the following free software products:
Perl by Larry Wall
- gd library by Thomas Boutell
- gifcode from David Koblas
+ libart by Raph Levien
+ freetype by David Turner, Robert Wilhelm, and Werner Lemberg
libpng by Glenn Randers-Pehrson / Andreas Eric Dilger / Guy Eric Schalnat
cgilib by Martin Schulze
zlib by Jean-loup Gailly and Mark Adler