GIF - Graphics Interchange Format
[File Formats]
- Copyright (c) 1987,1988,1989,1990 CompuServe Incorporated.
GIF is a Service Mark property of CompuServe Incorporated.
Graphics Interchange Format Programming Reference, 1990.
LZW Copyright Unisys.
- Patial Internal Implementation.
Decoding and encoding code were extracted from GIFLib 1.0.
Copyright (c) 1989 Gershon Elber.
Data Types: Byte
Color Spaces: MAP only, (Gray and Binary saved as MAP)
Compressions:
LZW - Lempel-Ziv & Welch [default]
Can have more than one image.
No alpha channel.
Internally the lines are arranged from top down to bottom.
Attributes:
ScreenHeight, ScreenWidth IM_USHORT (1) screen size [default to the first image size]
Interlaced IM_INT (1 | 0) default 0
Description (string)
TransparencyIndex IM_BYTE (1)
XScreen, YScreen IM_USHORT (1) screen position
UserInput IM_BYTE (1) [1, 0]
Disposal (string) [UNDEF, LEAVE, RBACK, RPREV]
Delay IM_USHORT (1)
Iterations IM_USHORT (1) (NETSCAPE2.0 Application Extension)
Comments:
Attributes after the last image are ignored.
Reads GIF87 and GIF89, but writes GIF89 always.
Ignored attributes: Background Color Index, Pixel Aspect Ratio,
Plain Text Extensions, Application Extensions...