write information chunks */ + if (info_ptr != NULL) + { +#ifdef PNG_WRITE_TEXT_SUPPORTED + int i; /* local index variable */ +#endif +#ifdef PNG_WRITE_tIME_SUPPORTED + /* Check to see if user has supplied a time chunk */ + if ((info_ptr->valid & PNG_INFO_tIME) && + !(png_ptr->mode & PNG_WROTE_tIME)) + png_write_tIME(png_ptr, &(info_ptr->mod_time)); + +#endif +#ifdef PNG_WRITE_TEXT_SUPPORTED + /* Loop through comment chunks */ + for (i = 0; i < info_ptr->num_text; i++) + { + png_debug2(2, "Writing trailer text chunk %d, type %d", i, + info_ptr->text[i].compression); + /* An internationalized chunk? */ + if (info_ptr->text[i].compression > 0) + { +#ifdef PNG_WRITE_iTXt_SUPPORTED + /* Write international chunk */ + png_write_iTXt(png_ptr, + info_ptr->text[i].compression, + info_ptr->text[i].key, + info_ptr->text[i].lang, + info_ptr->text[i].lang_key, + info_ptr->text[i].text); +#else + png_warning(png_ptr, "Unable to write international text"); +#endif + /* Mark this chunk as written */ + info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; + } + + else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt) + { +#ifdef PNG_WRITE_zTXt_SUPPORTED + /* Write compressed chunk */ + png_write_zTXt(png_ptr, info_ptr->text[i].key, + info_ptr->text[i].text, 0, + info_ptr->text[i].compression); +#else + png_warning(png_ptr, "Unable to write compressed text"); +#endif + /* Mark this chunk as written */ + info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR; + } + + else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE) + { +#ifdef PNG_WRITE_tEXt_SUPPORTED + /* Write uncompressed chunk */ + png_write_tEXt(png_ptr, info_ptr->text[i].key, + info_ptr->text[i].text, 0); +#else + png_warning(png_ptr, "Unable to write uncompressed text"); +#endif + + /* Mark this chunk as written */ + info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR; + } + } +#endif +#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED + write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT); +#endif + } + + png_ptr->mode |= PNG_AFTER_IDAT; + + /* Write end of PNG file */ + png_write_IEND(png_ptr); + + /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03, + * and restored again in libpng-1.2.30, may cause some applications that + * do not set png_ptr->output_flush_fn to crash. If your application + * experiences a problem, please try building libpng with + * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to + * png-mng-implement at lists.sf.net . + */ +#ifdef PNG_WRITE_FLUSH_SUPPORTED +# ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED + png_flush(png_ptr); +# endif +#endif +} + +#ifdef PNG_CONVERT_tIME_SUPPORTED +void PNGAPI +png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm * ttime) +{ + png_debug(1, "in png_convert_from_struct_tm"); + + ptime->year = (png_uint_16)(1900 + ttime->tm_year); + ptime->month = (png_byte)(ttime->tm_mon + 1); + ptime->day = (png_byte)ttime->tm_mday; + ptime->hour = (png_byte)ttime->tm_hour; + ptime->minute = (png_byte)ttime->tm_min; + ptime->second = (png_byte)ttime->tm_sec; +} + +void PNGAPI +png_convert_from_time_t(png_timep ptime, time_t ttime) +{ + struct tm *tbuf; + + png_debug(1, "in png_convert_from_time_t"); + + tbuf = gmtime(&ttime); + png_convert_from_struct_tm(ptime, tbuf); +} +#endif + +/* Initialize png_ptr structure, and allocate any memory needed */ +PNG_FUNCTION(png_structp,PNGAPI +png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr, + png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED) +{ +#ifndef PNG_USER_MEM_SUPPORTED + png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr, + error_fn, warn_fn, NULL, NULL, NULL); +#else + return png_create_write_struct_2(user_png_ver, error_ptr, error_fn, + warn_fn, NULL, NULL, NULL); +} + +/* Alternate initialize png_ptr structure, and allocate any memory needed */ +PNG_FUNCTION(png_structp,PNGAPI +png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr, + png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr, + png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED) +{ + png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr, + error_fn, warn_fn, mem_ptr, malloc_fn, free_fn); +#endif /* PNG_USER_MEM_SUPPORTED */ + if (png_ptr != NULL) + { + /* Set the zlib control values to defaults; they can be overridden by the + * application after the struct has been created. + */ + png_ptr->zbuffer_size = PNG_ZBUF_SIZE; + + /* The 'zlib_strategy' setting is irrelevant because png_default_claim in + * pngwutil.c defaults it according to whether or not filters will be + * used, and ignores this setting. + */ + png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY; + png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION; + png_ptr->zlib_mem_level = 8; + png_ptr->zlib_window_bits = 15; + png_ptr->zlib_method = 8; + +#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED + png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY; + png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION; + png_ptr->zlib_text_mem_level = 8; + png_ptr->zlib_text_window_bits = 15; + png_ptr->zlib_text_method = 8; +#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */ + + /* This is a highly dubious configuration option; by default it is off, + * but it may be appropriate for private builds that are testing + * extensions not conformant to the current specification, or of + * applications that must not fail to write at all costs! + */ +#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED + /* In stable builds only warn if an application error can be completely + * handled. + */ + png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN; +#endif + + /* App warnings are warnings in release (or release candidate) builds but + * are errors during development. + */ +#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC + png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN; +#endif + + /* TODO: delay this, it can be done in png_init_io() (if the app doesn't + * do it itself) avoiding setting the default function if it is not + * required. + */ + png_set_write_fn(png_ptr, NULL, NULL, NULL); + } + + return png_ptr; +} + + +/* Write a few rows of image data. If the image is interlaced, + * either you will have to write the 7 sub images, or, if you + * have called png_set_interlace_handling(), you will have to + * "write" the image seven times. + */ +void PNGAPI +png_write_rows(png_structrp png_ptr, png_bytepp row, + png_uint_32 num_rows) +{ + png_uint_32 i; /* row counter */ + png_bytepp rp; /* row pointer */ + + png_debug(1, "in png_write_rows"); + + if (png_ptr == NULL) + return; + + /* Loop through the rows */ + for (i = 0, rp = row; i < num_rows; i++, rp++) + { + png_write_row(png_ptr, *rp); + } +} + +/* Write the image. You only need to call this function once, even + * if you are writing an interlaced image. + */ +void PNGAPI +png_write_image(png_structrp png_ptr, png_bytepp image) +{ + png_uint_32 i; /* row index */ + int pass, num_pass; /* pass variables */ + png_bytepp rp; /* points to current row */ + + if (png_ptr == NULL) + return; + + png_debug(1, "in png_write_image"); + +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* Initialize interlace handling. If image is not interlaced, + * this will set pass to 1 + */ + num_pass = png_set_interlace_handling(png_ptr); +#else + num_pass = 1; +#endif + /* Loop through passes */ + for (pass = 0; pass < num_pass; pass++) + { + /* Loop through image */ + for (i = 0, rp = image; i < png_ptr->height; i++, rp++) + { + png_write_row(png_ptr, *rp); + } + } +} + +#ifdef PNG_MNG_FEATURES_SUPPORTED +/* Performs intrapixel differencing */ +static void +png_do_write_intrapixel(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_write_intrapixel"); + + if ((row_info->color_type & PNG_COLOR_MASK_COLOR)) + { + int bytes_per_pixel; + png_uint_32 row_width = row_info->width; + if (row_info->bit_depth == 8) + { + png_bytep rp; + png_uint_32 i; + + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + bytes_per_pixel = 3; + + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + bytes_per_pixel = 4; + + else + return; + + for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) + { + *(rp) = (png_byte)((*rp - *(rp + 1)) & 0xff); + *(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff); + } + } + +#ifdef PNG_WRITE_16BIT_SUPPORTED + else if (row_info->bit_depth == 16) + { + png_bytep rp; + png_uint_32 i; + + if (row_info->color_type == PNG_COLOR_TYPE_RGB) + bytes_per_pixel = 6; + + else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + bytes_per_pixel = 8; + + else + return; + + for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel) + { + png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1); + png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3); + png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5); + png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL); + png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL); + *(rp ) = (png_byte)((red >> 8) & 0xff); + *(rp + 1) = (png_byte)(red & 0xff); + *(rp + 4) = (png_byte)((blue >> 8) & 0xff); + *(rp + 5) = (png_byte)(blue & 0xff); + } + } +#endif /* PNG_WRITE_16BIT_SUPPORTED */ + } +} +#endif /* PNG_MNG_FEATURES_SUPPORTED */ + +/* Called by user to write a row of image data */ +void PNGAPI +png_write_row(png_structrp png_ptr, png_const_bytep row) +{ + /* 1.5.6: moved from png_struct to be a local structure: */ + png_row_info row_info; + + if (png_ptr == NULL) + return; + + png_debug2(1, "in png_write_row (row %u, pass %d)", + png_ptr->row_number, png_ptr->pass); + + /* Initialize transformations and other stuff if first time */ + if (png_ptr->row_number == 0 && png_ptr->pass == 0) + { + /* Make sure we wrote the header info */ + if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE)) + png_error(png_ptr, + "png_write_info was never called before png_write_row"); + + /* Check for transforms that have been set but were defined out */ +#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED) + if (png_ptr->transformations & PNG_INVERT_MONO) + png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined"); +#endif + +#if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED) + if (png_ptr->transformations & PNG_FILLER) + png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined"); +#endif +#if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \ + defined(PNG_READ_PACKSWAP_SUPPORTED) + if (png_ptr->transformations & PNG_PACKSWAP) + png_warning(png_ptr, + "PNG_WRITE_PACKSWAP_SUPPORTED is not defined"); +#endif + +#if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED) + if (png_ptr->transformations & PNG_PACK) + png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined"); +#endif + +#if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED) + if (png_ptr->transformations & PNG_SHIFT) + png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined"); +#endif + +#if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED) + if (png_ptr->transformations & PNG_BGR) + png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined"); +#endif + +#if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED) + if (png_ptr->transformations & PNG_SWAP_BYTES) + png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined"); +#endif + + png_write_start_row(png_ptr); + } + +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* If interlaced and not interested in row, return */ + if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) + { + switch (png_ptr->pass) + { + case 0: + if (png_ptr->row_number & 0x07) + { + png_write_finish_row(png_ptr); + return; + } + break; + + case 1: + if ((png_ptr->row_number & 0x07) || png_ptr->width < 5) + { + png_write_finish_row(png_ptr); + return; + } + break; + + case 2: + if ((png_ptr->row_number & 0x07) != 4) + { + png_write_finish_row(png_ptr); + return; + } + break; + + case 3: + if ((png_ptr->row_number & 0x03) || png_ptr->width < 3) + { + png_write_finish_row(png_ptr); + return; + } + break; + + case 4: + if ((png_ptr->row_number & 0x03) != 2) + { + png_write_finish_row(png_ptr); + return; + } + break; + + case 5: + if ((png_ptr->row_number & 0x01) || png_ptr->width < 2) + { + png_write_finish_row(png_ptr); + return; + } + break; + + case 6: + if (!(png_ptr->row_number & 0x01)) + { + png_write_finish_row(png_ptr); + return; + } + break; + + default: /* error: ignore it */ + break; + } + } +#endif + + /* Set up row info for transformations */ + row_info.color_type = png_ptr->color_type; + row_info.width = png_ptr->usr_width; + row_info.channels = png_ptr->usr_channels; + row_info.bit_depth = png_ptr->usr_bit_depth; + row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels); + row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width); + + png_debug1(3, "row_info->color_type = %d", row_info.color_type); + png_debug1(3, "row_info->width = %u", row_info.width); + png_debug1(3, "row_info->channels = %d", row_info.channels); + png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth); + png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth); + png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes); + + /* Copy user's row into buffer, leaving room for filter byte. */ + memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes); + +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* Handle interlacing */ + if (png_ptr->interlaced && png_ptr->pass < 6 && + (png_ptr->transformations & PNG_INTERLACE)) + { + png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass); + /* This should always get caught above, but still ... */ + if (row_info.width == 0) + { + png_write_finish_row(png_ptr); + return; + } + } +#endif + +#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED + /* Handle other transformations */ + if (png_ptr->transformations) + png_do_write_transformations(png_ptr, &row_info); +#endif + + /* At this point the row_info pixel depth must match the 'transformed' depth, + * which is also the output depth. + */ + if (row_info.pixel_depth != png_ptr->pixel_depth || + row_info.pixel_depth != png_ptr->transformed_pixel_depth) + png_error(png_ptr, "internal write transform logic error"); + +#ifdef PNG_MNG_FEATURES_SUPPORTED + /* Write filter_method 64 (intrapixel differencing) only if + * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and + * 2. Libpng did not write a PNG signature (this filter_method is only + * used in PNG datastreams that are embedded in MNG datastreams) and + * 3. The application called png_permit_mng_features with a mask that + * included PNG_FLAG_MNG_FILTER_64 and + * 4. The filter_method is 64 and + * 5. The color_type is RGB or RGBA + */ + if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && + (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING)) + { + /* Intrapixel differencing */ + png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1); + } +#endif + +/* Added at libpng-1.5.10 */ +#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED + /* Check for out-of-range palette index */ + if (row_info.color_type == PNG_COLOR_TYPE_PALETTE && + png_ptr->num_palette_max >= 0) + png_do_check_palette_indexes(png_ptr, &row_info); +#endif + + /* Find a filter if necessary, filter the row and write it out. */ + png_write_find_filter(png_ptr, &row_info); + + if (png_ptr->write_row_fn != NULL) + (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass); +} + +#ifdef PNG_WRITE_FLUSH_SUPPORTED +/* Set the automatic flush interval or 0 to turn flushing off */ +void PNGAPI +png_set_flush(png_structrp png_ptr, int nrows) +{ + png_debug(1, "in png_set_flush"); + + if (png_ptr == NULL) + return; + + png_ptr->flush_dist = (nrows < 0 ? 0 : nrows); +} + +/* Flush the current output buffers now */ +void PNGAPI +png_write_flush(png_structrp png_ptr) +{ + png_debug(1, "in png_write_flush"); + + if (png_ptr == NULL) + return; + + /* We have already written out all of the data */ + if (png_ptr->row_number >= png_ptr->num_rows) + return; + + png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH); + png_ptr->flush_rows = 0; + png_flush(png_ptr); +} +#endif /* PNG_WRITE_FLUSH_SUPPORTED */ + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED +static void png_reset_filter_heuristics(png_structrp png_ptr);/* forward decl */ +#endif + +/* Free any memory used in png_ptr struct without freeing the struct itself. */ +static void +png_write_destroy(png_structrp png_ptr) +{ + png_debug(1, "in png_write_destroy"); + + /* Free any memory zlib uses */ + if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) + deflateEnd(&png_ptr->zstream); + + /* Free our memory. png_free checks NULL for us. */ + png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list); + png_free(png_ptr, png_ptr->row_buf); +#ifdef PNG_WRITE_FILTER_SUPPORTED + png_free(png_ptr, png_ptr->prev_row); + png_free(png_ptr, png_ptr->sub_row); + png_free(png_ptr, png_ptr->up_row); + png_free(png_ptr, png_ptr->avg_row); + png_free(png_ptr, png_ptr->paeth_row); +#endif + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + /* Use this to save a little code space, it doesn't free the filter_costs */ + png_reset_filter_heuristics(png_ptr); + png_free(png_ptr, png_ptr->filter_costs); + png_free(png_ptr, png_ptr->inv_filter_costs); +#endif + +#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED + png_free(png_ptr, png_ptr->chunk_list); +#endif + + /* The error handling and memory handling information is left intact at this + * point: the jmp_buf may still have to be freed. See png_destroy_png_struct + * for how this happens. + */ +} + +/* Free all memory used by the write. + * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for + * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free + * the passed in info_structs but it would quietly fail to free any of the data + * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it + * has no png_ptr.) + */ +void PNGAPI +png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr) +{ + png_debug(1, "in png_destroy_write_struct"); + + if (png_ptr_ptr != NULL) + { + png_structrp png_ptr = *png_ptr_ptr; + + if (png_ptr != NULL) /* added in libpng 1.6.0 */ + { + png_destroy_info_struct(png_ptr, info_ptr_ptr); + + *png_ptr_ptr = NULL; + png_write_destroy(png_ptr); + png_destroy_png_struct(png_ptr); + } + } +} + +/* Allow the application to select one or more row filters to use. */ +void PNGAPI +png_set_filter(png_structrp png_ptr, int method, int filters) +{ + png_debug(1, "in png_set_filter"); + + if (png_ptr == NULL) + return; + +#ifdef PNG_MNG_FEATURES_SUPPORTED + if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && + (method == PNG_INTRAPIXEL_DIFFERENCING)) + method = PNG_FILTER_TYPE_BASE; + +#endif + if (method == PNG_FILTER_TYPE_BASE) + { + switch (filters & (PNG_ALL_FILTERS | 0x07)) + { +#ifdef PNG_WRITE_FILTER_SUPPORTED + case 5: + case 6: + case 7: png_app_error(png_ptr, "Unknown row filter for method 0"); + /* FALL THROUGH */ +#endif /* PNG_WRITE_FILTER_SUPPORTED */ + case PNG_FILTER_VALUE_NONE: + png_ptr->do_filter = PNG_FILTER_NONE; break; + +#ifdef PNG_WRITE_FILTER_SUPPORTED + case PNG_FILTER_VALUE_SUB: + png_ptr->do_filter = PNG_FILTER_SUB; break; + + case PNG_FILTER_VALUE_UP: + png_ptr->do_filter = PNG_FILTER_UP; break; + + case PNG_FILTER_VALUE_AVG: + png_ptr->do_filter = PNG_FILTER_AVG; break; + + case PNG_FILTER_VALUE_PAETH: + png_ptr->do_filter = PNG_FILTER_PAETH; break; + + default: + png_ptr->do_filter = (png_byte)filters; break; +#else + default: + png_app_error(png_ptr, "Unknown row filter for method 0"); +#endif /* PNG_WRITE_FILTER_SUPPORTED */ + } + + /* If we have allocated the row_buf, this means we have already started + * with the image and we should have allocated all of the filter buffers + * that have been selected. If prev_row isn't already allocated, then + * it is too late to start using the filters that need it, since we + * will be missing the data in the previous row. If an application + * wants to start and stop using particular filters during compression, + * it should start out with all of the filters, and then add and + * remove them after the start of compression. + */ + if (png_ptr->row_buf != NULL) + { +#ifdef PNG_WRITE_FILTER_SUPPORTED + if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL) + { + png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, + (png_ptr->rowbytes + 1)); + png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB; + } + + if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL) + { + if (png_ptr->prev_row == NULL) + { + png_warning(png_ptr, "Can't add Up filter after starting"); + png_ptr->do_filter = (png_byte)(png_ptr->do_filter & + ~PNG_FILTER_UP); + } + + else + { + png_ptr->up_row = (png_bytep)png_malloc(png_ptr, + (png_ptr->rowbytes + 1)); + png_ptr->up_row[0] = PNG_FILTER_VALUE_UP; + } + } + + if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL) + { + if (png_ptr->prev_row == NULL) + { + png_warning(png_ptr, "Can't add Average filter after starting"); + png_ptr->do_filter = (png_byte)(png_ptr->do_filter & + ~PNG_FILTER_AVG); + } + + else + { + png_ptr->avg_row = (png_bytep)png_malloc(png_ptr, + (png_ptr->rowbytes + 1)); + png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG; + } + } + + if ((png_ptr->do_filter & PNG_FILTER_PAETH) && + png_ptr->paeth_row == NULL) + { + if (png_ptr->prev_row == NULL) + { + png_warning(png_ptr, "Can't add Paeth filter after starting"); + png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH); + } + + else + { + png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr, + (png_ptr->rowbytes + 1)); + png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH; + } + } + + if (png_ptr->do_filter == PNG_NO_FILTERS) +#endif /* PNG_WRITE_FILTER_SUPPORTED */ + png_ptr->do_filter = PNG_FILTER_NONE; + } + } + else + png_error(png_ptr, "Unknown custom filter method"); +} + +/* This allows us to influence the way in which libpng chooses the "best" + * filter for the current scanline. While the "minimum-sum-of-absolute- + * differences metric is relatively fast and effective, there is some + * question as to whether it can be improved upon by trying to keep the + * filtered data going to zlib more consistent, hopefully resulting in + * better compression. + */ +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* GRR 970116 */ +/* Convenience reset API. */ +static void +png_reset_filter_heuristics(png_structrp png_ptr) +{ + /* Clear out any old values in the 'weights' - this must be done because if + * the app calls set_filter_heuristics multiple times with different + * 'num_weights' values we would otherwise potentially have wrong sized + * arrays. + */ + png_ptr->num_prev_filters = 0; + png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED; + if (png_ptr->prev_filters != NULL) + { + png_bytep old = png_ptr->prev_filters; + png_ptr->prev_filters = NULL; + png_free(png_ptr, old); + } + if (png_ptr->filter_weights != NULL) + { + png_uint_16p old = png_ptr->filter_weights; + png_ptr->filter_weights = NULL; + png_free(png_ptr, old); + } + + if (png_ptr->inv_filter_weights != NULL) + { + png_uint_16p old = png_ptr->inv_filter_weights; + png_ptr->inv_filter_weights = NULL; + png_free(png_ptr, old); + } + + /* Leave the filter_costs - this array is fixed size. */ +} + +static int +png_init_filter_heuristics(png_structrp png_ptr, int heuristic_method, + int num_weights) +{ + if (png_ptr == NULL) + return 0; + + /* Clear out the arrays */ + png_reset_filter_heuristics(png_ptr); + + /* Check arguments; the 'reset' function makes the correct settings for the + * unweighted case, but we must handle the weight case by initializing the + * arrays for the caller. + */ + if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int i; + + if (num_weights > 0) + { + png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr, + (png_uint_32)((sizeof (png_byte)) * num_weights)); + + /* To make sure that the weighting starts out fairly */ + for (i = 0; i < num_weights; i++) + { + png_ptr->prev_filters[i] = 255; + } + + png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr, + (png_uint_32)((sizeof (png_uint_16)) * num_weights)); + + png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr, + (png_uint_32)((sizeof (png_uint_16)) * num_weights)); + + for (i = 0; i < num_weights; i++) + { + png_ptr->inv_filter_weights[i] = + png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR; + } + + /* Safe to set this now */ + png_ptr->num_prev_filters = (png_byte)num_weights; + } + + /* If, in the future, there are other filter methods, this would + * need to be based on png_ptr->filter. + */ + if (png_ptr->filter_costs == NULL) + { + png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr, + (png_uint_32)((sizeof (png_uint_16)) * PNG_FILTER_VALUE_LAST)); + + png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr, + (png_uint_32)((sizeof (png_uint_16)) * PNG_FILTER_VALUE_LAST)); + } + + for (i = 0; i < PNG_FILTER_VALUE_LAST; i++) + { + png_ptr->inv_filter_costs[i] = + png_ptr->filter_costs[i] = PNG_COST_FACTOR; + } + + /* All the arrays are inited, safe to set this: */ + png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_WEIGHTED; + + /* Return the 'ok' code. */ + return 1; + } + else if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT || + heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED) + { + return 1; + } + else + { + png_warning(png_ptr, "Unknown filter heuristic method"); + return 0; + } +} + +/* Provide floating and fixed point APIs */ +#ifdef PNG_FLOATING_POINT_SUPPORTED +void PNGAPI +png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method, + int num_weights, png_const_doublep filter_weights, + png_const_doublep filter_costs) +{ + png_debug(1, "in png_set_filter_heuristics"); + + /* The internal API allocates all the arrays and ensures that the elements of + * those arrays are set to the default value. + */ + if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights)) + return; + + /* If using the weighted method copy in the weights. */ + if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int i; + for (i = 0; i < num_weights; i++) + { + if (filter_weights[i] <= 0.0) + { + png_ptr->inv_filter_weights[i] = + png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR; + } + + else + { + png_ptr->inv_filter_weights[i] = + (png_uint_16)(PNG_WEIGHT_FACTOR*filter_weights[i]+.5); + + png_ptr->filter_weights[i] = + (png_uint_16)(PNG_WEIGHT_FACTOR/filter_weights[i]+.5); + } + } + + /* Here is where we set the relative costs of the different filters. We + * should take the desired compression level into account when setting + * the costs, so that Paeth, for instance, has a high relative cost at low + * compression levels, while it has a lower relative cost at higher + * compression settings. The filter types are in order of increasing + * relative cost, so it would be possible to do this with an algorithm. + */ + for (i = 0; i < PNG_FILTER_VALUE_LAST; i++) if (filter_costs[i] >= 1.0) + { + png_ptr->inv_filter_costs[i] = + (png_uint_16)(PNG_COST_FACTOR / filter_costs[i] + .5); + + png_ptr->filter_costs[i] = + (png_uint_16)(PNG_COST_FACTOR * filter_costs[i] + .5); + } + } +} +#endif /* FLOATING_POINT */ + +#ifdef PNG_FIXED_POINT_SUPPORTED +void PNGAPI +png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method, + int num_weights, png_const_fixed_point_p filter_weights, + png_const_fixed_point_p filter_costs) +{ + png_debug(1, "in png_set_filter_heuristics_fixed"); + + /* The internal API allocates all the arrays and ensures that the elements of + * those arrays are set to the default value. + */ + if (!png_init_filter_heuristics(png_ptr, heuristic_method, num_weights)) + return; + + /* If using the weighted method copy in the weights. */ + if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int i; + for (i = 0; i < num_weights; i++) + { + if (filter_weights[i] <= 0) + { + png_ptr->inv_filter_weights[i] = + png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR; + } + + else + { + png_ptr->inv_filter_weights[i] = (png_uint_16) + ((PNG_WEIGHT_FACTOR*filter_weights[i]+PNG_FP_HALF)/PNG_FP_1); + + png_ptr->filter_weights[i] = (png_uint_16)((PNG_WEIGHT_FACTOR* + PNG_FP_1+(filter_weights[i]/2))/filter_weights[i]); + } + } + + /* Here is where we set the relative costs of the different filters. We + * should take the desired compression level into account when setting + * the costs, so that Paeth, for instance, has a high relative cost at low + * compression levels, while it has a lower relative cost at higher + * compression settings. The filter types are in order of increasing + * relative cost, so it would be possible to do this with an algorithm. + */ + for (i = 0; i < PNG_FILTER_VALUE_LAST; i++) + if (filter_costs[i] >= PNG_FP_1) + { + png_uint_32 tmp; + + /* Use a 32 bit unsigned temporary here because otherwise the + * intermediate value will be a 32 bit *signed* integer (ANSI rules) + * and this will get the wrong answer on division. + */ + tmp = PNG_COST_FACTOR*PNG_FP_1 + (filter_costs[i]/2); + tmp /= filter_costs[i]; + + png_ptr->inv_filter_costs[i] = (png_uint_16)tmp; + + tmp = PNG_COST_FACTOR * filter_costs[i] + PNG_FP_HALF; + tmp /= PNG_FP_1; + + png_ptr->filter_costs[i] = (png_uint_16)tmp; + } + } +} +#endif /* FIXED_POINT */ +#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */ + +void PNGAPI +png_set_compression_level(png_structrp png_ptr, int level) +{ + png_debug(1, "in png_set_compression_level"); + + if (png_ptr == NULL) + return; + + png_ptr->zlib_level = level; +} + +void PNGAPI +png_set_compression_mem_level(png_structrp png_ptr, int mem_level) +{ + png_debug(1, "in png_set_compression_mem_level"); + + if (png_ptr == NULL) + return; + + png_ptr->zlib_mem_level = mem_level; +} + +void PNGAPI +png_set_compression_strategy(png_structrp png_ptr, int strategy) +{ + png_debug(1, "in png_set_compression_strategy"); + + if (png_ptr == NULL) + return; + + /* The flag setting here prevents the libpng dynamic selection of strategy. + */ + png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY; + png_ptr->zlib_strategy = strategy; +} + +/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a + * smaller value of window_bits if it can do so safely. + */ +void PNGAPI +png_set_compression_window_bits(png_structrp png_ptr, int window_bits) +{ + if (png_ptr == NULL) + return; + + /* Prior to 1.6.0 this would warn but then set the window_bits value, this + * meant that negative window bits values could be selected which would cause + * libpng to write a non-standard PNG file with raw deflate or gzip + * compressed IDAT or ancillary chunks. Such files can be read and there is + * no warning on read, so this seems like a very bad idea. + */ + if (window_bits > 15) + { + png_warning(png_ptr, "Only compression windows <= 32k supported by PNG"); + window_bits = 15; + } + + else if (window_bits < 8) + { + png_warning(png_ptr, "Only compression windows >= 256 supported by PNG"); + window_bits = 8; + } + + png_ptr->zlib_window_bits = window_bits; +} + +void PNGAPI +png_set_compression_method(png_structrp png_ptr, int method) +{ + png_debug(1, "in png_set_compression_method"); + + if (png_ptr == NULL) + return; + + /* This would produce an invalid PNG file if it worked, but it doesn't and + * deflate will fault it, so it is harmless to just warn here. + */ + if (method != 8) + png_warning(png_ptr, "Only compression method 8 is supported by PNG"); + + png_ptr->zlib_method = method; +} + +/* The following were added to libpng-1.5.4 */ +#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED +void PNGAPI +png_set_text_compression_level(png_structrp png_ptr, int level) +{ + png_debug(1, "in png_set_text_compression_level"); + + if (png_ptr == NULL) + return; + + png_ptr->zlib_text_level = level; +} + +void PNGAPI +png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level) +{ + png_debug(1, "in png_set_text_compression_mem_level"); + + if (png_ptr == NULL) + return; + + png_ptr->zlib_text_mem_level = mem_level; +} + +void PNGAPI +png_set_text_compression_strategy(png_structrp png_ptr, int strategy) +{ + png_debug(1, "in png_set_text_compression_strategy"); + + if (png_ptr == NULL) + return; + + png_ptr->zlib_text_strategy = strategy; +} + +/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a + * smaller value of window_bits if it can do so safely. + */ +void PNGAPI +png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits) +{ + if (png_ptr == NULL) + return; + + if (window_bits > 15) + { + png_warning(png_ptr, "Only compression windows <= 32k supported by PNG"); + window_bits = 15; + } + + else if (window_bits < 8) + { + png_warning(png_ptr, "Only compression windows >= 256 supported by PNG"); + window_bits = 8; + } + + png_ptr->zlib_text_window_bits = window_bits; +} + +void PNGAPI +png_set_text_compression_method(png_structrp png_ptr, int method) +{ + png_debug(1, "in png_set_text_compression_method"); + + if (png_ptr == NULL) + return; + + if (method != 8) + png_warning(png_ptr, "Only compression method 8 is supported by PNG"); + + png_ptr->zlib_text_method = method; +} +#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */ +/* end of API added to libpng-1.5.4 */ + +void PNGAPI +png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn) +{ + if (png_ptr == NULL) + return; + + png_ptr->write_row_fn = write_row_fn; +} + +#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED +void PNGAPI +png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr + write_user_transform_fn) +{ + png_debug(1, "in png_set_write_user_transform_fn"); + + if (png_ptr == NULL) + return; + + png_ptr->transformations |= PNG_USER_TRANSFORM; + png_ptr->write_user_transform_fn = write_user_transform_fn; +} +#endif + + +#ifdef PNG_INFO_IMAGE_SUPPORTED +void PNGAPI +png_write_png(png_structrp png_ptr, png_inforp info_ptr, + int transforms, voidp params) +{ + if (png_ptr == NULL || info_ptr == NULL) + return; + + if ((info_ptr->valid & PNG_INFO_IDAT) == 0) + { + png_app_error(png_ptr, "no rows for png_write_image to write"); + return; + } + + /* Write the file header information. */ + png_write_info(png_ptr, info_ptr); + + /* ------ these transformations don't touch the info structure ------- */ + + /* Invert monochrome pixels */ + if (transforms & PNG_TRANSFORM_INVERT_MONO) +#ifdef PNG_WRITE_INVERT_SUPPORTED + png_set_invert_mono(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported"); +#endif + + /* Shift the pixels up to a legal bit depth and fill in + * as appropriate to correctly scale the image. + */ + if (transforms & PNG_TRANSFORM_SHIFT) +#ifdef PNG_WRITE_SHIFT_SUPPORTED + if (info_ptr->valid & PNG_INFO_sBIT) + png_set_shift(png_ptr, &info_ptr->sig_bit); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported"); +#endif + + /* Pack pixels into bytes */ + if (transforms & PNG_TRANSFORM_PACKING) +#ifdef PNG_WRITE_PACK_SUPPORTED + png_set_packing(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported"); +#endif + + /* Swap location of alpha bytes from ARGB to RGBA */ + if (transforms & PNG_TRANSFORM_SWAP_ALPHA) +#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED + png_set_swap_alpha(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported"); +#endif + + /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into + * RGB, note that the code expects the input color type to be G or RGB; no + * alpha channel. + */ + if (transforms & + (PNG_TRANSFORM_STRIP_FILLER_AFTER|PNG_TRANSFORM_STRIP_FILLER_BEFORE)) + { +#ifdef PNG_WRITE_FILLER_SUPPORTED + if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) + { + if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) + png_app_error(png_ptr, + "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported"); + + /* Continue if ignored - this is the pre-1.6.10 behavior */ + png_set_filler(png_ptr, 0, PNG_FILLER_AFTER); + } + + else if (transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) + png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported"); +#endif + } + + /* Flip BGR pixels to RGB */ + if (transforms & PNG_TRANSFORM_BGR) +#ifdef PNG_WRITE_BGR_SUPPORTED + png_set_bgr(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported"); +#endif + + /* Swap bytes of 16-bit files to most significant byte first */ + if (transforms & PNG_TRANSFORM_SWAP_ENDIAN) +#ifdef PNG_WRITE_SWAP_SUPPORTED + png_set_swap(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported"); +#endif + + /* Swap bits of 1, 2, 4 bit packed pixel formats */ + if (transforms & PNG_TRANSFORM_PACKSWAP) +#ifdef PNG_WRITE_PACKSWAP_SUPPORTED + png_set_packswap(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported"); +#endif + + /* Invert the alpha channel from opacity to transparency */ + if (transforms & PNG_TRANSFORM_INVERT_ALPHA) +#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED + png_set_invert_alpha(png_ptr); +#else + png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported"); +#endif + + /* ----------------------- end of transformations ------------------- */ + + /* Write the bits */ + png_write_image(png_ptr, info_ptr->row_pointers); + + /* It is REQUIRED to call this to finish writing the rest of the file */ + png_write_end(png_ptr, info_ptr); + + PNG_UNUSED(params) +} +#endif + + +#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED +#ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */ +/* Initialize the write structure - general purpose utility. */ +static int +png_image_write_init(png_imagep image) +{ + png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image, + png_safe_error, png_safe_warning); + + if (png_ptr != NULL) + { + png_infop info_ptr = png_create_info_struct(png_ptr); + + if (info_ptr != NULL) + { + png_controlp control = png_voidcast(png_controlp, + png_malloc_warn(png_ptr, (sizeof *control))); + + if (control != NULL) + { + memset(control, 0, (sizeof *control)); + + control->png_ptr = png_ptr; + control->info_ptr = info_ptr; + control->for_write = 1; + + image->opaque = control; + return 1; + } + + /* Error clean up */ + png_destroy_info_struct(png_ptr, &info_ptr); + } + + png_destroy_write_struct(&png_ptr, NULL); + } + + return png_image_error(image, "png_image_write_: out of memory"); +} + +/* Arguments to png_image_write_main: */ +typedef struct +{ + /* Arguments: */ + png_imagep image; + png_const_voidp buffer; + png_int_32 row_stride; + png_const_voidp colormap; + int convert_to_8bit; + /* Local variables: */ + png_const_voidp first_row; + ptrdiff_t row_bytes; + png_voidp local_row; +} png_image_write_control; + +/* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to + * do any necessary byte swapping. The component order is defined by the + * png_image format value. + */ +static int +png_write_image_16bit(png_voidp argument) +{ + png_image_write_control *display = png_voidcast(png_image_write_control*, + argument); + png_imagep image = display->image; + png_structrp png_ptr = image->opaque->png_ptr; + + png_const_uint_16p input_row = png_voidcast(png_const_uint_16p, + display->first_row); + png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row); + png_uint_16p row_end; + const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1; + int aindex = 0; + png_uint_32 y = image->height; + + if (image->format & PNG_FORMAT_FLAG_ALPHA) + { +# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED + if (image->format & PNG_FORMAT_FLAG_AFIRST) + { + aindex = -1; + ++input_row; /* To point to the first component */ + ++output_row; + } + + else +# endif + aindex = channels; + } + + else + png_error(png_ptr, "png_write_image: internal call error"); + + /* Work out the output row end and count over this, note that the increment + * above to 'row' means that row_end can actually be beyond the end of the + * row; this is correct. + */ + row_end = output_row + image->width * (channels+1); + + while (y-- > 0) + { + png_const_uint_16p in_ptr = input_row; + png_uint_16p out_ptr = output_row; + + while (out_ptr < row_end) + { + const png_uint_16 alpha = in_ptr[aindex]; + png_uint_32 reciprocal = 0; + int c; + + out_ptr[aindex] = alpha; + + /* Calculate a reciprocal. The correct calculation is simply + * component/alpha*65535 << 15. (I.e. 15 bits of precision); this + * allows correct rounding by adding .5 before the shift. 'reciprocal' + * is only initialized when required. + */ + if (alpha > 0 && alpha < 65535) + reciprocal = ((0xffff<<15)+(alpha>>1))/alpha; + + c = channels; + do /* always at least one channel */ + { + png_uint_16 component = *in_ptr++; + + /* The following gives 65535 for an alpha of 0, which is fine, + * otherwise if 0/0 is represented as some other value there is more + * likely to be a discontinuity which will probably damage + * compression when moving from a fully transparent area to a + * nearly transparent one. (The assumption here is that opaque + * areas tend not to be 0 intensity.) + */ + if (component >= alpha) + component = 65535; + + /* component<alpha, so component/alpha is less than one and + * component*reciprocal is less than 2^31. + */ + else if (component > 0 && alpha < 65535) + { + png_uint_32 calc = component * reciprocal; + calc += 16384; /* round to nearest */ + component = (png_uint_16)(calc >> 15); + } + + *out_ptr++ = component; + } + while (--c > 0); + + /* Skip to next component (skip the intervening alpha channel) */ + ++in_ptr; + ++out_ptr; + } + + png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row)); + input_row += display->row_bytes/(sizeof (png_uint_16)); + } + + return 1; +} + +/* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel + * is present it must be removed from the components, the components are then + * written in sRGB encoding. No components are added or removed. + * + * Calculate an alpha reciprocal to reverse pre-multiplication. As above the + * calculation can be done to 15 bits of accuracy; however, the output needs to + * be scaled in the range 0..255*65535, so include that scaling here. + */ +#define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha) + +static png_byte +png_unpremultiply(png_uint_32 component, png_uint_32 alpha, + png_uint_32 reciprocal/*from the above macro*/) +{ + /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0 + * is represented as some other value there is more likely to be a + * discontinuity which will probably damage compression when moving from a + * fully transparent area to a nearly transparent one. (The assumption here + * is that opaque areas tend not to be 0 intensity.) + * + * There is a rounding problem here; if alpha is less than 128 it will end up + * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the + * output change for this too. + */ + if (component >= alpha || alpha < 128) + return 255; + + /* component<alpha, so component/alpha is less than one and + * component*reciprocal is less than 2^31. + */ + else if (component > 0) + { + /* The test is that alpha/257 (rounded) is less than 255, the first value + * that becomes 255 is 65407. + * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore, + * be exact!) [Could also test reciprocal != 0] + */ + if (alpha < 65407) + { + component *= reciprocal; + component += 64; /* round to nearest */ + component >>= 7; + } + + else + component *= 255; + + /* Convert the component to sRGB. */ + return (png_byte)PNG_sRGB_FROM_LINEAR(component); + } + + else + return 0; +} + +static int +png_write_image_8bit(png_voidp argument) +{ + png_image_write_control *display = png_voidcast(png_image_write_control*, + argument); + png_imagep image = display->image; + png_structrp png_ptr = image->opaque->png_ptr; + + png_const_uint_16p input_row = png_voidcast(png_const_uint_16p, + display->first_row); + png_bytep output_row = png_voidcast(png_bytep, display->local_row); + png_uint_32 y = image->height; + const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1; + + if (image->format & PNG_FORMAT_FLAG_ALPHA) + { + png_bytep row_end; + int aindex; + +# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED + if (image->format & PNG_FORMAT_FLAG_AFIRST) + { + aindex = -1; + ++input_row; /* To point to the first component */ + ++output_row; + } + + else +# endif + aindex = channels; + + /* Use row_end in place of a loop counter: */ + row_end = output_row + image->width * (channels+1); + + while (y-- > 0) + { + png_const_uint_16p in_ptr = input_row; + png_bytep out_ptr = output_row; + + while (out_ptr < row_end) + { + png_uint_16 alpha = in_ptr[aindex]; + png_byte alphabyte = (png_byte)PNG_DIV257(alpha); + png_uint_32 reciprocal = 0; + int c; + + /* Scale and write the alpha channel. */ + out_ptr[aindex] = alphabyte; + + if (alphabyte > 0 && alphabyte < 255) + reciprocal = UNP_RECIPROCAL(alpha); + + c = channels; + do /* always at least one channel */ + *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal); + while (--c > 0); + + /* Skip to next component (skip the intervening alpha channel) */ + ++in_ptr; + ++out_ptr; + } /* while out_ptr < row_end */ + + png_write_row(png_ptr, png_voidcast(png_const_bytep, + display->local_row)); + input_row += display->row_bytes/(sizeof (png_uint_16)); + } /* while y */ + } + + else + { + /* No alpha channel, so the row_end really is the end of the row and it + * is sufficient to loop over the components one by one. + */ + png_bytep row_end = output_row + image->width * channels; + + while (y-- > 0) + { + png_const_uint_16p in_ptr = input_row; + png_bytep out_ptr = output_row; + + while (out_ptr < row_end) + { + png_uint_32 component = *in_ptr++; + + component *= 255; + *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component); + } + + png_write_row(png_ptr, output_row); + input_row += display->row_bytes/(sizeof (png_uint_16)); + } + } + + return 1; +} + +static void +png_image_set_PLTE(png_image_write_control *display) +{ + const png_imagep image = display->image; + const void *cmap = display->colormap; + const int entries = image->colormap_entries > 256 ? 256 : + (int)image->colormap_entries; + + /* NOTE: the caller must check for cmap != NULL and entries != 0 */ + const png_uint_32 format = image->format; + const int channels = PNG_IMAGE_SAMPLE_CHANNELS(format); + +# if defined(PNG_FORMAT_BGR_SUPPORTED) &&\ + defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED) + const int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 && + (format & PNG_FORMAT_FLAG_ALPHA) != 0; +# else +# define afirst 0 +# endif + +# ifdef PNG_FORMAT_BGR_SUPPORTED + const int bgr = (format & PNG_FORMAT_FLAG_BGR) ? 2 : 0; +# else +# define bgr 0 +# endif + + int i, num_trans; + png_color palette[256]; + png_byte tRNS[256]; + + memset(tRNS, 255, (sizeof tRNS)); + memset(palette, 0, (sizeof palette)); + + for (i=num_trans=0; i<entries; ++i) + { + /* This gets automatically converted to sRGB with reversal of the + * pre-multiplication if the color-map has an alpha channel. + */ + if (format & PNG_FORMAT_FLAG_LINEAR) + { + png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap); + + entry += i * channels; + + if (channels & 1) /* no alpha */ + { + if (channels >= 3) /* RGB */ + { + palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 * + entry[(2 ^ bgr)]); + palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 * + entry[1]); + palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 * + entry[bgr]); + } + + else /* Gray */ + palette[i].blue = palette[i].red = palette[i].green = + (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry); + } + + else /* alpha */ + { + png_uint_16 alpha = entry[afirst ? 0 : channels-1]; + png_byte alphabyte = (png_byte)PNG_DIV257(alpha); + png_uint_32 reciprocal = 0; + + /* Calculate a reciprocal, as in the png_write_image_8bit code above + * this is designed to produce a value scaled to 255*65535 when + * divided by 128 (i.e. asr 7). + */ + if (alphabyte > 0 && alphabyte < 255) + reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha; + + tRNS[i] = alphabyte; + if (alphabyte < 255) + num_trans = i+1; + + if (channels >= 3) /* RGB */ + { + palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)], + alpha, reciprocal); + palette[i].green = png_unpremultiply(entry[afirst + 1], alpha, + reciprocal); + palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha, + reciprocal); + } + + else /* gray */ + palette[i].blue = palette[i].red = palette[i].green = + png_unpremultiply(entry[afirst], alpha, reciprocal); + } + } + + else /* Color-map has sRGB values */ + { + png_const_bytep entry = png_voidcast(png_const_bytep, cmap); + + entry += i * channels; + + switch (channels) + { + case 4: + tRNS[i] = entry[afirst ? 0 : 3]; + if (tRNS[i] < 255) + num_trans = i+1; + /* FALL THROUGH */ + case 3: + palette[i].blue = entry[afirst + (2 ^ bgr)]; + palette[i].green = entry[afirst + 1]; + palette[i].red = entry[afirst + bgr]; + break; + + case 2: + tRNS[i] = entry[1 ^ afirst]; + if (tRNS[i] < 255) + num_trans = i+1; + /* FALL THROUGH */ + case 1: + palette[i].blue = palette[i].red = palette[i].green = + entry[afirst]; + break; + + default: + break; + } + } + } + +# ifdef afirst +# undef afirst +# endif +# ifdef bgr +# undef bgr +# endif + + png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette, + entries); + + if (num_trans > 0) + png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS, + num_trans, NULL); + + image->colormap_entries = entries; +} + +static int +png_image_write_main(png_voidp argument) +{ + png_image_write_control *display = png_voidcast(png_image_write_control*, + argument); + png_imagep image = display->image; + png_structrp png_ptr = image->opaque->png_ptr; + png_inforp info_ptr = image->opaque->info_ptr; + png_uint_32 format = image->format; + + int colormap = (format & PNG_FORMAT_FLAG_COLORMAP) != 0; + int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR) != 0; /* input */ + int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0; + int write_16bit = linear && !colormap && !display->convert_to_8bit; + +# ifdef PNG_BENIGN_ERRORS_SUPPORTED + /* Make sure we error out on any bad situation */ + png_set_benign_errors(png_ptr, 0/*error*/); +# endif + + /* Default the 'row_stride' parameter if required. */ + if (display->row_stride == 0) + display->row_stride = PNG_IMAGE_ROW_STRIDE(*image); + + /* Set the required transforms then write the rows in the correct order. */ + if (format & PNG_FORMAT_FLAG_COLORMAP) + { + if (display->colormap != NULL && image->colormap_entries > 0) + { + png_uint_32 entries = image->colormap_entries; + + png_set_IHDR(png_ptr, info_ptr, image->width, image->height, + entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)), + PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE, + PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); + + png_image_set_PLTE(display); + } + + else + png_error(image->opaque->png_ptr, + "no color-map for color-mapped image"); + } + + else + png_set_IHDR(png_ptr, info_ptr, image->width, image->height, + write_16bit ? 16 : 8, + ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) + + ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0), + PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); + + /* Counter-intuitively the data transformations must be called *after* + * png_write_info, not before as in the read code, but the 'set' functions + * must still be called before. Just set the color space information, never + * write an interlaced image. + */ + + if (write_16bit != 0) + { + /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */ + png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR); + + if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB)) + png_set_cHRM_fixed(png_ptr, info_ptr, + /* color x y */ + /* white */ 31270, 32900, + /* red */ 64000, 33000, + /* green */ 30000, 60000, + /* blue */ 15000, 6000 + ); + } + + else if (!(image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB)) + png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL); + + /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit + * space must still be gamma encoded. + */ + else + png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE); + + /* Write the file header. */ + png_write_info(png_ptr, info_ptr); + + /* Now set up the data transformations (*after* the header is written), + * remove the handled transformations from the 'format' flags for checking. + * + * First check for a little endian system if writing 16 bit files. + */ + if (write_16bit != 0) + { + PNG_CONST png_uint_16 le = 0x0001; + + if (*(png_const_bytep)&le) + png_set_swap(png_ptr); + } + +# ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED + if (format & PNG_FORMAT_FLAG_BGR) + { + if (!colormap && (format & PNG_FORMAT_FLAG_COLOR) != 0) + png_set_bgr(png_ptr); + format &= ~PNG_FORMAT_FLAG_BGR; + } +# endif + +# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED + if (format & PNG_FORMAT_FLAG_AFIRST) + { + if (!colormap && (format & PNG_FORMAT_FLAG_ALPHA) != 0) + png_set_swap_alpha(png_ptr); + format &= ~PNG_FORMAT_FLAG_AFIRST; + } +# endif + + /* If there are 16 or fewer color-map entries we wrote a lower bit depth + * above, but the application data is still byte packed. + */ + if (colormap && image->colormap_entries <= 16) + png_set_packing(png_ptr); + + /* That should have handled all (both) the transforms. */ + if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR | + PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0) + png_error(png_ptr, "png_write_image: unsupported transformation"); + + { + png_const_bytep row = png_voidcast(png_const_bytep, display->buffer); + ptrdiff_t row_bytes = display->row_stride; + + if (linear != 0) + row_bytes *= (sizeof (png_uint_16)); + + if (row_bytes < 0) + row += (image->height-1) * (-row_bytes); + + display->first_row = row; + display->row_bytes = row_bytes; + } + + /* Apply 'fast' options if the flag is set. */ + if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0) + { + png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS); + /* NOTE: determined by experiment using pngstest, this reflects some + * balance between the time to write the image once and the time to read + * it about 50 times. The speed-up in pngstest was about 10-20% of the + * total (user) time on a heavily loaded system. + */ + png_set_compression_level(png_ptr, 3); + } + + /* Check for the cases that currently require a pre-transform on the row + * before it is written. This only applies when the input is 16-bit and + * either there is an alpha channel or it is converted to 8-bit. + */ + if ((linear && alpha) || (!colormap && display->convert_to_8bit)) + { + png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr, + png_get_rowbytes(png_ptr, info_ptr))); + int result; + + display->local_row = row; + if (write_16bit != 0) + result = png_safe_execute(image, png_write_image_16bit, display); + else + result = png_safe_execute(image, png_write_image_8bit, display); + display->local_row = NULL; + + png_free(png_ptr, row); + + /* Skip the 'write_end' on error: */ + if (result == 0) + return 0; + } + + /* Otherwise this is the case where the input is in a format currently + * supported by the rest of the libpng write code; call it directly. + */ + else + { + png_const_bytep row = png_voidcast(png_const_bytep, display->first_row); + ptrdiff_t row_bytes = display->row_bytes; + png_uint_32 y = image->height; + + while (y-- > 0) + { + png_write_row(png_ptr, row); + row += row_bytes; + } + } + + png_write_end(png_ptr, info_ptr); + return 1; +} + +int PNGAPI +png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit, + const void *buffer, png_int_32 row_stride, const void *colormap) +{ + /* Write the image to the given (FILE*). */ + if (image != NULL && image->version == PNG_IMAGE_VERSION) + { + if (file != NULL) + { + if (png_image_write_init(image)) + { + png_image_write_control display; + int result; + + /* This is slightly evil, but png_init_io doesn't do anything other + * than this and we haven't changed the standard IO functions so + * this saves a 'safe' function. + */ + image->opaque->png_ptr->io_ptr = file; + + memset(&display, 0, (sizeof display)); + display.image = image; + display.buffer = buffer; + display.row_stride = row_stride; + display.colormap = colormap; + display.convert_to_8bit = convert_to_8bit; + + result = png_safe_execute(image, png_image_write_main, &display); + png_image_free(image); + return result; + } + + else + return 0; + } + + else + return png_image_error(image, + "png_image_write_to_stdio: invalid argument"); + } + + else if (image != NULL) + return png_image_error(image, + "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION"); + + else + return 0; +} + +int PNGAPI +png_image_write_to_file(png_imagep image, const char *file_name, + int convert_to_8bit, const void *buffer, png_int_32 row_stride, + const void *colormap) +{ + /* Write the image to the named file. */ + if (image != NULL && image->version == PNG_IMAGE_VERSION) + { + if (file_name != NULL) + { + FILE *fp = fopen(file_name, "wb"); + + if (fp != NULL) + { + if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer, + row_stride, colormap)) + { + int error; /* from fflush/fclose */ + + /* Make sure the file is flushed correctly. */ + if (fflush(fp) == 0 && ferror(fp) == 0) + { + if (fclose(fp) == 0) + return 1; + + error = errno; /* from fclose */ + } + + else + { + error = errno; /* from fflush or ferror */ + (void)fclose(fp); + } + + (void)remove(file_name); + /* The image has already been cleaned up; this is just used to + * set the error (because the original write succeeded). + */ + return png_image_error(image, strerror(error)); + } + + else + { + /* Clean up: just the opened file. */ + (void)fclose(fp); + (void)remove(file_name); + return 0; + } + } + + else + return png_image_error(image, strerror(errno)); + } + + else + return png_image_error(image, + "png_image_write_to_file: invalid argument"); + } + + else if (image != NULL) + return png_image_error(image, + "png_image_write_to_file: incorrect PNG_IMAGE_VERSION"); + + else + return 0; +} +#endif /* PNG_STDIO_SUPPORTED */ +#endif /* SIMPLIFIED_WRITE */ +#endif /* PNG_WRITE_SUPPORTED */ diff --git a/png/pngwtran.c b/png/pngwtran.c new file mode 100755 index 0000000..215bd68 --- /dev/null +++ b/png/pngwtran.c @@ -0,0 +1,572 @@ + +/* pngwtran.c - transforms the data in a row for PNG writers + * + * Last changed in libpng 1.6.9 [February 6, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +#include "pngpriv.h" + +#ifdef PNG_WRITE_SUPPORTED +#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED + +#ifdef PNG_WRITE_PACK_SUPPORTED +/* Pack pixels into bytes. Pass the true bit depth in bit_depth. The + * row_info bit depth should be 8 (one pixel per byte). The channels + * should be 1 (this only happens on grayscale and paletted images). + */ +static void +png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth) +{ + png_debug(1, "in png_do_pack"); + + if (row_info->bit_depth == 8 && + row_info->channels == 1) + { + switch ((int)bit_depth) + { + case 1: + { + png_bytep sp, dp; + int mask, v; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + sp = row; + dp = row; + mask = 0x80; + v = 0; + + for (i = 0; i < row_width; i++) + { + if (*sp != 0) + v |= mask; + + sp++; + + if (mask > 1) + mask >>= 1; + + else + { + mask = 0x80; + *dp = (png_byte)v; + dp++; + v = 0; + } + } + + if (mask != 0x80) + *dp = (png_byte)v; + + break; + } + + case 2: + { + png_bytep sp, dp; + int shift, v; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + sp = row; + dp = row; + shift = 6; + v = 0; + + for (i = 0; i < row_width; i++) + { + png_byte value; + + value = (png_byte)(*sp & 0x03); + v |= (value << shift); + + if (shift == 0) + { + shift = 6; + *dp = (png_byte)v; + dp++; + v = 0; + } + + else + shift -= 2; + + sp++; + } + + if (shift != 6) + *dp = (png_byte)v; + + break; + } + + case 4: + { + png_bytep sp, dp; + int shift, v; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + sp = row; + dp = row; + shift = 4; + v = 0; + + for (i = 0; i < row_width; i++) + { + png_byte value; + + value = (png_byte)(*sp & 0x0f); + v |= (value << shift); + + if (shift == 0) + { + shift = 4; + *dp = (png_byte)v; + dp++; + v = 0; + } + + else + shift -= 4; + + sp++; + } + + if (shift != 4) + *dp = (png_byte)v; + + break; + } + + default: + break; + } + + row_info->bit_depth = (png_byte)bit_depth; + row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels); + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, + row_info->width); + } +} +#endif + +#ifdef PNG_WRITE_SHIFT_SUPPORTED +/* Shift pixel values to take advantage of whole range. Pass the + * true number of bits in bit_depth. The row should be packed + * according to row_info->bit_depth. Thus, if you had a row of + * bit depth 4, but the pixels only had values from 0 to 7, you + * would pass 3 as bit_depth, and this routine would translate the + * data to 0 to 15. + */ +static void +png_do_shift(png_row_infop row_info, png_bytep row, + png_const_color_8p bit_depth) +{ + png_debug(1, "in png_do_shift"); + + if (row_info->color_type != PNG_COLOR_TYPE_PALETTE) + { + int shift_start[4], shift_dec[4]; + int channels = 0; + + if (row_info->color_type & PNG_COLOR_MASK_COLOR) + { + shift_start[channels] = row_info->bit_depth - bit_depth->red; + shift_dec[channels] = bit_depth->red; + channels++; + + shift_start[channels] = row_info->bit_depth - bit_depth->green; + shift_dec[channels] = bit_depth->green; + channels++; + + shift_start[channels] = row_info->bit_depth - bit_depth->blue; + shift_dec[channels] = bit_depth->blue; + channels++; + } + + else + { + shift_start[channels] = row_info->bit_depth - bit_depth->gray; + shift_dec[channels] = bit_depth->gray; + channels++; + } + + if (row_info->color_type & PNG_COLOR_MASK_ALPHA) + { + shift_start[channels] = row_info->bit_depth - bit_depth->alpha; + shift_dec[channels] = bit_depth->alpha; + channels++; + } + + /* With low row depths, could only be grayscale, so one channel */ + if (row_info->bit_depth < 8) + { + png_bytep bp = row; + png_size_t i; + unsigned int mask; + png_size_t row_bytes = row_info->rowbytes; + + if (bit_depth->gray == 1 && row_info->bit_depth == 2) + mask = 0x55; + + else if (row_info->bit_depth == 4 && bit_depth->gray == 3) + mask = 0x11; + + else + mask = 0xff; + + for (i = 0; i < row_bytes; i++, bp++) + { + int j; + unsigned int v, out; + + v = *bp; + out = 0; + + for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0]) + { + if (j > 0) + out |= v << j; + + else + out |= (v >> (-j)) & mask; + } + + *bp = (png_byte)(out & 0xff); + } + } + + else if (row_info->bit_depth == 8) + { + png_bytep bp = row; + png_uint_32 i; + png_uint_32 istop = channels * row_info->width; + + for (i = 0; i < istop; i++, bp++) + { + + const unsigned int c = i%channels; + int j; + unsigned int v, out; + + v = *bp; + out = 0; + + for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) + { + if (j > 0) + out |= v << j; + + else + out |= v >> (-j); + } + + *bp = (png_byte)(out & 0xff); + } + } + + else + { + png_bytep bp; + png_uint_32 i; + png_uint_32 istop = channels * row_info->width; + + for (bp = row, i = 0; i < istop; i++) + { + const unsigned int c = i%channels; + int j; + unsigned int value, v; + + v = png_get_uint_16(bp); + value = 0; + + for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c]) + { + if (j > 0) + value |= v << j; + + else + value |= v >> (-j); + } + *bp++ = (png_byte)((value >> 8) & 0xff); + *bp++ = (png_byte)(value & 0xff); + } + } + } +} +#endif + +#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED +static void +png_do_write_swap_alpha(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_write_swap_alpha"); + + { + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + if (row_info->bit_depth == 8) + { + /* This converts from ARGB to RGBA */ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + for (i = 0, sp = dp = row; i < row_width; i++) + { + png_byte save = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = save; + } + } + +#ifdef PNG_WRITE_16BIT_SUPPORTED + else + { + /* This converts from AARRGGBB to RRGGBBAA */ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + for (i = 0, sp = dp = row; i < row_width; i++) + { + png_byte save[2]; + save[0] = *(sp++); + save[1] = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = save[0]; + *(dp++) = save[1]; + } + } +#endif /* PNG_WRITE_16BIT_SUPPORTED */ + } + + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (row_info->bit_depth == 8) + { + /* This converts from AG to GA */ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + for (i = 0, sp = dp = row; i < row_width; i++) + { + png_byte save = *(sp++); + *(dp++) = *(sp++); + *(dp++) = save; + } + } + +#ifdef PNG_WRITE_16BIT_SUPPORTED + else + { + /* This converts from AAGG to GGAA */ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + for (i = 0, sp = dp = row; i < row_width; i++) + { + png_byte save[2]; + save[0] = *(sp++); + save[1] = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = save[0]; + *(dp++) = save[1]; + } + } +#endif /* PNG_WRITE_16BIT_SUPPORTED */ + } + } +} +#endif + +#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED +static void +png_do_write_invert_alpha(png_row_infop row_info, png_bytep row) +{ + png_debug(1, "in png_do_write_invert_alpha"); + + { + if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) + { + if (row_info->bit_depth == 8) + { + /* This inverts the alpha channel in RGBA */ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + for (i = 0, sp = dp = row; i < row_width; i++) + { + /* Does nothing + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + */ + sp+=3; dp = sp; + *(dp++) = (png_byte)(255 - *(sp++)); + } + } + +#ifdef PNG_WRITE_16BIT_SUPPORTED + else + { + /* This inverts the alpha channel in RRGGBBAA */ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + for (i = 0, sp = dp = row; i < row_width; i++) + { + /* Does nothing + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + *(dp++) = *(sp++); + */ + sp+=6; dp = sp; + *(dp++) = (png_byte)(255 - *(sp++)); + *(dp++) = (png_byte)(255 - *(sp++)); + } + } +#endif /* PNG_WRITE_16BIT_SUPPORTED */ + } + + else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) + { + if (row_info->bit_depth == 8) + { + /* This inverts the alpha channel in GA */ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + for (i = 0, sp = dp = row; i < row_width; i++) + { + *(dp++) = *(sp++); + *(dp++) = (png_byte)(255 - *(sp++)); + } + } + +#ifdef PNG_WRITE_16BIT_SUPPORTED + else + { + /* This inverts the alpha channel in GGAA */ + png_bytep sp, dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + for (i = 0, sp = dp = row; i < row_width; i++) + { + /* Does nothing + *(dp++) = *(sp++); + *(dp++) = *(sp++); + */ + sp+=2; dp = sp; + *(dp++) = (png_byte)(255 - *(sp++)); + *(dp++) = (png_byte)(255 - *(sp++)); + } + } +#endif /* PNG_WRITE_16BIT_SUPPORTED */ + } + } +} +#endif + +/* Transform the data according to the user's wishes. The order of + * transformations is significant. + */ +void /* PRIVATE */ +png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info) +{ + png_debug(1, "in png_do_write_transformations"); + + if (png_ptr == NULL) + return; + +#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED + if (png_ptr->transformations & PNG_USER_TRANSFORM) + if (png_ptr->write_user_transform_fn != NULL) + (*(png_ptr->write_user_transform_fn)) /* User write transform + function */ + (png_ptr, /* png_ptr */ + row_info, /* row_info: */ + /* png_uint_32 width; width of row */ + /* png_size_t rowbytes; number of bytes in row */ + /* png_byte color_type; color type of pixels */ + /* png_byte bit_depth; bit depth of samples */ + /* png_byte channels; number of channels (1-4) */ + /* png_byte pixel_depth; bits per pixel (depth*channels) */ + png_ptr->row_buf + 1); /* start of pixel data for row */ +#endif + +#ifdef PNG_WRITE_FILLER_SUPPORTED + if (png_ptr->transformations & PNG_FILLER) + png_do_strip_channel(row_info, png_ptr->row_buf + 1, + !(png_ptr->flags & PNG_FLAG_FILLER_AFTER)); +#endif + +#ifdef PNG_WRITE_PACKSWAP_SUPPORTED + if (png_ptr->transformations & PNG_PACKSWAP) + png_do_packswap(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_WRITE_PACK_SUPPORTED + if (png_ptr->transformations & PNG_PACK) + png_do_pack(row_info, png_ptr->row_buf + 1, + (png_uint_32)png_ptr->bit_depth); +#endif + +#ifdef PNG_WRITE_SWAP_SUPPORTED + if (png_ptr->transformations & PNG_SWAP_BYTES) + png_do_swap(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_WRITE_SHIFT_SUPPORTED + if (png_ptr->transformations & PNG_SHIFT) + png_do_shift(row_info, png_ptr->row_buf + 1, + &(png_ptr->shift)); +#endif + +#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_SWAP_ALPHA) + png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_ALPHA) + png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_WRITE_BGR_SUPPORTED + if (png_ptr->transformations & PNG_BGR) + png_do_bgr(row_info, png_ptr->row_buf + 1); +#endif + +#ifdef PNG_WRITE_INVERT_SUPPORTED + if (png_ptr->transformations & PNG_INVERT_MONO) + png_do_invert(row_info, png_ptr->row_buf + 1); +#endif +} +#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */ +#endif /* PNG_WRITE_SUPPORTED */ diff --git a/png/pngwutil.c b/png/pngwutil.c new file mode 100755 index 0000000..cfc3312 --- /dev/null +++ b/png/pngwutil.c @@ -0,0 +1,3026 @@ + +/* pngwutil.c - utilities to write a PNG file + * + * Last changed in libpng 1.6.11 [June 12, 2014] + * Copyright (c) 1998-2014 Glenn Randers-Pehrson + * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) + * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) + * + * This code is released under the libpng license. + * For conditions of distribution and use, see the disclaimer + * and license in png.h + */ + +#include "pngpriv.h" + +#ifdef PNG_WRITE_SUPPORTED + +#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED +/* Place a 32-bit number into a buffer in PNG byte order. We work + * with unsigned numbers for convenience, although one supported + * ancillary chunk uses signed (two's complement) numbers. + */ +void PNGAPI +png_save_uint_32(png_bytep buf, png_uint_32 i) +{ + buf[0] = (png_byte)((i >> 24) & 0xff); + buf[1] = (png_byte)((i >> 16) & 0xff); + buf[2] = (png_byte)((i >> 8) & 0xff); + buf[3] = (png_byte)(i & 0xff); +} + +/* Place a 16-bit number into a buffer in PNG byte order. + * The parameter is declared unsigned int, not png_uint_16, + * just to avoid potential problems on pre-ANSI C compilers. + */ +void PNGAPI +png_save_uint_16(png_bytep buf, unsigned int i) +{ + buf[0] = (png_byte)((i >> 8) & 0xff); + buf[1] = (png_byte)(i & 0xff); +} +#endif + +/* Simple function to write the signature. If we have already written + * the magic bytes of the signature, or more likely, the PNG stream is + * being embedded into another stream and doesn't need its own signature, + * we should call png_set_sig_bytes() to tell libpng how many of the + * bytes have already been written. + */ +void PNGAPI +png_write_sig(png_structrp png_ptr) +{ + png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; + +#ifdef PNG_IO_STATE_SUPPORTED + /* Inform the I/O callback that the signature is being written */ + png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE; +#endif + + /* Write the rest of the 8 byte signature */ + png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes], + (png_size_t)(8 - png_ptr->sig_bytes)); + + if (png_ptr->sig_bytes < 3) + png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; +} + +/* Write the start of a PNG chunk. The type is the chunk type. + * The total_length is the sum of the lengths of all the data you will be + * passing in png_write_chunk_data(). + */ +static void +png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name, + png_uint_32 length) +{ + png_byte buf[8]; + +#if defined(PNG_DEBUG) && (PNG_DEBUG > 0) + PNG_CSTRING_FROM_CHUNK(buf, chunk_name); + png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length); +#endif + + if (png_ptr == NULL) + return; + +#ifdef PNG_IO_STATE_SUPPORTED + /* Inform the I/O callback that the chunk header is being written. + * PNG_IO_CHUNK_HDR requires a single I/O call. + */ + png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR; +#endif + + /* Write the length and the chunk name */ + png_save_uint_32(buf, length); + png_save_uint_32(buf + 4, chunk_name); + png_write_data(png_ptr, buf, 8); + + /* Put the chunk name into png_ptr->chunk_name */ + png_ptr->chunk_name = chunk_name; + + /* Reset the crc and run it over the chunk name */ + png_reset_crc(png_ptr); + + png_calculate_crc(png_ptr, buf + 4, 4); + +#ifdef PNG_IO_STATE_SUPPORTED + /* Inform the I/O callback that chunk data will (possibly) be written. + * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls. + */ + png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA; +#endif +} + +void PNGAPI +png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string, + png_uint_32 length) +{ + png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length); +} + +/* Write the data of a PNG chunk started with png_write_chunk_header(). + * Note that multiple calls to this function are allowed, and that the + * sum of the lengths from these calls *must* add up to the total_length + * given to png_write_chunk_header(). + */ +void PNGAPI +png_write_chunk_data(png_structrp png_ptr, png_const_bytep data, + png_size_t length) +{ + /* Write the data, and run the CRC over it */ + if (png_ptr == NULL) + return; + + if (data != NULL && length > 0) + { + png_write_data(png_ptr, data, length); + + /* Update the CRC after writing the data, + * in case that the user I/O routine alters it. + */ + png_calculate_crc(png_ptr, data, length); + } +} + +/* Finish a chunk started with png_write_chunk_header(). */ +void PNGAPI +png_write_chunk_end(png_structrp png_ptr) +{ + png_byte buf[4]; + + if (png_ptr == NULL) return; + +#ifdef PNG_IO_STATE_SUPPORTED + /* Inform the I/O callback that the chunk CRC is being written. + * PNG_IO_CHUNK_CRC requires a single I/O function call. + */ + png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC; +#endif + + /* Write the crc in a single operation */ + png_save_uint_32(buf, png_ptr->crc); + + png_write_data(png_ptr, buf, (png_size_t)4); +} + +/* Write a PNG chunk all at once. The type is an array of ASCII characters + * representing the chunk name. The array must be at least 4 bytes in + * length, and does not need to be null terminated. To be safe, pass the + * pre-defined chunk names here, and if you need a new one, define it + * where the others are defined. The length is the length of the data. + * All the data must be present. If that is not possible, use the + * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end() + * functions instead. + */ +static void +png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name, + png_const_bytep data, png_size_t length) +{ + if (png_ptr == NULL) + return; + + /* On 64 bit architectures 'length' may not fit in a png_uint_32. */ + if (length > PNG_UINT_31_MAX) + png_error(png_ptr, "length exceeds PNG maxima"); + + png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length); + png_write_chunk_data(png_ptr, data, length); + png_write_chunk_end(png_ptr); +} + +/* This is the API that calls the internal function above. */ +void PNGAPI +png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string, + png_const_bytep data, png_size_t length) +{ + png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data, + length); +} + +/* This is used below to find the size of an image to pass to png_deflate_claim, + * so it only needs to be accurate if the size is less than 16384 bytes (the + * point at which a lower LZ window size can be used.) + */ +static png_alloc_size_t +png_image_size(png_structrp png_ptr) +{ + /* Only return sizes up to the maximum of a png_uint_32, do this by limiting + * the width and height used to 15 bits. + */ + png_uint_32 h = png_ptr->height; + + if (png_ptr->rowbytes < 32768 && h < 32768) + { + if (png_ptr->interlaced) + { + /* Interlacing makes the image larger because of the replication of + * both the filter byte and the padding to a byte boundary. + */ + png_uint_32 w = png_ptr->width; + unsigned int pd = png_ptr->pixel_depth; + png_alloc_size_t cb_base; + int pass; + + for (cb_base=0, pass=0; pass<=6; ++pass) + { + png_uint_32 pw = PNG_PASS_COLS(w, pass); + + if (pw > 0) + cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass); + } + + return cb_base; + } + + else + return (png_ptr->rowbytes+1) * h; + } + + else + return 0xffffffffU; +} + +#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED + /* This is the code to hack the first two bytes of the deflate stream (the + * deflate header) to correct the windowBits value to match the actual data + * size. Note that the second argument is the *uncompressed* size but the + * first argument is the *compressed* data (and it must be deflate + * compressed.) + */ +static void +optimize_cmf(png_bytep data, png_alloc_size_t data_size) +{ + /* Optimize the CMF field in the zlib stream. The resultant zlib stream is + * still compliant to the stream specification. + */ + if (data_size <= 16384) /* else windowBits must be 15 */ + { + unsigned int z_cmf = data[0]; /* zlib compression method and flags */ + + if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70) + { + unsigned int z_cinfo; + unsigned int half_z_window_size; + + z_cinfo = z_cmf >> 4; + half_z_window_size = 1U << (z_cinfo + 7); + + if (data_size <= half_z_window_size) /* else no change */ + { + unsigned int tmp; + + do + { + half_z_window_size >>= 1; + --z_cinfo; + } + while (z_cinfo > 0 && data_size <= half_z_window_size); + + z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4); + + data[0] = (png_byte)z_cmf; + tmp = data[1] & 0xe0; + tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f; + data[1] = (png_byte)tmp; + } + } + } +} +#else +# define optimize_cmf(dp,dl) ((void)0) +#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */ + +/* Initialize the compressor for the appropriate type of compression. */ +static int +png_deflate_claim(png_structrp png_ptr, png_uint_32 owner, + png_alloc_size_t data_size) +{ + if (png_ptr->zowner != 0) + { + char msg[64]; + + PNG_STRING_FROM_CHUNK(msg, owner); + msg[4] = ':'; + msg[5] = ' '; + PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner); + /* So the message that results is "<chunk> using zstream"; this is an + * internal error, but is very useful for debugging. i18n requirements + * are minimal. + */ + (void)png_safecat(msg, (sizeof msg), 10, " using zstream"); +# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC + png_warning(png_ptr, msg); + + /* Attempt sane error recovery */ + if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */ + { + png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT"); + return Z_STREAM_ERROR; + } + + png_ptr->zowner = 0; +# else + png_error(png_ptr, msg); +# endif + } + + { + int level = png_ptr->zlib_level; + int method = png_ptr->zlib_method; + int windowBits = png_ptr->zlib_window_bits; + int memLevel = png_ptr->zlib_mem_level; + int strategy; /* set below */ + int ret; /* zlib return code */ + + if (owner == png_IDAT) + { + if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) + strategy = png_ptr->zlib_strategy; + + else if (png_ptr->do_filter != PNG_FILTER_NONE) + strategy = PNG_Z_DEFAULT_STRATEGY; + + else + strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY; + } + + else + { +# ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED + level = png_ptr->zlib_text_level; + method = png_ptr->zlib_text_method; + windowBits = png_ptr->zlib_text_window_bits; + memLevel = png_ptr->zlib_text_mem_level; + strategy = png_ptr->zlib_text_strategy; +# else + /* If customization is not supported the values all come from the + * IDAT values except for the strategy, which is fixed to the + * default. (This is the pre-1.6.0 behavior too, although it was + * implemented in a very different way.) + */ + strategy = Z_DEFAULT_STRATEGY; +# endif + } + + /* Adjust 'windowBits' down if larger than 'data_size'; to stop this + * happening just pass 32768 as the data_size parameter. Notice that zlib + * requires an extra 262 bytes in the window in addition to the data to be + * able to see the whole of the data, so if data_size+262 takes us to the + * next windowBits size we need to fix up the value later. (Because even + * though deflate needs the extra window, inflate does not!) + */ + if (data_size <= 16384) + { + /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to + * work round a Microsoft Visual C misbehavior which, contrary to C-90, + * widens the result of the following shift to 64-bits if (and, + * apparently, only if) it is used in a test. + */ + unsigned int half_window_size = 1U << (windowBits-1); + + while (data_size + 262 <= half_window_size) + { + half_window_size >>= 1; + --windowBits; + } + } + + /* Check against the previous initialized values, if any. */ + if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) && + (png_ptr->zlib_set_level != level || + png_ptr->zlib_set_method != method || + png_ptr->zlib_set_window_bits != windowBits || + png_ptr->zlib_set_mem_level != memLevel || + png_ptr->zlib_set_strategy != strategy)) + { + if (deflateEnd(&png_ptr->zstream) != Z_OK) + png_warning(png_ptr, "deflateEnd failed (ignored)"); + + png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED; + } + + /* For safety clear out the input and output pointers (currently zlib + * doesn't use them on Init, but it might in the future). + */ + png_ptr->zstream.next_in = NULL; + png_ptr->zstream.avail_in = 0; + png_ptr->zstream.next_out = NULL; + png_ptr->zstream.avail_out = 0; + + /* Now initialize if required, setting the new parameters, otherwise just + * to a simple reset to the previous parameters. + */ + if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) + ret = deflateReset(&png_ptr->zstream); + + else + { + ret = deflateInit2(&png_ptr->zstream, level, method, windowBits, + memLevel, strategy); + + if (ret == Z_OK) + png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; + } + + /* The return code is from either deflateReset or deflateInit2; they have + * pretty much the same set of error codes. + */ + if (ret == Z_OK) + png_ptr->zowner = owner; + + else + png_zstream_error(png_ptr, ret); + + return ret; + } +} + +/* Clean up (or trim) a linked list of compression buffers. */ +void /* PRIVATE */ +png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp) +{ + png_compression_bufferp list = *listp; + + if (list != NULL) + { + *listp = NULL; + + do + { + png_compression_bufferp next = list->next; + + png_free(png_ptr, list); + list = next; + } + while (list != NULL); + } +} + +#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED +/* This pair of functions encapsulates the operation of (a) compressing a + * text string, and (b) issuing it later as a series of chunk data writes. + * The compression_state structure is shared context for these functions + * set up by the caller to allow access to the relevant local variables. + * + * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size + * temporary buffers. From 1.6.0 it is retained in png_struct so that it will + * be correctly freed in the event of a write error (previous implementations + * just leaked memory.) + */ +typedef struct +{ + png_const_bytep input; /* The uncompressed input data */ + png_alloc_size_t input_len; /* Its length */ + png_uint_32 output_len; /* Final compressed length */ + png_byte output[1024]; /* First block of output */ +} compression_state; + +static void +png_text_compress_init(compression_state *comp, png_const_bytep input, + png_alloc_size_t input_len) +{ + comp->input = input; + comp->input_len = input_len; + comp->output_len = 0; +} + +/* Compress the data in the compression state input */ +static int +png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name, + compression_state *comp, png_uint_32 prefix_len) +{ + int ret; + + /* To find the length of the output it is necessary to first compress the + * input, the result is buffered rather than using the two-pass algorithm + * that is used on the inflate side; deflate is assumed to be slower and a + * PNG writer is assumed to have more memory available than a PNG reader. + * + * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an + * upper limit on the output size, but it is always bigger than the input + * size so it is likely to be more efficient to use this linked-list + * approach. + */ + ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len); + + if (ret != Z_OK) + return ret; + + /* Set up the compression buffers, we need a loop here to avoid overflowing a + * uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited + * by the output buffer size, so there is no need to check that. Since this + * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits + * in size. + */ + { + png_compression_bufferp *end = &png_ptr->zbuffer_list; + png_alloc_size_t input_len = comp->input_len; /* may be zero! */ + png_uint_32 output_len; + + /* zlib updates these for us: */ + png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input); + png_ptr->zstream.avail_in = 0; /* Set below */ + png_ptr->zstream.next_out = comp->output; + png_ptr->zstream.avail_out = (sizeof comp->output); + + output_len = png_ptr->zstream.avail_out; + + do + { + uInt avail_in = ZLIB_IO_MAX; + + if (avail_in > input_len) + avail_in = (uInt)input_len; + + input_len -= avail_in; + + png_ptr->zstream.avail_in = avail_in; + + if (png_ptr->zstream.avail_out == 0) + { + png_compression_buffer *next; + + /* Chunk data is limited to 2^31 bytes in length, so the prefix + * length must be counted here. + */ + if (output_len + prefix_len > PNG_UINT_31_MAX) + { + ret = Z_MEM_ERROR; + break; + } + + /* Need a new (malloc'ed) buffer, but there may be one present + * already. + */ + next = *end; + if (next == NULL) + { + next = png_voidcast(png_compression_bufferp, png_malloc_base + (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr))); + + if (next == NULL) + { + ret = Z_MEM_ERROR; + break; + } + + /* Link in this buffer (so that it will be freed later) */ + next->next = NULL; + *end = next; + } + + png_ptr->zstream.next_out = next->output; + png_ptr->zstream.avail_out = png_ptr->zbuffer_size; + output_len += png_ptr->zstream.avail_out; + + /* Move 'end' to the next buffer pointer. */ + end = &next->next; + } + + /* Compress the data */ + ret = deflate(&png_ptr->zstream, + input_len > 0 ? Z_NO_FLUSH : Z_FINISH); + + /* Claw back input data that was not consumed (because avail_in is + * reset above every time round the loop). + */ + input_len += png_ptr->zstream.avail_in; + png_ptr->zstream.avail_in = 0; /* safety */ + } + while (ret == Z_OK); + + /* There may be some space left in the last output buffer, this needs to + * be subtracted from output_len. + */ + output_len -= png_ptr->zstream.avail_out; + png_ptr->zstream.avail_out = 0; /* safety */ + comp->output_len = output_len; + + /* Now double check the output length, put in a custom message if it is + * too long. Otherwise ensure the z_stream::msg pointer is set to + * something. + */ + if (output_len + prefix_len >= PNG_UINT_31_MAX) + { + png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long"); + ret = Z_MEM_ERROR; + } + + else + png_zstream_error(png_ptr, ret); + + /* Reset zlib for another zTXt/iTXt or image data */ + png_ptr->zowner = 0; + + /* The only success case is Z_STREAM_END, input_len must be 0, if not this + * is an internal error. + */ + if (ret == Z_STREAM_END && input_len == 0) + { + /* Fix up the deflate header, if required */ + optimize_cmf(comp->output, comp->input_len); + + /* But Z_OK is returned, not Z_STREAM_END; this allows the claim + * function above to return Z_STREAM_END on an error (though it never + * does in the current versions of zlib.) + */ + return Z_OK; + } + + else + return ret; + } +} + +/* Ship the compressed text out via chunk writes */ +static void +png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp) +{ + png_uint_32 output_len = comp->output_len; + png_const_bytep output = comp->output; + png_uint_32 avail = (sizeof comp->output); + png_compression_buffer *next = png_ptr->zbuffer_list; + + for (;;) + { + if (avail > output_len) + avail = output_len; + + png_write_chunk_data(png_ptr, output, avail); + + output_len -= avail; + + if (output_len == 0 || next == NULL) + break; + + avail = png_ptr->zbuffer_size; + output = next->output; + next = next->next; + } + + /* This is an internal error; 'next' must have been NULL! */ + if (output_len > 0) + png_error(png_ptr, "error writing ancillary chunked compressed data"); +} +#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */ + +#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \ + defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED) +/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification, + * and if invalid, correct the keyword rather than discarding the entire + * chunk. The PNG 1.0 specification requires keywords 1-79 characters in + * length, forbids leading or trailing whitespace, multiple internal spaces, + * and the non-break space (0x80) from ISO 8859-1. Returns keyword length. + * + * The 'new_key' buffer must be 80 characters in size (for the keyword plus a + * trailing '\0'). If this routine returns 0 then there was no keyword, or a + * valid one could not be generated, and the caller must png_error. + */ +static png_uint_32 +png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key) +{ + png_const_charp orig_key = key; + png_uint_32 key_len = 0; + int bad_character = 0; + int space = 1; + + png_debug(1, "in png_check_keyword"); + + if (key == NULL) + { + *new_key = 0; + return 0; + } + + while (*key && key_len < 79) + { + png_byte ch = (png_byte)(0xff & *key++); + + if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/)) + *new_key++ = ch, ++key_len, space = 0; + + else if (space == 0) + { + /* A space or an invalid character when one wasn't seen immediately + * before; output just a space. + */ + *new_key++ = 32, ++key_len, space = 1; + + /* If the character was not a space then it is invalid. */ + if (ch != 32) + bad_character = ch; + } + + else if (bad_character == 0) + bad_character = ch; /* just skip it, record the first error */ + } + + if (key_len > 0 && space) /* trailing space */ + { + --key_len, --new_key; + if (bad_character == 0) + bad_character = 32; + } + + /* Terminate the keyword */ + *new_key = 0; + + if (key_len == 0) + return 0; + + /* Try to only output one warning per keyword: */ + if (*key) /* keyword too long */ + png_warning(png_ptr, "keyword truncated"); + + else if (bad_character != 0) + { + PNG_WARNING_PARAMETERS(p) + + png_warning_parameter(p, 1, orig_key); + png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character); + + png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'"); + } + + return key_len; +} +#endif + +/* Write the IHDR chunk, and update the png_struct with the necessary + * information. Note that the rest of this code depends upon this + * information being correct. + */ +void /* PRIVATE */ +png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height, + int bit_depth, int color_type, int compression_type, int filter_type, + int interlace_type) +{ + png_byte buf[13]; /* Buffer to store the IHDR info */ + + png_debug(1, "in png_write_IHDR"); + + /* Check that we have valid input data from the application info */ + switch (color_type) + { + case PNG_COLOR_TYPE_GRAY: + switch (bit_depth) + { + case 1: + case 2: + case 4: + case 8: +#ifdef PNG_WRITE_16BIT_SUPPORTED + case 16: +#endif + png_ptr->channels = 1; break; + + default: + png_error(png_ptr, + "Invalid bit depth for grayscale image"); + } + break; + + case PNG_COLOR_TYPE_RGB: +#ifdef PNG_WRITE_16BIT_SUPPORTED + if (bit_depth != 8 && bit_depth != 16) +#else + if (bit_depth != 8) +#endif + png_error(png_ptr, "Invalid bit depth for RGB image"); + + png_ptr->channels = 3; + break; + + case PNG_COLOR_TYPE_PALETTE: + switch (bit_depth) + { + case 1: + case 2: + case 4: + case 8: + png_ptr->channels = 1; + break; + + default: + png_error(png_ptr, "Invalid bit depth for paletted image"); + } + break; + + case PNG_COLOR_TYPE_GRAY_ALPHA: + if (bit_depth != 8 && bit_depth != 16) + png_error(png_ptr, "Invalid bit depth for grayscale+alpha image"); + + png_ptr->channels = 2; + break; + + case PNG_COLOR_TYPE_RGB_ALPHA: +#ifdef PNG_WRITE_16BIT_SUPPORTED + if (bit_depth != 8 && bit_depth != 16) +#else + if (bit_depth != 8) +#endif + png_error(png_ptr, "Invalid bit depth for RGBA image"); + + png_ptr->channels = 4; + break; + + default: + png_error(png_ptr, "Invalid image color type specified"); + } + + if (compression_type != PNG_COMPRESSION_TYPE_BASE) + { + png_warning(png_ptr, "Invalid compression type specified"); + compression_type = PNG_COMPRESSION_TYPE_BASE; + } + + /* Write filter_method 64 (intrapixel differencing) only if + * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and + * 2. Libpng did not write a PNG signature (this filter_method is only + * used in PNG datastreams that are embedded in MNG datastreams) and + * 3. The application called png_permit_mng_features with a mask that + * included PNG_FLAG_MNG_FILTER_64 and + * 4. The filter_method is 64 and + * 5. The color_type is RGB or RGBA + */ + if ( +#ifdef PNG_MNG_FEATURES_SUPPORTED + !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && + ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) && + (color_type == PNG_COLOR_TYPE_RGB || + color_type == PNG_COLOR_TYPE_RGB_ALPHA) && + (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) && +#endif + filter_type != PNG_FILTER_TYPE_BASE) + { + png_warning(png_ptr, "Invalid filter type specified"); + filter_type = PNG_FILTER_TYPE_BASE; + } + +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + if (interlace_type != PNG_INTERLACE_NONE && + interlace_type != PNG_INTERLACE_ADAM7) + { + png_warning(png_ptr, "Invalid interlace type specified"); + interlace_type = PNG_INTERLACE_ADAM7; + } +#else + interlace_type=PNG_INTERLACE_NONE; +#endif + + /* Save the relevent information */ + png_ptr->bit_depth = (png_byte)bit_depth; + png_ptr->color_type = (png_byte)color_type; + png_ptr->interlaced = (png_byte)interlace_type; +#ifdef PNG_MNG_FEATURES_SUPPORTED + png_ptr->filter_type = (png_byte)filter_type; +#endif + png_ptr->compression_type = (png_byte)compression_type; + png_ptr->width = width; + png_ptr->height = height; + + png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels); + png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width); + /* Set the usr info, so any transformations can modify it */ + png_ptr->usr_width = png_ptr->width; + png_ptr->usr_bit_depth = png_ptr->bit_depth; + png_ptr->usr_channels = png_ptr->channels; + + /* Pack the header information into the buffer */ + png_save_uint_32(buf, width); + png_save_uint_32(buf + 4, height); + buf[8] = (png_byte)bit_depth; + buf[9] = (png_byte)color_type; + buf[10] = (png_byte)compression_type; + buf[11] = (png_byte)filter_type; + buf[12] = (png_byte)interlace_type; + + /* Write the chunk */ + png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13); + + if ((png_ptr->do_filter) == PNG_NO_FILTERS) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE || + png_ptr->bit_depth < 8) + png_ptr->do_filter = PNG_FILTER_NONE; + + else + png_ptr->do_filter = PNG_ALL_FILTERS; + } + + png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */ +} + +/* Write the palette. We are careful not to trust png_color to be in the + * correct order for PNG, so people can redefine it to any convenient + * structure. + */ +void /* PRIVATE */ +png_write_PLTE(png_structrp png_ptr, png_const_colorp palette, + png_uint_32 num_pal) +{ + png_uint_32 i; + png_const_colorp pal_ptr; + png_byte buf[3]; + + png_debug(1, "in png_write_PLTE"); + + if (( +#ifdef PNG_MNG_FEATURES_SUPPORTED + !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) && +#endif + num_pal == 0) || num_pal > 256) + { + if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) + { + png_error(png_ptr, "Invalid number of colors in palette"); + } + + else + { + png_warning(png_ptr, "Invalid number of colors in palette"); + return; + } + } + + if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR)) + { + png_warning(png_ptr, + "Ignoring request to write a PLTE chunk in grayscale PNG"); + + return; + } + + png_ptr->num_palette = (png_uint_16)num_pal; + png_debug1(3, "num_palette = %d", png_ptr->num_palette); + + png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3)); +#ifdef PNG_POINTER_INDEXING_SUPPORTED + + for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++) + { + buf[0] = pal_ptr->red; + buf[1] = pal_ptr->green; + buf[2] = pal_ptr->blue; + png_write_chunk_data(png_ptr, buf, (png_size_t)3); + } + +#else + /* This is a little slower but some buggy compilers need to do this + * instead + */ + pal_ptr=palette; + + for (i = 0; i < num_pal; i++) + { + buf[0] = pal_ptr[i].red; + buf[1] = pal_ptr[i].green; + buf[2] = pal_ptr[i].blue; + png_write_chunk_data(png_ptr, buf, (png_size_t)3); + } + +#endif + png_write_chunk_end(png_ptr); + png_ptr->mode |= PNG_HAVE_PLTE; +} + +/* This is similar to png_text_compress, above, except that it does not require + * all of the data at once and, instead of buffering the compressed result, + * writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out + * because it calls the write interface. As a result it does its own error + * reporting and does not return an error code. In the event of error it will + * just call png_error. The input data length may exceed 32-bits. The 'flush' + * parameter is exactly the same as that to deflate, with the following + * meanings: + * + * Z_NO_FLUSH: normal incremental output of compressed data + * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush + * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up + * + * The routine manages the acquire and release of the png_ptr->zstream by + * checking and (at the end) clearing png_ptr->zowner, it does some sanity + * checks on the 'mode' flags while doing this. + */ +void /* PRIVATE */ +png_compress_IDAT(png_structrp png_ptr, png_const_bytep input, + png_alloc_size_t input_len, int flush) +{ + if (png_ptr->zowner != png_IDAT) + { + /* First time. Ensure we have a temporary buffer for compression and + * trim the buffer list if it has more than one entry to free memory. + * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been + * created at this point, but the check here is quick and safe. + */ + if (png_ptr->zbuffer_list == NULL) + { + png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp, + png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr))); + png_ptr->zbuffer_list->next = NULL; + } + + else + png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next); + + /* It is a terminal error if we can't claim the zstream. */ + if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK) + png_error(png_ptr, png_ptr->zstream.msg); + + /* The output state is maintained in png_ptr->zstream, so it must be + * initialized here after the claim. + */ + png_ptr->zstream.next_out = png_ptr->zbuffer_list->output; + png_ptr->zstream.avail_out = png_ptr->zbuffer_size; + } + + /* Now loop reading and writing until all the input is consumed or an error + * terminates the operation. The _out values are maintained across calls to + * this function, but the input must be reset each time. + */ + png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); + png_ptr->zstream.avail_in = 0; /* set below */ + for (;;) + { + int ret; + + /* INPUT: from the row data */ + uInt avail = ZLIB_IO_MAX; + + if (avail > input_len) + avail = (uInt)input_len; /* safe because of the check */ + + png_ptr->zstream.avail_in = avail; + input_len -= avail; + + ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush); + + /* Include as-yet unconsumed input */ + input_len += png_ptr->zstream.avail_in; + png_ptr->zstream.avail_in = 0; + + /* OUTPUT: write complete IDAT chunks when avail_out drops to zero, note + * that these two zstream fields are preserved across the calls, therefore + * there is no need to set these up on entry to the loop. + */ + if (png_ptr->zstream.avail_out == 0) + { + png_bytep data = png_ptr->zbuffer_list->output; + uInt size = png_ptr->zbuffer_size; + + /* Write an IDAT containing the data then reset the buffer. The + * first IDAT may need deflate header optimization. + */ +# ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED + if (!(png_ptr->mode & PNG_HAVE_IDAT) && + png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) + optimize_cmf(data, png_image_size(png_ptr)); +# endif + + png_write_complete_chunk(png_ptr, png_IDAT, data, size); + png_ptr->mode |= PNG_HAVE_IDAT; + + png_ptr->zstream.next_out = data; + png_ptr->zstream.avail_out = size; + + /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with + * the same flush parameter until it has finished output, for NO_FLUSH + * it doesn't matter. + */ + if (ret == Z_OK && flush != Z_NO_FLUSH) + continue; + } + + /* The order of these checks doesn't matter much; it just effect which + * possible error might be detected if multiple things go wrong at once. + */ + if (ret == Z_OK) /* most likely return code! */ + { + /* If all the input has been consumed then just return. If Z_FINISH + * was used as the flush parameter something has gone wrong if we get + * here. + */ + if (input_len == 0) + { + if (flush == Z_FINISH) + png_error(png_ptr, "Z_OK on Z_FINISH with output space"); + + return; + } + } + + else if (ret == Z_STREAM_END && flush == Z_FINISH) + { + /* This is the end of the IDAT data; any pending output must be + * flushed. For small PNG files we may still be at the beginning. + */ + png_bytep data = png_ptr->zbuffer_list->output; + uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out; + +# ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED + if (!(png_ptr->mode & PNG_HAVE_IDAT) && + png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) + optimize_cmf(data, png_image_size(png_ptr)); +# endif + + png_write_complete_chunk(png_ptr, png_IDAT, data, size); + png_ptr->zstream.avail_out = 0; + png_ptr->zstream.next_out = NULL; + png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT; + + png_ptr->zowner = 0; /* Release the stream */ + return; + } + + else + { + /* This is an error condition. */ + png_zstream_error(png_ptr, ret); + png_error(png_ptr, png_ptr->zstream.msg); + } + } +} + +/* Write an IEND chunk */ +void /* PRIVATE */ +png_write_IEND(png_structrp png_ptr) +{ + png_debug(1, "in png_write_IEND"); + + png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0); + png_ptr->mode |= PNG_HAVE_IEND; +} + +#ifdef PNG_WRITE_gAMA_SUPPORTED +/* Write a gAMA chunk */ +void /* PRIVATE */ +png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma) +{ + png_byte buf[4]; + + png_debug(1, "in png_write_gAMA"); + + /* file_gamma is saved in 1/100,000ths */ + png_save_uint_32(buf, (png_uint_32)file_gamma); + png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4); +} +#endif + +#ifdef PNG_WRITE_sRGB_SUPPORTED +/* Write a sRGB chunk */ +void /* PRIVATE */ +png_write_sRGB(png_structrp png_ptr, int srgb_intent) +{ + png_byte buf[1]; + + png_debug(1, "in png_write_sRGB"); + + if (srgb_intent >= PNG_sRGB_INTENT_LAST) + png_warning(png_ptr, + "Invalid sRGB rendering intent specified"); + + buf[0]=(png_byte)srgb_intent; + png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1); +} +#endif + +#ifdef PNG_WRITE_iCCP_SUPPORTED +/* Write an iCCP chunk */ +void /* PRIVATE */ +png_write_iCCP(png_structrp png_ptr, png_const_charp name, + png_const_bytep profile) +{ + png_uint_32 name_len; + png_uint_32 profile_len; + png_byte new_name[81]; /* 1 byte for the compression byte */ + compression_state comp; + png_uint_32 temp; + + png_debug(1, "in png_write_iCCP"); + + /* These are all internal problems: the profile should have been checked + * before when it was stored. + */ + if (profile == NULL) + png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */ + + profile_len = png_get_uint_32(profile); + + if (profile_len < 132) + png_error(png_ptr, "ICC profile too short"); + + temp = (png_uint_32) (*(profile+8)); + if (temp > 3 && (profile_len & 0x03)) + png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)"); + + { + png_uint_32 embedded_profile_len = png_get_uint_32(profile); + + if (profile_len != embedded_profile_len) + png_error(png_ptr, "Profile length does not match profile"); + } + + name_len = png_check_keyword(png_ptr, name, new_name); + + if (name_len == 0) + png_error(png_ptr, "iCCP: invalid keyword"); + + new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE; + + /* Make sure we include the NULL after the name and the compression type */ + ++name_len; + + png_text_compress_init(&comp, profile, profile_len); + + /* Allow for keyword terminator and compression byte */ + if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK) + png_error(png_ptr, png_ptr->zstream.msg); + + png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len); + + png_write_chunk_data(png_ptr, new_name, name_len); + + png_write_compressed_data_out(png_ptr, &comp); + + png_write_chunk_end(png_ptr); +} +#endif + +#ifdef PNG_WRITE_sPLT_SUPPORTED +/* Write a sPLT chunk */ +void /* PRIVATE */ +png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette) +{ + png_uint_32 name_len; + png_byte new_name[80]; + png_byte entrybuf[10]; + png_size_t entry_size = (spalette->depth == 8 ? 6 : 10); + png_size_t palette_size = entry_size * spalette->nentries; + png_sPLT_entryp ep; +#ifndef PNG_POINTER_INDEXING_SUPPORTED + int i; +#endif + + png_debug(1, "in png_write_sPLT"); + + name_len = png_check_keyword(png_ptr, spalette->name, new_name); + + if (name_len == 0) + png_error(png_ptr, "sPLT: invalid keyword"); + + /* Make sure we include the NULL after the name */ + png_write_chunk_header(png_ptr, png_sPLT, + (png_uint_32)(name_len + 2 + palette_size)); + + png_write_chunk_data(png_ptr, (png_bytep)new_name, + (png_size_t)(name_len + 1)); + + png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1); + + /* Loop through each palette entry, writing appropriately */ +#ifdef PNG_POINTER_INDEXING_SUPPORTED + for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++) + { + if (spalette->depth == 8) + { + entrybuf[0] = (png_byte)ep->red; + entrybuf[1] = (png_byte)ep->green; + entrybuf[2] = (png_byte)ep->blue; + entrybuf[3] = (png_byte)ep->alpha; + png_save_uint_16(entrybuf + 4, ep->frequency); + } + + else + { + png_save_uint_16(entrybuf + 0, ep->red); + png_save_uint_16(entrybuf + 2, ep->green); + png_save_uint_16(entrybuf + 4, ep->blue); + png_save_uint_16(entrybuf + 6, ep->alpha); + png_save_uint_16(entrybuf + 8, ep->frequency); + } + + png_write_chunk_data(png_ptr, entrybuf, entry_size); + } +#else + ep=spalette->entries; + for (i = 0; i>spalette->nentries; i++) + { + if (spalette->depth == 8) + { + entrybuf[0] = (png_byte)ep[i].red; + entrybuf[1] = (png_byte)ep[i].green; + entrybuf[2] = (png_byte)ep[i].blue; + entrybuf[3] = (png_byte)ep[i].alpha; + png_save_uint_16(entrybuf + 4, ep[i].frequency); + } + + else + { + png_save_uint_16(entrybuf + 0, ep[i].red); + png_save_uint_16(entrybuf + 2, ep[i].green); + png_save_uint_16(entrybuf + 4, ep[i].blue); + png_save_uint_16(entrybuf + 6, ep[i].alpha); + png_save_uint_16(entrybuf + 8, ep[i].frequency); + } + + png_write_chunk_data(png_ptr, entrybuf, entry_size); + } +#endif + + png_write_chunk_end(png_ptr); +} +#endif + +#ifdef PNG_WRITE_sBIT_SUPPORTED +/* Write the sBIT chunk */ +void /* PRIVATE */ +png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type) +{ + png_byte buf[4]; + png_size_t size; + + png_debug(1, "in png_write_sBIT"); + + /* Make sure we don't depend upon the order of PNG_COLOR_8 */ + if (color_type & PNG_COLOR_MASK_COLOR) + { + png_byte maxbits; + + maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 : + png_ptr->usr_bit_depth); + + if (sbit->red == 0 || sbit->red > maxbits || + sbit->green == 0 || sbit->green > maxbits || + sbit->blue == 0 || sbit->blue > maxbits) + { + png_warning(png_ptr, "Invalid sBIT depth specified"); + return; + } + + buf[0] = sbit->red; + buf[1] = sbit->green; + buf[2] = sbit->blue; + size = 3; + } + + else + { + if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth) + { + png_warning(png_ptr, "Invalid sBIT depth specified"); + return; + } + + buf[0] = sbit->gray; + size = 1; + } + + if (color_type & PNG_COLOR_MASK_ALPHA) + { + if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth) + { + png_warning(png_ptr, "Invalid sBIT depth specified"); + return; + } + + buf[size++] = sbit->alpha; + } + + png_write_complete_chunk(png_ptr, png_sBIT, buf, size); +} +#endif + +#ifdef PNG_WRITE_cHRM_SUPPORTED +/* Write the cHRM chunk */ +void /* PRIVATE */ +png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy) +{ + png_byte buf[32]; + + png_debug(1, "in png_write_cHRM"); + + /* Each value is saved in 1/100,000ths */ + png_save_int_32(buf, xy->whitex); + png_save_int_32(buf + 4, xy->whitey); + + png_save_int_32(buf + 8, xy->redx); + png_save_int_32(buf + 12, xy->redy); + + png_save_int_32(buf + 16, xy->greenx); + png_save_int_32(buf + 20, xy->greeny); + + png_save_int_32(buf + 24, xy->bluex); + png_save_int_32(buf + 28, xy->bluey); + + png_write_complete_chunk(png_ptr, png_cHRM, buf, 32); +} +#endif + +#ifdef PNG_WRITE_tRNS_SUPPORTED +/* Write the tRNS chunk */ +void /* PRIVATE */ +png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha, + png_const_color_16p tran, int num_trans, int color_type) +{ + png_byte buf[6]; + + png_debug(1, "in png_write_tRNS"); + + if (color_type == PNG_COLOR_TYPE_PALETTE) + { + if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette) + { + png_app_warning(png_ptr, + "Invalid number of transparent colors specified"); + return; + } + + /* Write the chunk out as it is */ + png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, + (png_size_t)num_trans); + } + + else if (color_type == PNG_COLOR_TYPE_GRAY) + { + /* One 16 bit value */ + if (tran->gray >= (1 << png_ptr->bit_depth)) + { + png_app_warning(png_ptr, + "Ignoring attempt to write tRNS chunk out-of-range for bit_depth"); + + return; + } + + png_save_uint_16(buf, tran->gray); + png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2); + } + + else if (color_type == PNG_COLOR_TYPE_RGB) + { + /* Three 16 bit values */ + png_save_uint_16(buf, tran->red); + png_save_uint_16(buf + 2, tran->green); + png_save_uint_16(buf + 4, tran->blue); +#ifdef PNG_WRITE_16BIT_SUPPORTED + if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) +#else + if (buf[0] | buf[2] | buf[4]) +#endif + { + png_app_warning(png_ptr, + "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8"); + return; + } + + png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6); + } + + else + { + png_app_warning(png_ptr, "Can't write tRNS with an alpha channel"); + } +} +#endif + +#ifdef PNG_WRITE_bKGD_SUPPORTED +/* Write the background chunk */ +void /* PRIVATE */ +png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type) +{ + png_byte buf[6]; + + png_debug(1, "in png_write_bKGD"); + + if (color_type == PNG_COLOR_TYPE_PALETTE) + { + if ( +#ifdef PNG_MNG_FEATURES_SUPPORTED + (png_ptr->num_palette || + (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) && +#endif + back->index >= png_ptr->num_palette) + { + png_warning(png_ptr, "Invalid background palette index"); + return; + } + + buf[0] = back->index; + png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1); + } + + else if (color_type & PNG_COLOR_MASK_COLOR) + { + png_save_uint_16(buf, back->red); + png_save_uint_16(buf + 2, back->green); + png_save_uint_16(buf + 4, back->blue); +#ifdef PNG_WRITE_16BIT_SUPPORTED + if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) +#else + if (buf[0] | buf[2] | buf[4]) +#endif + { + png_warning(png_ptr, + "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8"); + + return; + } + + png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6); + } + + else + { + if (back->gray >= (1 << png_ptr->bit_depth)) + { + png_warning(png_ptr, + "Ignoring attempt to write bKGD chunk out-of-range for bit_depth"); + + return; + } + + png_save_uint_16(buf, back->gray); + png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2); + } +} +#endif + +#ifdef PNG_WRITE_hIST_SUPPORTED +/* Write the histogram */ +void /* PRIVATE */ +png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist) +{ + int i; + png_byte buf[3]; + + png_debug(1, "in png_write_hIST"); + + if (num_hist > (int)png_ptr->num_palette) + { + png_debug2(3, "num_hist = %d, num_palette = %d", num_hist, + png_ptr->num_palette); + + png_warning(png_ptr, "Invalid number of histogram entries specified"); + return; + } + + png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2)); + + for (i = 0; i < num_hist; i++) + { + png_save_uint_16(buf, hist[i]); + png_write_chunk_data(png_ptr, buf, (png_size_t)2); + } + + png_write_chunk_end(png_ptr); +} +#endif + +#ifdef PNG_WRITE_tEXt_SUPPORTED +/* Write a tEXt chunk */ +void /* PRIVATE */ +png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, + png_size_t text_len) +{ + png_uint_32 key_len; + png_byte new_key[80]; + + png_debug(1, "in png_write_tEXt"); + + key_len = png_check_keyword(png_ptr, key, new_key); + + if (key_len == 0) + png_error(png_ptr, "tEXt: invalid keyword"); + + if (text == NULL || *text == '\0') + text_len = 0; + + else + text_len = strlen(text); + + if (text_len > PNG_UINT_31_MAX - (key_len+1)) + png_error(png_ptr, "tEXt: text too long"); + + /* Make sure we include the 0 after the key */ + png_write_chunk_header(png_ptr, png_tEXt, + (png_uint_32)/*checked above*/(key_len + text_len + 1)); + /* + * We leave it to the application to meet PNG-1.0 requirements on the + * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of + * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them. + * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. + */ + png_write_chunk_data(png_ptr, new_key, key_len + 1); + + if (text_len != 0) + png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len); + + png_write_chunk_end(png_ptr); +} +#endif + +#ifdef PNG_WRITE_zTXt_SUPPORTED +/* Write a compressed text chunk */ +void /* PRIVATE */ +png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, + png_size_t text_len, int compression) +{ + png_uint_32 key_len; + png_byte new_key[81]; + compression_state comp; + + png_debug(1, "in png_write_zTXt"); + PNG_UNUSED(text_len) /* Always use strlen */ + + if (compression == PNG_TEXT_COMPRESSION_NONE) + { + png_write_tEXt(png_ptr, key, text, 0); + return; + } + + if (compression != PNG_TEXT_COMPRESSION_zTXt) + png_error(png_ptr, "zTXt: invalid compression type"); + + key_len = png_check_keyword(png_ptr, key, new_key); + + if (key_len == 0) + png_error(png_ptr, "zTXt: invalid keyword"); + + /* Add the compression method and 1 for the keyword separator. */ + new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE; + ++key_len; + + /* Compute the compressed data; do it now for the length */ + png_text_compress_init(&comp, (png_const_bytep)text, + text == NULL ? 0 : strlen(text)); + + if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK) + png_error(png_ptr, png_ptr->zstream.msg); + + /* Write start of chunk */ + png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len); + + /* Write key */ + png_write_chunk_data(png_ptr, new_key, key_len); + + /* Write the compressed data */ + png_write_compressed_data_out(png_ptr, &comp); + + /* Close the chunk */ + png_write_chunk_end(png_ptr); +} +#endif + +#ifdef PNG_WRITE_iTXt_SUPPORTED +/* Write an iTXt chunk */ +void /* PRIVATE */ +png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key, + png_const_charp lang, png_const_charp lang_key, png_const_charp text) +{ + png_uint_32 key_len, prefix_len; + png_size_t lang_len, lang_key_len; + png_byte new_key[82]; + compression_state comp; + + png_debug(1, "in png_write_iTXt"); + + key_len = png_check_keyword(png_ptr, key, new_key); + + if (key_len == 0) + png_error(png_ptr, "iTXt: invalid keyword"); + + /* Set the compression flag */ + switch (compression) + { + case PNG_ITXT_COMPRESSION_NONE: + case PNG_TEXT_COMPRESSION_NONE: + compression = new_key[++key_len] = 0; /* no compression */ + break; + + case PNG_TEXT_COMPRESSION_zTXt: + case PNG_ITXT_COMPRESSION_zTXt: + compression = new_key[++key_len] = 1; /* compressed */ + break; + + default: + png_error(png_ptr, "iTXt: invalid compression"); + } + + new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE; + ++key_len; /* for the keywod separator */ + + /* We leave it to the application to meet PNG-1.0 requirements on the + * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of + * any non-Latin-1 characters except for NEWLINE. ISO PNG, however, + * specifies that the text is UTF-8 and this really doesn't require any + * checking. + * + * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. + * + * TODO: validate the language tag correctly (see the spec.) + */ + if (lang == NULL) lang = ""; /* empty language is valid */ + lang_len = strlen(lang)+1; + if (lang_key == NULL) lang_key = ""; /* may be empty */ + lang_key_len = strlen(lang_key)+1; + if (text == NULL) text = ""; /* may be empty */ + + prefix_len = key_len; + if (lang_len > PNG_UINT_31_MAX-prefix_len) + prefix_len = PNG_UINT_31_MAX; + else + prefix_len = (png_uint_32)(prefix_len + lang_len); + + if (lang_key_len > PNG_UINT_31_MAX-prefix_len) + prefix_len = PNG_UINT_31_MAX; + else + prefix_len = (png_uint_32)(prefix_len + lang_key_len); + + png_text_compress_init(&comp, (png_const_bytep)text, strlen(text)); + + if (compression != 0) + { + if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK) + png_error(png_ptr, png_ptr->zstream.msg); + } + + else + { + if (comp.input_len > PNG_UINT_31_MAX-prefix_len) + png_error(png_ptr, "iTXt: uncompressed text too long"); + + /* So the string will fit in a chunk: */ + comp.output_len = (png_uint_32)/*SAFE*/comp.input_len; + } + + png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len); + + png_write_chunk_data(png_ptr, new_key, key_len); + + png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len); + + png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len); + + if (compression != 0) + png_write_compressed_data_out(png_ptr, &comp); + + else + png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.input_len); + + png_write_chunk_end(png_ptr); +} +#endif + +#ifdef PNG_WRITE_oFFs_SUPPORTED +/* Write the oFFs chunk */ +void /* PRIVATE */ +png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset, + int unit_type) +{ + png_byte buf[9]; + + png_debug(1, "in png_write_oFFs"); + + if (unit_type >= PNG_OFFSET_LAST) + png_warning(png_ptr, "Unrecognized unit type for oFFs chunk"); + + png_save_int_32(buf, x_offset); + png_save_int_32(buf + 4, y_offset); + buf[8] = (png_byte)unit_type; + + png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9); +} +#endif +#ifdef PNG_WRITE_pCAL_SUPPORTED +/* Write the pCAL chunk (described in the PNG extensions document) */ +void /* PRIVATE */ +png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0, + png_int_32 X1, int type, int nparams, png_const_charp units, + png_charpp params) +{ + png_uint_32 purpose_len; + png_size_t units_len, total_len; + png_size_tp params_len; + png_byte buf[10]; + png_byte new_purpose[80]; + int i; + + png_debug1(1, "in png_write_pCAL (%d parameters)", nparams); + + if (type >= PNG_EQUATION_LAST) + png_error(png_ptr, "Unrecognized equation type for pCAL chunk"); + + purpose_len = png_check_keyword(png_ptr, purpose, new_purpose); + + if (purpose_len == 0) + png_error(png_ptr, "pCAL: invalid keyword"); + + ++purpose_len; /* terminator */ + + png_debug1(3, "pCAL purpose length = %d", (int)purpose_len); + units_len = strlen(units) + (nparams == 0 ? 0 : 1); + png_debug1(3, "pCAL units length = %d", (int)units_len); + total_len = purpose_len + units_len + 10; + + params_len = (png_size_tp)png_malloc(png_ptr, + (png_alloc_size_t)(nparams * (sizeof (png_size_t)))); + + /* Find the length of each parameter, making sure we don't count the + * null terminator for the last parameter. + */ + for (i = 0; i < nparams; i++) + { + params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1); + png_debug2(3, "pCAL parameter %d length = %lu", i, + (unsigned long)params_len[i]); + total_len += params_len[i]; + } + + png_debug1(3, "pCAL total length = %d", (int)total_len); + png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len); + png_write_chunk_data(png_ptr, new_purpose, purpose_len); + png_save_int_32(buf, X0); + png_save_int_32(buf + 4, X1); + buf[8] = (png_byte)type; + buf[9] = (png_byte)nparams; + png_write_chunk_data(png_ptr, buf, (png_size_t)10); + png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len); + + for (i = 0; i < nparams; i++) + { + png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]); + } + + png_free(png_ptr, params_len); + png_write_chunk_end(png_ptr); +} +#endif + +#ifdef PNG_WRITE_sCAL_SUPPORTED +/* Write the sCAL chunk */ +void /* PRIVATE */ +png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width, + png_const_charp height) +{ + png_byte buf[64]; + png_size_t wlen, hlen, total_len; + + png_debug(1, "in png_write_sCAL_s"); + + wlen = strlen(width); + hlen = strlen(height); + total_len = wlen + hlen + 2; + + if (total_len > 64) + { + png_warning(png_ptr, "Can't write sCAL (buffer too small)"); + return; + } + + buf[0] = (png_byte)unit; + memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */ + memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */ + + png_debug1(3, "sCAL total length = %u", (unsigned int)total_len); + png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len); +} +#endif + +#ifdef PNG_WRITE_pHYs_SUPPORTED +/* Write the pHYs chunk */ +void /* PRIVATE */ +png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit, + png_uint_32 y_pixels_per_unit, + int unit_type) +{ + png_byte buf[9]; + + png_debug(1, "in png_write_pHYs"); + + if (unit_type >= PNG_RESOLUTION_LAST) + png_warning(png_ptr, "Unrecognized unit type for pHYs chunk"); + + png_save_uint_32(buf, x_pixels_per_unit); + png_save_uint_32(buf + 4, y_pixels_per_unit); + buf[8] = (png_byte)unit_type; + + png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9); +} +#endif + +#ifdef PNG_WRITE_tIME_SUPPORTED +/* Write the tIME chunk. Use either png_convert_from_struct_tm() + * or png_convert_from_time_t(), or fill in the structure yourself. + */ +void /* PRIVATE */ +png_write_tIME(png_structrp png_ptr, png_const_timep mod_time) +{ + png_byte buf[7]; + + png_debug(1, "in png_write_tIME"); + + if (mod_time->month > 12 || mod_time->month < 1 || + mod_time->day > 31 || mod_time->day < 1 || + mod_time->hour > 23 || mod_time->second > 60) + { + png_warning(png_ptr, "Invalid time specified for tIME chunk"); + return; + } + + png_save_uint_16(buf, mod_time->year); + buf[2] = mod_time->month; + buf[3] = mod_time->day; + buf[4] = mod_time->hour; + buf[5] = mod_time->minute; + buf[6] = mod_time->second; + + png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7); +} +#endif + +/* Initializes the row writing capability of libpng */ +void /* PRIVATE */ +png_write_start_row(png_structrp png_ptr) +{ +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; +#endif + + png_alloc_size_t buf_size; + int usr_pixel_depth; + + png_debug(1, "in png_write_start_row"); + + usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth; + buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1; + + /* 1.5.6: added to allow checking in the row write code. */ + png_ptr->transformed_pixel_depth = png_ptr->pixel_depth; + png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth; + + /* Set up row buffer */ + png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size); + + png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE; + +#ifdef PNG_WRITE_FILTER_SUPPORTED + /* Set up filtering buffer, if using this filter */ + if (png_ptr->do_filter & PNG_FILTER_SUB) + { + png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1); + + png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB; + } + + /* We only need to keep the previous row if we are using one of these. */ + if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) + { + /* Set up previous row buffer */ + png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size); + + if (png_ptr->do_filter & PNG_FILTER_UP) + { + png_ptr->up_row = (png_bytep)png_malloc(png_ptr, + png_ptr->rowbytes + 1); + + png_ptr->up_row[0] = PNG_FILTER_VALUE_UP; + } + + if (png_ptr->do_filter & PNG_FILTER_AVG) + { + png_ptr->avg_row = (png_bytep)png_malloc(png_ptr, + png_ptr->rowbytes + 1); + + png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG; + } + + if (png_ptr->do_filter & PNG_FILTER_PAETH) + { + png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr, + png_ptr->rowbytes + 1); + + png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH; + } + } +#endif /* PNG_WRITE_FILTER_SUPPORTED */ + +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* If interlaced, we need to set up width and height of pass */ + if (png_ptr->interlaced) + { + if (!(png_ptr->transformations & PNG_INTERLACE)) + { + png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - + png_pass_ystart[0]) / png_pass_yinc[0]; + + png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 - + png_pass_start[0]) / png_pass_inc[0]; + } + + else + { + png_ptr->num_rows = png_ptr->height; + png_ptr->usr_width = png_ptr->width; + } + } + + else +#endif + { + png_ptr->num_rows = png_ptr->height; + png_ptr->usr_width = png_ptr->width; + } +} + +/* Internal use only. Called when finished processing a row of data. */ +void /* PRIVATE */ +png_write_finish_row(png_structrp png_ptr) +{ +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* Start of interlace block in the y direction */ + static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* Offset to next interlace block in the y direction */ + static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; +#endif + + png_debug(1, "in png_write_finish_row"); + + /* Next row */ + png_ptr->row_number++; + + /* See if we are done */ + if (png_ptr->row_number < png_ptr->num_rows) + return; + +#ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* If interlaced, go to next pass */ + if (png_ptr->interlaced) + { + png_ptr->row_number = 0; + if (png_ptr->transformations & PNG_INTERLACE) + { + png_ptr->pass++; + } + + else + { + /* Loop until we find a non-zero width or height pass */ + do + { + png_ptr->pass++; + + if (png_ptr->pass >= 7) + break; + + png_ptr->usr_width = (png_ptr->width + + png_pass_inc[png_ptr->pass] - 1 - + png_pass_start[png_ptr->pass]) / + png_pass_inc[png_ptr->pass]; + + png_ptr->num_rows = (png_ptr->height + + png_pass_yinc[png_ptr->pass] - 1 - + png_pass_ystart[png_ptr->pass]) / + png_pass_yinc[png_ptr->pass]; + + if (png_ptr->transformations & PNG_INTERLACE) + break; + + } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0); + + } + + /* Reset the row above the image for the next pass */ + if (png_ptr->pass < 7) + { + if (png_ptr->prev_row != NULL) + memset(png_ptr->prev_row, 0, + (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels* + png_ptr->usr_bit_depth, png_ptr->width)) + 1); + + return; + } + } +#endif + + /* If we get here, we've just written the last row, so we need + to flush the compressor */ + png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH); +} + +#ifdef PNG_WRITE_INTERLACING_SUPPORTED +/* Pick out the correct pixels for the interlace pass. + * The basic idea here is to go through the row with a source + * pointer and a destination pointer (sp and dp), and copy the + * correct pixels for the pass. As the row gets compacted, + * sp will always be >= dp, so we should never overwrite anything. + * See the default: case for the easiest code to understand. + */ +void /* PRIVATE */ +png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass) +{ + /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* Start of interlace block */ + static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* Offset to next interlace block */ + static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + png_debug(1, "in png_do_write_interlace"); + + /* We don't have to do anything on the last pass (6) */ + if (pass < 6) + { + /* Each pixel depth is handled separately */ + switch (row_info->pixel_depth) + { + case 1: + { + png_bytep sp; + png_bytep dp; + int shift; + int d; + int value; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + dp = row; + d = 0; + shift = 7; + + for (i = png_pass_start[pass]; i < row_width; + i += png_pass_inc[pass]) + { + sp = row + (png_size_t)(i >> 3); + value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01; + d |= (value << shift); + + if (shift == 0) + { + shift = 7; + *dp++ = (png_byte)d; + d = 0; + } + + else + shift--; + + } + if (shift != 7) + *dp = (png_byte)d; + + break; + } + + case 2: + { + png_bytep sp; + png_bytep dp; + int shift; + int d; + int value; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + dp = row; + shift = 6; + d = 0; + + for (i = png_pass_start[pass]; i < row_width; + i += png_pass_inc[pass]) + { + sp = row + (png_size_t)(i >> 2); + value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03; + d |= (value << shift); + + if (shift == 0) + { + shift = 6; + *dp++ = (png_byte)d; + d = 0; + } + + else + shift -= 2; + } + if (shift != 6) + *dp = (png_byte)d; + + break; + } + + case 4: + { + png_bytep sp; + png_bytep dp; + int shift; + int d; + int value; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + + dp = row; + shift = 4; + d = 0; + for (i = png_pass_start[pass]; i < row_width; + i += png_pass_inc[pass]) + { + sp = row + (png_size_t)(i >> 1); + value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f; + d |= (value << shift); + + if (shift == 0) + { + shift = 4; + *dp++ = (png_byte)d; + d = 0; + } + + else + shift -= 4; + } + if (shift != 4) + *dp = (png_byte)d; + + break; + } + + default: + { + png_bytep sp; + png_bytep dp; + png_uint_32 i; + png_uint_32 row_width = row_info->width; + png_size_t pixel_bytes; + + /* Start at the beginning */ + dp = row; + + /* Find out how many bytes each pixel takes up */ + pixel_bytes = (row_info->pixel_depth >> 3); + + /* Loop through the row, only looking at the pixels that matter */ + for (i = png_pass_start[pass]; i < row_width; + i += png_pass_inc[pass]) + { + /* Find out where the original pixel is */ + sp = row + (png_size_t)i * pixel_bytes; + + /* Move the pixel */ + if (dp != sp) + memcpy(dp, sp, pixel_bytes); + + /* Next pixel */ + dp += pixel_bytes; + } + break; + } + } + /* Set new row width */ + row_info->width = (row_info->width + + png_pass_inc[pass] - 1 - + png_pass_start[pass]) / + png_pass_inc[pass]; + + row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, + row_info->width); + } +} +#endif + +/* This filters the row, chooses which filter to use, if it has not already + * been specified by the application, and then writes the row out with the + * chosen filter. + */ +static void +png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row, + png_size_t row_bytes); + +#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1) +#define PNG_HISHIFT 10 +#define PNG_LOMASK ((png_uint_32)0xffffL) +#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT)) +void /* PRIVATE */ +png_write_find_filter(png_structrp png_ptr, png_row_infop row_info) +{ + png_bytep best_row; +#ifdef PNG_WRITE_FILTER_SUPPORTED + png_bytep prev_row, row_buf; + png_uint_32 mins, bpp; + png_byte filter_to_do = png_ptr->do_filter; + png_size_t row_bytes = row_info->rowbytes; +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + int num_p_filters = png_ptr->num_prev_filters; +#endif + + png_debug(1, "in png_write_find_filter"); + +#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS) + { + /* These will never be selected so we need not test them. */ + filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH); + } +#endif + + /* Find out how many bytes offset each pixel is */ + bpp = (row_info->pixel_depth + 7) >> 3; + + prev_row = png_ptr->prev_row; +#endif + best_row = png_ptr->row_buf; +#ifdef PNG_WRITE_FILTER_SUPPORTED + row_buf = best_row; + mins = PNG_MAXSUM; + + /* The prediction method we use is to find which method provides the + * smallest value when summing the absolute values of the distances + * from zero, using anything >= 128 as negative numbers. This is known + * as the "minimum sum of absolute differences" heuristic. Other + * heuristics are the "weighted minimum sum of absolute differences" + * (experimental and can in theory improve compression), and the "zlib + * predictive" method (not implemented yet), which does test compressions + * of lines using different filter methods, and then chooses the + * (series of) filter(s) that give minimum compressed data size (VERY + * computationally expensive). + * + * GRR 980525: consider also + * + * (1) minimum sum of absolute differences from running average (i.e., + * keep running sum of non-absolute differences & count of bytes) + * [track dispersion, too? restart average if dispersion too large?] + * + * (1b) minimum sum of absolute differences from sliding average, probably + * with window size <= deflate window (usually 32K) + * + * (2) minimum sum of squared differences from zero or running average + * (i.e., ~ root-mean-square approach) + */ + + + /* We don't need to test the 'no filter' case if this is the only filter + * that has been chosen, as it doesn't actually do anything to the data. + */ + if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE) + { + png_bytep rp; + png_uint_32 sum = 0; + png_size_t i; + int v; + + for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++) + { + v = *rp; + sum += (v < 128) ? v : 256 - v; + } + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + png_uint_32 sumhi, sumlo; + int j; + sumlo = sum & PNG_LOMASK; + sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */ + + /* Reduce the sum if we match any of the previous rows */ + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE) + { + sumlo = (sumlo * png_ptr->filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + sumhi = (sumhi * png_ptr->filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + /* Factor in the cost of this filter (this is here for completeness, + * but it makes no sense to have a "cost" for the NONE filter, as + * it has the minimum possible computational cost - none). + */ + sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >> + PNG_COST_SHIFT; + + sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >> + PNG_COST_SHIFT; + + if (sumhi > PNG_HIMASK) + sum = PNG_MAXSUM; + + else + sum = (sumhi << PNG_HISHIFT) + sumlo; + } +#endif + mins = sum; + } + + /* Sub filter */ + if (filter_to_do == PNG_FILTER_SUB) + /* It's the only filter so no testing is needed */ + { + png_bytep rp, lp, dp; + png_size_t i; + + for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; + i++, rp++, dp++) + { + *dp = *rp; + } + + for (lp = row_buf + 1; i < row_bytes; + i++, rp++, lp++, dp++) + { + *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); + } + + best_row = png_ptr->sub_row; + } + + else if (filter_to_do & PNG_FILTER_SUB) + { + png_bytep rp, dp, lp; + png_uint_32 sum = 0, lmins = mins; + png_size_t i; + int v; + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + /* We temporarily increase the "minimum sum" by the factor we + * would reduce the sum of this filter, so that we can do the + * early exit comparison without scaling the sum each time. + */ + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int j; + png_uint_32 lmhi, lmlo; + lmlo = lmins & PNG_LOMASK; + lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; + + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB) + { + lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> + PNG_COST_SHIFT; + + lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> + PNG_COST_SHIFT; + + if (lmhi > PNG_HIMASK) + lmins = PNG_MAXSUM; + + else + lmins = (lmhi << PNG_HISHIFT) + lmlo; + } +#endif + + for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; + i++, rp++, dp++) + { + v = *dp = *rp; + + sum += (v < 128) ? v : 256 - v; + } + + for (lp = row_buf + 1; i < row_bytes; + i++, rp++, lp++, dp++) + { + v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); + + sum += (v < 128) ? v : 256 - v; + + if (sum > lmins) /* We are already worse, don't continue. */ + break; + } + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int j; + png_uint_32 sumhi, sumlo; + sumlo = sum & PNG_LOMASK; + sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; + + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB) + { + sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> + PNG_COST_SHIFT; + + sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> + PNG_COST_SHIFT; + + if (sumhi > PNG_HIMASK) + sum = PNG_MAXSUM; + + else + sum = (sumhi << PNG_HISHIFT) + sumlo; + } +#endif + + if (sum < mins) + { + mins = sum; + best_row = png_ptr->sub_row; + } + } + + /* Up filter */ + if (filter_to_do == PNG_FILTER_UP) + { + png_bytep rp, dp, pp; + png_size_t i; + + for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, + pp = prev_row + 1; i < row_bytes; + i++, rp++, pp++, dp++) + { + *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff); + } + + best_row = png_ptr->up_row; + } + + else if (filter_to_do & PNG_FILTER_UP) + { + png_bytep rp, dp, pp; + png_uint_32 sum = 0, lmins = mins; + png_size_t i; + int v; + + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int j; + png_uint_32 lmhi, lmlo; + lmlo = lmins & PNG_LOMASK; + lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; + + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP) + { + lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >> + PNG_COST_SHIFT; + + lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >> + PNG_COST_SHIFT; + + if (lmhi > PNG_HIMASK) + lmins = PNG_MAXSUM; + + else + lmins = (lmhi << PNG_HISHIFT) + lmlo; + } +#endif + + for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, + pp = prev_row + 1; i < row_bytes; i++) + { + v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); + + sum += (v < 128) ? v : 256 - v; + + if (sum > lmins) /* We are already worse, don't continue. */ + break; + } + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int j; + png_uint_32 sumhi, sumlo; + sumlo = sum & PNG_LOMASK; + sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; + + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP) + { + sumlo = (sumlo * png_ptr->filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + sumhi = (sumhi * png_ptr->filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >> + PNG_COST_SHIFT; + + sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >> + PNG_COST_SHIFT; + + if (sumhi > PNG_HIMASK) + sum = PNG_MAXSUM; + + else + sum = (sumhi << PNG_HISHIFT) + sumlo; + } +#endif + + if (sum < mins) + { + mins = sum; + best_row = png_ptr->up_row; + } + } + + /* Avg filter */ + if (filter_to_do == PNG_FILTER_AVG) + { + png_bytep rp, dp, pp, lp; + png_uint_32 i; + + for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, + pp = prev_row + 1; i < bpp; i++) + { + *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); + } + + for (lp = row_buf + 1; i < row_bytes; i++) + { + *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) + & 0xff); + } + best_row = png_ptr->avg_row; + } + + else if (filter_to_do & PNG_FILTER_AVG) + { + png_bytep rp, dp, pp, lp; + png_uint_32 sum = 0, lmins = mins; + png_size_t i; + int v; + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int j; + png_uint_32 lmhi, lmlo; + lmlo = lmins & PNG_LOMASK; + lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; + + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG) + { + lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >> + PNG_COST_SHIFT; + + lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >> + PNG_COST_SHIFT; + + if (lmhi > PNG_HIMASK) + lmins = PNG_MAXSUM; + + else + lmins = (lmhi << PNG_HISHIFT) + lmlo; + } +#endif + + for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, + pp = prev_row + 1; i < bpp; i++) + { + v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); + + sum += (v < 128) ? v : 256 - v; + } + + for (lp = row_buf + 1; i < row_bytes; i++) + { + v = *dp++ = + (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff); + + sum += (v < 128) ? v : 256 - v; + + if (sum > lmins) /* We are already worse, don't continue. */ + break; + } + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int j; + png_uint_32 sumhi, sumlo; + sumlo = sum & PNG_LOMASK; + sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; + + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE) + { + sumlo = (sumlo * png_ptr->filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + sumhi = (sumhi * png_ptr->filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >> + PNG_COST_SHIFT; + + sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >> + PNG_COST_SHIFT; + + if (sumhi > PNG_HIMASK) + sum = PNG_MAXSUM; + + else + sum = (sumhi << PNG_HISHIFT) + sumlo; + } +#endif + + if (sum < mins) + { + mins = sum; + best_row = png_ptr->avg_row; + } + } + + /* Paeth filter */ + if (filter_to_do == PNG_FILTER_PAETH) + { + png_bytep rp, dp, pp, cp, lp; + png_size_t i; + + for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, + pp = prev_row + 1; i < bpp; i++) + { + *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); + } + + for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) + { + int a, b, c, pa, pb, pc, p; + + b = *pp++; + c = *cp++; + a = *lp++; + + p = b - c; + pc = a - c; + +#ifdef PNG_USE_ABS + pa = abs(p); + pb = abs(pc); + pc = abs(p + pc); +#else + pa = p < 0 ? -p : p; + pb = pc < 0 ? -pc : pc; + pc = (p + pc) < 0 ? -(p + pc) : p + pc; +#endif + + p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; + + *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); + } + best_row = png_ptr->paeth_row; + } + + else if (filter_to_do & PNG_FILTER_PAETH) + { + png_bytep rp, dp, pp, cp, lp; + png_uint_32 sum = 0, lmins = mins; + png_size_t i; + int v; + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int j; + png_uint_32 lmhi, lmlo; + lmlo = lmins & PNG_LOMASK; + lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; + + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH) + { + lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >> + PNG_COST_SHIFT; + + lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >> + PNG_COST_SHIFT; + + if (lmhi > PNG_HIMASK) + lmins = PNG_MAXSUM; + + else + lmins = (lmhi << PNG_HISHIFT) + lmlo; + } +#endif + + for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, + pp = prev_row + 1; i < bpp; i++) + { + v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); + + sum += (v < 128) ? v : 256 - v; + } + + for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) + { + int a, b, c, pa, pb, pc, p; + + b = *pp++; + c = *cp++; + a = *lp++; + +#ifndef PNG_SLOW_PAETH + p = b - c; + pc = a - c; +#ifdef PNG_USE_ABS + pa = abs(p); + pb = abs(pc); + pc = abs(p + pc); +#else + pa = p < 0 ? -p : p; + pb = pc < 0 ? -pc : pc; + pc = (p + pc) < 0 ? -(p + pc) : p + pc; +#endif + p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; +#else /* PNG_SLOW_PAETH */ + p = a + b - c; + pa = abs(p - a); + pb = abs(p - b); + pc = abs(p - c); + + if (pa <= pb && pa <= pc) + p = a; + + else if (pb <= pc) + p = b; + + else + p = c; +#endif /* PNG_SLOW_PAETH */ + + v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); + + sum += (v < 128) ? v : 256 - v; + + if (sum > lmins) /* We are already worse, don't continue. */ + break; + } + +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) + { + int j; + png_uint_32 sumhi, sumlo; + sumlo = sum & PNG_LOMASK; + sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; + + for (j = 0; j < num_p_filters; j++) + { + if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH) + { + sumlo = (sumlo * png_ptr->filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + + sumhi = (sumhi * png_ptr->filter_weights[j]) >> + PNG_WEIGHT_SHIFT; + } + } + + sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >> + PNG_COST_SHIFT; + + sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >> + PNG_COST_SHIFT; + + if (sumhi > PNG_HIMASK) + sum = PNG_MAXSUM; + + else + sum = (sumhi << PNG_HISHIFT) + sumlo; + } +#endif + + if (sum < mins) + { + best_row = png_ptr->paeth_row; + } + } +#endif /* PNG_WRITE_FILTER_SUPPORTED */ + + /* Do the actual writing of the filtered row data from the chosen filter. */ + png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1); + +#ifdef PNG_WRITE_FILTER_SUPPORTED +#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED + /* Save the type of filter we picked this time for future calculations */ + if (png_ptr->num_prev_filters > 0) + { + int j; + + for (j = 1; j < num_p_filters; j++) + { + png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1]; + } + + png_ptr->prev_filters[j] = best_row[0]; + } +#endif +#endif /* PNG_WRITE_FILTER_SUPPORTED */ +} + + +/* Do the actual writing of a previously filtered row. */ +static void +png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row, + png_size_t full_row_length/*includes filter byte*/) +{ + png_debug(1, "in png_write_filtered_row"); + + png_debug1(2, "filter = %d", filtered_row[0]); + + png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH); + + /* Swap the current and previous rows */ + if (png_ptr->prev_row != NULL) + { + png_bytep tptr; + + tptr = png_ptr->prev_row; + png_ptr->prev_row = png_ptr->row_buf; + png_ptr->row_buf = tptr; + } + + /* Finish row - updates counters and flushes zlib if last row */ + png_write_finish_row(png_ptr); + +#ifdef PNG_WRITE_FLUSH_SUPPORTED + png_ptr->flush_rows++; + + if (png_ptr->flush_dist > 0 && + png_ptr->flush_rows >= png_ptr->flush_dist) + { + png_write_flush(png_ptr); + } +#endif +} +#endif /* PNG_WRITE_SUPPORTED */ |
