| <!DOCTYPE html> |
| <title> |
| Not re-snap once after a scroll operation has finished without snapping |
| because the scroll destination was outside of the snap proximity threshold. |
| </title> |
| <!-- This test assumes that all major browsers' default scroll-snap proximity |
| thresholds are greater than 200px. --> |
| <link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" /> |
| <link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1780154"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <style> |
| div { |
| position: absolute; |
| margin: 0; |
| } |
| |
| #scroller { |
| height: 600px; |
| width: 600px; |
| overflow: hidden; |
| scroll-snap-type: y proximity; |
| } |
| |
| .snap { |
| width: 300px; |
| height: 300px; |
| background-color: green; |
| scroll-snap-align: start; |
| } |
| |
| .area { |
| width: 2000px; |
| height: 2000px; |
| } |
| </style> |
| |
| <div id="scroller"> |
| <div class="area"></div> |
| <div class="snap" style="top: 0px;"></div> |
| <div class="snap" style="top: 500px;"></div> |
| </div> |
| |
| <script> |
| test(() => { |
| // The initial snap position is at (0, 0). |
| assert_equals(scroller.scrollTop, 0); |
| assert_equals(scroller.scrollLeft, 0); |
| |
| // Scroll to a position where it's outside of the scroll-snap proximity |
| // threshold, so that it won't trigger snapping. |
| scroller.scrollTo(0, 250); |
| |
| assert_equals(scroller.scrollTop, 250); |
| assert_equals(scroller.scrollLeft, 0); |
| |
| // Changing the initial snap target position, but still it's outside of the |
| // threshold. |
| document.querySelectorAll(".snap")[0].style.top = "10px"; |
| |
| // Not re-snap to the last snap point. |
| assert_equals(scroller.scrollTop, 250); |
| assert_equals(scroller.scrollLeft, 0); |
| }, "Not re-snap once after a scroll operation has finished without snapping " + |
| "because the scroll destination was outside of the snap proximity threshold."); |
| </script> |
