gify-parse

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

Notes

gify-parse is just a fork of gify by rfrench that is intended to encapsulate the logic into a Node.js module and to provide a command-line interface.

Installation

Install via npm registry:

$ 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:

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 print out the GIF file's information on 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.
• globalPaletteColorsRGB ([r,g,b]) - An array of objects containing the R, G, B values of the color palette. (Beppe)
• 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,
  globalPaletteColorsRGB: 
   [ { r: 142, g: 44, b: 14 },
     { r: 109, g: 32, b: 15 },
     { r: 143, g: 37, b: 16 },
     { r: 150, g: 53, b: 17 },
     { r: 56, g: 21, b: 1 },
     { r: 136, g: 41, b: 14 },
     { r: 59, g: 14, b: 0 },
     { r: 140, g: 42, b: 10 },
     { r: 120, g: 68, b: 37 },
     { r: 120, g: 56, b: 36 },
     { r: 102, g: 51, b: 21 },
     { r: 103, g: 54, b: 35 },
     { r: 121, g: 100, b: 75 },
     { r: 154, g: 115, b: 87 },
     { r: 86, g: 51, b: 21 },
     { r: 69, g: 20, b: 3 },
     { r: 177, g: 139, b: 145 },
     { r: 119, g: 72, b: 50 },
     { r: 102, g: 69, b: 39 },
     { r: 86, g: 38, b: 19 },
     { r: 137, g: 99, b: 72 },
     { r: 206, g: 77, b: 80 },
     { r: 165, g: 115, b: 87 },
     { r: 172, g: 52, b: 42 },
     { r: 121, g: 84, b: 55 },
     { r: 220, g: 138, b: 103 },
     { r: 86, g: 36, b: 5 },
     { r: 54, g: 18, b: 1 },
     { r: 135, g: 89, b: 68 },
     { r: 119, g: 88, b: 68 },
     { r: 135, g: 69, b: 52 },
     { r: 157, g: 120, b: 140 },
     { r: 72, g: 36, b: 19 },
     { r: 71, g: 35, b: 5 },
     { r: 102, g: 39, b: 19 },
     { r: 137, g: 104, b: 83 },
     { r: 209, g: 110, b: 77 },
     { r: 151, g: 106, b: 84 },
     { r: 135, g: 54, b: 37 },
     { r: 211, g: 181, b: 210 },
     { r: 174, g: 133, b: 114 },
     { r: 104, g: 71, b: 51 },
     { r: 101, g: 36, b: 5 },
     { r: 107, g: 21, b: 4 },
     { r: 210, g: 107, b: 109 },
     { r: 168, g: 71, b: 52 },
     { r: 254, g: 245, b: 254 },
     { r: 85, g: 36, b: 35 },
     { r: 155, g: 119, b: 100 },
     { r: 86, g: 22, b: 2 },
     { r: 206, g: 82, b: 54 },
     { r: 135, g: 68, b: 36 },
     { r: 182, g: 150, b: 167 },
     { r: 209, g: 85, b: 104 },
     { r: 88, g: 53, b: 35 },
     { r: 134, g: 86, b: 55 },
     { r: 175, g: 103, b: 49 },
     { r: 207, g: 171, b: 182 },
     { r: 229, g: 110, b: 136 },
     { r: 152, g: 104, b: 72 },
     { r: 71, g: 22, b: 18 },
     { r: 153, g: 69, b: 52 },
     { r: 136, g: 53, b: 21 },
     { r: 152, g: 54, b: 37 },
     { r: 204, g: 145, b: 138 },
     { r: 119, g: 38, b: 19 },
     { r: 115, g: 49, b: 7 },
     { r: 242, g: 216, b: 243 },
     { r: 152, g: 69, b: 35 },
     { r: 109, g: 53, b: 72 },
     { r: 118, g: 37, b: 6 },
     { r: 169, g: 56, b: 65 },
     { r: 107, g: 90, b: 67 },
     { r: 136, g: 37, b: 19 },
     { r: 53, g: 7, b: 0 },
     { r: 239, g: 103, b: 113 },
     { r: 103, g: 53, b: 52 },
     { r: 170, g: 46, b: 22 },
     { r: 56, g: 34, b: 6 },
     { r: 182, g: 86, b: 103 },
     { r: 152, g: 52, b: 21 },
     { r: 137, g: 104, b: 102 },
     { r: 152, g: 86, b: 70 },
     { r: 152, g: 119, b: 119 },
     { r: 184, g: 161, b: 208 },
     { r: 170, g: 85, b: 69 },
     { r: 152, g: 100, b: 44 },
     { r: 102, g: 50, b: 6 },
     { r: 151, g: 38, b: 21 },
     { r: 118, g: 55, b: 53 },
     { r: 244, g: 178, b: 139 },
     { r: 152, g: 85, b: 53 },
     { r: 254, g: 206, b: 168 },
     { r: 120, g: 87, b: 85 },
     { r: 139, g: 82, b: 109 },
     { r: 152, g: 86, b: 35 },
     { r: 151, g: 105, b: 102 },
     { r: 233, g: 107, b: 81 },
     { r: 73, g: 50, b: 19 },
     { r: 101, g: 39, b: 36 },
     ... 156 more items ],
  loopCount: 0,
  height: 400,
  width: 720,
  animated: true,
  images: 
   [ { identifier: '0',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '1',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '2',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '3',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '4',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '5',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '6',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '7',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '8',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '9',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '10',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '11',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '12',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '13',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '14',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '15',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '16',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '17',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '18',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '19',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '20',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '21',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '22',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '23',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 },
     { identifier: '24',
       localPalette: false,
       localPaletteSize: 0,
       interlace: false,
       comments: [],
       text: '',
       left: 0,
       top: 0,
       width: 720,
       height: 400,
       delay: 40,
       disposal: 1 } ],
  isBrowserDuration: true,
  duration: 1000,
  durationIE: 2500,
  durationSafari: 1000,
  durationFirefox: 1000,
  durationChrome: 1000,
  durationOpera: 1000 }

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