<!DOCTYPE html>
<html class=reftest-wait>
<title>View transitions: use css tags for shared elements</title>
<link rel="help" href="https://github.com/WICG/view-transitions">
<link rel="author" href="mailto:vmpstr@chromium.org">
<link rel="match" href="css-tags-shared-element-ref.html">

<script src="/common/reftest-wait.js"></script>
<style>
div { contain: paint; }
#left {
  background: green;
  width: 100px;
  height: 100px;
  position: absolute;
  top: 50px;
  left: 50px;
}
#right {
  width: 50px;
  height: 50px;
  background: blue;
  position: absolute;
  top: 50px;
  left: 250px;
}
.left-tag {
  view-transition-name: left-element;
}
.right-tag {
  view-transition-name: right-element;
}

.hidden {
  background: pink;
  width: 10px;
  height: 10px;
  view-transition-name: hidden;
}

html::view-transition-group(hidden) { animation-duration: 300s; }
html::view-transition-image-pair(hidden) { animation: unset; opacity: 0; }

html::view-transition-group(left-element),
html::view-transition-group(right-element) { animation-duration: 0s; }

html::view-transition-new(left-element),
html::view-transition-new(right-element) { animation: unset; opacity: 0; }

html::view-transition-old(left-element),
html::view-transition-old(right-element) { animation: unset; opacity: 1; }

html::view-transition-group(root) { animation: unset; opacity: 0; }
html::view-transition { background: lightpink; }

</style>

<div id=left class="left-tag"></div>
<div id=right class="right-tag"></div>

<div id=hidden class=hidden></div>

<script>
failIfNot(document.startViewTransition, "Missing document.startViewTransition");

async function runTest() {
  document.startViewTransition(() => {
    left.classList.remove("left-tag");
    left.classList.add("right-tag");

    right.classList.remove("right-tag");
    right.classList.add("left-tag");

    requestAnimationFrame(() => requestAnimationFrame(takeScreenshot))
  });
}
onload = () => requestAnimationFrame(() => requestAnimationFrame(runTest));
</script>

