| Tom McKee | 69105b6 | 2019-09-13 19:16:41 | [diff] [blame] | 1 | <!DOCTYPE HTML> |
| 2 | <meta charset=utf-8> |
| 3 | <title>Largest Contentful Paint: size when image overflows</title> |
| Tom McKee | 69105b6 | 2019-09-13 19:16:41 | [diff] [blame] | 4 | <body> |
| 5 | <style> |
| 6 | body { |
| 7 | /* Preventing a scrollbar from showing and removing any margins simplifies |
| 8 | the calculations below. */ |
| 9 | overflow: hidden; |
| 10 | margin: 0px; |
| 11 | } |
| 12 | </style> |
| 13 | <script src="/resources/testharness.js"></script> |
| 14 | <script src="/resources/testharnessreport.js"></script> |
| 15 | <script src="resources/largest-contentful-paint-helpers.js"></script> |
| 16 | <script> |
| 17 | let beforeRender; |
| 18 | const viewportWidth = document.documentElement.clientWidth; |
| 19 | const viewportHeight = document.documentElement.clientHeight; |
| Blink WPT Bot | 8e56de1 | 2020-10-02 20:11:40 | [diff] [blame^] | 20 | const imgWidth = 100; |
| 21 | const imgHeight = 50; |
| Tom McKee | 69105b6 | 2019-09-13 19:16:41 | [diff] [blame] | 22 | async_test(function (t) { |
| Blink WPT Bot | 8e56de1 | 2020-10-02 20:11:40 | [diff] [blame^] | 23 | assert_implements(window.LargestContentfulPaint, "LargestContentfulPaint is not implemented"); |
| Tom McKee | 69105b6 | 2019-09-13 19:16:41 | [diff] [blame] | 24 | const beforeLoad = performance.now(); |
| 25 | new PerformanceObserver( |
| 26 | t.step_func_done(function(entryList) { |
| 27 | assert_equals(entryList.getEntries().length, 1); |
| 28 | const entry = entryList.getEntries()[0]; |
| 29 | const url = window.location.origin + '/images/green-100x50.png'; |
| 30 | // To compute the size, compute the percentage of the image visible and |
| Blink WPT Bot | 8e56de1 | 2020-10-02 20:11:40 | [diff] [blame^] | 31 | // scale by its natural dimensions. In this test, the image is expanded to twice its size |
| 32 | // but place towards the bottom right corner of the viewport, so it is |
| Tom McKee | 69105b6 | 2019-09-13 19:16:41 | [diff] [blame] | 33 | // effectively clipped to 50% by 50% of its display size. Scaling by |
| 34 | // its natural width and height of 100px and 50px respectively, leads |
| 35 | // to a weighted size of 50 by 25. |
| Blink WPT Bot | 8e56de1 | 2020-10-02 20:11:40 | [diff] [blame^] | 36 | const truncatedWidth = imgWidth / 2; |
| 37 | const truncatedHeight = imgHeight / 2; |
| Tom McKee | 69105b6 | 2019-09-13 19:16:41 | [diff] [blame] | 38 | const weightedSize = truncatedWidth * truncatedHeight; |
| 39 | checkImage(entry, url, 'image_id', weightedSize, beforeLoad); |
| 40 | }) |
| 41 | ).observe({type: 'largest-contentful-paint', buffered: true}); |
| 42 | // Add an image, setting width and height equal to viewport. |
| 43 | img = document.createElement('img'); |
| 44 | img.src = '/images/green-100x50.png'; |
| 45 | img.id = 'image_id'; |
| Blink WPT Bot | 8e56de1 | 2020-10-02 20:11:40 | [diff] [blame^] | 46 | img.width = imgWidth * 2; |
| 47 | img.height = imgHeight * 2; |
| 48 | img.style.position = 'absolute'; |
| 49 | img.style.left = viewportWidth - imgWidth + 'px'; |
| 50 | img.style.top = viewportHeight - imgHeight + 'px'; |
| Tom McKee | 69105b6 | 2019-09-13 19:16:41 | [diff] [blame] | 51 | document.body.appendChild(img); |
| 52 | }, 'The intersectionRect of an img element overflowing is computed correctly'); |
| 53 | </script> |
| 54 | </body> |
