test_smoothness.html

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<html>

<head>

  <title>Test Frame Uniformity While Scrolling</title>

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

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

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

  <script type="application/javascript" src="apz_test_utils.js"></script>

  <script type="application/javascript" src="apz_test_native_event_utils.js"></script>

  <style>

  #content {

    height: 5000px;

    background: repeating-linear-gradient(#EEE, #EEE 100px, #DDD 100px, #DDD 200px);

  </style>

  <script type="text/javascript">

    var scrollEvents = 100;

    var i = 0;

    // Scroll points

    var x = 100;

    var y = 150;

    SimpleTest.waitForExplicitFinish();

    var utils = SpecialPowers.getDOMWindowUtils(window);

    async function sendScrollEvent() {

      var scrollDiv = document.getElementById("content");

      if (i < scrollEvents) {

        i++;

        // Scroll diff

        var dx = 0;

        var dy = -10; // Negative to scroll down

        await synthesizeNativeWheel(scrollDiv, x, y, dx, dy);

        window.requestAnimationFrame(sendScrollEvent);

      } else {

        // Locally, with silk and apz + e10s, retina 15" mbp usually get ~1.0 - 1.5

        // w/o silk + e10s + apz, I get up to 7. Lower is better.

        // Windows, I get ~3. Values are not valid w/o hardware vsync

        var uniformities = utils.getFrameUniformityTestData();

        for (var j = 0; j < uniformities.layerUniformities.length; j++) {

          var layerResult = uniformities.layerUniformities[j];

          var layerAddr = layerResult.layerAddress;

          var uniformity = layerResult.frameUniformity;

          var msg = "Layer: " + layerAddr.toString(16) + " Uniformity: " + uniformity;

          SimpleTest.ok((uniformity >= 0) && (uniformity < 4.0), msg);

        SimpleTest.finish();

    function startTest() {

      window.requestAnimationFrame(sendScrollEvent);

    if (!isApzEnabled()) {

      SimpleTest.ok(true, "APZ not enabled, skipping test");

      SimpleTest.finish();

    </script>

</head>

<body>

  <div id="content">

  </div>

</body>

</html>