<!DOCTYPE html>
<html id="top">
<meta charset="utf-8">
<title>View timeline nested subject</title>
<link rel="help" href="https://drafts.csswg.org/scroll-animations-1/#viewtimeline-interface">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/web-animations/testcommon.js"></script>
<script src="/scroll-animations/scroll-timelines/testcommon.js"></script>
<script src="/scroll-animations/view-timelines/testcommon.js"></script>
<style type="text/css">
#container {
overflow-y: scroll;
height: 300px;
width: 300px;
}
.big-spacer {
height: 800px;
}
.small-spacer {
height: 100px;
}
#block {
background-color: #ddd;
}
#target {
background-color: green;
height: 100px;
width: 100px;
}
</style>
<body>
<div id="container">
<div class="big-spacer"></div>
<div id="block">
<div class="small-spacer"></div>
<div id="target"></div>
</div>
<div class="big-spacer"></div>
</div>
</body>
<script type="text/javascript">
promise_test(async t => {
container.scrollTop = 0;
await waitForNextFrame();
const anim = CreateViewTimelineOpacityAnimation(t, target);
const timeline = anim.timeline;
await anim.ready;
// start offset = 800 + 100 - 300 = 600
// end offset = 800 + 100 + 100 = 1000
// scroll limit = L = 800 + 200 + 800 - 300 = 1500
// progress = P = (current - start) / (end - start)
// P(0) = -600 / 400 = -1.5
// P(L) = 900 / 400 = 2.5
// Initially before start-offset and animation effect is in the before
// phase.
assert_percents_equal(timeline.currentTime, -150,
"Timeline's currentTime at container start boundary");
assert_percents_equal(anim.currentTime, -150,
"Animation's currentTime at container start boundary");
assert_equals(getComputedStyle(target).opacity, "1",
'Effect is inactive in the before phase');
// Advance to the start offset, which triggers entry to the active phase.
container.scrollTop = 600;
await waitForNextFrame();
assert_percents_equal(timeline.currentTime, 0,
"Timeline's current time at start offset");
assert_percents_equal(anim.currentTime, 0,
"Animation's current time at start offset");
assert_equals(getComputedStyle(target).opacity, '0.3',
'Effect at the start of the active phase');
// Advance to the midpoint of the animation.
container.scrollTop = 800;
await waitForNextFrame();
assert_percents_equal(timeline.currentTime, 50,
"Timeline's currentTime at midpoint");
assert_percents_equal(anim.currentTime, 50,
"Animation's currentTime at midpoint");
assert_equals(getComputedStyle(target).opacity,'0.5',
'Effect at the midpoint of the active range');
// Advance to the end of the animation.
container.scrollTop = 1000;
await waitForNextFrame();
assert_percents_equal(timeline.currentTime, 100,
"Timeline's currentTime at end offset");
assert_percents_equal(anim.currentTime, 100,
"Animation's currentTime at end offset");
assert_equals(getComputedStyle(target).opacity, '1',
'Effect is in the after phase at effect end time');
// Advance to the scroll limit.
container.scrollTop = 1600;
await waitForNextFrame();
assert_percents_equal(timeline.currentTime, 225,
"Timeline's currentTime at scroll limit");
// Hold time set when the animation finishes, which clamps the value of
// the animation's currentTime.
assert_percents_equal(anim.currentTime, 100,
"Animation's currentTime at scroll limit");
// In the after phase, so the effect should not be applied.
assert_equals(getComputedStyle(target).opacity, '1',
'After phase at scroll limit');
}, 'View timeline with subject that is not a direct descendant of the ' +
'scroll container');
</script>
</html>
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