| <!DOCTYPE HTML> |
| <meta charset=utf-8> |
| <title>Element Timing: observe large elements</title> |
| <body> |
| <style> |
| body { |
| margin: 0; |
| } |
| </style> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="resources/element-timing-helpers.js"></script> |
| <script> |
| let beforeRender; |
| async_test(function (t) { |
| const observer = new PerformanceObserver( |
| t.step_func_done(function(entryList) { |
| assert_equals(entryList.getEntries().length, 1); |
| const entry = entryList.getEntries()[0]; |
| const index = window.location.href.lastIndexOf('/'); |
| const pathname = window.location.href.substring(0, index) + |
| '/resources/square20.jpg'; |
| checkElement(entry, pathname, '', 'large_one', beforeRender); |
| // Assume viewport hasn't changed, so the element occupies all of it. |
| checkRect(entry, |
| [0, document.documentElement.clientWidth, 0, 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. |
| const img = document.createElement('img'); |
| img.src = 'resources/square20.jpg'; |
| img.width = document.documentElement.clientWidth; |
| img.height = document.documentElement.clientHeight; |
| img.setAttribute('id', 'large_one'); |
| document.body.appendChild(img); |
| beforeRender = performance.now(); |
| }; |
| }, 'Large img element is observable.'); |
| </script> |
| |
| </body> |
