js-imagediff

JavaScript / Canvas based imagediff utility.

API

• createCanvas() create a new Canvas element.
• createImageData(width, height) create a new ImageData object.
• isImage(object) tests for Image object.
• isCanvas(object) tests for Canvas object.
• isContext(object) tests for CanvasRenderingContext2D object.
• isImageData(object) tests for ImageData object.
• isImageType(object) tests for any of the above.
• toImageData(object) converts image type object to a new ImageData object.
• equal(a, b) tests image type objects for equality.
• diff(a, b) performs an image diff on a and b, returning a - b.
• noConflict() removes imagediff from the global space for compatibility, returning imagediff.

Unit Testing Canvas

JS ImageDiff opens up the easy testing of Canvas and other image-like objects in JavaScript. js-imagediff supplies two Jasmine matchers to make this easier.

• toImageDiffEqual() expect a result to equal another image type.
• toBeImageData() expect a result to be ImageData.

On failed tests, toImageDiffEqual() will display the expected image, the actual image and the imagediff of the two letting you easily spot mistakes.

To use matchers:

  beforeEach(function () {
    this.addMatchers(imagediff.jasmine);
  });

Demo

A demo is available at http://humblesoftware.github.com/js-imagediff/ A Jasmine test demo is available at A demo is available at http://humblesoftware.github.com/js-imagediff/test.html

Changelog

1.0.2

* Added optional width / height parameters to `createCanvas` for symmetry with `createImageData`. * Fixed issue with `toImageDiffEqual()` matcher and non Node types - will no convert ImageData and contexts to Canvas elements for display.

1.0.1

* Moved library to imagediff.js * Added Jasmine matchers * Minor bug fixes, lint fixes.

Author

Carl Sutherland carl@humblesoftware.com http://www.humblesoftware.com