css/motion/offset-path-bounding-client-rect.html

<!DOCTYPE html>
<html>
<title>The bounding client rect of an element should reflect offset-path</title>
<link rel="help" href="https://drafts.csswg.org/motion/#offset-path-property">
<link rel="help" href="https://crbug.com/463409688">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  body {
    margin: 0;
  }
  #blue {
    background: radial-gradient(lightblue, blue);
    width: 60px;
    height: 60px;
    offset-path: circle(100px at 150px 150px);
    position: relative;
    left: 100px;
  }
  #purple {
    background: radial-gradient(fuchsia, purple);
    width: 60px;
    height: 60px;
    offset-path: border-box;
    position: relative;
    left: 100px;
  }
</style>
<body>
<div id="blue"></div>
<div id="purple"></div>
<div id="log"></div>
<script>
  function check_rect(id, expected) {
    test(() => {
      const rect = document.getElementById(id).getBoundingClientRect();
      for (const prop in expected) {
        assert_equals(rect[prop], expected[prop], `#${id} client rect.${prop}`);
      }
    }, `Bounding client rect for #${id}`);
  }

  check_rect('blue', {
    x: 220,
    y: 120,
    width: 60,
    height: 60
  });

  check_rect('purple', {
    x: -30,
    y: -30,
    width: 60,
    height: 60
  });
</script>
</body>
</html>