grunt-screenshot-element

Take a screenshot of a DOM element.

Getting Started

This plugin requires Grunt ~0.4.1

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-screenshot-element --save-dev

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

grunt.loadNpmTasks('grunt-screenshot-element');

The "screenshot-element" task

Overview

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

grunt.initConfig({
  screenshot-element: {
    options: {
      // Task-specific options go here.
    },
    your_target: {
      // Target-specific options and images list go here.
    },
  },
})

Options

The options are by priority, from the less specific to the most precise, e.g: options < your_target.options < your_target.files[n].options

options.selector

Type: String Default value: 'svg

The selector of the element you want to screenshot (NB: The element is selected with document.querySelector which mean that only the first one will be selected.)

options.viewport

Type: Object Default value: { width: 1024, height: 768 }

An object with two keys, width and height, it will set the viewport of the page.

options.css

Type: String Default value: none

Add CSS to the page before taking a screenshot.

options.js

Type: String Default value: none

Add JavaScript to the page before taking a screenshot.

options.url

Type: String Default value: none

The URL of the page you want to screenshot.

options.file

Type: String Default value: ``

The output of the screenshot.

options.timeout

Type: Number Default value: 4

The number of milliseconds when after which the screenshot will be taken.

options.limit

Type: Number Default: Number of CPU cores (require('os').cpus().length) with a minimum of 2

Limit of how many PhantomJS instances to run concurrently.

options.paperSize

The contents parameter can be a string that will be evaluated, it's necessary if you want to use the phantom object.

options.settings

Images

images are set for each targets, they are an array of objects, you can re-specify options for each image.

Usage Examples

Default Options

This example will create a screenshot of the #hplogo on http://www.google.fr and will save it to images/google.png. The viewport of the browser will be of 1024 by 768.

grunt.initConfig({
    'screenshot-element': {
        options: {
            selector: '#main'
          , viewport: {
                width: 1024
              , height: 768
            }
        }
      , chart: {
            options: {
                selector: '.chart'
              , css: 'body { background: red; }'
              , js: '$("#button").click()'
            }
          , images: [
                {
                    url: 'http://www.google.fr'
                  , file: 'images/google.png'
                  , selector: '#hplogo'
                }
            ]
        }
    }
})

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style.

Release History

• 2014-04-11 v0.1.9 Added limit option
• 2013-12-05 v0.1.7 Add paperSize & settings options (the native one) & make images optional
• 2013-11-28 v0.1.6 Put lodash in dependencies
• 2013-11-25 v0.1.5 Debug viewport and remove grunt.util._
• 2013-10-28 v0.1.4 Added js option to add JavaScript to the page
• 2013-08-19 v0.1.3 Fixes selector option
• 2013-08-19 v0.1.2 Added timeout option
• 2013-08-19 v0.1.1 Fixes package.json
• 2013-07-26 v0.1.0 First release