| <!DOCTYPE html> |
| <html> |
| |
| <head> |
| <link rel="help" href="https://drafts.csswg.org/css-scroll-snap-2/#snap-events" /> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="/dom/events/scrolling/scroll_support.js"></script> |
| <script src="/css/css-scroll-snap-2/resources/common.js"></script> |
| <script src="/web-animations/testcommon.js"></script> |
| </head> |
| |
| <body> |
| <style> |
| #scroller { |
| overflow: scroll; |
| scroll-snap-type: y mandatory; |
| height: 200px; |
| width: 200px; |
| border: solid 1px; |
| position: absolute; |
| } |
| |
| .snap_area { |
| position: absolute; |
| width: 100px; |
| left: calc(50% - 50px); |
| } |
| |
| #outer_snap_area { |
| scroll-snap-align: start none; |
| height: 1000px; |
| background-color: blue; |
| } |
| |
| #inner_snap_area { |
| scroll-snap-align: start none; |
| height: 100px; |
| top: 100px; |
| background-color: yellow; |
| } |
| </style> |
| <div id="scroller"> |
| <div id="outer_snap_area" class="snap_area"></div> |
| <div id="inner_snap_area" class="snap_area"></div> |
| </div> |
| <script> |
| let scroller = document.getElementById("scroller"); |
| |
| async function reset(t) { |
| inner_snap_area.style.height = "100px"; |
| inner_snap_area.style.scrollSnapAlign = "start none"; |
| outer_snap_area.style.scrollSnapAlign = "start none"; |
| scroller.style.scrollSnapType = "y mandatory"; |
| await resetTargetScrollState(t, scroller); |
| } |
| |
| async function setup(t) { |
| checkSnapEventSupport("scrollsnapchange"); |
| await reset(t); |
| await waitForCompositorCommit(); |
| assert_equals(scroller.scrollTop, 0, "test precondition: scroller " + |
| "is not scrolled."); |
| } |
| |
| promise_test(async (t) => { |
| await setup(t); |
| let target_snap_position = inner_snap_area.offsetTop + |
| inner_snap_area.offsetHeight; |
| // Scroll to an offset close to the bottom of the inner snap area and |
| // expect to snap to an offset just below this snap area. |
| let scrollend_promise = waitForScrollendEventNoTimeout(scroller); |
| scroller.scrollTo(0, target_snap_position - 10); |
| await scrollend_promise; |
| assert_equals(scroller.scrollTop, target_snap_position, |
| "scroller snaps to just below the inner snap area."); |
| // We are just below the inner snap area. Increase its height so that it |
| // is larger than the snapport and straddled by the snapport. Verify |
| // that we snap to its bottom. |
| let scrollsnapchange_promise = waitForScrollSnapChangeEvent(scroller); |
| inner_snap_area.style.height = |
| `${scroller.clientHeight + inner_snap_area.clientHeight - 10}px`; |
| const evt = await scrollsnapchange_promise; |
| assertSnapEvent(evt, { block: inner_snap_area, inline: null }); |
| target_snap_position = inner_snap_area.offsetTop + |
| inner_snap_area.offsetHeight - scroller.clientHeight; |
| assert_equals(scroller.scrollTop, target_snap_position, |
| "scroller snaps to the bottom of the smaller snap area (which is " + |
| "now covering)."); |
| }, "scrollsnapchange fires after snap area is snapped to upon layout change."); |
| |
| promise_test(async (t) => { |
| await setup(t); |
| let target_snap_position = inner_snap_area.offsetTop + |
| inner_snap_area.offsetHeight; |
| // Scroll to an offset close to the bottom of the inner snap area and |
| // expect to snap to an offset just below this snap area. |
| let scrollend_promise = waitForScrollendEventNoTimeout(scroller); |
| scroller.scrollTo(0, target_snap_position - 10); |
| await scrollend_promise; |
| assert_equals(scroller.scrollTop, target_snap_position, |
| "scroller snaps to just below the inner snap area."); |
| // We are just below the inner snap area. Increase its height so that it |
| // is larger than the snapport making the current scroll position |
| // a valid covering position within the inner snap area. |
| let scrollsnapchange_promise = waitForScrollSnapChangeEvent(scroller, false); |
| inner_snap_area.style.height = |
| `${scroller.clientHeight + inner_snap_area.clientHeight + 10}px`; |
| const evt = await scrollsnapchange_promise; |
| assertSnapEvent(evt, { block: inner_snap_area, inline: null }); |
| assert_equals(scroller.scrollTop, target_snap_position, |
| "scroller maintains offset which is now covering within inner area"); |
| }, "scrollsnapchange fires after snap area is snapped to upon layout change " + |
| "without scroll."); |
| |
| promise_test(async(t) => { |
| await setup(t); |
| await waitForCompositorCommit(); |
| let scrollsnapchange_promise = waitForScrollSnapChangeEvent(scroller, false); |
| scroller.style.scrollSnapType = "none"; |
| let evt = await scrollsnapchange_promise; |
| assertSnapEvent(evt, { block: null, inline: null }); |
| scrollsnapchange_promise = waitForScrollSnapChangeEvent(scroller, false); |
| scroller.style.scrollSnapType = "y mandatory"; |
| evt = await scrollsnapchange_promise; |
| assertSnapEvent(evt, { block: outer_snap_area, inline: null }); |
| }, "scrollsnapchange fires when container stops snapping"); |
| |
| promise_test(async(t) => { |
| await setup(t); |
| await waitForCompositorCommit(); |
| let scrollsnapchange_promise = waitForScrollSnapChangeEvent(scroller, false); |
| inner_snap_area.style.scrollSnapAlign = "none"; |
| outer_snap_area.style.scrollSnapAlign = "none"; |
| let evt = await scrollsnapchange_promise; |
| assertSnapEvent(evt, { block: null, inline: null }); |
| scrollsnapchange_promise = waitForScrollSnapChangeEvent(scroller, false); |
| inner_snap_area.style.scrollSnapAlign = "start"; |
| outer_snap_area.style.scrollSnapAlign = "start"; |
| evt = await scrollsnapchange_promise; |
| assertSnapEvent(evt, { block: outer_snap_area, inline: null }); |
| }, "scrollsnapchange fires when snap container no longer has snap areas"); |
| </script> |
| </body> |
| </html> |
