helper_hittest_checkerboard.html

Enable keyboard shortcuts

<!DOCTYPE HTML>

<html>

<head>

  <title>APZ hit-testing over a checkerboarded area</title>

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

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

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

  <meta name="viewport" content="width=device-width"/>

</head>

<body>

 <div id="scroller" style="width: 300px; height: 300px; overflow:scroll; margin-top: 100px; margin-left: 50px">

  <!-- Make the contents tall enough to be sure we can checkerboard -->

  <div id="contents" style="width: 100%; height: 5000px; background-image: linear-gradient(blue,red)">

  </div>

 </div>

 <div id="make_root_scrollable" style="height: 5000px"></div>

</body>

<script type="application/javascript">

async function test() {

  var config = getHitTestConfig();

  var utils = config.utils;

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

  // Activate the scrollframe but keep the main-thread scroll position at 0.

  // Also apply an async scroll offset in the y-direction such that the

  // scrollframe scrolls all the way to the bottom of its range, where it's

  // sure to checkerboard.

  utils.setDisplayPortForElement(0, 0, 300, 1000, scroller, 1);

  await promiseApzFlushedRepaints();

  var scrollY = scroller.scrollTopMax;

  utils.setAsyncScrollOffset(scroller, 0, scrollY);

  // Tick the refresh driver once to make sure the compositor has applied the

  // async scroll offset (for WebRender hit-testing we need to make sure WR has

  // the latest info).

  utils.advanceTimeAndRefresh(16);

  utils.restoreNormalRefresh();

  var scrollerViewId = utils.getViewId(scroller);

  // Hit-test the middle of the scrollframe, which is now inside the

  // checkerboarded region, and check that we hit the scrollframe and

  // not its parent.

  checkHitResult(hitTest(centerOf(scroller)),

                 APZHitResultFlags.VISIBLE,

                 scrollerViewId,

                 utils.getLayersId(),

                 "active scrollframe");

waitUntilApzStable()

.then(test)

.then(subtestDone, subtestFailed);

</script>

</html>