gecko/content/canvas/test/test_2d.state.saverestore.globalAlpha.html

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HTML

<!DOCTYPE HTML>
<title>Canvas test: 2d.state.saverestore.globalAlpha</title>
<!-- Testing: save()/restore() works for globalAlpha -->
<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>
SimpleTest.waitForExplicitFinish();
MochiKit.DOM.addLoadEvent(function () {
var canvas = document.getElementById('c');
var ctx = canvas.getContext('2d');
// Test that restore() undoes any modifications
var old = ctx.globalAlpha;
ctx.save();
ctx.globalAlpha = 0.5;
ctx.restore();
ok(ctx.globalAlpha === old, "ctx.globalAlpha === old");
// Also test that save() doesn't modify the values
ctx.globalAlpha = 0.5;
old = ctx.globalAlpha;
// we're not interested in failures caused by get(set(x)) != x (e.g.
// from rounding), so compare against d instead of against 0.5
ctx.save();
ok(ctx.globalAlpha === old, "ctx.globalAlpha === old");
ctx.restore();
SimpleTest.finish();
});
</script>