grunt-spritesmith

Grunt task for converting a set of images into a spritesheet and corresponding CSS variables.

npm install grunt-spritesmith
165 downloads in the last day
41 271 downloads in the last week
76 728 downloads in the last month

grunt-spritesmith Build status

Grunt task for converting a set of images into a spritesheet and corresponding CSS variables.

A folder of icons processed by grunt-spritesmith:

Fork icon + GitHub icon + Twitter icon =

generates a spritesheet:

Spritesheet

and CSS variables (available in CSS, JSON, SASS, SCSS, LESS, Stylus):

$fork_offset_x = 0px;
$fork_offset_y = 0px;
$fork_width = 32px;
$fork_height = 32px;
...
$github_offset_x = -32px;
$github_offset_y = 0px;
$github_width = 32px;
$github_height = 32px;
...

Cross-platform support

grunt-spritesmith is supported and tested on Windows, Linux, and Mac OSX.

Getting Started

grunt-spritesmith can be installed via npm: npm install grunt-spritesmith

If you would like to use an engine with external dependencies, verify you have satisfied its requirements.

Then, add and configure it to your grunt file (grunt.js or Gruntfile.js depending on your version):

module.exports = function (grunt) {
  // Configure grunt
  grunt.initConfig({
    sprite:{
      all: {
        src: 'path/to/your/sprites/*.png',
        destImg: 'destination/of/spritesheet.png',
        destCSS: 'destination/of/sprites.css'
      }
    }
  });

  // Load in `grunt-spritesmith`
  grunt.loadNpmTasks('grunt-spritesmith');

Run the grunt sprite task:

$ grunt sprite
Running "sprite:all" (sprite) task
Files "spritesheet.png", "sprites.styl" created.

Done, without errors.

Results are a spritesheet and CSS:

Spritesheet

.icon-fork {
  background-image: url(spritesheet.png);
  background-position: 0px 0px;
  width: 32px;
  height: 32px;
}
...

Usage

grunt-spritesmith is a grunt multitask. It is configured on a per-task basis using the following template:

grunt.initConfig({
  'sprite': {
    'all': {
      // Sprite files to read in
      'src': ['public/images/sprites/*.png'],

      // Location to output spritesheet
      'destImg': 'public/images/sprite.png',

      // Stylus with variables under sprite names
      'destCSS': 'public/css/sprite_positions.styl',

      // OPTIONAL: Manual override for imgPath specified in CSS
      'imgPath': '../sprite.png',

      // OPTIONAL: Specify algorithm (top-down, left-right, diagonal [\ format],
          // alt-diagonal [/ format], binary-tree [best packing])
      // Visual representations can be found below
      'algorithm': 'alt-diagonal',

      // OPTIONAL: Specify padding between images
      'padding': 2,

      // OPTIONAL: Specify engine (auto, phantomjs, canvas, gm, pngsmith)
      'engine': 'canvas',

      // OPTIONAL: Specify CSS format (inferred from destCSS' extension by default)
          // (stylus, scss, scss_maps, sass, less, json, json_array, css)
      'cssFormat': 'json',

      // OPTIONAL: Specify a function or Mustache template to use for rendering destCSS
          // Mutually exclusive to cssFormat
      // More information can be found below
      'cssTemplate': 'public/css/sprite_positions.styl.mustache',

      // OPTIONAL: Map variable of each sprite
      'cssVarMap': function (sprite) {
        // `sprite` has `name`, `image` (full path), `x`, `y`
        //   `width`, `height`, `total_width`, `total_height`
        // EXAMPLE: Prefix all sprite names with 'sprite-'
        sprite.name = 'sprite-' + sprite.name;
      },

      // OPTIONAL: Specify settings for algorithm
      'algorithmOpts': {
        // Skip sorting of images for algorithm (useful for sprite animations)
        'sort': false
      },

      // OPTIONAL: Specify settings for engine
      'engineOpts': {
        'imagemagick': true
      },

      // OPTIONAL: Specify img options
      'imgOpts': {
         // Format of the image (inferred from destImg' extension by default) (jpg, png)
         'format': 'png',

         // gm only: Quality of image
         'quality': 90,

         // phantomjs only: Milliseconds to wait before terminating PhantomJS script
         'timeout': 10000
      },

      // OPTIONAL: Specify css options
      'cssOpts': {
        // Some templates allow for skipping of function declarations
        'functions': false,

        // CSS template allows for overriding of CSS selectors
        'cssClass': function (item) {
          return '.sprite-' + item.name;
        }
      }
    }
  }
});

Algorithms

top-down (default) left-right diagonal alt-diagonal binary-tree
top-down left-right diagonal alt-diagonal binary-tree

For best packing, use binary-tree which uses a solution to the rectangle packing problem.

If you are worried about sprites being visible within other sprites, use alt-diagonal.

If you are using a repeating background, top-down or left-right depending on your occasion.

The diagonal algorithm exists for you if you need it.

cssTemplate

The cssTemplate option allows for specification of a custom templating function or Mustache template to render your CSS.

If you pass in a Function, it should have a signature of function (params) {} and return a String.

If you pass in a String, we treat this as a path; reading in the file and rendering it via mustache.js. The template will be passed the same params as in the Function case.

An example template is https://github.com/twolfson/json2css/blob/4.2.0/lib/templates/stylus.template.mustache

params

params is an object with some normalization nicities from json2css, our default collection of templates.

  • params Object
    • items Object[] - Array of sprite information
      • name String - Name of the sprite file (sans extension)
      • x Number - Horizontal position of sprite's left edge in spritesheet
      • y Number - Vertical position of sprite's top edge in spritesheet
      • width Number - Width of sprite
      • height Number - Height of sprite
      • total_width Number - Width of entire spritesheet
      • total_height Number - Height of entire spritesheet
      • image String - Relative URL path from CSS to spritesheet
      • escaped_image String - URL encoded image
      • source_image String - Path to the original sprite file
      • offset_x Number - Negative value of x. Useful to background-position
      • offset_y Number - Negative value of y. Useful to background-position
      • px Object - Container for numeric values including px
        • x String - x suffixed with px
        • y String - y suffixed with px
        • width String - width suffixed with px
        • height String - height suffixed with px
        • total_width String - total_width suffixed with px
        • total_height String - total_height suffixed with px
        • offset_x String - offset_x suffixed with px
        • offset_y String - offset_y suffixed with px
    • options Object - Options passed in via cssOpts in grunt-spritesmith config

An example sprite item is

{
  "name": "sprite2",
  "x": 10,
  "y": 20,
  "width": 20,
  "height": 30,
  "total_width": 80,
  "total_height": 100,
  "image": "nested/dir/spritesheet.png",
  "escaped_image": "nested/dir/spritesheet.png",
  "source_image": "path/to/original/sprite.png",
  "offset_x": -10,
  "offset_y": -20,
  "px": {
    "x": "10px",
    "y": "20px",
    "width": "20px",
    "height": "30px",
    "total_width": "80px",
    "total_height": "100px",
    "offset_x": "-10px",
    "offset_y": "-20px"
  }
}

Requirements

For cross-platform accessibility, spritesmith has and supports multiple sprite engines. However, each of these current engines has a different set of external dependencies.

If you are running into issues, consult the FAQ section.

pngsmith

The pngsmith engine uses pngparse, an JavaScript png parser, to interpret images into ndarrays. This requires no additional steps before installation.

Key differences: It requires no additional installation steps but you are limited to .png files for your source files.

phantomjs

The phantomjs engine relies on having phantomjs installed on your machine. Visit the phantomjs website for installation instructions.

Key differences: phantomjs is the easiest engine to install that supports all image formats.

spritesmith has been tested against phantomjs@1.9.0.

canvas

The canvas engine uses node-canvas which has a dependency on Cairo.

Key differences: canvas has the best performance (useful for over 100 sprites). However, it is UNIX only.

Instructions on how to install Cairo are provided in the node-canvas wiki.

Additionally, you will need to install node-gyp for the C++ bindings.

sudo npm install -g node-gyp

gm (Graphics Magick / Image Magick)

The gm engine depends on Graphics Magick or Image Magick.

Key differences: gm has the most options for export via imgOpts.

For the best results, install from the site rather than through a package manager (e.g. apt-get). This avoids potential transparency issues which have been reported.

spritesmith has been developed and tested against 1.3.17.

Image Magick is implicitly discovered. However, you can explicitly use it via engineOpts

{
  'engineOpts': {
    'imagemagick': true
  }
}

FAQs

I am seeing errors during installation.

If npm exits normally, everything should work. These errors are being caused by npm attempting to install the various spritesmith engines.

spritesmith is saying my engine "could not be loaded"

If you have specified an engine in your config, then you must satisfy its requirements before installing grunt-spritesmith.

To remedy this, verify you have installed the appropriate set of requirements for your engine:

https://github.com/Ensighten/grunt-spritesmith#requirements

Afterwards, re-install grunt-spritesmith so it detects the satisfied requirements for your engine.

npm install grunt-spritesmith

spritesmith is saying "no spritesmith engine could be loaded for your machine"

If you are running grunt-spritesmith before 1.21.0, then you have not satisfied any of the requirements for any of the engines before installing grunt-spritesmith. If you are running 1.21.0 or greater, then there is a bug and please open a new issue.

The current version of grunt-spritesmith can be determined via npm ls grunt-spritesmith.

To remedy the issue before 1.21.0, choose an engine and verify you have installed the appropriate set of requirements:

https://github.com/Ensighten/grunt-spritesmith#requirements

Afterwards, re-install grunt-spritesmith so it detects the satisfied requirements for your engine.

npm install grunt-spritesmith

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint via grunt and test via npm test.

Algorithms

Algorithms are maintained via twolfson/layout. If you would like to add one, please submit it via a pull request.

Engines and image options

Engines and image options are maintained via Ensighten/spritesmith. If you would like to add one, please submit it via a pull request.

CSS formats

CSS formats are maintained via twolfson/json2css. If you would like to add one, please submit it via a pull request.

Attribution

GitHub and Twitter icons were taken from Alex Peattie's JustVector Social Icons.

Fork designed by P.J. Onori from The Noun Project

Plus and Equals icons were built using the Ubuntu Light typeface.

Donating

Support this project and others by twolfson via gittip.

Support via Gittip

License

Copyright (c) 2012-2013 Ensighten

Licensed under the MIT license.

npm loves you