PNG Source Code and Libraries

For those of you who like to go the do-it-yourself route, here are the tools to make your PNG code go (some of which are provided with ready-to-go executables, notably gif2png). If the primary SwRI ftp site is busy, try UUNET (central US), or HENSA (UK) instead. (This page was formerly called Code from the PNG Development Group. Much of the code was indeed written by members of the Group, but the collection below has evolved into something more general now.)

See also the application toolkits page for PNG-supporting libraries, DLLs and Java classes that do not include source code.

Latest releases:

libpng 1.0.3 [Y2K]
zlib 1.1.3 [Y2K]

Libraries:

libpng [Guy Eric Schalnat, Andreas Dilger, Glenn Randers-Pehrson and others] - the official PNG reference library, ANSI C source code (includes ansi2knr.c, though); requires zlib 1.0.4 or later.
- version 1.0.3, gzip'd tar format, 232899 bytes [also here]
- version 1.0.3, zipfile format, 265799 bytes [also here]
- Gilles Vollant's modified MMX-optimized interlace-handling and filtering routines - based on Intel's code (below) but updated for version 1.0.3 and MSVC++ 6.0.
- Intel's original MMX-optimized interlace-handling routines and compression-filter routines - C and assembler optimizations, including MMX, specifically for the Pentium II; may improve performance on other Intel chips (e.g., Pentium MMX and/or Pentium III); based on version 1.0.1 code.
- version 0.89c, gzip'd tar format, 118k (still required for a few old apps)
- version 0.89c, zipfile format, 131k
Unofficial pre-compiled binaries are also available:
- version 1.0.3, HP-UX static and dynamic libraries (includes links to zlib; mirror sites in Germany, France, Netherlands, Italy, Canada, US (WI and UT), South Africa, Japan)
- version 1.0.2, BeOS R3 and R4 binaries for PowerPC and Intel
- version 1.0.2, Macintosh CodeWarrior binaries for 68k, 380k (see here for info; includes project to build PowerPC binaries)
- version 1.0.2, Linux x86 binaries:
  - shared library, glibc2-based (Debian package format); 119k
  - static library and headers, glibc2-based (Debian package format); 143k
  - (check here if Debian links break)
- version 1.0.2, Linux Alpha binaries:
  - shared library, glibc2-based (Debian package format); 115k
  - static library and headers, glibc2-based (Debian package format); 154k
  - (check here if Debian links break)
- version 1.0.2, Linux SPARC binaries:
  - shared library, glibc2-based (Debian package format); 113k
  - static library and headers, glibc2-based (Debian package format); 142k
  - (check here if Debian links break)
- version 1.0.2, Linux 68k binaries:
  - shared library, glibc2-based (Debian package format); 106k
  - static library and headers, glibc2-based (Debian package format); 132k
  - (check here if Debian links break)
- version 1.0.2, Linux PowerPC binaries:
  - shared library, glibc2-based (Debian package format); 114k
  - static library and headers, glibc2-based (Debian package format); 150k
  - (check here if Debian links break)
- version 1.0.2, Linux StrongARM binaries:
  - shared library, glibc2-based (Debian package format); 111k
  - static library and headers, glibc2-based (Debian package format); 140k
  - (check here if Debian links break)
- version 1.0.1, Linux x86 binaries:
  - shared library, glibc2-based (Red Hat RPM format); 99k
  - static library and headers, glibc2-based (Red Hat RPM format); 110k
  - (check here if Red Hat links break)
- version 1.0.1, Linux SPARC binaries:
  - shared library, glibc2-based (Red Hat RPM format); 110k
  - static library and headers, glibc2-based (Red Hat RPM format); 112k
  - (check here if Red Hat links break)
- version 0.85, OS/2 static binaries, 160k (see also OS/2 gif2png port below)
zlib [Jean-loup Gailly and Mark Adler] - the official PNG compression library, K&R source code. (The link is a pointer to source code, technical info, documentation and binaries.)
Image Library [Colosseum Builders] - version of 1 May 1998 and later; read/write. (This is a library of freely available C++ sources for various image formats, including PNG.)
Java Image Content Handlers [ADI Limited / Justin Couch] - all versions; read-only; uses libpng, zlib, libjpeg and libtiff; freeware (LGPL). (This is reportedly a fast and efficient image library--it uses native libraries for decoding--with support for PNG, JPEG, TIFF, GIF, BMP, TGA and PBM/PGM/PPM. As supplied, it is designed for Java 2 [JDK 1.2], but source code is included, and it can be trivially modified to work with JDK 1.1. Write support will probably appear in a separate package.)
Sixlegs Java PNG [Six-Legged Software] (Java) - all versions; read-only; freeware (LGPL as of version 1.0). (This is Chris Nokleberg's Java 1.1 PNG package, including source code. Version 0.6 supported transparency, gamma correction, progressive display, grayscale conversion, etc. Version 0.7 added support for sRGB, iCCP, and private chunk-handling. Version 0.8 added support for oFFs, pCAL, sBIT, sCAL and sPLT. Version 0.9 reduced memory usage and added support for iTXt. Version 1.0[a] is the first version released with full source code under the LGPL and includes a workaround for a bug in IE4 and IE5. Write support is now planned for a separate package.)
PNGImageProducer [Jason Marshall] - version 0.88 (final public release) and earlier; requires java.util.zip (zlib 1.0.4) from JDK 1.1 or later; zipfile format; 55k. (In accordance with Jason's wishes, this package has been pulled, at least for now.)
Pnglets [Roger E. Critchlow, Jr.] - all versions; write-only; freeware (GPL). (This is a PNG drawing library written in JavaScript [not Java!]; it can be used to create client-side line drawings on the fly. Pnglets was inspired by and is partly based on algorithms in the gd library [which was never updated for PNG support], but the package draws from other sources as well.)
there is not much available in the way of free Pascal source code, but Oliver Fromme's dumping4 included source code for reading PNGs, and Derek Benner's book includes source code that purports to read and write PNGs (see the 23 September 1997 entry on the PNG News page for opposing viewpoints and less-than-favorable user feedback, however)

Converters:

pnmtopng-2.37.2.tar.gz [Alexander Lehmann, Willem van Schaik] - the official NetPBM PNG converters (pnmtopng, pngtopnm), C source code, version 2.37.2; requires netpbm libraries, libpng and zlib; 28k. (For the sake of search commands, we'll mention pngtoppm and ppmtopng here, too. Version 2.37.2 is Greg's second semi-official release.)
pnmtopng, `pamquant' with alpha-channel support [Greg Roelofs] - unofficial NetPBM extensions to support a piped alpha channel; in particular, a full 32-bit RGBA PNG can be quantized to an 8-bit RGBA-palette PNG
pngstuff-linux-x86-libc5.tgz - unofficial Linux x86 executables for pnmtopng package; provided by Dave Flater; 107k. (Also includes gif2png.)
gif2png-0.6.zip [Alexander Lehmann] - the official GIF-to-PNG converter, C source code, version 0.6 (very stable!); requires libpng and zlib; 22k
gif2pngx-0.6a.zip - the official GIF-to-PNG converter, DOS executables; 137k
gif2png-0.6.lha - unofficial Amiga executables for GIF-to-PNG converter; 403k. (Click here if link breaks.)
pngstuff-linux-x86-libc5.tgz - unofficial Linux x86 executables for GIF-to-PNG converter; provided by Dave Flater; 107k. (Also includes pnmtopng converters.)
g2p_os2.zip - unofficial OS/2 executables for GIF-to-PNG converter, version 0.5; ported by Network Cybernetics Corporation (includes static libpng and zlib libraries)
pngUtilAppls.sit.hqx - unofficial Macintosh executables for GIF-to-PNG converter; ported by Mark Fleming; 296k. (Also includes ptot, pngcheck and libpng's minimal pngtest; sources available as well [831k].)
see also The Exorcist on the converters page (Windows 9x/NT graphical port with drag and drop support)
tiff2png-0.6.tar.gz [Willem van Schaik] - the semi-official TIFF-to-PNG converter, C source code; requires libtiff, libpng and zlib; 130k (README for version 0.6)
ptot.tar.gz [Lee Daniel Crocker] - the semi-official PNG-to-TIFF converter, C source code; stand-alone (does not require any other libraries); 32k. (See pngUtilAppls.sit.hqx in gif2png section above for Macintosh version.)
pngmeta-1.6.tar.gz [Dave Beckett] - the official PNG meta-information extractor, ANSI C source code, version 1.6; requires libpng 0.85 and zlib 0.95 or later; 8k. (This ``converts'' from PNG to text; that is, it extracts information from the tEXt and zTXt chunks--e.g., for indexing by WWW search engines.)

Testers:

pngcheck-zlib.zip [Alexander Lehmann, Andreas Dilger, Greg Roelofs and others] - the official PNG integrity tester, C source code, with semi-official zlib and MNG extensions (version 1.99-grr0); stand-alone (requires neither libraries nor graphics capability, although can be linked with zlib for enhanced functionality); 21k.
pngcheck-linux-libc5.zip - official Linux x86 (libc5) executables for PNG tester, version 1.99-grr0; 28k.
pngcheck-win32.zip - official Windows 9x/NT executables for PNG tester, version 1.99-grr0; statically linked; 58k.
pngcheck-win32-dyn.zip - official Windows 9x/NT executables for PNG tester, version 1.99-grr0; dynamically linked (includes zlib.dll, version 1.1.3); 74k.
pngcheck-1.97.lha - unofficial Amiga executables for PNG tester; 24K. (Click here if link breaks.)
(See pngUtilAppls.sit.hqx in gif2png section above for Macintosh version.)

Here are the other PNG-related pages at this site:

Last modified 1 May 1999 by newt@pobox.com , you betcha.