isabella232 / gif.js

JavaScript GIF encoding library

gif.js

JavaScript GIF encoder that runs in your browser.

Uses typed arrays and web workers to render each frame in the background, it's really fast!

Demo - http://jnordberg.github.io/gif.js/

Works in browsers supporting: Web Workers, File API and Typed Arrays

Usage

Include gif.js found in dist/ in your page. Also make sure to have gif.worker.js in the same location.

var gif = new GIF({
  workers: 2,
  quality: 10
});

// add an image element
gif.addFrame(imageElement);

// or a canvas element
gif.addFrame(canvasElement, {delay: 200});

// or copy the pixels from a canvas context
gif.addFrame(ctx, {copy: true});

gif.on('finished', function(blob) {
  window.open(URL.createObjectURL(blob));
});

gif.render();

Options

Options can be passed to the constructor or using the setOptions method.

Name	Default	Description
repeat	0	repeat count, -1 = no repeat, 0 = forever
quality	10	pixel sample interval, lower is better
workers	2	number of web workers to spawn
workerScript	gif.worker.js	url to load worker script from
background	#fff	background color where source image is transparent
width	null	output image width
height	null	output image height
transparent	null	transparent hex color, 0x00FF00 = green
dither	false	dithering method, e.g. FloydSteinberg-serpentine
debug	false	whether to print debug information to console

If width or height is null image size will be deteremined by first frame added.

Available dithering methods are:

• FloydSteinberg
• FalseFloydSteinberg
• Stucki
• Atkinson

You can add -serpentine to use serpentine scanning, e.g. Stucki-serpentine.

addFrame options

Name	Default	Description
delay	500	frame delay
copy	false	copy the pixel data
dispose	-1	frame disposal code. See GIF89a Spec

Acknowledgements

gif.js is based on:

• Kevin Weiner's Animated gif encoder classes
• Neural-Net color quantization algorithm by Anthony Dekker
• Thibault Imbert's as3gif

Dithering code contributed by @PAEz and @panrafal

License

The MIT License (MIT)

Copyright (c) 2013 Johan Nordberg

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.