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<!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(t => {
// 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>
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