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diff --git a/tiff/html/v4.0.0.html b/tiff/html/v4.0.0.html new file mode 100755 index 0000000..9694a1e --- /dev/null +++ b/tiff/html/v4.0.0.html @@ -0,0 +1,269 @@ +<HTML> +<HEAD> +<TITLE> + Changes in TIFF v4.0.0 +</TITLE> +</HEAD> + +<BODY BGCOLOR=white> +<FONT FACE="Helvetica, Arial, Sans"> +<FONT FACE="Helvetica, Arial, Sans"> + +<BASEFONT SIZE=4> +<B><FONT SIZE=+3>T</FONT>IFF <FONT SIZE=+2>C</FONT>HANGE <FONT SIZE=+2>I</FONT>NFORMATION</B> +<BASEFONT SIZE=3> + +<UL> +<HR SIZE=4 WIDTH=65% ALIGN=left> +<B>Current Version</B>: v4.0.0<BR> +<B>Previous Version</B>: <A HREF=v3.9.5.html>v3.9.5</a><BR> +<B>Master FTP Site</B>: <A HREF="ftp://ftp.remotesensing.org/pub/libtiff"> +ftp.remotesensing.org</a>, directory pub/libtiff</A><BR> +<B>Master HTTP Site</B>: <A HREF="http://download.osgeo.org/libtiff"> +http://download.osgeo.org/libtiff</a> +<HR SIZE=4 WIDTH=65% ALIGN=left> +</UL> + +<P> +This document describes the changes made to the software between the +<I>previous</I> and <I>current</I> versions (see above). If you don't +find something listed here, then it was not done in this timeframe, or +it was not considered important enough to be mentioned. Please consult +the ChangeLog file in the source package for full change details. The +following information is located here: +<UL> +<LI><A HREF="#hightlights">Major Changes</A> +<LI><A HREF="#configure">Changes in the software configuration</A> +<LI><A HREF="#libtiff">Changes in libtiff</A> +<LI><A HREF="#tools">Changes in the tools</A> +<LI><A HREF="#contrib">Changes in the contrib area</A> +</UL> +<p> +<P><HR WIDTH=65% ALIGN=left> + +<!---------------------------------------------------------------------------> + +<P><A NAME="highlights"><B><FONT SIZE=+3>M</FONT>AJOR CHANGES:</B></A></P> + +BigTIFF support changes: + +<UL> + + <LI>The options parameter in the TIFFOpen and TIFFClientOpen funcs has + been extended. When creating new files, you can add option '4' to + specify you want to create a ClassicTIFF file, though that is the + default and the option is not strictly necessary. (As such, old + calling code will continue to function and create ClassicTIFF files.) + Or you can add option '8' to specify you want to create a BigTIFF file + instead. This new option is also reflected in some of the tools we + already upgraded. For instance, you can use the -8 option on tiffcp to + have tiffcp produce BigTIFF files instead of the default ClassicTIFF. + (Whilst on additional option is provided for version selection when + creating new files, no such option is necessary when reading TIFF + files. LibTiff reads ClassicTIFF and BigTIFF both, and the application + does not need to be aware which TIFF version an opened file is.) + + <LI>Although the tag count in BigTIFF is 64bit, we restricted the + count in the implementation to a much more reasonable size. This is + necessary in current implementation, because all tag data gets read + automatically in the IFD reading stage, so if there's half a dozen + private tags with multiple gigabytes of data that causes considerable + overhead even if the application level is never interested in these + tags. Our choice to ignore tags with data longer then a certain sanity + value is much needed as things stand. We also recommend to step away + from writing tiles that are 8 kilobyte in their uncompressed form, or + writing single-line strips, in really big files, resulting in mega's + of tiles or strips. It's much more efficient to choose bigger tile or + strip sizes, up to several megabyte if needed, and have a few kilo of + tiles or strips instead. + + <LI>Although it's rare, some application code does directly access + file offsets. Some of these are automatically upgraded because they + used the toff_t type, others need to be aware that the datatype + changed and need to start using toff_t or uint64. This impacts access + to tags like the EXIF IFD tag, for example, or the SubIfds tag, or to + StripOffsets or TileOffsets, the return type of functions like + TIFFCurrentDirOffset, and a parameter type to functions like + TIFFSetSubDirectory. + + <LI>Although it's rare, some application code does use structures + like TIFFHeader or TIFFDirEntry that used to be an exact binary + representation of TIFF structures. These need to change. The old + TIFFHeader structure is replaced by the new TIFFHeaderClassic, + TIFFHeaderBig, and TIFFHeaderCommon structures that are an exact + binary representation of the ClassicTIFF and BigTIFF header, and of + the part that is common to both. There is no new equivalent for the + old TIFFDirEntry structure (or more precisely, there is still a + TIFFDirEntry structure, but it is changed, moved to library-private + definition, and no longer an exact binary representation of the tag + structure of either TIFF version). + + <LI>Sizer functions, like TIFFTileSize or TIFFScanlineSize and the + like, return a tmsize_t value (tmsize_t is defined as int32 on 32bit + machines, and int64 on 64bit machines, and as such it is meant to + represent signed memory sizes). This is because we figure 98% of the + calling code uses the return value as sizes in allocations and the + like. So, any overflow that is theoretically possible with BigTIFF + when LibTiff is running on a 32bit system, is best detected inside the + sizer functions and it is best to return a type that makes sense as a + memory size. If your calling code is the exception and is interested + in actual file size, you best use the newer TIFFTileSize64 or + TIFFScanlineSize64 function that returns an uint64 type. + + <LI>These TIFF tags require a 64-bit type as an argument in + libtiff 4.0.0: + <UL> + <LI> TIFFTAG_FREEBYTECOUNTS + <LI> TIFFTAG_FREEOFFSETS + <LI> TIFFTAG_STRIPBYTECOUNTS + <LI> TIFFTAG_STRIPOFFSETS + <LI> TIFFTAG_TILEBYTECOUNTS + <LI> TIFFTAG_TILEOFFSETS + </UL> + +</UL> + +Other important backward incompatible changes in the public API: + +<UL> + <LI> TIFFRewriteField() renamed into _TIFFRewriteField() and moved out + from the public interface (from tiffio.h to tiffiop.h). Type of its + 'count' parameter changed from uint32 to tmsize_t. + + <LI> TIFFMergeFieldInfo() returns non-void result now. It returns 0 + if successful and -1 if failed. Though this is now obsoleted function + and should not be used in new programs. Use the new tag extension + scheme instead. + + <LI> TIFFFieldWithTag() and TIFFFieldWithName() functions now return + pointer to TIFFField constant object instead of TIFFFieldInfo. + + <LI> TIFFReassignTagToIgnore() function and TIFFIgnoreSense enumeration + have been removed. They was unused and never been used properly. + Should be unneeded for high-level applications. + + <LI> TIFFTagValue structure removed from the public tiffio.h + to private tif_dir.h and not accessible anymore. It should be unneeded + for high-level applications. + +</UL> + +<P><HR WIDTH=65% ALIGN=left> +<!---------------------------------------------------------------------------> + +<P><A NAME="configure"><B><FONT SIZE=+3>C</FONT>HANGES IN THE SOFTWARE CONFIGURATION:</B></A></P> + +<UL> + + <LI>Updated autotools: Autoconf 2.68, Automake 1.11.1, libtool + 2.4. + + <LI>Enabled support for Automake silent build rules + (--enable-silent-rules or 'make V=0') + + <LI>Enabled support for Automake colorized and parallel tests. + + <LI>Added detection of 64-bit integer types since libtiff 4.0 + requires use of 64-bit signed and unsigned integer types. + + <LI>Libtiff now provides a more comprehensive test suite with + over 72 tests, which may be executed on Unix-like systems, or + under Microsoft Windows using MinGW/MSYS or Cygwin. + + <LI>--disable-lzma configure option to disable use of liblzma. + + <LI>--enable-defer-strile-load configure option to enable + experimental deferred strip/tile offset/size loading. May + cause some extremely sophisticated uses of libtiff to fail. + + <LI>--enable-chunky-strip-read configure option to enable + experimental enable reading large strips in chunks in + TIFFReadScanline(). + + <LI>Now always uses WIN32 native I/O functions for Microsoft + Windows except for under Cygwin. + + <LI>Now provides a pkg-config support file (libtiff-4.pc). + +</UL> + +<P><HR WIDTH=65% ALIGN=left> + +<!---------------------------------------------------------------------------> + +<P><A NAME="libtiff"><B><FONT SIZE=+3>C</FONT>HANGES IN LIBTIFF:</B></A></P> + +<UL> + + <LI>Patches/fixes made to stable libtiff (v3.9.X) are also + applied to 4.0.0. There are too many to list here. See the + distribution ChangeLog for a detailed change list. + + <LI>There is considerable change in some files like + tif_dirread and tif_dirwrite. These changes don't impact + backwards compatibility, they are mostly a clean rewrite that + does allow BigTIFF support as well as somewhat more robust + reading of the unexpected already and will also serve future + API extension but does not impact current API or functionality + in a negative way that you need to know about. + + <LI>Although there is still a functional definition for types + like toff_t (file offset), tstrip_t (strip index number), etc, + we recommend against using these in newer code. We have + learned that it is next to impossible to use these + consistently and make real abstraction of the binary format of + these types. Instead, at a certain level we always end up + doing casts anyway, and taking the exact binary format into + account, so these types are nothing but dangerously misleading + and obfuscating. You do not need to update calling code that + uses them, as 99.9% of such code will continue to work. But we + recommend against using them in newer calling code, and we + started replacing them with binary clear types like uint16, + uint32 and such in the library. + + <LI>We do use and will continue to use one functional type + that is an exception to the above rule, being tmsize_t. This + is a signed memory size type, i.e. it is int32 on 32bit + machines, or int64 on 64bit machines. + + <LI>Optionally support LZMA compression via TIFF tag 34925. + Tiffcp supports compression levels similar to "-c lzma:p1" or + "-c zip:p9 for setting the LZMA compression parameters. + + <LI>Optionally defer the load of strip/tile offset and size + tags for optimized scanning of directories. Enabled with the + --enable-defer-strile-load configure option (DEFER_STRILE_LOAD + #define in tif_config.h). + + <LI>Optionally enable experimental support for reading big + strips in chunks. Enabled with the --enable-chunky-strip-read + configure option. + +</UL> + +<P><HR WIDTH=65% ALIGN=left> + +<!--------------------------------------------------------------------------> + +<P><A NAME="tools"><B><FONT SIZE=+3>C</FONT>HANGES IN THE TOOLS:</B></A></P> + +<UL> + + <LI>tiffset: add -d and -sd switches to allow operation on + a particular directory, not just the first. + +</UL> + +<P><HR WIDTH=65% ALIGN=left> + +<!---------------------------------------------------------------------------> + +<P><A NAME="contrib"><B><FONT SIZE=+3>C</FONT>HANGES IN THE CONTRIB AREA:</B></A></P> + +<UL> +</UL> + +Last updated $Date: 2011-04-09 21:01:00 $. + +</BODY> +</HTML> |