scroll-timeline-in-delay-omta.html

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<!DOCTYPE html>

<html class="reftest-wait reftest-no-flush">

<head>

<title>Scroll the scroll-driven animation from the active phase to delay</title>

<style>

  @keyframes anim {

    from { translate: 100px; }

    to { translate: 200px; }

  #scroller {

    width: 100px;

    height: 100px;

    overflow: scroll;

    scrollbar-width: none;

    scroll-timeline: --scroll_timeline;

  #target {

    width: 100px;

    height: 100px;

    background: green;

    rotate: 45deg;

    translate: 50px;

    animation-name: anim;

    animation-duration: 5s;

    animation-timing-function: linear;

    animation-delay: 5s;

    animation-timeline: --scroll_timeline;

</style>

<script>

window.addEventListener("MozReftestInvalidate", async () => {

  const scroller = document.getElementById("scroller");

  scroller.scrollTop = 75;

  // Wait for the MozAfterPaint to make the view id of |scroller| gets ready.

  window.addEventListener('MozAfterPaint', async () => {

    let utils = SpecialPowers.wrap(window).windowUtils;

    utils.setAsyncScrollOffset(scroller, 0, -50);

    await new Promise(function(resolve, reject) {

      let repaintDone = function() {

        SpecialPowers.Services.obs.removeObserver(

          repaintDone,

          "apz-repaints-flushed"

);

        resolve();

};

      SpecialPowers.Services.obs.addObserver(repaintDone,

                                             "apz-repaints-flushed");

      if (!utils.flushApzRepaints()) {

        repaintDone();

});

    // Wait for composition and then take the snapshot.

    await new Promise(resolve => { requestAnimationFrame(resolve); });

    await new Promise(resolve => { requestAnimationFrame(resolve); });

    document.documentElement.classList.remove('reftest-wait');

  }, {once: true});

});

</script>

</head>

<body>

  <div id="scroller">

    <div style="height: 100px; padding-bottom: 100px;"></div>

  </div>

  <div id="target"></div>

</body>

</html>