| Steve Kobes | eab5fd8 | 2019-11-27 20:52:07 | [diff] [blame] | 1 | <!DOCTYPE html> |
| 2 | <title>Layout Instability: shift in pointerdown becoming scroll</title> |
| 3 | <link rel="help" href="https://wicg.github.io/layout-instability/" /> |
| 4 | <style> |
| 5 | |
| 6 | body { margin: 0; height: 2000px; } |
| 7 | #box { |
| 8 | left: 0px; |
| 9 | top: 0px; |
| 10 | width: 400px; |
| 11 | height: 500px; |
| 12 | background: yellow; |
| 13 | position: relative; |
| 14 | } |
| 15 | |
| 16 | </style> |
| 17 | <div id="box"></div> |
| 18 | <script src="/resources/testharness.js"></script> |
| 19 | <script src="/resources/testharnessreport.js"></script> |
| 20 | <script src="/resources/testdriver.js"></script> |
| 21 | <script src="/resources/testdriver-actions.js"></script> |
| 22 | <script src="/resources/testdriver-vendor.js"></script> |
| 23 | <script src="resources/util.js"></script> |
| 24 | <script> |
| 25 | |
| 26 | const box = document.querySelector("#box"); |
| 27 | box.addEventListener("pointerdown", (e) => { |
| 28 | // Generate a layout shift before we know what type of input this pointer |
| 29 | // event sequence will become. |
| 30 | box.style.top = "100px"; |
| 31 | e.preventDefault(); |
| 32 | }); |
| 33 | |
| 34 | generateScrollSequence = () => new test_driver.Actions() |
| 35 | .addPointer("tp1", "touch") |
| 36 | .pointerMove(0, 100, {sourceName: "tp1"}) |
| 37 | .pointerDown({sourceName: "tp1"}) |
| 38 | .pointerMove(0, 0, {sourceName: "tp1"}) |
| 39 | .pause(100) |
| 40 | .pointerUp({sourceName: "tp1"}) |
| 41 | .pause(100); |
| 42 | |
| 43 | promise_test(async () => { |
| 44 | const watcher = new ScoreWatcher; |
| 45 | |
| 46 | // Wait for the initial render to complete. |
| 47 | await waitForAnimationFrames(2); |
| 48 | |
| 49 | // Send pointer events for a touch scroll. |
| 50 | await generateScrollSequence().send(); |
| 51 | |
| 52 | // The box is 400 x 500 and moves by 100px. |
| 53 | const expectedScore = computeExpectedScore(400 * (500 + 100), 100); |
| 54 | |
| 55 | // Both scores should increase (scroll doesn't count as input for the purpose |
| 56 | // of the LayoutShift.hadRecentInput bit). |
| 57 | assert_equals(watcher.score, expectedScore); |
| 58 | assert_equals(watcher.scoreWithInputExclusion, expectedScore); |
| 59 | |
| 60 | }, "Shift in pointerdown reported when it becomes a scroll."); |
| 61 | |
| 62 | </script> |
