gifencoder

gifencoder

Streaming server-side animated (and non-animated) gif generation for node.js

Installation

This module is installed via npm:

$ npm install gifencoder

Streaming API - Duplex Piping with Writes

You can also stream writes of pixel data (or canvas contexts) to the encoder:

const GIFEncoder = require('gifencoder');
const encoder = new GIFEncoder(854, 480);
const pngFileStream = require('png-file-stream');
const fs = require('fs');

const stream = pngFileStream('test/**/frame?.png')
  .pipe(encoder.createWriteStream({ repeat: -1, delay: 500, quality: 10 }))
  .pipe(fs.createWriteStream('myanimated.gif'));

stream.on('finish', function () {
  // Process generated GIF
});

// Alternately, you can wrap the "finish" event in a Promise
await new Promise((resolve, reject) => {
  stream.on('finish', resolve);
  stream.on('error', reject);
});

NB: The chunks that get emitted by your read stream must either by a 1-dimensional bitmap of RGBA data (either an array or Buffer), or a canvas 2D context.

Example: Streaming API - Reads

You can also use a streaming API to receive data:

const GIFEncoder = require('gifencoder');
const { createCanvas } = require('canvas');
const fs = require('fs');

const encoder = new GIFEncoder(320, 240);
// stream the results as they are available into myanimated.gif
encoder.createReadStream().pipe(fs.createWriteStream('myanimated.gif'));

encoder.start();
encoder.setRepeat(0);   // 0 for repeat, -1 for no-repeat
encoder.setDelay(500);  // frame delay in ms
encoder.setQuality(10); // image quality. 10 is default.

// use node-canvas
const canvas = createCanvas(320, 240);
const ctx = canvas.getContext('2d');

// red rectangle
ctx.fillStyle = '#ff0000';
ctx.fillRect(0, 0, 320, 240);
encoder.addFrame(ctx);

// green rectangle
ctx.fillStyle = '#00ff00';
ctx.fillRect(0, 0, 320, 240);
encoder.addFrame(ctx);

// blue rectangle
ctx.fillStyle = '#0000ff';
ctx.fillRect(0, 0, 320, 240);
encoder.addFrame(ctx);

encoder.finish();

The above code will generate the following animated GIF:

Contributing

gifencoder is an OPEN Open Source Project. This means that:

Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.

See the CONTRIBUTING.md file for more details.

Contributors

gifencoder is only possible due to the excellent work of the following contributors:

Kevin Weiner	[e-mail]
Thibault Imbert	http://www.bytearray.org/
Eugene Ware	GitHub/eugeneware
Raine Virta	GitHub/raine
Paul Ochoa	GitHub/rochoa
Heikki Pora	GitHub/heikkipora