Blitz - WPT: position-visibility-no-overflow-scroll-002.html

wpt / css / css-anchor-position / position-visibility-no-overflow-scroll-002.html

/css/css-anchor-position/position-visibility-no-overflow-scroll-002.html

<!DOCTYPE html>
<html class="reftest-wait">
<title>CSS Anchor Positioning Test: position-visibility: no-overflow + scrolling + position-area</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#position-visibility">
<link rel="match" href="position-visibility-no-overflow-scroll-ref.html">
<style>
  #container {
    position: relative;
    width: 400px;
    height: 150px;
    overflow: hidden;
  }
  #scroll-container {
    overflow: hidden scroll;
    scrollbar-width: none;
    width: 100%;
    height: 100%;
  }

  .anchor {
    width: 100px;
    height: 100px;
    background: orange;
    display: inline-block;
  }

  .target {
    position: absolute;
    position-visibility: no-overflow;
    width: 100px;
    height: 100px;
  }

  .display-none {
    display: none;
  }
</style>

<div id="container">
<div id="scroll-container">
  <div class="anchor" style="anchor-name: --a1;">anchor1</div>
  <div class="anchor" style="anchor-name: --a2; position: relative; top: 100px">anchor2</div>
  <div id="target1" class="target display-none" style="position-anchor: --a1; position-area: bottom; background: green">target1</div>
  <div id="target2" class="target display-none" style="position-anchor: --a2; position-area: top; background: red">target2</div>
  <div style="height: 300px"></div>
</div>
</div>

<script>
requestAnimationFrame(() => {
  requestAnimationFrame(() => {
    document.getElementById('scroll-container').scrollTop = 50;
    // Force position-area grid computation after the scroll.
    // Initial scroll position causes position area grid for #target1 to have
    // not enough height, as it is bounded by the absolute containing block [1].
    // This causes #target1 to overflow the position area grid applied containing
    // block, which would cause it to shift up [2], overlapping anchor1.
    // [1]: https://drafts.csswg.org/css-anchor-position-1/#position-area-grid-resolution
    // [2]: https://drafts.csswg.org/css-anchor-position-1/#position-area-alignment
    target1.classList.remove('display-none');
    target2.classList.remove('display-none');
    document.documentElement.classList.remove('reftest-wait');
  });
});
</script>
</html>

/css/css-anchor-position/position-visibility-no-overflow-scroll-ref.html

<!DOCTYPE html>
<style>
  #scroll-container {
    overflow: hidden scroll;
    scrollbar-width: none;
    width: 400px;
    height: 150px;
  }

  .anchor {
    width: 100px;
    height: 100px;
    background: orange;
    display: inline-block;
  }

  .target {
    width: 100px;
    height: 100px;
  }
</style>

<div id="scroll-container">
  <div class="anchor">anchor1</div>
  <div class="anchor" style="position: relative; top: 100px">anchor2</div>
  <div id="target1" class="target" style="background: green">target1</div>
  <div style="height: 200px"></div>
</div>
<script>
document.getElementById('scroll-container').scrollTop = 50;
</script>