40 lines
1.8 KiB
HTML
40 lines
1.8 KiB
HTML
<!DOCTYPE HTML>
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<meta charset=utf-8>
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<title>Element Timing: observe element with buffered flag</title>
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<body>
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<style>
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body {
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margin: 0;
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}
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</style>
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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="resources/element-timing-helpers.js"></script>
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<script>
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async_test(t => {
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assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented");
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const beforeRender = performance.now();
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const img = document.createElement('img');
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// Initial observer used to know when entry has been dispatched
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new PerformanceObserver(() => {
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// Second observer should require buffered flag to receive the already-dispatched entry.
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new PerformanceObserver(t.step_func_done(entryList => {
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assert_equals(entryList.getEntries().length, 1);
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const entry = entryList.getEntries()[0];
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const pathname = window.location.origin + '/images/black-rectangle.png';
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checkElement(entry, pathname, 'my_image', 'my_id', beforeRender, document.getElementById('my_id'));
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// Test that viewport size is at least 100, so element is fully visible.
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assert_greater_than_equal(document.documentElement.clientWidth, 100, 'Width should be >= 100');
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assert_greater_than_equal(document.documentElement.clientHeight, 100, 'Height should be >= 100');
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checkRect(entry, [0, 100, 0, 50]);
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checkNaturalSize(entry, 100, 50);
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})).observe({type: 'element', buffered: true});
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}).observe({type: 'element'});
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img.src = '/images/black-rectangle.png';
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img.setAttribute('elementtiming', 'my_image');
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img.setAttribute('id', 'my_id');
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document.body.appendChild(img);
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}, 'Element Timing entries are observable via buffered flag.');
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</script>
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</body>
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