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<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>Clicking on the content (not scrollbar) should interrupt animations</title>
<script type="application/javascript" src="apz_test_native_event_utils.js"></script>
<script type="application/javascript" src="apz_test_utils.js"></script>
<script src="/tests/SimpleTest/paint_listener.js"></script>
<script src="/tests/SimpleTest/EventUtils.js"></script>
<script type="application/javascript">
async function test() {
var scroller = document.documentElement;
var verticalScrollbarWidth = window.innerWidth - scroller.clientWidth;
if (verticalScrollbarWidth == 0) {
ok(true, "Scrollbar width is zero on this platform, test is useless here");
// The anchor is the fixed-pos div that we use to calculate coordinates to
// click on the scrollbar. That way we don't have to recompute coordinates
// as the page scrolls. The anchor is at the bottom-right corner of the
// content area.
var anchor = document.getElementById('anchor');
var xoffset = (verticalScrollbarWidth / 2);
// Get a y-coord near the bottom of the vertical scrollbar track. Assume the
// vertical thumb is near the top of the scrollback track (since scroll
// position starts off at zero) and won't get in the way. Also assume the
// down arrow button, if there is one, is square.
var yoffset = 0 - verticalScrollbarWidth - 5;
// Take control of the refresh driver
let utils = SpecialPowers.getDOMWindowUtils(window);
// Click at the bottom of the scrollbar track to trigger a page-down kind of
// scroll. This should use "desktop zooming" scrollbar code which should
// trigger an APZ scroll animation.
await promiseNativeMouseEventWithAPZAndWaitForEvent({
type: "click",
target: anchor,
offsetX: xoffset,
offsetY: yoffset,
eventTypeToWait: "mouseup"
// Run a few frames, that should be enough to let the scroll animation
// start. We check to make sure the scroll position has changed.
for (let i = 0; i < 5; i++) {
await promiseOnlyApzControllerFlushed();
let curPos = scroller.scrollTop;
ok(curPos > 0,
`Scroll offset has moved down some, to ${curPos}`);
// Now we click on the content, which should cancel the animation. Run
// everything to reach a stable state.
await promiseNativeMouseEventWithAPZAndWaitForEvent({
type: "click",
target: anchor,
offsetX: -5,
offsetY: -5,
for (let i = 0; i < 1000; i++) {
await promiseOnlyApzControllerFlushed();
// Ensure the scroll position hasn't changed since the last time we checked,
// which indicates the animation got interrupted.
is(scroller.scrollTop, curPos, `Scroll position hasn't changed again`);
.then(subtestDone, subtestFailed);
<div style="position:fixed; bottom: 0; right: 0; width: 1px; height: 1px" id="anchor"></div>
<div style="height: 300vh; margin-bottom: 10000px; background-image: linear-gradient(red,blue)"></div>
The above div is sized to 3x screen height so the linear gradient is more steep in terms of
color/pixel. We only scroll a few pages worth so we don't need the gradient all the way down.
And then we use a bottom-margin to make the page really big so the scrollthumb is
relatively small, giving us lots of space to click on the scrolltrack.