electron-screenshot-app

Make screenshots

Install

$ npm install electron-screenshot-app --save

Usage

var app = require('electron').app;
var screenshot = require('electron-screenshot-app');

  app.on('ready', function(){
    screenshot({
      url: 'http://sassdoc.com',
      width: 1920,
      height: 1080
    },
    function(err, image){
      // image.data is a Node Buffer
      // image.size contains width and height
      // image.devicePixelRatio will contain window.devicePixelRatio
    })
  });

API

screenshot(options, callback(err, img))

Takes a screenshots with options. The callback is called with an img object like

{
  data: <Buffer >
  size: {
    width: X
    height: N
  }
}

The screenshot is always saved as an png file.

options

url

Required Type: String

delay

Type: number (milliseconds)
Default: 0

Useful when the site does things after load that you want to capture.

width

Type: number Default: 0

Specify the with of the browser window

height

Type: number Default: 0

Specify the height of the browser window

crop

Type: Object
Default: undefined

A crop object may look like this:

{
  x : 10,
  y : 10,
  width : 100,
  height : 100
}

css

Type: String
Default: undefined

This css will be injected into the page before the screenshot is taken.

js

Type: String || Function
Default: undefined

This is either a String or a Function. If it is a String it must contain a function definition that takes on parameter e.g.

js: 'function(takeScreenshot){ /*Do some stuff*/ takeScreenshot();}'

or

js: 'takeScreenshot => { /*Do some stuff*/ takeScreenshot();}'

If it is a function you can just add it like:

js: function(takeScreenshot){ /*Do some stuff*/ takeScreenshot();}

or

js: (takeScreenshot) => { /*Do some stuff*/ takeScreenshot();}

transparent

Type: Boolean
Default: false

This will enable transparency. Keep in mind that most site do set a background color on the html/body tag. You can overwrite this by using the css option using something like html,body{ background-color: transparent !important;}.

page

Type: Boolean
Default: false

This will try to capture the whole page. width and height are considered the minimum size.

loadEvent

Type: String Default: undefined

The name of a custom page side event which can be used to trigger the page capture. This can be useful for client heavy javascript sites which take much longer to initialise than the time take to load the DOM. Such sites can send an event in the following manner.

    var evt = document.createEvent("Event");
    evt.initEvent("cust-loaded",true,true);
    document.dispatchEvent(evt);

format

Type: String Default: png

format to encode the image. only 'jpeg' or 'png' are supported

quality

Type: number Default: 80

If format is 'jpeg', defines the quality of the image '0-100'

Changelog

4.0.3

• Add missing loadevent back. Thanks nealshail

4.0.2

• Fixed a bug where the wrong function was passed to the javascript function. (#8)

4.0.1

• Update to electron@1.3.1

4.0.0

• Use view-painted Event instead of requestAnimationFrame hack.
• Update to electron@1.3.1

3.1.1

• Fix screenshot bug on windows. See here.

3.1.0

• Add support for specifying options.js to contain a JS function that will be executed.

3.0.2

• Fix a bug in correctly merging nodeIntegration: false.

3.0.1

• Improve page size detection.

3.0.0

• Upgrade to electron@1.1.0
• Change option name of loadevent to loadEvent
• Removed nodeIntegration. Use webPreferences.nodeIntegration instead.
• Removed secure. Use webPreferences.webSecurity instead

2.2.0

• Update to electron@0.36.7
• Add support for jpeg using the format option.
• Add a custom loadevent that can be send by the page.
• Make it possible to disable webSecurity via secure option.

Thanks to nealshail for these features.

2.1.0

• Update to electron@0.36.6
• Allow all options to be passed to electron

2.0.0

• Update to electron@0.36.5

1.1.2

• Improve workaround introduced in 1.1.1

1.1.1

• Add workaround for electron issue #2510 in electron >= 0.30.6 on a Mac

1.1.0

• Use new dom-ready event (>electron@0.31.1) to inject custom css into page before screenshot is taken.
• Expose cleanup to callback to ensure that the window is closed after data was processed.

1.0.0

• Inital release