| <!DOCTYPE html> |
| <html> |
| <head> |
| <title>Fling within a large target is not interrupted by scroll snap</title> |
| <link rel="help" href="https://drafts.csswg.org/css-scroll-snap/"/> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="/resources/testdriver.js"></script> |
| <script src="/resources/testdriver-actions.js"></script> |
| <script src="/resources/testdriver-vendor.js"></script> |
| <script src="/dom/events/scrolling/scroll_support.js"></script> |
| </head> |
| <body> |
| <style> |
| main { |
| scroll-snap-type: y; |
| |
| overflow: auto; |
| height: 100vh; |
| } |
| |
| div { |
| scroll-snap-align: start; |
| width: 80vw; |
| height: 800vh; |
| background: yellow; |
| border: solid black 3px; |
| } |
| </style> |
| <main id="scroller"> |
| <div></div> |
| </main> |
| <script> |
| promise_test(async (t) => { |
| await waitForCompositorReady(); |
| const scroller = document.getElementById("scroller"); |
| assert_equals(scroller.scrollTop, 0, "scroller not initially scrolled"); |
| |
| let initial_scroll_top = scroller.scrollTop; |
| let last_scroll_top = initial_scroll_top; |
| const scroll_listener = () => { |
| assert_greater_than_equal(scroller.scrollTop, last_scroll_top, |
| "fling did not move backwards."); |
| last_scroll_top = scroller.scrollTop; |
| } |
| scroller.addEventListener("scroll", scroll_listener); |
| // We expect pointercancel to be triggered when scrolling starts due to |
| // the touch-fling. If we instead get a pointerup event, we know that |
| // scrolling isn't happening and we can immediately fail the test instead |
| // of waiting for a timeout. |
| const pointer_promise = () => { |
| return new Promise((resolve, reject) => { |
| document.addEventListener("pointerup", reject, { once: true }); |
| document.addEventListener("pointercancel", resolve, { once: true }); |
| }); |
| }; |
| |
| try { |
| const scrollend_promise = waitForScrollendEventNoTimeout(scroller); |
| await touchFlingInTarget(/*pixels_to_scroll*/100, scroller, "down"); |
| await pointer_promise; |
| await scrollend_promise; |
| } catch(e) { |
| assert_unreached("Failed to trigger touch fling."); |
| } |
| |
| assert_greater_than(last_scroll_top, initial_scroll_top, |
| "received at least one scroll update."); |
| assert_greater_than_equal(scroller.scrollTop, last_scroll_top, |
| "fling did not move backwards at the end of the scroll."); |
| }, "fling within a large area is not interrupted by scroll snap"); |
| </script> |
| </body> |
| </html> |
