| <!DOCTYPE html> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <style> |
| @font-face { |
| font-family: 'TestFaceSmaller'; |
| src: url('/fonts/CSSTest/csstest-basic-regular.ttf?pipe=trickle(d0.5)'); |
| size-adjust: 30%; |
| font-display: swap; |
| } |
| |
| .test { |
| font-family: 'TestFaceSmaller'; |
| } |
| |
| </style> |
| <!-- |
| Web-font styled text that gets resized during swap period should not make a |
| LCP emission if the new size is smaller than the current LCP element size. |
| --> |
| <div class="test">LCP: Web Font Styled Text Resize</div> |
| <script> |
| function LCPEntryList(t) { |
| return new Promise(resolve => { |
| let = lcpEntries = []; |
| new PerformanceObserver((entryList, observer) => { |
| lcpEntries = lcpEntries.concat(entryList.getEntries()); |
| if (lcpEntries) { |
| // Adding timeout to wait a bit more so that if there are more than |
| // expected LCP entries emitted, they can be observed. |
| t.step_timeout(() => { |
| resolve(lcpEntries); |
| observer.disconnect(); |
| }, 200); |
| } |
| }).observe({ type: 'largest-contentful-paint', buffered: true }); |
| }); |
| } |
| |
| promise_test(async t => { |
| await document.fonts.ready; |
| |
| // Verify web font is loaded. |
| assert_own_property(window, 'PerformanceResourceTiming', "ResourceTiming not supported"); |
| let url = '/fonts/CSSTest/csstest-basic-regular.ttf?pipe=trickle(d0.5)'; |
| var absoluteURL = new URL(url, location.href).href; |
| assert_equals(performance.getEntriesByName(absoluteURL).length, 1, 'Web font should be downloaded'); |
| |
| // Verify web font is available. |
| assert_true(document.fonts.check('10px TestFaceSmaller'), 'Font should be the web font added'); |
| |
| // Verify there is only one LCP entry. |
| let entryList = await LCPEntryList(t); |
| assert_equals(entryList.length, 1, 'Web font styled text resize that occurs during swap period but is smaller should not make a new LCP emission.') |
| |
| }, "LCP should be not updated if the web font styled text resizes to be smaller during the swap period"); |
| </script> |