third_party/WebKit/ManualTests/canvas-putImageData-flicker.html

   1 <!DOCTYPE html>
   2 <html>
   3 <body>
   4 This is a test should draw a fine filtered checkerboard pattern with no flickering. <br>
   5 This is a regression test for https://bugs.webkit.org/show_bug.cgi?id=64321. <br>
   6 <canvas id="c" width="300" height="300" style="width : 600px; height : 600px"></canvas>
   7 <script type="text/javascript">
   8 var canvas = document.getElementById('c');
   9 var ctx = canvas.getContext('2d');
  10
  11 for (var x = 0; x < canvas.width; x++) {
  12     for (var y = 0; y < canvas.height; y++) {
  13         ctx.fillStyle = ((x + y) % 2) ? 'black' : 'white';
  14         ctx.fillRect(x, y, 1, 1);
  15     }
  16 }
  17
  18 var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
  19
  20 function draw() {
  21     ctx.putImageData(imageData, 0, 0);
  22     window.setTimeout(draw, 0);
  23 }
  24
  25 draw();
  26 </script>
  27 </body>
  28 </html>