| <!doctype html> |
| <html> |
| <head> |
| <link rel="help" href="https://html.spec.whatwg.org/multipage/webappapis.html#update-the-rendering"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| </head> |
| <body> |
| <script> |
| /* Coarsen to 5 microseconds or coarser */ |
| const COARSE_RESOLUTION = 0.005; |
| |
| const CUSTOM_TIMELINE_DELTA = 0.002; |
| const FLOATING_POINT_ERROR_EPSILON = 0.01; |
| |
| // Note that this test would fail if the platform introduces a jitter. |
| // It is recommended that platforms that implement jitter run this test |
| // with a flag that turns jitter off, if possible. |
| |
| const customTimeline = new DocumentTimeline({originTime: CUSTOM_TIMELINE_DELTA}); |
| promise_test(async t => { |
| for (let i = 0; i < 32; ++i) { |
| const timestamp = await new Promise(resolve => requestAnimationFrame(ts => resolve(ts))); |
| const coarse_timestamp = Math.round(timestamp / COARSE_RESOLUTION) * COARSE_RESOLUTION; |
| assert_approx_equals(timestamp, coarse_timestamp, FLOATING_POINT_ERROR_EPSILON, |
| "timestamp should be coarsened"); |
| assert_approx_equals(timestamp, document.timeline.currentTime, FLOATING_POINT_ERROR_EPSILON, |
| "document.timeline.currentTimeline should be the same as the rAF callback"); |
| assert_approx_equals(customTimeline.currentTime + CUSTOM_TIMELINE_DELTA, |
| timestamp, FLOATING_POINT_ERROR_EPSILON, |
| "originTime for custom timeline should not be coarsened"); |
| } |
| }); |
| </script> |
| </body> |
| </html> |
