helper_overflowhidden_zoom.html

Enable keyboard shortcuts

<!DOCTYPE HTML>

<html>

<head>

  <meta charset="utf-8">

  <meta name="viewport" content="width=device-width, minimum-scale=1.0">

  <title>Tests that zooming in and out doesn't change the scroll position on an overflow hidden document</title>

  <script type="application/javascript" src="apz_test_utils.js"></script>

  <script type="application/javascript" src="apz_test_native_event_utils.js"></script>

  <script src="/tests/SimpleTest/paint_listener.js"></script>

  <style>

    html,body {

      overflow: hidden;

  </style>

</head>

<body>

  <div style="height: 20000px; background-color: green"></div>

  <script>

    const utils = SpecialPowers.getDOMWindowUtils(window);

    async function test() {

      is(await getResolution(), 1.0, "should not be zoomed (1)");

      is(window.scrollX, 0, "shouldn't have scrolled (2)");

      is(window.scrollY, 0, "shouldn't have scrolled (3)");

      is(visualViewport.pageTop, 0, "shouldn't have scrolled (4)");

      is(visualViewport.pageLeft, 0, "shouldn't have scrolled (5)");

      // Force reconstruction of the root scroll frame to trigger bug 1665332.

      document.documentElement.style.display = "flex";

      document.documentElement.offsetLeft;

      document.documentElement.style.display = "";

      document.documentElement.offsetLeft;

      is(await getResolution(), 1.0, "should not be zoomed (6)");

      is(window.scrollX, 0, "shouldn't have scrolled (7)");

      is(window.scrollY, 0, "shouldn't have scrolled (8)");

      is(visualViewport.pageTop, 0, "shouldn't have scrolled (9)");

      is(visualViewport.pageLeft, 0, "shouldn't have scrolled (10)");

      // Zoom in

      SpecialPowers.getDOMWindowUtils(window).setResolutionAndScaleTo(4.0);

      await promiseApzFlushedRepaints();

      is(await getResolution(), 4.0, "should be zoomed (11)");

      is(window.scrollX, 0, "shouldn't have scrolled (12)");

      is(window.scrollY, 0, "shouldn't have scrolled (13)");

      is(visualViewport.pageTop, 0, "shouldn't have scrolled (14)");

      is(visualViewport.pageLeft, 0, "shouldn't have scrolled (15)");

      // Scroll so the visual viewport offset is non-zero

      utils.scrollToVisual(20000, 20000, utils.UPDATE_TYPE_MAIN_THREAD,

                           utils.SCROLL_MODE_INSTANT);

      await promiseApzFlushedRepaints();

      is(await getResolution(), 4.0, "should be zoomed (16)");

      is(window.scrollX, 0, "shouldn't have scrolled (17)");

      is(window.scrollY, 0, "shouldn't have scrolled (18)");

      isnot(visualViewport.pageTop, 0, "should have scrolled (19)");

      isnot(visualViewport.pageLeft, 0, "should have scrolled (20)");

      // Zoom back out

      SpecialPowers.getDOMWindowUtils(window).setResolutionAndScaleTo(1.0);

      await promiseApzFlushedRepaints();

      is(await getResolution(), 1.0, "should not be zoomed (21)");

      is(window.scrollX, 0, "shouldn't have scrolled (22)");

      is(window.scrollY, 0, "shouldn't have scrolled (23)");

      is(visualViewport.pageTop, 0, "shouldn't have scrolled (24)");

      is(visualViewport.pageLeft, 0, "shouldn't have scrolled (25)");

    waitUntilApzStable()

    .then(test)

    .then(subtestDone, subtestFailed);

  </script>

</body>

</html>