| <!DOCTYPE HTML> |
| <meta charset=utf-8> |
| <title>Element Timing: multiple images</title> |
| <body> |
| <style> |
| body { |
| margin: 0; |
| } |
| #img1 { |
| display: block; |
| margin-left: auto; |
| margin-right: auto; |
| } |
| #img2 { |
| margin-top:150px; |
| margin-left:50px; |
| } |
| </style> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="resources/element-timing-helpers.js"></script> |
| <script> |
| let beforeRender, image1Observed=0, image2Observed=0, image3Observed=0; |
| async_test(function (t) { |
| assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented"); |
| const observer = new PerformanceObserver( |
| t.step_func(function(entryList) { |
| entryList.getEntries().forEach( entry => { |
| if (entry.identifier === 'image1') { |
| if (image1Observed) { |
| assert_unreached("Observer received image1 more than once"); |
| t.done(); |
| } |
| image1Observed = 1; |
| const pathname1 = window.location.origin + '/element-timing/resources/square100.png'; |
| // The images do not contain ID, so expect an empty ID. |
| checkElement(entry, pathname1, 'image1', 'img1', beforeRender, |
| document.getElementById('img1')); |
| // This image is horizontally centered. |
| // Using abs and comparing to 1 because the viewport sizes could be odd. |
| // If a size is odd, then image cannot be in the pure center, but left |
| // and right should still be very close to their estimated coordinates. |
| assert_less_than_equal(Math.abs(entry.intersectionRect.left - |
| (document.documentElement.clientWidth / 2 - 50)), 1, |
| 'left of rect for image1'); |
| assert_less_than_equal(Math.abs(entry.intersectionRect.right - |
| (document.documentElement.clientWidth / 2 + 50)), 1, |
| 'right of rect for image1'); |
| assert_equals(entry.intersectionRect.top, 0, 'top of rect for image1'); |
| assert_equals(entry.intersectionRect.bottom, |
| 100, 'bottom of rect for image1'); |
| checkNaturalSize(entry, 100, 100); |
| } |
| else if (entry.identifier === 'image2') { |
| if (image2Observed) { |
| assert_unreached("Observer received image2 more than once"); |
| t.done(); |
| } |
| image2Observed = 1; |
| const pathname2 = window.location.origin + '/element-timing/resources/square20.png'; |
| checkElement(entry, pathname2, 'image2', 'img2', beforeRender, |
| document.getElementById('img2')); |
| // This image should be below image 1, and should respect the margin. |
| checkRect(entry, [50, 250, 250, 450], "of image2"); |
| checkNaturalSize(entry, 20, 20); |
| } |
| else if (entry.identifier === 'image3') { |
| if (image3Observed) { |
| assert_unreached("Observer received image3 more than once"); |
| t.done(); |
| } |
| image3Observed = 1; |
| const pathname3 = window.location.origin + '/element-timing/resources/circle.svg'; |
| checkElement(entry, pathname3, 'image3', 'img3', beforeRender, |
| document.getElementById('img3')); |
| // This image is just to the right of image2. |
| checkRect(entry, [250, 450, 250, 450], "of image3"); |
| checkNaturalSize(entry, 200, 200); |
| } |
| else { |
| assert_unreached("Received an unexpected identifier."); |
| t.done(); |
| } |
| if (image1Observed && image2Observed && image3Observed) { |
| t.done(); |
| } |
| }); |
| }) |
| ); |
| observer.observe({entryTypes: ['element']}); |
| function addImage(number, source, width=0) { |
| const img = document.createElement('img'); |
| img.src = source; |
| // Set a different id and elementtiming value for each image. |
| img.id = 'img' + number; |
| img.setAttribute('elementtiming', 'image' + number); |
| if (width !== 0) |
| img.width = width; |
| document.body.appendChild(img); |
| } |
| // Add the images during onload to be sure that the observer is registered in |
| // time to observe the element timing. |
| window.onload = () => { |
| addImage(1, 'resources/square100.png'); |
| // Use requestAnimationFrame and a timeout to ensure that the images are |
| // processed in the order we want. |
| requestAnimationFrame( () => { |
| t.step_timeout( () => { |
| // Set the size equal to that of image3 to make positioning easier. |
| addImage(2, 'resources/square20.png', 200); |
| requestAnimationFrame( () => { |
| t.step_timeout( () => { |
| addImage(3, 'resources/circle.svg'); |
| }, 0); |
| }); |
| }, 0); |
| }); |
| beforeRender = performance.now(); |
| }; |
| }, 'PerformanceObserver can observe multiple image elements.'); |
| </script> |
| </body> |