OS/2 PNG Version 0.1 Documentation
==================================

* INTRODUCTION

The file os2png01.zip contains libpng.dll and gif2png.exe.
gif2png is a program which converts GIF files to the new,
improved and free graphic format PNG (Portable Network Graphic).
libpng is a general-purpose library for working with PNG
files, and it is used by gif2png.

PNG was developed after Unisys decided to enforce their patent
on the LZW compression algorithm. As a result of this patent,
developers of software which uses GIF must pay royalties.
PNG ("ping") was developed to replace GIF without requiring the
payment of roytalties. PNG not only replaces GIF, but it also
fixes many of GIF's shortcomings and adds new features.


* libpng

libpng is a library designed to make the implementation of PNG
software easier. The source code and instructions for its use
are available at the PNG FTP site (see below).

libpng is Copyright (c) 1995 Guy Eric Schalnat, Group 42, Inc.


* gif2png

Refer to the file README for details of gif2png.


* PNG FTP and Web sites

The source code for libpng, gif2png, zlib and other stuff, along
with the PNG specification is available at the PNG FTP site:

ftp://ftp.uu.net/graphics/png

and also on the WWW:

http://sunsite.unc.edu/boutell/png.html


* REQUIREMENTS

This has only been tested under Warp, but it should work on any
version of OS/2 from 2.0 up.

You will also need os2zl093.zip which contains zlib.dll, the
compression library used by libpng. os2zl903.zip should be available
at the same places as os2png01.zip

Put zlib.dll and libpng.dll in a directory in your libpath and put
gif2png anywhere you want (probably in your path).


* MISCELANEOUS

I ported gif2png and libpng to OS/2 myself, so don't bug the authors
with OS/2 related questions. If you have any questions about this
distribution, please e-mail me. Note that I'm not an expert on PNG,
but I'll do my best to answer questions.

I hope to write a PNG viewer for PM soon and include it in the next
release.


Lachlan O'Dea
drizzt@yoyo.cc.monash.edu.au
http://yoyo.cc.monash.edu.au/~drizzt/index.html
Finger me or visit my web page for my public PGP key.

25 August 1995
