77 lines
2.5 KiB
Plaintext
77 lines
2.5 KiB
Plaintext
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Known bugs and suggested enhancements in libpng-1.0.5
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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-1.1.0. About 160 loops will be turned around
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in libpng-1.1.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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Much of this was completed in libpng-1.0.5h, but gamma compensation
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is not yet done in fixed-point arithmetic.
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4. October 1999 -- BUG
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pngvcrd.c is failing for interlaced PNGs that have empty passes.
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STATUS: A check for "width != 0" is required in several places.
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Fixed in libpng-1.0.5a/1.1.0
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5. October 1999 -- BUG
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Under MSVC++6.0 with debugging enabled, heap corruption was detected
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while destroying the png_write_ptr.
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STATUS: This was fixed by modifying png_set_text (in pngset.c) to
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refrain from writing into the user's text_ptr. With this fix, however,
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pngwrite.c, while destroying the info_ptr, was failing to free the
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text->key strings. Fix for the latter problem is to duplicate code
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from png.c.
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Fixed in libpng-1.0.5a/1.1.0
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6. December 1999 -- new BUG
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The png_text structure was modified in libpng-1.0.5e in a manner that
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is not backward compatible (the lang member was added, and the
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translated_key member was added to libpng-1.0.5g)
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STATUS: Fixed in libpng-1.0.5j/1.1.0
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7. December 1999 -- BUG
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The new pnggccrd.c has syntax errors when compiled with gcc.
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STATUS: Under investigation.
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