<!DOCTYPE html>
<meta charset=utf8>
<title>Test getComputedStyle on a CSS animation with scroll timeline in a content visibility subtree using content-visibility: auto</title>
<link rel="help" href="https://drafts.csswg.org/css-contain-2/">
<script src="/web-animations/testcommon.js"></script>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
#container {
content-visibility: auto;
}
#scrollContainer {
height: 100vh;
overflow-y: scroll;
scroll-timeline-name: --targetTimeline;
}
#innerspacer {
height: 300vh;
}
@keyframes fade {
from { opacity: 1; }
to { opacity: 0; }
}
#target {
background: green;
height: 100px;
width: 100px;
}
.animate {
animation-name: fade;
animation-duration: 1ms;
animation-direction: alternate;
animation-timeline: --targetTimeline;
}
</style>
<body>
<div id="log"></div>
<div id="spacer"></div>
<div id="scrollContainer">
<div id="container"></div>
<div id="innerspacer"></div>
</div>
</body>
<script>
"use strict";
function createAnimatingElement(test, name) {
const container = document.getElementById('container');
const target = document.createElement('div');
container.appendChild(target);
target.id = 'target';
target.className = name;
return target;
}
promise_test(async t => {
const container = document.getElementById('container');
const target = createAnimatingElement(t, 'animate');
scrollContainer.scrollTop = 10000;
const animation = target.getAnimations()[0];
await animation.ready;
await waitForAnimationFrames(1);
let expectedOpacity = parseFloat(getComputedStyle(target).opacity);
assert_approx_equals(expectedOpacity, 0, 0.1, 'scrollContainer scrolls to bottom, so the opacity should be 0');
document.getElementById('spacer').style.height = '300vh';
await waitForAnimationFrames(1);
assert_equals(parseFloat(getComputedStyle(target).opacity), expectedOpacity, 'Opacity does not change when it is hidden by c-v');
scrollContainer.scrollTop = 0;
assert_equals(parseFloat(getComputedStyle(target).opacity), expectedOpacity, 'The animation is hidden by c-v, so opacity does not change even if scrollTop changes');
await waitForAnimationFrames(2);
document.getElementById('spacer').style.height = '0vh';
await waitForAnimationFrames(2);
assert_equals(getComputedStyle(target).opacity, '1', 'Now that the animation is visible, opacity should be updated');
}, 'Animation with scroll-timeline should be affected c-v');
</script>
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