position-visibility-anchors-visible-after-scroll-out.html

<!DOCTYPE html>
<html class=reftest-wait>
<meta charset="utf-8">
<meta name="assert" content="Scrolling an anchor out of view should cause a position-visibility: anchors-visible element to disappear." />
<title>CSS Anchor Positioning Test: position-visibility: anchors-visible</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#position-visibility">
<link rel="match" href="position-visibility-anchors-visible-after-scroll-out-ref.html">
<script src="/common/reftest-wait.js"></script>
<script src="/common/rendering-utils.js"></script>
<style>
  #scroll-container {
    overflow: hidden scroll;
    width: 300px;
    height: 100px;
  }

  #anchor {
    anchor-name: --a1;
    width: 100px;
    height: 100px;
    background: orange;
  }

  #spacer {
    height: 100px;
  }

  #target {
    position-anchor: --a1;
    position-visibility: anchors-visible;
    position-area: bottom;
    width: 100px;
    height: 100px;
    background: red;
    position: absolute;
    top: 0;
    left: 0;
  }
</style>

<div id="scroll-container">
  <div id="anchor">anchor</div>
  <div id="spacer"></div>
  <div id="target">target</div>
</div>

<script>
  // #target should be initially visible because it is anchored to #anchor,
  // which is visible.

  waitForAtLeastOneFrame().then(() => {
    // Scroll #anchor so that it is out of view.
    const scroller = document.getElementById('scroll-container');
    scroller.scrollTop = 100;

    // #target should now be invisible.
    takeScreenshot();
  });
</script>

chromium/third_party/blink/web_tests/external/wpt/css/css-anchor-position/position-visibility-anchors-visible-after-scroll-out.html