content/canvas/test/test_2d.clearRect.globalalpha.html

   1 <!DOCTYPE HTML>
   2 <title>Canvas test: 2d.clearRect.globalalpha</title>
   3 <script src="/MochiKit/MochiKit.js"></script>
   4 <script src="/tests/SimpleTest/SimpleTest.js"></script>
   5 <link rel="stylesheet" href="/tests/SimpleTest/test.css">
   6 <body>
   7 <canvas id="c" width="100" height="50" style="background: #0f0"><p class="fallback">FAIL (fallback content)</p></canvas>
   8 <script>
   9 function isPixel(ctx, x,y, r,g,b,a, pos, colour, d) {
  10     var pixel = ctx.getImageData(x, y, 1, 1);
  11     var pr = pixel.data[0],
  12         pg = pixel.data[1],
  13         pb = pixel.data[2],
  14         pa = pixel.data[3];
  15     ok(r-d <= pr && pr <= r+d &&
  16        g-d <= pg && pg <= g+d &&
  17        b-d <= pb && pb <= b+d &&
  18        a-d <= pa && pa <= a+d,
  19        "pixel "+pos+" is "+pr+","+pg+","+pb+","+pa+"; expected "+colour+" +/- "+d);
  20 }
  21
  22 SimpleTest.waitForExplicitFinish();
  23 MochiKit.DOM.addLoadEvent(function () {
  24
  25 var canvas = document.getElementById('c');
  26 var ctx = canvas.getContext('2d');
  27
  28 ctx.fillStyle = '#f00';
  29 ctx.fillRect(0, 0, 100, 50);
  30 ctx.globalAlpha = 0.1;
  31 ctx.clearRect(0, 0, 100, 50);
  32 isPixel(ctx, 50,25, 0,0,0,0, "50,25", "0,0,0,0", 0);
  33
  34 SimpleTest.finish();
  35
  36 });
  37 </script>
  38