grunt-image-resize


> Resizing images made easy - thanks to ImageMagick.

Getting Started

This plugin requires Grunt ^0.4.5 and ImageMagick.

$3

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:

``shell
npm install grunt-image-resize --save-dev
`

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

`js
grunt.loadNpmTasks('grunt-image-resize');
`

$3


Make sure ImageMagick is installed on your system and properly set up in your PATH.

Ubuntu:

`shell
$ apt-get install imagemagick
`

Mac OS X (using Homebrew):

`shell
$ brew install imagemagick
`

Windows & others:

http://www.imagemagick.org/script/binary-releases.php

Confirm that ImageMagick is properly set up by executing convert -help in a terminal.

The "image_resize" task

$3


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

`js
grunt.initConfig({
image_resize: {
options: {
width: 100,
height: 100,
overwrite: true
},
your_target: {
// Target-specific file lists and/or options go here.
},
},
})
`

$3

#### options.width
Type: Number
Default value: 0 (only if height is defined)

A number value that is passed as pixel or percentage value to imagemagick.

#### options.height
Type: Number
Default value: 0 (only if width is defined)

A number value that is passed as pixel or percentage value to imagemagick.

#### options.overwrite
Type: Boolean
Default value: true

Determines whether file that already exist under this destination will be overwritten.

#### options.upscale
Type: Boolean
Default value: false

Determines whether images will be upscaled. If set to false (default), image will be copied instead of resized if it would be upscaled by resizing.

#### options.crop
Type: Boolean
Default value: false

Determines whether images will be cropped after resizing to exactly match options.width and options.height.

#### options.gravity
Type: String
Default value: Center
Possible values: NorthWest, North, NorthEast, West, Center, East, SouthWest, South, SouthEast

When cropping images this sets the image gravity. Doesn't have any effect, if options.crop is false.

#### options.concurrency
Type: Number
Default value: Number of CPUs

Determines how many resize operations are executed in parallel.

#### options.quality
Type: Number
Default value: 1

Determines the output quality of the resized image. Ranges from 0 (really bad) to 1 (almost lossless). Only applies to jpg images.

#### options.autoOrient
Type: Boolean
Default value: false

Determines if resized image will be rotated according to EXIF information. Only applies to jpg images.

$3

#### Default Options
In this example, the default options are used to resize an image to 100px width. So if the test/fixtures/wikipedia.png file has a width of 500px, the generated result would be a 100px wide tmp/wikipedia.png.

`js
grunt.initConfig({
image_resize: {
resize: {
options: {
width: 100
},
files: {
'tmp/wikipedia.png': 'test/fixtures/wikipedia.png'
}
}
}
})
`

#### Prevent overwriting
In this example, we prevent the destination file from being overwritten if it already exists. It the file tmp/wikipedia.png already exists, for example because we just ran the task configuration above, this would not overwrite tmp/wikipedia.png. The file tmp/wikipedia.png would still be 100px wide.

`js
grunt.initConfig({
image_resize: {
no_overwrite: {
options: {
width: 50,
overwrite: false
},
files: {
'tmp/wikipedia.png': 'test/fixtures/wikipedia.png'
}
}
}
})
`

#### Allow upscaling
By default, the task does not resize images which would be upscaled. It only allows downscaling. You can allow upscaling by setting the upscale option to true. Otherwise images will copied instead of resized when they would be upscaled by resizing.

`js
grunt.initConfig({
image_resize: {
no_overwrite: {
options: {
width: 600,
upscale: true
},
files: {
'tmp/wikipedia.png': 'test/fixtures/wikipedia.png'
}
}
}
})
`

#### Resize all the images in a directory

`js
grunt.initConfig({
image_resize: {
resize: {
options: {
width: 100,
},
src: 'src/*.JPG',
dest: 'dest/'
}
}
})
``

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.