### pnmtopng-2.37.5 README file

    ** PNMTOPNG / PNGTOPNM
    ** version 2.37.5 - 24 October 2000

    [This is a semi-official bug-fix and enhancement release; I sort of took over
     maintenance of this package while Willem was on an extended bike trip, and
     for now I'm continuing with periodic, small updates.  Version 2.37 (March
     1998) was never publicly released, partly because Willem had hoped to quiet
     gcc's "<var> might be clobbered by `longjmp'" warnings.  Those are fixed in
     2.37.2; under Solaris, they resulted in stack corruption even when there was
     no error in the image files or libraries.  Version 2.37.3 fixes a minor bug
     w.r.t. error exits and generally does cleaner error exits (close files, etc.)
     Version 2.37.4 fixes a bug that caused 16-shade grayscale images to be written
     as 8-bit grayscale instead of (smaller) 4-bit colormapped images (bug report,
     analysis and fix by Rafal Rzeczkowski), and it supports the new/upcoming
     pbmplus release.  Version 2.37.5 fixes a bug in -transparent handling (pnmtopng
     no longer chooses an approximate color if the specified one isn't present) and
     quiets a gcc warning in the non-16-bit version.
     --Greg Roelofs]

    The utilities pnmtopng and pngtopnm are based on other pbm tools and require
    the libraries included in the pbmplus/netpbm package. Also required are the
    png library and the zlib compression library.

    These can be found at:
    	ftp://swrinde.nde.swri.edu/pub/png/src/libpng-*
    	ftp://swrinde.nde.swri.edu/pub/png/src/zlib-*
    	ftp://ftp.x.org/contrib/utilities/netpbm-1mar1994*
    or see
    	http://www.libpng.org/pub/png/apps/pnmtopng.html
    	http://netpbm.sourceforge.net/
    	http://www.acme.com/software/pbmplus/		[update coming soon?]

    To compile and install a makefile is provided. Do check the directories
    where you have put the required libraries. Then either accommodate the
    makefile or make links from generic names (e.g., zlib) to version-specific
    directories (e.g., zlib-1.1.3), which is the recommended way.

    For testing purposes, have a look at the test-set PngSuite.tar.gz, which
    contains a small test-image for every PNG color type and for most PNG chunk
    types. It can be found at:
    	http://www.schaik.com/pngsuite/pngsuite.html
    	ftp://swrinde.nde.swri.edu/pub/png/images/suite/

    Other web pages with PNG images are at:
    	http://www.libpng.org/pub/png/png-textures.html
    	http://www.libpng.org/pub/png/pngs-img.html
    	http://www.libpng.org/pub/png/pngpic2.html
    	http://www.libpng.org/pub/png/colorcube/
    	http://www.libpng.org/pub/png/pngmisc.html#images

    ------
    Alexander Lehmann <lehmann@usa.net>
    Willem van Schaik <willem@schaik.com>
    Greg Roelofs <newt@pobox.com>