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libpng/KNOWNBUG
2009-04-06 16:04:47 -05:00

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Known bugs and suggested enhancements in libpng-1.0.5
1. March 15, 1998 -- OPTIMIZATION -- Kevin Bracey
Loops need to be optimized everywhere
Make them count down instead of up -- Kevin Bracey
Optimizing compilers don't need this, and making
the change would be error prone -- Tom Lane, Glenn R-P
Question whether i-- or --i is better.
STATUS: Under investigation, postponed until after
libpng-1.1.0. About 160 loops will be turned around
in libpng-1.1.Nn, for testing.
2. July 4, 1998 -- ENHANCEMENT -- Glenn R-P
libpng-1.0.5 and earlier transform colors to gamma=1.0 space for
merging with background, and then back to the image's gamma. The
bit_depth of the intermediate (gamma=1.0) representation is probably
not sufficient. In the typical gamma=1/2.2 situation, the linear
pixels need about 4 more bits than the gamma-encoded ones, to avoid
loss of precision. A similar situation exists with the rgb_to_gray
operation.
STATUS: under development.
3. September 1999 -- ENHANCEMENT --
It should be possible to use libpng without floating-point aritmetic.
STATUS: Under investigation, implementation postponed until after
libpng-1.0.5. The application interface will change because replacements
for the png_set_gAMA(), png_set_cHRM(), and corresponding png_get_()
functions will be needed.
4. October 1999 -- BUG
pngvcrd.c is failing for interlaced PNGs that have empty passes.
STATUS: A check for "width != 0" is required in several places.
Fixed in libpng-1.0.5a/1.1.0
5. October 1999 -- BUG
Under MSVC++6.0 with debugging enabled, heap corruption was detected
while destroying the png_write_ptr.
STATUS: This was fixed by modifying png_set_text (in pngset.c) to
refrain from writing into the user's text_ptr. With this fix, however,
pngwrite.c, while destroying the info_ptr, was failing to free the
text->key strings. Fix for the latter problem is to duplicate code
from png.c.
Fixed in libpng-1.0.5a/1.1.0
6. December 1999 -- new BUG
The png_text structure was modified in libpng-1.0.5e in a manner that
is not backward compatible (the lang member was added, and the
translated_key member was added to libpng-1.0.5g)
STATUS: Will be fixed before the next public release.