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Spritesmith

Utility that takes image files and generates spritesheets and coordinate maps.

Once you have satisfied the requirements, spritesmith can be installed via npm install spritesmith.

Spritesmith is also available as a grunt and gulp plugin.

var sprites = ['sprite1.png', 'sprite2.jpg', 'sprite3.png'];
spritesmith({'src': sprites}, function (err, result) {
  result.image; // Binary string representation of image
  result.coordinates; // Object mapping filename to {x, y, width, height} of image
  result.properties; // Object with metadata about spritesheet {width, height}
});

Installation

spritesmith can be installed via npm: npm install spritesmith

Each engine has system level depedencies. Visit the requirements section for more information.

During installation, you may see errors for other engines. These should be ignored unless npm crashes.

Documentation

Spritesmith is a standalone function

/**
 * Spritesmith generation function
 * @param {Object} params Parameters for spritesmith
 * @param {String[]} [params.src] Images to generate into sprite sheet
 * @param {String} [params.engine="auto"] Engine to use
      (phantomjs, canvas, gm, pngsmith or user-defined via Spritesmith.addEngine)
 * @param {String} [params.algorithm="top-down"] Algorithm to pack images with
 * @param {Number} [params.padding] Padding to use between images
 * @param {Mixed} [params.engineOpts] Options to pass through to engine for settings
 * @param {Mixed} [params.algorithmOpts] Options to pass through to algorithm for layout
 * @param {Mixed} [params.exportOpts] Options to pass through to engine for export
 * @param {Function} callback Function that receives compiled spritesheet and map
 * @returns {Mixed} callback[0] err If an error was encountered, this will be returned to callback
 * @returns {Object} callback[1] result Result object of spritesmith
 * @returns {String} callback[1].image Binary string representation of image
 * @returns {Object} callback[1].coordinates Map from file name to an object containing x, y, height, and width information about the source image
 * @returns {Object} callback[1].properties Properties about the spritesheet itself
 * @returns {Object} callback[1].properties.width Width of the spritesheet
 * @returns {Object} callback[1].properties.height Height of the spritesheet
 */

PhantomJS export options

For the phantomjs engine, the current output options are:

{
  'timeout': 10000 // Milliseconds to wait until terminating PhantomJS script
}

Canvas export options

For the canvas engine, the current output options are:

{
  'format': 'png' // Format to export the canvas to (png or jpeg)
}

gm export options

For the gm engine, the current output options are:

{
  'format': 'png', // Format to export the canvas to (png or jpeg)
  'quality': 75 // Quality of the output image
}

Available packing algorithms

The available packing algorithms are: top-down, left-right, diagonal (\ format), alt-diagonal (/ format), binary-tree (best packing possible).

algorithmOpts

All algorithms provide the current options:

{
  'sort': false // Stops sorting of images (default for all algorithms)
}

Adding new engines

Engine specifications can be found in spritesmith-engine-test.

New engines can be added via Spritesmith.addEngine(name, engine);.

Some existing engines are:

• canvassmith
• pngsmith
• phantomjssmith
• gmsmith

Adding new packing algorithms

Algorithms are maintained inside of twolfson/layout. Example algorithms can be found in twolfson/layout/lib/algorithms.

New algorithms can be added via Spritesmith.Layout.addAlgorithm(name, algorithm);.

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.

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
  }
}

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.

Donating

Support this project and others by twolfson via gittip.

License

Copyright (c) 2012 - 2013 Ensighten

Licensed under the MIT license.