dom/canvas/test/test_2d.composite.canvas.difference.html

   1 <!DOCTYPE HTML>
   2 <title>Canvas test: 2d.composite.canvas.xor</title>
   3 <script src="/tests/SimpleTest/SimpleTest.js"></script>
   4 <link rel="stylesheet" href="/tests/SimpleTest/test.css">
   5 <body>
   6 <canvas id="c" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>
   7 <script>
   8 function isPixel(ctx, x,y, r,g,b,a, pos, colour, d) {
   9     var pixel = ctx.getImageData(x, y, 1, 1);
  10     var pr = pixel.data[0],
  11         pg = pixel.data[1],
  12         pb = pixel.data[2],
  13         pa = pixel.data[3];
  14     ok(r-d <= pr && pr <= r+d &&
  15        g-d <= pg && pg <= g+d &&
  16        b-d <= pb && pb <= b+d &&
  17        a-d <= pa && pa <= a+d,
  18        "pixel "+pos+" is "+pr+","+pg+","+pb+","+pa+"; expected "+colour+" +/- "+d);
  19 }
  20
  21 SimpleTest.waitForExplicitFinish();
  22 addLoadEvent(function () {
  23
  24 var canvas = document.getElementById('c');
  25 var ctx = canvas.getContext('2d');
  26
  27
  28 var canvas2 = document.createElement('canvas');
  29 canvas2.width = canvas.width;
  30 canvas2.height = canvas.height;
  31 var ctx2 = canvas2.getContext('2d');
  32 ctx2.drawImage(document.getElementById('yellow75.png'), 0, 0);
  33 ctx.fillStyle = 'rgba(0, 255, 255, 0.5)';
  34 ctx.fillRect(0, 0, 100, 50);
  35 ctx.globalCompositeOperation = 'difference';
  36 ctx.drawImage(canvas2, 0, 0);
  37 isPixel(ctx, 50,25, 218,145,146,223, "50,25", "218,145,146,223", 5);
  38
  39 SimpleTest.finish();
  40
  41 });
  42 </script>
  43 <img src="image_yellow75.png" id="yellow75.png" class="resource">
  44