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Diffstat (limited to 'layout/base/tests/chrome/test_scrolling_repaints.html')
| -rw-r--r-- | layout/base/tests/chrome/test_scrolling_repaints.html | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/layout/base/tests/chrome/test_scrolling_repaints.html b/layout/base/tests/chrome/test_scrolling_repaints.html new file mode 100644 index 0000000000..605e598c52 --- /dev/null +++ b/layout/base/tests/chrome/test_scrolling_repaints.html @@ -0,0 +1,48 @@ +<!DOCTYPE HTML> +<html> +<head> + <title>Test that we don't get unnecessary repaints due to subpixel shifts</title> + <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script> + <script src="chrome://mochikit/content/tests/SimpleTest/paint_listener.js"></script> + <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/> +</head> +<!-- Need a timeout here to allow paint unsuppression before we start the test --> +<body onload="setTimeout(startTest,0)"> +<div id="t" style="width:400px; height:100px; background:yellow; overflow:hidden"> + <div style="height:40px;"></div> + <div id="e" style="height:30px; background:lime"></div> + <div style="height:60.4px; background:pink"></div> +</div> +<pre id="test"> +<script type="application/javascript"> +SimpleTest.waitForExplicitFinish(); + +var t = document.getElementById("t"); +var e = document.getElementById("e"); +var utils = window.windowUtils; + +function startTest() { + // Do a scroll to ensure we trigger activity heuristics. + waitForAllPaintsFlushed(function () { + t.scrollTop = 5; + // Scroll down as far as we can, to put our rendering layer at a subpixel offset within the layer + waitForAllPaintsFlushed(function () { + t.scrollTop = 1000; + waitForAllPaintsFlushed(function () { + // Clear paint state now and scroll again. + utils.checkAndClearPaintedState(e); + // scroll up a little bit. This should not cause anything to be repainted. + t.scrollTop = t.scrollTop - 10; + waitForAllPaintsFlushed(function () { + var painted = utils.checkAndClearPaintedState(e); + is(painted, false, "Fully-visible scrolled element should not have been painted"); + SimpleTest.finish(); + }); + }); + }); + }); +} +</script> +</pre> +</body> +</html> |