testing/web-platform/tests/html/canvas/offscreen/drawing-images-to-the-canvas/2d.drawImage.alpha.html

   1 <!DOCTYPE html>
   2 <!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
   3 <title>OffscreenCanvas test: 2d.drawImage.alpha</title>
   4 <meta name="timeout" content="long">
   5 <script src="/resources/testharness.js"></script>
   6 <script src="/resources/testharnessreport.js"></script>
   7 <script src="/html/canvas/resources/canvas-tests.js"></script>
   8
   9 <h1>2d.drawImage.alpha</h1>
  10 <p class="desc"></p>
  11
  12
  13 <script>
  14 var t = async_test("");
  15 var t_pass = t.done.bind(t);
  16 var t_fail = t.step_func(function(reason) {
  17     throw reason;
  18 });
  19 t.step(function() {
  20
  21 var canvas = new OffscreenCanvas(100, 50);
  22 var ctx = canvas.getContext('2d');
  23
  24 ctx.fillStyle = '#0f0';
  25 ctx.fillRect(0, 0, 100, 50);
  26 ctx.globalAlpha = 0;
  27 var promise = new Promise(function(resolve, reject) {
  28     var xhr = new XMLHttpRequest();
  29     xhr.open("GET", '/images/red.png');
  30     xhr.responseType = 'blob';
  31     xhr.send();
  32     xhr.onload = function() {
  33         resolve(xhr.response);
  34     };
  35 });
  36 promise.then(function(response) {
  37     createImageBitmap(response).then(bitmap => {
  38         ctx.drawImage(bitmap, 0, 0);
  39         _assertPixelApprox(canvas, 50,25, 0,255,0,255, 2);
  40     }, t_fail);
  41 }).then(t_pass, t_fail);
  42
  43 });
  44 </script>