<meta charset=utf-8>

<title>Element Timing: intersectionRect when image overflows</title>

body {

margin: 200px 100px;

}

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="resources/element-timing-helpers.js"></script>

let beforeRender;

let img;

async_test(function (t) {

assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented");

const observer = new PerformanceObserver(

t.step_func_done(function(entryList) {

assert_equals(entryList.getEntries().length, 1);

const entry = entryList.getEntries()[0];

const pathname = window.location.origin + '/element-timing/resources/square20.png';

checkElement(entry, pathname, 'not_fully_visible', '', beforeRender, img);

// Image will not be fully visible. It should start from the top left part

// of the document, excluding the margin, and then overflow.

checkRect(entry,

[100, document.documentElement.clientWidth, 200, document.documentElement.clientHeight]);

checkNaturalSize(entry, 20, 20);

})

);

observer.observe({entryTypes: ['element']});

// We add the image during onload to be sure that the observer is registered

// in time for it to observe the element timing.

window.onload = () => {

// Add an image setting width and height equal to viewport.

img = document.createElement('img');

img.src = 'resources/square20.png';

img.setAttribute('elementtiming', 'not_fully_visible');

img.width = document.documentElement.clientWidth;

img.height = document.documentElement.clientHeight;

document.body.appendChild(img);

beforeRender = performance.now();

};

}, 'The intersectionRect of an img element overflowing is computed correctly');