The GIF decoder and encoder used by Gif Animator support the following aspects of the GIF specification:

FeatureSupported?
Animation Width / HeightYes
Background ColorYes
Pixel Aspect RatioNo 1
Global Color TableYes
Local Color TableYes
Color Table SortingNo
Application ExtensionsNo 2
User Input FlagNo
Frame ImagesYes
Frame PositionsYes
Frame DurationsYes
Frame Undraw MethodsYes
Frame TransparencyYes
LZW Compressed Image DataYes
Uncompressed Image DataYes
Interlaced GraphicsYes3
Comment ExtensionsYes 4
Plain Text Extension (ASCII art)No

Unless otherwise specified, if the decoder or encoder does not support, or fully support, a given feature it will be ignored and processing of the remainder of the GIF file will continue as expected.

Notes

  1. The pixel aspect ratio is both read from and written to a GIF file, so if frames in an existing animation contains a custom value, this will be preserved. The Gif Animator itself makes no direct use of the value if set however and provides no scope for setting this manually.
  2. Both the encoder and decoder recognize the NETSCAPE2.0 and ANIMEXTS1.0 extensions for specifying how the animation should loop. The decoder will ignore any unrecognized extension blocks, this information will then be lost if the animation is subsequently saved.
  3. While GIF files using interlacing can be opened, any files saved using Gif Animator will not be interlaced
  4. Comments which precede a frame will be associated with that particular frame. Comments which appear after all frames are associated with the animation.