| <!DOCTYPE html> |
| <link rel="help" href="https://drafts.csswg.org/css-scroll-snap-1/#scroll-snap-type" /> |
| <title>Mouse-wheel scroll snapping speed</title> |
| <meta name="assert" |
| content="Test passes if mousewheel snaps without pausing"> |
| <style> |
| #scroller { |
| scroll-snap-type: block mandatory; |
| overflow: scroll; |
| height: 400px; |
| width: 400px |
| } |
| #space { |
| width: 200px; |
| height: 4000px; |
| } |
| .box { |
| scroll-snap-align: start; |
| background: blue; |
| margin-bottom: 10px; |
| width: 100px; |
| height: 100px; |
| } |
| </style> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="/resources/testdriver.js"></script> |
| <script src="/resources/testdriver-vendor.js"></script> |
| <script src="/resources/testdriver-actions.js"></script> |
| <script src="../support/common.js"></script> |
| <div id="scroller"> |
| <div class="box"></div> |
| <div class="box"></div> |
| <div id="space"></div> |
| </div> |
| <script> |
| promise_test(async t => { |
| const scroller = document.getElementById("scroller"); |
| scroller.scrollTo(0, 0); |
| assert_equals(scroller.scrollTop, 0, "verify test pre-condition"); |
| const scrollTop = () => { |
| return scroller.scrollTop; |
| }; |
| const scrollPromise = waitForScrollEvent(scroller); |
| const wheelPromise = waitForWheelEvent(scroller); |
| const actions = new test_driver.Actions() |
| .scroll(50, 50, 0, 50, {origin: scroller, duration: 100}); |
| await actions.send(); |
| await wheelPromise; |
| await scrollPromise; |
| let scrollEndTime; |
| let snapEndTime; |
| // Detect first pause in scrolling. |
| const scrollStabilizedPromise = |
| waitForAnimationEnd(scrollTop).then((timestamp) => { |
| scrollEndTime = timestamp; |
| }); |
| const snapEndPromise = |
| waitForScrollTo(scroller, () => { |
| return scroller.scrollTop; |
| }, 110).then((evt) => { |
| snapEndTime = evt.timestamp; |
| }); |
| await Promise.all([scrollStabilizedPromise, snapEndPromise]); |
| assert_equals(scroller.scrollTop, 110, |
| 'Failed to advance to next snap target'); |
| assert_true(snapEndTime < scrollEndTime, |
| 'Detected pause in scrolling before reaching snap target'); |
| }, "Wheel-scroll triggers snap to target position immediately."); |
| </script> |