electron/docs/api/desktop-capturer.md

desktopCapturer

The desktopCapturer module can be used to get available sources that can be used to be captured with getUserMedia.

// In the renderer process.
var desktopCapturer = require('electron').desktopCapturer;

desktopCapturer.getSources({types: ['window', 'screen']}, function(error, sources) {
  if (error) throw error;
  for (var i = 0; i < sources.length; ++i) {
    if (sources[i].name == "Electron") {
      navigator.webkitGetUserMedia({
        audio: false,
        video: {
          mandatory: {
            chromeMediaSource: 'desktop',
            chromeMediaSourceId: sources[i].id,
            minWidth: 1280,
            maxWidth: 1280,
            minHeight: 720,
            maxHeight: 720
          }
        }
      }, gotStream, getUserMediaError);
      return;
    }
  }
});

function gotStream(stream) {
  document.querySelector('video').src = URL.createObjectURL(stream);
}

function getUserMediaError(e) {
  console.log('getUserMediaError');
}

Methods

The desktopCapturer module has the following methods:

desktopCapturer.getSources(options, callback)

• options Object
  • types Array - An array of String that lists the types of desktop sources to be captured, available types are screen and window.
  • thumbnailSize Object (optional) - The suggested size that thumbnail should be scaled, it is {width: 150, height: 150} by default.
• callback Function

Starts a request to get all desktop sources, callback will be called with callback(error, sources) when the request is completed.

The sources is an array of Source objects, each Source represents a captured screen or individual window, and has following properties:

• id String - The id of the captured window or screen used in navigator.webkitGetUserMedia. The format looks like window:XX or screen:XX where XX is a random generated number.
• name String - The described name of the capturing screen or window. If the source is a screen, the name will be Entire Screen or Screen <index>; if it is a window, the name will be the window's title.
• thumbnail NativeImage - A thumbnail image.

Note: There is no guarantee that the size of source.thumbnail is always the same as the thumnbailSize in options. It also depends on the scale of the screen or window.