libpng/KNOWNBUG
2009-04-06 16:04:29 -05:00

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Known bugs and suggested enhancements in libpng-1.0.2
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-1.0.2. About 160 loops will be turned around
in libpng-1.0.Nn, for testing.
2. June 15, 1998 -- BUG -- Evan Light
Under some conditions, 16-bit grayscale images aren't properly
expanded to rgb, because png_read_start_row() returns too small a
value of max_pixel_depth when png_set_filler() has also been called.
STATUS: Fixed in libpng-1.0.2a
3. June 16, 1998 -- BUG -- Matt McConnell
When reading interlaced images with a progressive reader, in some
cases (interlaced images less than 3 pixels high) some passes are
not skipped that should be.
STATUS: Fixed in libpng-1.0.2a
4. July 3, 1998 -- ENHANCEMENT -- Glenn R-P
Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
STATUS: Done in libpng-1.0.2a, awaiting comment on resulting test
images.
5. July 4, 1998 -- ENHANCEMENT -- Glenn R-P
libpng-1.0.2 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.
6. August 20, 1998 -- BUG -- Kevin Bracey
When using the filler transformation, the filler isn't written
into the leftmost pixel of each row.
Also, the filler operation isn't being done right when writing
files. Some code that was removed from png_set_filler() in
libpng 1.0.1a shouldn't have been removed.
STATUS: Fixed in libpng-1.0.2a
7. August 23, 1998 -- BUG -- Duncan Simpson
"static pngcharp tIME_string" should be changed to
"static char tIME_string[30]" in pngtest.c
STATUS: Fixed in libpng-1.0.2a
8. August 24, 1998 -- BUG -- John Cromer
Order of byte-swap and shift operations seems to be incorrect in
png_do_write_transformations()
STATUS: Under investigation.
9. September 11, 1998 -- ENHANCEMENT -- L. Peter Deutsch
The PNG_NO_STDIO macro should be split into PNG_NO_STDIO
and PNG_NO_CONSOLE_STDIO.
STATUS: Done in libpng-1.0.2a