1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 /** 6 * Function to take the screenshot of the current screen. 7 * @param {function(HTMLCanvasElement)} callback Callback for returning the 8 * canvas with the screenshot on it. 9 */ 10 function takeScreenshot(callback) { 11 var screenshotStream = null; 12 var video = document.createElement('video'); 13 14 video.addEventListener('canplay', function(e) { 15 if (screenshotStream) { 16 var canvas = document.createElement('canvas'); 17 canvas.setAttribute('width', video.videoWidth); 18 canvas.setAttribute('height', video.videoHeight); 19 canvas.getContext('2d').drawImage( 20 video, 0, 0, video.videoWidth, video.videoHeight); 21 22 video.pause(); 23 video.src = ''; 24 25 screenshotStream.stop(); 26 screenshotStream = null; 27 28 callback(canvas); 29 } 30 }, false); 31 32 navigator.webkitGetUserMedia( 33 { 34 video: { 35 mandatory: { 36 chromeMediaSource: 'screen', 37 maxWidth: 4096, 38 maxHeight: 2560 39 } 40 } 41 }, 42 function(stream) { 43 if (stream) { 44 screenshotStream = stream; 45 video.src = window.URL.createObjectURL(screenshotStream); 46 video.play(); 47 } 48 }, 49 function(err) { 50 console.error('takeScreenshot failed: ' + 51 err.name + '; ' + err.message + '; ' + err.constraintName); 52 } 53 ); 54 } 55
