Crate gif

GIF en- and decoding library

GIF en- and decoder written in Rust (API Documentation).

GIF encoding and decoding library

This library provides all functions necessary to de- and encode GIF files.

High level interface

The high level interface consists of the two types Encoder and Decoder. They as builders for the actual en- and decoders and can be used to set various options beforehand.

Decoding GIF files

// Open the file
use std::fs::File;
use gif::SetParameter;
let mut decoder = gif::Decoder::new(File::open("tests/samples/sample_1.gif").unwrap());
// Configure the decoder such that it will expand the image to RGBA.
decoder.set(gif::ColorOutput::RGBA);
// Read the file header
let mut decoder = decoder.read_info().unwrap();
while let Some(frame) = decoder.read_next_frame().unwrap() {
    // Process every frame
}

Encoding GIF files

The encoder can be used so save simple computer generated images:

use gif::{Frame, Encoder, Repeat, SetParameter};
use std::fs::File;
use std::borrow::Cow;
 
let color_map = &[0xFF, 0xFF, 0xFF, 0, 0, 0];
let (width, height) = (6, 6);
let mut beacon_states = [[
    0, 0, 0, 0, 0, 0,
    0, 1, 1, 0, 0, 0,
    0, 1, 1, 0, 0, 0,
    0, 0, 0, 1, 1, 0,
    0, 0, 0, 1, 1, 0,
    0, 0, 0, 0, 0, 0,
], [
    0, 0, 0, 0, 0, 0,
    0, 1, 1, 0, 0, 0,
    0, 1, 0, 0, 0, 0,
    0, 0, 0, 0, 1, 0,
    0, 0, 0, 1, 1, 0,
    0, 0, 0, 0, 0, 0,
]];
let mut image = File::create("tests/samples/beacon.gif").unwrap();;
let mut encoder = Encoder::new(&mut image, width, height, color_map).unwrap();
encoder.set(Repeat::Infinite).unwrap();
for state in &beacon_states {
    let mut frame = Frame::default();
    frame.width = width;
    frame.height = height;
    frame.buffer = Cow::Borrowed(&*state);
    encoder.write_frame(&frame).unwrap();
}

Frame::from_* can be used to convert a true color image to a paletted image with a maximum of 256 colors:

use std::fs::File;
 
// Get pixel data from some source
let mut pixels: Vec<u8> = vec![0; 30_000];
// Create frame from data
let frame = gif::Frame::from_rgb(100, 100, &mut *pixels);
// Create encoder
let mut image = File::create("target/indexed_color.gif").unwrap();
let mut encoder = gif::Encoder::new(&mut image, frame.width, frame.height, &[]).unwrap();
// Write frame to file
encoder.write_frame(&frame).unwrap();

C API

The C API is unstable and widely untested. It can be activated using the feature flag c_api.

Structs

Decoder	GIF decoder
Encoder	GIF encoder.
Frame	A GIF frame
MemoryLimit	Memory limit in bytes. MemoryLimit::Some(0) means that there is no memory limit set.
Reader	GIF decoder
StreamingDecoder	GIF decoder which supports streaming

Enums

Block	Known GIF block types
ColorOutput	Output mode for the image data
Decoded	Indicates whether a certain object has been decoded
DecodingError	Decoding error.
DisposalMethod	Disposal method
Extension	Known GIF extensions
ExtensionData	Extension data.
Extensions	Configures how extensions should be handled
Repeat	Number of repetitions

Traits

Parameter	Configuration parameter trait.
SetParameter	Implemented for objects that have parameters.