51 lines
1.8 KiB
Plaintext
51 lines
1.8 KiB
Plaintext
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Known bugs and suggested enhancements in libpng-1.0.4
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1. March 15, 1998 -- OPTIMIZATION -- Kevin Bracey
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Loops need to be optimized everywhere
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Make them count down instead of up -- Kevin Bracey
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Optimizing compilers don't need this, and making
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the change would be error prone -- Tom Lane, Glenn R-P
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Question whether i-- or --i is better.
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STATUS: Under investigation, postponed until after
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libpng-1.0.5. About 160 loops will be turned around
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in libpng-1.0.Nn, for testing.
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2. July 4, 1998 -- ENHANCEMENT -- Glenn R-P
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libpng-1.0.5 and earlier transform colors to gamma=1.0 space for
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merging with background, and then back to the image's gamma. The
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bit_depth of the intermediate (gamma=1.0) representation is probably
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not sufficient. In the typical gamma=1/2.2 situation, the linear
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pixels need about 4 more bits than the gamma-encoded ones, to avoid
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loss of precision. A similar situation exists with the rgb_to_gray
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operation.
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STATUS: under development.
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3. September 1999 -- ENHANCEMENT --
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It should be possible to use libpng without floating-point aritmetic.
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STATUS: Under investigation, implementation postponed until after
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libpng-1.0.5. The application interface will change because replacements
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for the png_set_gAMA(), png_set_cHRM(), and corresponding png_get_()
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functions will be needed.
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4. September 1999 -- BUG --
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Portions of the new MMX code in pngvcrd.c are defined out because the
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did not work properly. When PNGVCRD_INTERLACE_BUG_IS_FIXED is defined,
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to enable the code, pngtest pngtest.png pngout.png results in a
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"Debug error! Damage before normal block # 57 at 0x007e19f0" on
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a Pentium II with MMX system. This seems to be caused by the heap
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being trashed before a free() in png_read_destroy().
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When PNGVCRD_COMBINE_BUG_IS_FIXED is defined (what?)
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