src/tools/perf/page_sets/tough_canvas_cases/canvas2d_balls_common/bouncing_balls_draw_back_as_canvas.js

   1 // Copyright (c) 2012 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 var backImageCanvas;
   6
   7 function prepareBackground() {
   8   var backImage = document.getElementById('backImage');
   9   backImageCanvas = document.createElement('canvas');
  10   backImageCanvas.width = backImage.naturalWidth;
  11   backImageCanvas.height = backImage.naturalHeight;
  12   var backContext = backImageCanvas.getContext('2d');
  13   backContext.drawImage(backImage, 0, 0);
  14 }
  15
  16 function drawBackground() {
  17   canvasContext.drawImage(backImageCanvas, 0, 0, canvasWidth, canvasHeight);
  18 }