intersection-observer/svg-image.html

<!DOCTYPE html>
<title>IntersectionObserver observing an SVG image element changing position</title>
<meta name="viewport" content="width=device-width,initial-scale=1">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/intersection-observer-test-utils.js"></script>
<svg width="400" height="10000">
    <!-- Ensure the svg bounds are unchanged with a white fill -->
    <rect x="-5000" y="-5000" width="10000" height="10000" fill="white"/>
    <image id="target" x="0" y="100vh" width="100px" height="100px" href="data:image/gif;base64,R0lGODlhAQABAJAAAMjIyAAAACwAAAAAAQABAAACAgQBADs%3D"/>
</svg>
<script>
const viewportWidth = document.documentElement.clientWidth;
const viewportHeight = document.documentElement.clientHeight;
setup(() => {
  window.entries = [];
  window.target = document.getElementById("target");
  window.targetRect = target.getBoundingClientRect();
});
runTestCycle(function() {
  assert_true(!!target, "target exists");
  const observer = new IntersectionObserver(function(changes) {
    entries = entries.concat(changes);
  });
  observer.observe(target);
  entries = entries.concat(observer.takeRecords());
  assert_equals(entries.length, 0, "No initial notifications");
  runTestCycle(step0, "First rAF.");
});
function step0() {
  target.setAttribute('y', '0');
  runTestCycle(step1, "change image location");
  // The numbers in brackets are target client rect; intersection rect;
  // and root bounds.
  checkLastEntry(entries, 0, [
    // the 8 pixels comes from the html body padding.
    8, 8 + targetRect.width, viewportHeight+8, viewportHeight+8 + targetRect.height,
    0, 0, 0, 0,
    0, viewportWidth, 0, viewportHeight,
    false,
  ]);
}
function step1() {
    checkLastEntry(entries, 1, [
    8, 8 + targetRect.width, 8, 8 + targetRect.height,
    8, 8 + targetRect.width, 8, 8 + targetRect.height,
    0, viewportWidth, 0, viewportHeight,
    true,
  ]);
}
</script>