57 lines
2.7 KiB
Plaintext
57 lines
2.7 KiB
Plaintext
The quantization and dithering code in pngquant is lifted from Jef Poskanzer's
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'ppmquant', part of his wonderful PBMPLUS tool suite.
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Greg Roelofs hacked it into a (in his words) "slightly cheesy" 'pamquant' back
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in 1997 (see http://pobox.com/~newt/greg_rgba.html) and finally he ripped out
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the cheesy file-I/O parts and replaced them with nice PNG code in December
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2000. The PNG reading and writing code is a merged and slightly simplified
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version of readpng, readpng2, and writepng from his book "PNG: The Definitive
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Guide."
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In 2014 Greg has relicensed the code under the simplified BSD license.
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Note that both licenses are basically BSD-like; that is, use the code however
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you like, as long as you acknowledge its origins.
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pngquant.c:
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© 1989, 1991 by Jef Poskanzer.
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted, provided
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that the above copyright notice appear in all copies and that both that
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copyright notice and this permission notice appear in supporting
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documentation. This software is provided "as is" without express or
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implied warranty.
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pngquant.c and rwpng.c/h:
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© 1997-2002 by Greg Roelofs; based on an idea by Stefan Schneider.
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© 2009-2014 by Kornel Lesiński.
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All rights reserved.
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Redistribution and use in source and binary forms, with or without modification,
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are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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