forked from Mirrors/freeswitch
270 lines
10 KiB
HTML
270 lines
10 KiB
HTML
<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>
|