Blitz - WPT: anchor-center-scroll-vertical-wm-001.html

wpt / css / css-anchor-position / anchor-center-scroll-vertical-wm-001.html

/css/css-anchor-position/anchor-center-scroll-vertical-wm-001.html

<!DOCTYPE html>
<title>CSS Anchor Positioning Test: scroll adjusted anchor-center with a vertical writing-mode containing block</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#anchor-center">
<link rel="match" href="anchor-center-scroll-vertical-wm-001-ref.html">
<meta name="assert" content="An abspos box with justify-self:anchor-center whose containing block is a vertical writing mode stays centered on its anchor along the block (vertical) axis after the anchor's scroller scrolls.">
<style>
  body { margin: 0; }
  /* The containing block of #anchored. Its vertical writing-mode makes
     justify-self the property that controls the vertical (Y) axis. */
  #cb {
    position: relative;
    writing-mode: vertical-rl;
    width: 400px;
    height: 400px;
  }
  /* Reset to horizontal so the scroller's internal layout/scroll matches
     the horizontal-writing-mode scroll tests. */
  #scroller {
    writing-mode: horizontal-tb;
    width: 400px;
    height: 400px;
    overflow: auto;
    background: orange;
  }
  #spacer { height: 100px; }
  #anchor {
    width: 100px;
    height: 100px;
    background: pink;
    anchor-name: --anchor;
  }
  #anchored {
    position: absolute;
    position-anchor: --anchor;
    justify-self: anchor-center;
    left: 0;
    width: 50px;
    height: 50px;
    background: purple;
  }
  #filler { height: 1000px; }
</style>
<div id="cb">
  <div id="scroller">
    <div id="spacer"></div>
    <div id="anchor"></div>
    <div id="filler"></div>
  </div>
  <div id="anchored"></div>
</div>
<script>
  scroller.offsetTop;
  scroller.scrollTop = 100;
</script>

/css/css-anchor-position/anchor-center-scroll-vertical-wm-001-ref.html

<!DOCTYPE html>
<title>CSS Test Reference</title>
<body style="margin:0">
  <!-- Reproduces the post-scroll layout with a real scroller so the scrollbar
       matches the test. The anchored box is a static child of the anchor,
       centered on it vertically (25px = (100 - 50) / 2). -->
  <div id="scroller" style="width:400px;height:400px;overflow:auto;background:orange">
    <div style="height:100px"></div>
    <div style="width:100px;height:100px;background:pink">
      <div style="height:25px"></div>
      <div style="width:50px;height:50px;background:purple"></div>
    </div>
    <div style="height:1000px"></div>
  </div>
</body>
<script>
  scroller.scrollTop = 100;
</script>