OptiPNG - Revision history
==========================

Legend
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 + Added or improved feature.
 - Removed feature.
 * Modified code (e.g. for architectural improvements).
 ! Fixed bug.
!! Fixed dangerous bug, that might cause accidental data loss.


Version 0.4.5   31-may-2004
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 + Upgraded zlib to version 1.2.1.f-cos2 [private]
 + Upgraded libpng to version 1.0.15-cos2 [private]
 * Changed user option -nx to -nz.
 + Added user option to preserve file attributes (file mode,
   time stamp, etc.) when applicable.
   (Thanks to Nehal Mistry for the suggestion.)
 ! Fixed an incorrect initialization of zlib window bits.
 ! Displayed an error message when the search space was invalid.
!! Fixed a palette reduction problem for bit depths below 8.
 ! Eliminated memory leaks.
   (Thanks to Niels de Koning for the help.)


Version 0.4.4	20-nov-2003
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 + Upgraded zlib to version 1.2.1
 + Added support for the Z_RLE strategy.


Version 0.4.3	12-aug-2003
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 ! Fixed a reduction problem that caused an assertion failure.
   (Thanks to Dimitri Papadopoulos for the report.)


Version 0.4.2	30-jun-2003
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 + Enhanced the support for palette size reductions:
   trailing sterile palette entries are removed even when
   the bit depth is below 8.
 ! Enforced recompression when the new IDAT has the same size,
   but other chunks have been reduced.
 + Displayed the IDAT size difference as a percentage.
   (Thanks to Nehal Mistry for the suggestion.)


Version 0.4.1	19-may-2003
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 ! Fixed the removal of trailing sterile palette entries.


Version 0.4	12-may-2003
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 + Added support for palette-to-gray reductions.
 + Added partial support for palette size reductions.
 ! Fixed the reporting of invalid command-line options.
 ! Eliminated a spurious warning when the zlib window size
   is set to 256.


Version 0.3.2	11-mar-2003
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 + Added support for updating sBIT during reductions.
 ! Fixed the reduction of the alpha channel.


Version 0.3.1	25-feb-2003
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 ! Fixed the encoding of interlaced images when they become
   bigger than the input.
 + Added the HISTORY document (this file).


Version 0.3	24-feb-2003
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 This is the first public release of OptiPNG.
 + Added support for iterating through zlib memory levels.
 + Added support for collapsing IDAT, avoiding calls to
   png_set_compression_buffer_size().
   This reduces the memory requirements.
 + Added support for lossless reduction of the image type:
   RGB[A] -> G[A], RGBA -> RGB, GA -> G
 + Added many user options.
 + Added documentation.


Version 0.2	27-dec-2001
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 + Added support for optimization level presets.
 + Added user option for changing the interlacing.


Version 0.1	17-dec-2001
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 + Added support for chunk I/O status annotation.
   This improves the speed of OptiPNG significantly.
 * Structured exception handling is provided by cexcept.


Version 0.0	10-dec-2001
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This is the very first version of OptiPNG.
It compresses IDAT repeatedly, iterating through zlib compression
and strategy levels, and PNG filters.