helper_doubletap_zoom_noscroll.html

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<!DOCTYPE HTML>

<html>

<head>

  <meta charset="utf-8">

  <meta name="viewport" content="width=2100"/>

  <title>Check that double tapping something tall that we are already zoomed to doesn't scroll (it zooms out)</title>

  <script src="apz_test_native_event_utils.js"></script>

  <script src="apz_test_utils.js"></script>

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

  <script>

function within(a, b, tolerance) {

  return (Math.abs(a-b) < tolerance);

async function test() {

  let useTouchpad = (location.search == "?touchpad");

  let resolution = await getResolution();

  let initial_resolution = resolution;

  ok(resolution > 0,

     "The initial_resolution is " + resolution + ", which is some sane value");

  ok(window.scrollY == 0, "window not scrolled");

  info("window.scrollY " + window.scrollY);

  // Check that double-tapping once zooms in

  await doubleTapOn(document.getElementById("target"), 10, 10, useTouchpad);

  let prev_resolution = resolution;

  resolution = await getResolution();

  ok(resolution > prev_resolution, "The first double-tap has increased the resolution to " + resolution);

  ok(window.scrollY == 0, "window not scrolled");

  info("window.scrollY " + window.scrollY);

  let x = document.getElementById("target").getBoundingClientRect().width/2;

  let y = window.visualViewport.height - 20;

  // Check that near the bottom doesn't scroll but zooms out

  await doubleTapOn(document.getElementById("target"), x, y, useTouchpad);

  prev_resolution = resolution;

  resolution = await getResolution();

  ok(resolution < prev_resolution, "The second double-tap has decreased the resolution to " + resolution);

  // slight float inaccuracy, not sure why

  ok(within(resolution, initial_resolution, 0.0002), "The second double-tap has restored the resolution to " + resolution);

  ok(window.scrollY == 0, "window not scrolled");

  info("window.scrollY " + window.scrollY);

waitUntilApzStable()

.then(test)

.then(subtestDone, subtestFailed);

  </script>

</head>

<body>

<div id="target" style="background: grey; width: 50vw; height: 300vh;">

</body>

</html>