https://github.com/devongovett/gif-stream
A streaming GIF encoder and decoder
https://github.com/devongovett/gif-stream
Last synced: over 1 year ago
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A streaming GIF encoder and decoder
- Host: GitHub
- URL: https://github.com/devongovett/gif-stream
- Owner: devongovett
- Created: 2014-11-15T03:03:21.000Z (over 11 years ago)
- Default Branch: master
- Last Pushed: 2018-11-19T14:39:56.000Z (over 7 years ago)
- Last Synced: 2025-02-27T05:51:12.677Z (over 1 year ago)
- Language: JavaScript
- Size: 293 KB
- Stars: 53
- Watchers: 5
- Forks: 7
- Open Issues: 4
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Metadata Files:
- Readme: README.md
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README
# gif-stream
A streaming GIF encoder and decoder for Node and the browser
## Installation
npm install gif-stream
For the browser, you can build using [Browserify](http://browserify.org/).
## Decoding Example
This example uses the [concat-frames](https://github.com/devongovett/concat-frames)
module to collect the output of the GIF decoder into an array of frame objects.
```javascript
var GIFDecoder = require('gif-stream/decoder');
var concat = require('concat-frames');
// decode a GIF file to RGB pixels
fs.createReadStream('in.gif')
.pipe(new GIFDecoder)
.pipe(concat(function(frames) {
// frames is an array of frame objects
// each one has a `pixels` property containing
// the raw RGB pixel data for that frame, as
// well as the width, height, etc.
}));
```
## Encoding Example
You can encode a GIF by writing or piping indexed/quantized data to a `GIFEncoder` stream.
If you write data to it manually, you need to first quantize the pixel data to produce a
color palette and a buffer of indexed pixels. You can use the [neuquant](https://github.com/devongovett/neuquant)
module to do this.
Alternatively, if you have a stream of RGB data already, you can pipe it first to a neuquant
stream, and then to a GIF encoder, which will do the hard work of quantizing and writing
indexed data for you.
```javascript
var GIFEncoder = require('gif-stream/encoder');
var neuquant = require('neuquant');
// encode an animated GIF file by writing pixels to it.
// you need to manually quantize the data to produce a palette and indexed pixels.
var q = neuquant.quantize(pixels);
var enc = new GIFEncoder(width, height, { palette: q.palette });
enc.pipe(fs.createWriteStream('out.gif'));
// write indexed data
enc.end(q.indexed);
// or, pipe data from another RGB stream
// boom: streaming image transcoding!
fs.createReadStream('rgb.png')
.pipe(new PNGDecoder)
.pipe(new neuquant.Stream)
.pipe(new GIFEncoder)
.pipe(fs.createWriteStream('out.gif'));
// maybe you want to preserve the original palette and indexing?
// you can do that too!
fs.createReadStream('rgb.png')
.pipe(new GIFDecoder({indexed: true}))
.pipe(new GIFEncoder)
.pipe(fs.createWriteStream('out.gif'));
// somewhat useless example, but this may be useful for instance
// if you are breaking an animated GIF into multiple static GIFs
```
## License
MIT