chromium/third_party/blink/web_tests/external/wpt/css/css-scroll-snap/snap-after-relayout/multiple-aligned-targets/prefer-inner-target.html

<!DOCTYPE html>
<html>
  <head>
    <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="/dom/events/scrolling/scroll_support.js"></script>
    <script src="/resources/testdriver.js"></script>
    <script src="/resources/testdriver-actions.js"></script>
    <script src="/resources/testdriver-vendor.js"></script>
    <script src="resources/common.js" ></script>
  </head>
  <body>
    <style>
      .scroller {
        overflow: scroll;
        position: relative;
        height: 400px;
        width: 400px;
        border:solid 1px black;
        scroll-snap-type: y mandatory;
      }
      .no-snap { scroll-snap-align: none }
      .scroller div:focus {
        border: solid 1px red;
      }
      .large-space {
        height: 300vh;
        width: 300vw;
        position: absolute;
      }
      .target {
        scroll-snap-align: start;
        position: absolute;
        width: 100px;
        height: 100px;
        border: solid 1px black;
      }
      .top {
        top: 0px;
      }
      .left {
        left: 0px;
      }
      .right {
        left: 200px;
      }
      .bottom {
        top: 200px;
      }
      .inner {
        text-align: right;
      }
      .inner1 {
        height: 150px;
        width: 150px;
        top: 150px;
        left: 100px;
        background-color: blue;
      }
      .inner2 {
        height: 100px;
        width: 100px;
        top: 150px;
        left: 100px;
        background-color: pink;
      }
      .inner3 {
        height: 75px;
        width: 75px;
        top: 150px;
        left: 100px;
        background-color: green;
      }
      .inner4 {
        height: 50px;
        width: 50px;
        top: 150px;
        left: 100px;
        background-color: grey;
      }
      .outer {
        height: 200px;
        width: 200px;
        top: 150px;
        left: 50px;
        left: 50px;
        background-color: yellow;
      }
    </style>
    <div id="scroller" class="scroller">
      <div class="large-space"></div>
      <div class="top left target">Top Left</div>
      <div class="top right target">Top Right</div>
      <div class="outer target" id="outer">Outer</div>
      <div class="inner inner1 target" id="inner1">I1</div>
      <div class="inner inner2 target" id="inner2">I2</div>
      <div class="inner inner3 target" id="inner3">I3</div>
      <div class="inner inner4 target" id="inner4">I4</div>
    </div>
    <script>
      function cleanup() {
        inner.style.top = 100;
        outer.style.top = 100;
      }
      window.onload = (async () => {
        const inner1 = document.getElementById("inner1");
        const inner2 = document.getElementById("inner2");
        const inner3 = document.getElementById("inner3");
        const inner4 = document.getElementById("inner4");
        const outer = document.getElementById("outer");
        const scroller = document.getElementById("scroller");

        promise_test(async (t) => {
          await waitForCompositorCommit();

          await runScrollSnapSelectionVerificationTest(t, scroller,
            /*aligned_elements_x=*/[],
            /*aligned_elements_y=*/[inner1, inner2, inner3, inner4,  outer],
            /*axis=*/"y",
            /*expected_target_x*/null,
            /*expected_target_y*/inner4);

          // Push inner4 outside the snapport. It should no longer be considered
          // the snap target; inner3 is next in line.
          inner4.style.left = "500px";
          await runScrollSnapSelectionVerificationTest(t, scroller,
            /*aligned_elements_x=*/[],
            /*aligned_elements_y=*/[inner1, inner2, inner3, inner4,  outer],
            /*axis=*/"y",
            /*expected_target_x*/null,
            /*expected_target_y*/inner3);

          // Reset inner4's style.
          inner4.style.left = "100px";
        }, "snap container selects innermost area as snap target");

        promise_test(async (t) => {
          t.add_cleanup(() => {
            outer.style.top = "150px";
          });
          await waitForCompositorCommit();

          // Move outer target below inner targets.
          outer.style.top = "400px";

          // Snap to now-below outer target.
          scroller.scrollTop = outer.offsetTop;

          runLayoutSnapSeletionVerificationTest(t, scroller,
            [inner1, inner2, inner3, inner4], outer, "y");
        }, "snap container follows selected snap target after layout change " +
           "(the pre-existing snap target should not be overriden because of " +
           "the innermost area)");
      });
    </script>
  </body>
</html>