content/canvas/test/test_2d.composite.solid.difference.html

<!DOCTYPE HTML>
<title>Canvas test: 2d.composite.solid.lighter</title>
<script src="/MochiKit/MochiKit.js"></script>
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<link rel="stylesheet" href="/tests/SimpleTest/test.css">
<body>
<canvas id="c" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>
<script>
function isPixel(ctx, x,y, r,g,b,a, pos, colour, d) {
    var pixel = ctx.getImageData(x, y, 1, 1);
    var pr = pixel.data[0],
        pg = pixel.data[1],
        pb = pixel.data[2],
        pa = pixel.data[3];
    ok(r-d <= pr && pr <= r+d &&
       g-d <= pg && pg <= g+d &&
       b-d <= pb && pb <= b+d &&
       a-d <= pa && pa <= a+d,
       "pixel "+pos+" is "+pr+","+pg+","+pb+","+pa+"; expected "+colour+" +/- "+d);
}

SimpleTest.waitForExplicitFinish();
addLoadEvent(function () {

var canvas = document.getElementById('c');
var ctx = canvas.getContext('2d');


ctx.fillStyle = 'rgba(0, 255, 255, 1.0)';
ctx.fillRect(0, 0, 100, 50);
ctx.globalCompositeOperation = 'difference';
ctx.fillStyle = 'rgba(255, 255, 0, 1.0)';
ctx.fillRect(0, 0, 100, 50);
isPixel(ctx, 50,25, 255,0,255,255, "50,25", "255,0,255,255", 5);

SimpleTest.finish();

});
</script>
