PNGNQ-S9 - PNG NEUQUANT WITH SAIKI 9 MODIFICATIONS
VERSION 2.0.2

NOTES:

pngnq-s9 is derived from pngnq, and incorporates various changes and feature
additions made by Adrian Pellas-Rice.  It is a separately maintained project.

pngnq is a tool for quantizing PNG images in RGBA format.  Pngnq is an
adaptation by Stuart Coyle and later Kornel Lesiński of Greg Roelf's pnqquant
program using Anthony Dekker's neuquant algorithm.

Stuarts Preface:
    Pngnq exists because I needed a lot of png images in RGBA format to be
    quantized. After some searching, the only tool I could find that worked was
    pngquant. I tried pngquant but found that the median cut algorithm that it
    uses, with or without dithering, gave inferior looking results to the
    neuquant algorithm. You can see the difference demonstrated on the neuquant
    web page:  
    http://members.ozemail.com.au/~dekker/NEUQUANT.HTML.

    The program was written to fulfill the specific needs of the small project
    I was working on, and as such does not have all the functionality one could
    want.

    I use Greg Roelf's png reading and writing code unchanged for the most
    part.  The pngnq source code includes neuquant32, which is an extension of
    Anthony Dekker's neuquant, to make it handle 4 channels of pixel data.

Kornel's Preface:
    Major rewrite by Kornel Lesiński, adding double precision, dithering,
    better handling of alpha transparency and more. Thanks!

Saiki 9 Preface:
    Adrian's modifications to pngnq added a large number of new command line
    options and involved a 75% rewrite of neuquant32.c.  These changes are
    summarised in pngnq-s9.odt.

    Version 2.0.2 includes the following changes:
    - The -P option will retain the supplied palette colours in the ordinal
      positions in which they were provided, rather than reordering them to 
      save a little space.
    - A flaw in the handling of YUV colours with very high or low Y values
      has been rectified.
    - Removal of some unnecessary files / elements that complicate 
      portability.

REQUIREMENTS:
	Pngnq depends on the libpng and libz libraries.
	You will need libpng >=1.2.8 installed. 
	If you have this then you will have libz. 
    On windows you will require the libpng13.dll 
	which can be downloaded from several sites.

Copyright (c) Stuart Coyle 2004-2009 stuart.coyle@gmail.com
Copyright (c) Adrian Pellas-Rice and others.

Consult all sources for details of copyrights held on this program.
