test_transformed_scrolling_repaints_2.html

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<!DOCTYPE HTML>

<html>

<head>

  <title>Test that scaled elements with scrolled contents don't repaint unnecessarily when we scroll inside them (1.1 scale)</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <script src="/tests/SimpleTest/paint_listener.js"></script>

  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>

</head>

<body onload="setPrefAndStartTest()">

<div id="t" style="transform: scale(1.1, 1.1); transform-origin:top left; width:200px; height:100px; background:yellow; overflow:hidden">

  <div style="height:40px;"></div>

  <div id="e" style="height:30px; background:lime"></div>

  <div style="height:300px; background:yellow"></div>

</div>

<pre id="test">

<script type="application/javascript">

SimpleTest.waitForExplicitFinish();

var t = document.getElementById("t");

var e = document.getElementById("e");

var utils = SpecialPowers.getDOMWindowUtils(window);

function startTest() {

  // Do a couple of scrolls to ensure we've triggered activity heuristics

  waitForAllPaintsFlushed(function () {

    t.scrollTop = 5;

    waitForAllPaintsFlushed(function () {

      t.scrollTop = 10;

      waitForAllPaintsFlushed(function () {

        // Clear paint state now and scroll again.

        utils.checkAndClearPaintedState(e);

        t.scrollTop = 20;

        waitForAllPaintsFlushed(function () {

          var painted = utils.checkAndClearPaintedState(e);

          is(painted, false, "Fully-visible scrolled element should not have been painted");

          SimpleTest.finish();

});

});

});

});

function setPrefAndStartTest() {

  SpecialPowers.pushPrefEnv(

    {"set": [["layers.single-tile.enabled", false]]},

    // Need a timeout here to allow paint unsuppression before we start the test

    function() {

      setTimeout(startTest, 0);

);

</script>

</pre>

</body>

</html>