content/canvas/test/test_2d.gradient.interpolate.alpha.html

   1 <!DOCTYPE HTML>
   2 <title>Canvas test: 2d.gradient.interpolate.alpha</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"><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 = '#ff0';
  29 ctx.fillRect(0, 0, 100, 50);
  30 var g = ctx.createLinearGradient(0, 0, 100, 0);
  31 g.addColorStop(0, 'rgba(0,0,255, 0)');
  32 g.addColorStop(1, 'rgba(0,0,255, 1)');
  33 ctx.fillStyle = g;
  34 ctx.fillRect(0, 0, 100, 50);
  35 isPixel(ctx, 25,25, 191,191,63,255, "25,25", "191,191,63,255", 3);
  36 isPixel(ctx, 50,25, 127,127,127,255, "50,25", "127,127,127,255", 3);
  37 isPixel(ctx, 75,25, 63,63,191,255, "75,25", "63,63,191,255", 3);
  38
  39 SimpleTest.finish();
  40
  41 });
  42 </script>
  43