| <!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="/dom/events/scrolling/scroll_support.js"></script> |
| <script src="../support/common.js"></script> |
| |
| <div id="scroller"> |
| <div class="box"></div> |
| <div id="target" class="box"></div> |
| <div id="space"></div> |
| </div> |
| <script> |
| promise_test(async t => { |
| await waitForCompositorReady(); |
| 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 targetBounds = |
| document.getElementById('target').getBoundingClientRect(); |
| const dy = targetBounds.top / 2 + 1; |
| const actions = new test_driver.Actions() |
| .scroll(50, 50, 0, dy, {origin: scroller, duration: 100}); |
| await actions.send(); |
| await wheelPromise; |
| await scrollPromise; |
| // Detect first pause in scrolling. As expected to snap right at the end of |
| // the scroll, there should be no appreciable pause before the snap takes |
| // place. Once the scrolling settles, we are expected to be at the snap |
| // position. |
| const scrollStabilizedPromise = waitForAnimationEnd(scrollTop); |
| await scrollStabilizedPromise; |
| assert_approx_equals(scroller.scrollTop, 110, 0.5, |
| 'Failed to advance to next snap target'); |
| }, "Wheel-scroll triggers snap to target position without intermediate pause."); |
| </script> |
