1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
<!doctype HTML>
<html>
<meta charset="utf8">
<title>Content Visibility: resize observer interactions</title>
<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
<meta name="assert" content="content-visibility hidden subtrees do not trigger resize observer">
<style>
.hidden {
content-visibility: hidden;
}
</style>
<div id="container">
<div id="resize" style="width: 50px; height: 50px">
</div>
</div>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
async_test(t => {
let didCallback = false;
function runTest() {
let resizeCallback = function (entries) {
didCallback = true;
}
let resizeObserver = new ResizeObserver(resizeCallback);
resizeObserver.observe(resize);
requestAnimationFrame(t.step_func(step2));
}
function step2() {
assert_true(didCallback, 'Resize observation should happen in first frame after registering');
didCallback = false;
const container = document.getElementById("container");
container.classList.add("hidden");
// Change the size of #resize. This should cause a resize observation, but
// only when the element becomes unhidden.
resize.style.width = '100px';
requestAnimationFrame(t.step_func(step3));
}
function step3() {
assert_false(didCallback, 'ResizeObsever should not run during while unrendered');
requestAnimationFrame(t.step_func(step4));
}
function step4() {
assert_false(didCallback, 'ResizeObsever should not run while unrendered');
const container = document.getElementById("container");
container.classList.remove("hidden");
requestAnimationFrame(t.step_func_done(step5));
}
function step5() {
assert_true(didCallback, 'ResizeObsevers should now run once becoming visible');
}
window.onload = function() {
requestAnimationFrame(() => requestAnimationFrame(t.step_func(runTest)));
};
}, "ResizeObserver skipped while hidden");
</script>
</html>
|
