GIF

Animated GIFs need a spec that, in particular, specifies how to handle timings (not all browsers honor all values, so we should specify what needs to be honored exactly)

Implementations

Gecko

• http://mxr.mozilla.org/mozilla-central/source/image/decoders/nsGIFDecoder2.h
• http://mxr.mozilla.org/mozilla-central/source/image/decoders/GIF2.h
• http://mxr.mozilla.org/mozilla-central/source/image/decoders/nsGIFDecoder2.cpp

WebKit

• http://trac.webkit.org/browser/trunk/Source/WebCore/platform/image-decoders/gif/GIFImageDecoder.h
• http://trac.webkit.org/browser/trunk/Source/WebCore/platform/image-decoders/gif/GIFImageReader.h
• http://trac.webkit.org/browser/trunk/Source/WebCore/platform/image-decoders/gif/GIFImageDecoder.cpp
• http://trac.webkit.org/browser/trunk/Source/WebCore/platform/image-decoders/gif/GIFImageReader.cpp
• http://trac.webkit.org/browser/trunk/Source/WebCore/platform/image-decoders/ImageDecoder.cpp

Blink

• https://chromium.googlesource.com/chromium/blink/+/master/Source/core/platform/image-decoders/gif/GIFImageDecoder.h
• https://chromium.googlesource.com/chromium/blink/+/master/Source/core/platform/image-decoders/gif/GIFImageReader.h
• https://chromium.googlesource.com/chromium/blink/+/master/Source/core/platform/image-decoders/gif/GIFImageDecoder.cpp
• https://chromium.googlesource.com/chromium/blink/+/master/Source/core/platform/image-decoders/gif/GIFImageReader.cpp
• https://chromium.googlesource.com/chromium/blink/+/master/Source/core/platform/image-decoders/ImageDecoder.cpp

Other

• http://sourceforge.net/p/giflib/code/ci/master/tree/ (giflib)
• https://github.com/jnordberg/gif.js (gif.js)
• https://github.com/deanm/omggif (omggif)
• https://github.com/avik-das/giferly (giferly)
• http://code.google.com/p/gifdotnet/source/browse/ (gifdotnet)

References

Specifications

• GIF87a: Text (Stanford) / Text (W3C)
• GIF89a: Text / HTML
• GIF Application Extensions:
  • NETSCAPE 2.0
    • GIF Application Extension: NETSCAPE2.0
    • Netscape Looping Application Extension
    • Netscape Buffering Application Extension
  • ANIMEXTS 1.0
    • AnimExts Looping Application Extension
  • ICCRGBG1 012
    • Specification ICC.1:2004-10 (Profile version 4.2.0.0) – Image technology colour management: Architecture, profile format, and data structure (section B.6)
  • XMP Data XMP
    • XMP Specification, Part 3: Storage in Files (section 2.1.2)
  • fractint
    • fractint encoder source code

Further details

• Wikipedia:Graphics Interchange Format
• GIF File Format
• What's in a GIF
• Gifology: Understanding GIF Files & GIF Animation
• All About GIF89a

Test images

• ImageTestSuite
  • Documentation
  • Images (Archive)
  • Images (SVN)