grunt-jimp

Grunt wrapper for Jimp, the Javascript Image Manipulation Program

Jimp is a native javascript image manipulation library, and does not require ImageMagick or GraphicsMagick. All credit for Jimp goes to Oliver Moran, and the original library can be found here.

Getting Started

This plugin requires Grunt.

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

npm install grunt-jimp --save-dev

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:

grunt.loadNpmTasks('grunt-jimp');

The "jimp" task

Overview

In your project's Gruntfile, add a section named jimp to the data object passed into grunt.initConfig().

grunt.initConfig({
  jimp: {
    options: {
      // Task-specific options go here.
    },
    your_target: {
      // Target-specific file lists and/or options go here.
    },
  },
})

Options

options.suffix

Type: String Default value: ''

A value appended to the filename of the processed image. For example, providing a suffix of "jimp" will result in a filename "myimage.jimp.jpg".

options.actions

Type: Object Default value: {}

The Jimp actions to be run against the image. Each key in the object is an action, whilst the value is the argument to be passed in to that action.

• A true Boolean will run action without any arguments e.g. { sepia: true } will call image.sepia()
• An Integer or String will be passed directly in to the action e.g. { blur: 10 } will call image.blur(10)
• An Array will be passed in to the action as multiple parameters e.g. { crop: [0, 0, 200, 300] } will call image.crop(0, 0, 200, 300)

Usage Examples

grunt.initConfig({
  jimp: {
    options: {
      suffix: 'crop',
        actions: {
          blur: 30,
          scale: 0.5,
          greyscale: true,
          crop: [0, 0, 500, 300],
        }
    },
    files: [{
      expand: true,
      cwd: 'test/fixtures/',
      src: ['**/*.{jpg,jpeg,png,bmp}'],
      dest: 'tmp/'
    }],
  },
})

This will create a file called <filename>.crop.<ext> with the following properties:

• 30px blur
• 0.5 scale of source image
• Greyscale (black and white)
• A 500x300 crop taken from position 0, 0 (top left) of the source image

Further Usage

For further usage consult the Jimp documentation and usage examples.

Notes

This package does not support the following Jimp methods, as of initial release:

• blit
• composite
• mask

Basically if multiple Jimp images are required for the action, they are not currently possible in this Grunt task. I'm working on it!

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 and test your code using Grunt.

Release History

(Nothing yet)

License

Copyright (c) 2015 Max Barry. Licensed under the MIT license.