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Release 1.3b2

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1 parent 9429d4b commit 4f5d7595278513ab3996c10718b139a8143ab734 @pornel committed Mar 6, 2011
Showing with 25 additions and 15 deletions.
  1. +16 −2 CHANGELOG
  2. +1 −1 COPYRIGHT
  3. +7 −11 README
  4. +1 −1 pngquant.c
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@@ -1,12 +1,26 @@
+version 1.3
+-----------
+ - significant changes to the algorithm: use of variance
+ to find largest dimensioin and to split most varying boxes
+ - use of premultiplied alpha for color blending
+ - conversion of output to gamma 2.2
+ - performance optimisations for 64-bit CPUs
+
+version 1.2
+-----------
+ - color computation done in floating point
+ - gamma correction applied
+ - dropped support for very old systems & compilers
+
version 1.1
-------------
+-----------
- alpha-sensitive color reduction and dithering
- support -- and - arguments in command line
- number of colors optional (defaults to 256)
- increased maximum number of colors in histogram
version 1.0
-------------
+-----------
- cleaned up Makefile.unx (better gcc optimizations, "clean" target)
- recompiled binaries with zlib 1.1.4
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@@ -21,7 +21,7 @@ pngquant.c:
Copyright (C) 1989, 1991 by Jef Poskanzer.
Copyright (C) 1997, 2000, 2002 by Greg Roelofs; based on an idea by
Stefan Schneider.
-
+
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, provided
that the above copyright notice appear in all copies and that both that
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@@ -1,24 +1,20 @@
-This is pngquant, a quantization utility for PNG images. Image quantization
-is the process of the reducing the number of colors in an image.
+This is a modified version of pngquant (http://pornel.net/pngquant)
Typically, pngquant is used to convert 32-bit RGBA PNGs to 8-bit RGBA-palette
PNGs in order to save file space. For example, for the web.
-Currently the following quantization algorithms are supported:
-- ordered
-- diffusion (Floyd-Steinberg)
-
-This utility works on Linux and UNIX systems (including Mac OS X) as well as
-modern Windows platforms.
+This utility works on Linux and UNIX systems (including Mac OS X) and should
+work on modern Windows platforms.
Pngquant provides the following features:
- reduction of all PNG image types to a palette with 256 colors or less
+- diffusion (Floyd-Steinberg)
- automatic optimization of tRNS chunks
- batch conversion of multiple files, e.g.: pngquant 256 *.png
- Unix-style stdin/stdout chaining, e.g.: ... | pngquant 16 | ...
These features are currently lacking:
-- no ancillary chunk preservation (except gAMA)
+- no ancillary chunk preservation
- no preservation of significant-bits info after rescaling (sBIT chunk)
- no mapfile support
- no "native" handling of 16-bit-per-sample files or gray+alpha files
@@ -39,5 +35,5 @@ change log, see the CHANGELOG file.
The INSTALL file explains how to build pngquant from source.
-NOTE: This is a modified version of the regular 'pngquant' tool. The homepage of
- the latter is: http://www.libpng.org/pub/png/apps/pngquant.html
+The homepage of original pngquant is:
+http://www.libpng.org/pub/png/apps/pngquant.html
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@@ -26,7 +26,7 @@
/* GRR TO DO: if all samples are 0 or maxval, eliminate gAMA chunk (rwpng.c) */
-#define PNGQUANT_VERSION "1.3a (February 2011)"
+#define PNGQUANT_VERSION "1.3b (March 2011)"
#define PNGQUANT_USAGE "\
usage: pngquant [options] [ncolors] [pngfile [pngfile ...]]\n\

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