1998-04-21 20:03:57 +00:00
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2000-11-19 00:19:14 +00:00
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Known bugs and suggested enhancements in libpng-1.0.8
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1998-04-21 20:03:57 +00:00
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2000-11-19 00:19:14 +00:00
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0: November 3, 2000 -- BUG -- incorrect iCCP chunk is written
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2000-07-08 18:19:41 +00:00
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2000-11-19 00:19:14 +00:00
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The compression_type byte in the iCCP chunk written by libpng is
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usually incorrect.
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Status: Fixed in libpng-1.0.9beta1
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1. October 12, 2000 -- BUG -- pngtest fails
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The three WRITEFILE calls in pngtest.c are incorrect. They must be
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changed to read
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WRITEFILE((png_FILE_p)png_ptr->io_ptr, data, length, check);
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WRITEFILE(io_ptr, near_data, length, check);
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WRITEFILE(io_ptr, buf, written, err);
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2. August 28, 2000 -- BUG -- pnggccrd.c
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The interlacing() function has still not been fully converted and
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will not compile under gcc-2.95.2; it is currently ifdef'ed out.
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STATUS: Fixed in libpng-1.0.9. There were also bugs in pngvcrd.c
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which have been fixed. The replacement files are available at the
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PNG web site (http://www.libpng.org/pub/png).
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3. 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-2.0.0. About 160 loops will be turned around
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in libpng-2.0.x betaxx, for testing.
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4. 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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5. September 1999 -- ENHANCEMENT --
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It should be possible to use libpng without floating-point arithmetic.
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STATUS: Under investigation, implementation postponed until after
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libpng-2.0.0.
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Much of this was completed in libpng-1.0.6, but gamma compensation
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is not yet done in fixed-point arithmetic.
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2000-02-05 05:40:16 +00:00
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