1.4.0 • Public • Published

gmsmith Build status

GM engine for spritesmith.


gmsmith depends on gm which depends on GraphicsMagick.

I have found it is best to install from the site rather than through a package manager (e.g. apt-get) to get the latest as well as without transparency issues.

This module has been developed and tested against 1.3.17.

Alertnatively, you can use ImageMagick which is implicitly discovered if gm is not installed.

Getting Started

Install the module with: npm install gmsmith

// Load in our dependencies
var Gmsmith = require('gmsmith');

// Create a new engine
var gmsmith = new Gmsmith();

// Interpret some images from disk
gmsmith.createImages(['img1.jpg', 'img2.png'], function handleImages (err, imgs) {
  // If there was an error, throw it
  if (err) {
    throw err;

  // We recieve images in the same order they were given
  imgs[0].width; // 50 (pixels)
  imgs[0].height; // 100 (pixels)

  // Create a canvas that fits our images (200px wide, 300px tall)
  var canvas = gmsmith.createCanvas(200, 300);

  // Add the images to our canvas (at x=0, y=0 and x=50, y=100 respectively)
  canvas.addImage(imgs[0], 0, 0);
  canvas.addImage(imgs[1], 50, 100);

  // Export canvas to image
  var resultStream = canvas['export']({format: 'png'});
  resultStream; // Readable stream outputting PNG image of the canvas


This module was built to the specification for spritesmith engines.

Specification version: 2.0.0

new Engine(options)

This is also known as new Gmsmith.

Our Engine constructor provides support for the following options:

engine.createImages(images, cb)

Our createImages methods supports the following types of images:

  • image String - Filepath to image
  • image Object - Vinyl object with null for image (uses provided filepath)

We accept but don't fully support the following types of images:

  • image Object - Vinyl object with buffer for image (ignores contents, uses provided filepath)
  • image Object - Vinyl object with stream for image (ignores contents, uses provided filepath)


Our export method provides support for the following options:

  • options Object
    • format String - Output image format to callback with. Currently, png and jpeg are available.
    • quality Number - Quality of output image on a scale from 0 to 100


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


Support this project and others by twolfson via donations.


Copyright (c) 2013 Todd Wolfson

Licensed under the MIT license.

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