| <!DOCTYPE html> |
| <title> |
| The scroller should try to resnap to targets for both axes if possible. |
| </title> |
| <link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap" /> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <style> |
| div { |
| position: absolute; |
| margin: 0; |
| } |
| |
| #scroller { |
| height: 500px; |
| width: 500px; |
| overflow: hidden; |
| scroll-snap-type: both mandatory; |
| } |
| |
| #x-axis-target { |
| scroll-snap-align: none start; |
| background-color: blue; |
| width: 100px; |
| height: 100px; |
| top: 400px; |
| left: 200px; |
| } |
| |
| #y-axis-target { |
| scroll-snap-align: start none; |
| background-color: green; |
| width: 100px; |
| height: 100px; |
| top: 200px; |
| left: 400px; |
| } |
| |
| #far-x-axis-target { |
| scroll-snap-align: none start; |
| background-color: blue; |
| width: 100px; |
| height: 100px; |
| top: 1200px; |
| left: 300px; |
| } |
| |
| #far-y-axis-target { |
| scroll-snap-align: start none; |
| background-color: green; |
| width: 100px; |
| height: 100px; |
| top: 300px; |
| left: 1200px; |
| } |
| |
| .area { |
| width: 2000px; |
| height: 2000px; |
| } |
| </style> |
| |
| <div id="scroller"> |
| <div class="area"></div> |
| <div id="x-axis-target"></div> |
| <div id="y-axis-target"></div> |
| <div id="far-x-axis-target"></div> |
| <div id="far-y-axis-target"></div> |
| </div> |
| |
| <script> |
| |
| const x_target = document.getElementById("x-axis-target"); |
| const y_target = document.getElementById("y-axis-target"); |
| const scroller = document.getElementById("scroller"); |
| |
| test(() => { |
| // The scroller should be snapped to the two closest points on first layout. |
| assert_equals(scroller.scrollTop, 200); |
| assert_equals(scroller.scrollLeft, 200); |
| x_target.style.setProperty("left", "1000px"); |
| y_target.style.setProperty("top", "1000px"); |
| |
| // The style change makes it impossible for the scroller to snap to both |
| // targets, but at least one of the targets should be preserved. The scroller |
| // should then re-evaluate the snap point for the other axis. |
| const snapped_to_x = scroller.scrollLeft == 1000 && scroller.scrollTop == 300; |
| const snapped_to_y = scroller.scrollTop == 1000 && scroller.scrollLeft == 300; |
| assert_true(snapped_to_x || snapped_to_y); |
| }, "Scroller should snap to at least one of the targets if unable to snap to\ |
| both after a layout change."); |
| </script> |
