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<meta charset="utf-8">
<meta name="viewport" content="width=2100"/>
<title>Check that double tapping an element that doesn't fill the width of the viewport as maximum zoom centers it</title>
<script type="application/javascript" src="apz_test_native_event_utils.js"></script>
<script type="application/javascript" src="apz_test_utils.js"></script>
<script src="/tests/SimpleTest/paint_listener.js"></script>
<script type="application/javascript">
async function test() {
let useTouchpad = ( == "?touchpad");
var resolution = await getResolution();
ok(resolution > 0,
"The initial_resolution is " + resolution + ", which is some sane value");
// Check that double-tapping once zooms in
await doubleTapOn(document.getElementById("target"), 10, 10, useTouchpad);
var prev_resolution = resolution;
resolution = await getResolution();
ok(resolution > 2*prev_resolution, "The first double-tap has increased the resolution to " + resolution);
info("window.innerWidth " + window.innerWidth); // value when writing this test: 1280
info("visualViewport.offsetLeft " + visualViewport.offsetLeft); //value when writing this test: 625 with bug, 537 with fix
info("visualViewport.width " + visualViewport.width); // value when writing this test: 253
// the left hand edge of the div is at window.innerWidth/2
// we want approximately half of the visual viewport width to be to the left of that point.
// we have to remove the 50 pixels for the width of the div from that first though.
// we multiply that by 80% to factor in the 15 pixel margin we give the zoomed-to element
// (we don't hard code 15 though since we might want to tweak that)
ok(visualViewport.offsetLeft < window.innerWidth/2 - 0.8*(visualViewport.width-50)/2, "moved over far enough");
// and then have a sanity check that it's not too small.
// using the same 20% factor as before but in the other direction.
ok(visualViewport.offsetLeft > window.innerWidth/2 - 1.2*(visualViewport.width-50)/2, "but not too far");
.then(subtestDone, subtestFailed);
<div id="target" style="background: blue; width: 50px; height: 50px; position: absolute; left: 50vw;"></div>