<!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;
}
.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;
}
</style>
<div id="scroller" class="scroller">
<div class="large-space no-snap" tabindex="1" id="space"></div>
<div id="topleft" tabindex="1" class="top left target">top left</div>
<div id="topright" tabindex="1" class="top right target">top right</div>
<div id="bottomleft" tabindex="1" class="bottom left target">bottom left</div>
<div id="bottomright" tabindex="1" class="bottom right target">bottom right</div>
</div>
<script>
window.onload = () => {
const bottomright = document.getElementById("bottomright");
const bottomleft = document.getElementById("bottomleft");
const scroller = document.getElementById("scroller");
async function commonInitialization() {
await waitForCompositorCommit();
assert_equals(scroller.scrollTop, 0, "snapped to top row");
}
promise_test(async (t) => {
await commonInitialization();
focusAndAssert(bottomright);
await runScrollSnapSelectionVerificationTest(t, scroller,
/*aligned_elements_x=*/[],
/*aligned_elements_y=*/[bottomright, bottomleft],
/*axis=*/"y",
/*expected_target_x=*/null,
/*expected_target_y=*/bottomright);
focusAndAssert(bottomleft);
await runScrollSnapSelectionVerificationTest(t, scroller,
/*aligned_elements_x=*/[],
/*aligned_elements_y=*/[bottomright, bottomleft],
/*axis=*/"y",
/*expected_target_x=*/null,
/*expected_target_y=*/bottomleft);
}, "scroller selects focused target from aligned choices on snap");
promise_test(async (t) => {
t.add_cleanup(() => {
bottomright.style.left = "200px";
})
await commonInitialization();
// Move bottomright out of the snapport.
bottomright.style.left = "500px";
// Set focus on bottomright without scrolling to it.
focusAndAssert(bottomright, true);
await runScrollSnapSelectionVerificationTest(t, scroller,
/*aligned_elements_x=*/[],
/*aligned_elements_y=*/[bottomright, bottomleft],
/*axis=*/"y",
/*expected_target_x=*/null,
/*expected_target_y=*/bottomleft);
}, "out-of-viewport focused element is not the selected snap target.");
promise_test(async(t) => {
t.add_cleanup(() => {
bottomleft.style.top = "200px";
});
await commonInitialization();
// Set focus on bottomright without scrolling to it.
focusAndAssert(bottomright, true);
// Move bottomleft below bottomright.
bottomleft.style.top = "400px";
// Snap to bottomleft.
scroller.scrollTop = bottomleft.offsetTop;
// Test that if bottomright is also shifted so that it is aligned with
// bottomleft, bottomleft remains the selected snap target, despite
// bottomright's having focus.
await runLayoutSnapSeletionVerificationTest(t, scroller, [bottomright],
bottomleft, "y");
}, "scroller follows selected snap target through layout shift," +
"regardless of focus");
}
</script>
</body>
</html>
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