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[libpng16] Renamed contrib/tools/fixitxt to contrib/tools/png-fix-itxt.

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Added information in the documentation about problems with and fixes for
the bad CRC and bad iTXt chunk situations.
This commit is contained in:
Glenn Randers-Pehrson
2013-05-08 19:46:10 -05:00
parent 122bec17f2
commit ff141eb21e
7 changed files with 63 additions and 23 deletions
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20
libpng-manual.txt
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@@ -1,6 +1,6 @@
libpng-manual.txt - A description on how to use and modify libpng
libpng version 1.6.3beta05 - May 6, 2013
libpng version 1.6.3beta05 - May 9, 2013
Updated and distributed by Glenn Randers-Pehrson
<glennrp at users.sourceforge.net>
Copyright (c) 1998-2013 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng
Based on:
libpng versions 0.97, January 1998, through 1.6.3beta05 - May 6, 2013
libpng versions 0.97, January 1998, through 1.6.3beta05 - May 9, 2013
Updated and distributed by Glenn Randers-Pehrson
Copyright (c) 1998-2013 Glenn Randers-Pehrson
@@ -5035,6 +5035,20 @@ The machine-generated configure files are no longer included in branches
libpng16 and later of the GIT repository. They continue to be included
in the tarball releases, however.
Libpng-1.6.0 and later use the CMF bytes at the beginning of the IDAT stream
to set the size of the sliding window for reading instead of using the default
32-kbyte sliding window size. It was discovered that there are hundreds of PNG
files in the wild that have incorrect CMF bytes that cause libpng to now issue
a "too far back" error and reject the file. Libpng-1.6.3 provides a way to
revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a 32-kbyte
sliding window), and provides a tool (called "contrib/tools/pnginflate"),
for optimizing the CMF bytes correctly.
Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
length, which resulted in PNG files that cannot be read beyond the bad iTXt
chunk. This error was fixed in libpng-1.6.3, and a tool (called
contrib/tools/png-fix-itxt) has been added to the libpng distribution.
XIII. Detecting libpng
The png_get_io_ptr() function has been present since libpng-0.88, has never
@@ -5197,7 +5211,7 @@ Other rules can be inferred by inspecting the libpng source.
XVI. Y2K Compliance in libpng
May 6, 2013
May 9, 2013
Since the PNG Development group is an ad-hoc body, we can't make
an official declaration.