Kiet Ho
815dc06640
Automatic update from web-platform-tests WebKit export of https://bugs.webkit.org/show_bug.cgi?id=295009 -- wpt-commits: 2d623bd1ab81ec5cc998ffd485860bdc14a61272 wpt-pr: 54345
76 lines
2.1 KiB
HTML
76 lines
2.1 KiB
HTML
<!DOCTYPE html>
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<title>CSS Anchor Positioning: basic last successful position fallback on pseudo-elements</title>
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<link rel="author" title="Kiet Ho" href="mailto:kiet.ho@apple.com">
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<link rel="help" href="https://drafts.csswg.org/css-anchor-position/#last-successful-position-fallback">
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<script src="/resources/testharness.js"></script>
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<script src="/resources/testharnessreport.js"></script>
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<script src="support/test-common.js"></script>
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<style>
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#container {
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position: relative;
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width: 400px;
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height: 400px;
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background: teal;
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}
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#anchor {
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position: relative;
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top: 100px;
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left: 100px;
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width: 100px;
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height: 100px;
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background: red;
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anchor-name: --a;
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}
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#anchored::before {
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position-anchor: --a;
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/*
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We can't use position-area, since there's no way to access offsetTop of
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pseudo-elements to check for position. Instead, we have to use anchor()
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and check the computed inset values.
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*/
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bottom: anchor(top);
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left: anchor(left);
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position-try-fallbacks: flip-block;
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position: absolute;
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width: 100px;
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height: 200px;
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background: lime;
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content: "";
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}
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</style>
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<div id="container">
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<div id="anchor"></div>
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<div id="anchored"></div>
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</div>
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<script>
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promise_test(async () => {
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await waitUntilNextAnimationFrame();
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await waitUntilNextAnimationFrame();
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const anchoredStyle = getComputedStyle(anchored, "::before");
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assert_equals(anchoredStyle.top, "200px");
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}, "Starts rendering with flip-block");
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promise_test(async () => {
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anchor.style.top = "150px";
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await waitUntilNextAnimationFrame();
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await waitUntilNextAnimationFrame();
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const anchoredStyle = getComputedStyle(anchored, "::before");
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assert_equals(anchoredStyle.top, "250px");
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}, "No successful position, keep flip-block");
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promise_test(async () => {
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anchor.style.top = "200px";
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await waitUntilNextAnimationFrame();
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await waitUntilNextAnimationFrame();
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const anchoredStyle = getComputedStyle(anchored, "::before");
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assert_equals(anchoredStyle.top, "0px");
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}, "Base position without fallback now successful");
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</script>
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