gify-parse

A Node.JS module for parsing information on (animated) GIF files.

Notes

gify-parse is a fork of gify 1.0 by rfrench to simply provide a Node.JS module and command-line interface.

Installation

Install with the Node.JS package manager npm:

$ npm install gify-parse

or

Install via git clone:

$ git clone git://github.com/jonashavers/node-gify-parse.git
$ cd node-gify-parse
$ npm install
  

Usage

Usage inside your Node.JS modules:

```javascript
var fs = require('fs');
var gifyParse = require('gify-parse');

var buffer = fs.readFileSync('test.gif');
var gifInfo = gifyParse.getInfo(buffer);

console.log(gifInfo);
```

Usage of the CLI (command-line interface):

$ gifyParse <file> [option]

e.g.

$ gifyParse test.gif
$ gifyParse test.gif -p duration
$ gifyParse test.gif -p images.0.delay

The examples above parse the file test.gif and prints the GIF file's information to the console.

Requirements

gify-parse requires

• jDataView for reading binary files,
• commander.js for the CLI.

Methods

• isAnimated(sourceArrayBuffer) (bool)
• getInfo(sourceArrayBuffer) (gifInfo)

info Properties

• valid (bool) - Determines if the GIF is valid.
• animated (bool) - Determines if the GIF is animated.
• globalPalette (bool) - Determines if the GIF has a global color palette.
• globalPaletteSize (int) - Size of the global color palette.
• height (int) - Canvas height.
• width (int) - Canvas width.
• loopCount (int) - Total number of times the GIF will loop. 0 represents infitine.
• images ([images]) - Array of images contained in the GIF.
• isBrowserDuration (bool) - If any of the delay times are lower than the minimum value, this value will be set to true.
• duration (int) - Actual duration calculated from the delay time for each image. If isBrowserDuration is false, you should use this value.
• durationIE (int) - Duration for Internet Explorer (16fps)
• durationSafari (int) - Duration for Safari in milliseconds (16fps)
• durationFirefox (int) - Duration for Firefox in milliseconds (50fps)
• durationChrome (int) - Duration for Chrome in milliseconds (50fps)
• durationOpera (int) - Duration for Opera in milliseconds (50fps)

image Properties

• top (int) - Image top position (Y).
• left (int) - Image left position (X).
• height (int) - Image height.
• width (int) - Image width.
• localPalette (bool) - Image has a local color palette.
• localPaletteSize (int) - Size of the local color palette.
• interlace (bool) - Image is/is not interlaced.
• delay (int) - Delay time in milliseconds.
• disposal (int) - Disposal method. (0-7). See this for more details.

Example

{
  "valid": true,
  "globalPalette": true,
  "globalPaletteSize": 256,
  "loopCount": 0,
  "height": 1610,
  "width": 899,
  "animated": true,
  "images": [
    {
      "localPalette": false,
      "localPaletteSize": 0,
      "interlace": false,
      "left": 0,
      "top": 0,
      "width": 1610,
      "height": 899,
      "delay": 350,
      "disposal": 0
    },
    {
      "localPalette": true,
      "localPaletteSize": 256,
      "interlace": false,
      "left": 0,
      "top": 0,
      "width": 1610,
      "height": 899,
      "delay": 350,
      "disposal": 0
    },
    {
      "localPalette": true,
      "localPaletteSize": 256,
      "interlace": false,
      "left": 0,
      "top": 0,
      "width": 1610,
      "height": 899,
      "delay": 350,
      "disposal": 0
    }
  ],
  "isBrowserDuration": false,
  "duration": 2800,
  "durationIE": 2800,
  "durationSafari": 2800,
  "durationFirefox": 2800,
  "durationChrome": 2800,
  "durationOpera": 2800
}

Resources

• What's In A GIF - Bit by Byte - Hands down the best write up on GIFs I've found.
• GIF98 - GIF98 RFC.
• Animated GIF Frame Rate by Browser - An awesome breakdown of how each browser renders animated GIFs. Thanks to Jeremiah Johnson for doing the hard work.
• GIF Format - GIF blocks.
• Hexfiend - Awesome open source HEX editor (OSX)

License

Licence: MIT