gif.h File Reference

Graphics Interchange Format codec. More...

#include "tinyimg/codec/codec.h"

Go to the source code of this file.

Variables
const TinyCodec	tiny_codec_gif
	The GIF codec.

Detailed Description

Graphics Interchange Format codec.

Author

Gregory Mitchell (me@gm.nosp@m.itch.nosp@m.215.x.nosp@m.yz)

Version

1.0.0

Date

2026-09-02

Copyright

Copyright (c) 2026

Variable Documentation

tiny_codec_gif

const TinyCodec tiny_codec_gif

extern

The GIF codec.

Decodes the first frame of either version, with a global or a local color table, interlaced or not, and honors the graphic control extension's transparent index. probe reports how many frames the file holds, so an animation is identifiable without decoding it; composing or re-timing frames is out of scope.

The canvas is the logical screen the file declares rather than the frame, which for a frame smaller than the screen or placed at an offset is what a viewer shows. A file with a transparent index decodes to four channels and one without to three.

Encoding writes a single frame with one global color table. An image already inside 256 colors keeps them exactly, so a logo or a flat illustration round trips without loss; anything wider goes through an octree quantizer with Floyd-Steinberg error diffusion, which is applied when and only when colors had to be discarded. A source with alpha spends one palette entry on a transparent index, since the format has no partial transparency to spend it on.

Note

LZW is decoded into a whole index plane rather than streamed a row at a time. The plane is one byte per pixel, an eighth of what the RGBA plane the other row-streaming codecs avoid would cost, and the format's codes cross row boundaries freely, so streaming would need a pull interface for what is already the cheapest buffer in the library.