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Diffstat (limited to 'png/pngwrite.c')
| -rw-r--r-- | png/pngwrite.c | 2437 |
1 files changed, 2437 insertions, 0 deletions
diff --git a/png/pngwrite.c b/png/pngwrite.c new file mode 100644 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 */ |