Blitz - WPT: multicol-gap-decorations-repaint-on-content-resize.html

wpt / css / css-gaps / multicol / multicol-gap-decorations-repaint-on-content-resize.html

/css/css-gaps/multicol/multicol-gap-decorations-repaint-on-content-resize.html

<!DOCTYPE html>
<html class="reftest-wait">
<head>
  <title>CSS Gap Decorations: repaint when multicol content height changes</title>
  <link rel="help" href="https://drafts.csswg.org/css-gaps-1/">
  <link rel="match" href="multicol-gap-decorations-repaint-on-content-resize-ref.html">
  <link rel="author" title="Kevin Babbitt" href="mailto:kbabbitt@microsoft.com">
  <meta name="assert" content="Gap decorations repaint correctly when multicol content height changes, causing column rule positions to update">
  <style>
    .multicol-container {
      columns: 2;
      column-fill: auto;
      column-gap: 20px;
      width: 160px;
      height: 50px;
      background: red;
      column-rule: 20px solid green;
    }

    .content {
      background: green;
      /* Start at 30px (fits in one column), will change to 100px (overflows
         into second column). The column rule should repaint at the correct
         position between the two columns. */
      height: 30px;
    }
  </style>
</head>
<body>
  <p>Test passes if there is a filled green rectangle and <strong>no red</strong>.</p>
  <div class="multicol-container">
    <div id="content" class="content"></div>
  </div>
  <script>
    // Use double requestAnimationFrame to ensure style is computed and painted.
    requestAnimationFrame(() => {
      requestAnimationFrame(() => {
        // Change the content height so it overflows into a second column.
        // The column rule should repaint between the two columns.
        document.getElementById('content').style.height = '100px';
        document.documentElement.classList.remove("reftest-wait");
      });
    });
  </script>
</body>
</html>

/css/css-gaps/multicol/multicol-gap-decorations-repaint-on-content-resize-ref.html

<!DOCTYPE html>
<html>
<head>
  <title>CSS Gap Decorations: repaint when multicol content height changes (reference)</title>
  <link rel="author" title="Kevin Babbitt" href="mailto:kbabbitt@microsoft.com">
  <style>
    .multicol-container {
      columns: 2;
      column-fill: auto;
      column-gap: 20px;
      width: 160px;
      height: 50px;
      background: red;
      column-rule: 20px solid green;
    }

    .content {
      background: green;
      /* Final height after change */
      height: 100px;
    }
  </style>
</head>
<body>
  <p>Test passes if there is a filled green rectangle and <strong>no red</strong>.</p>
  <div class="multicol-container">
    <div class="content"></div>
  </div>
</body>
</html>