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<!doctype HTML>
<html>
<meta charset="utf8">
<title>Content Visibility: measure layout</title>
<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
<meta name="assert" content="content-visibility hidden element layout is correct">
<meta name="assert" content="content-visibility hidden element's subtree layout is correct">
<style>
#container {
background: lightgreen;
contain: layout;
}
.hidden {
content-visibility: hidden;
}
#sizer {
width: 100px;
height: 100px;
}
.child {
width: 20px;
height: 20%;
background: cyan;
}
#spacer {
width: 150px;
height: 150px;
background: green;
}
</style>
<div id="parent"></div>
<div id="spacer"></div>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
async_test((t) => {
function createChild(id) {
const child = document.createElement("div");
child.classList = "child";
child.id = id;
return child;
}
function measureForced() {
t.step(() => {
// Ensure children are laid out; this forces a layout if it wasn't done.
assert_equals(document.getElementById("0").offsetTop, 0, "0 forced");
assert_equals(document.getElementById("1").offsetTop, 20, "1 forced");
assert_equals(document.getElementById("2").offsetTop, 40, "2 forced");
// Both parent should be 0 height, since it's hidden. Both parent and spacers
// should have 8 offsetTop.
assert_equals(document.getElementById("parent").offsetTop, 8, "parent forced");
assert_equals(document.getElementById("spacer").offsetTop, 8, "spacer forced");
});
}
function measureWhenVisible() {
t.step(() => {
// Ensure children are still laid out.
assert_equals(document.getElementById("0").offsetTop, 0, "0 when visible");
assert_equals(document.getElementById("1").offsetTop, 20, "1 when visible");
assert_equals(document.getElementById("2").offsetTop, 40, "2 when visible");
// Now the parent should encompass a container, so spacer is pushed down.
assert_equals(document.getElementById("parent").offsetTop, 8, "parent when visible");
assert_equals(document.getElementById("spacer").offsetTop, 108, "spacer when visible");
});
}
function construct(container) {
const sizer = document.createElement("div");
sizer.id = "sizer";
container.appendChild(sizer);
sizer.appendChild(createChild("0"));
sizer.appendChild(createChild("1"));
sizer.appendChild(createChild("2"));
}
async function runTest() {
const container = document.createElement("div");
container.id = "container";
document.getElementById("parent").appendChild(container);
container.classList.add("hidden");
requestAnimationFrame(() => {
construct(container);
measureForced();
container.classList.remove("hidden");
requestAnimationFrame(() => requestAnimationFrame(() => {
measureWhenVisible();
t.done();
}));
});
}
window.onload = function() {
requestAnimationFrame(() => requestAnimationFrame(runTest));
};
}, "Measure Forced Layout");
</script>
</html>
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