87 lines
2.3 KiB
HTML
87 lines
2.3 KiB
HTML
<!DOCTYPE html>
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<meta name="viewport" content="width=device-width">
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<title>
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Snap to points of combinations of two different elements
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</title>
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<link rel="help" href="https://drafts.csswg.org/css-scroll-snap-1/"/>
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<script src="/resources/testharness.js"></script>
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<script src="/resources/testharnessreport.js"></script>
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<style>
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div {
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position: absolute;
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margin: 0px;
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}
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#scroller {
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height: 600px;
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width: 600px;
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overflow: hidden;
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scroll-snap-type: both mandatory;
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}
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#space {
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width: 2000px;
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height: 2000px;
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}
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#left-top {
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/*
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* the scroll position of this `scroll-snap-align: start start` is (200, 200)
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*/
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left: 200px;
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top: 200px;
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height: 450px;
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width: 450px;
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background-color: rgb(255, 0, 0);
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opacity: 0.5;
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scroll-snap-align: start start;
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}
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#right-bottom {
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/*
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* the scroll position of this `scroll-snap-align: end end` is (50, 250),
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* i.e, (`left` - scroll container's `width` + this element's `width,
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`top` - scroll container's `height` + this element's `height)
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*/
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left: 600px;
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top: 800px;
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width: 50px;
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height: 50px;
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background-color: rgb(0, 255, 0);
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opacity: 0.5;
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scroll-snap-align: end end;
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}
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</style>
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<div id="scroller">
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<div id="space"></div>
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<div id="left-top"></div>
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<div id="right-bottom"></div>
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</div>
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<script>
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test(t => {
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// There are four combinations of snap positions defined by #top-left and
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// #right-bottom elements.
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// (200, 200), (50, 250), (200, 250) and (50, 200).
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// But snapping to (50, 200) leaves the snap area of #right-bottom element
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// outside of the snapport, thus it won't be a valid snap position.
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const scroller = document.getElementById("scroller");
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// The nearest valid snap position from (0, 0) is (50, 250).
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assert_equals(scroller.scrollLeft, 50);
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assert_equals(scroller.scrollTop, 250);
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// (50, 200) is not valid, thus the nearest one from (100, 150) is (200, 200).
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scroller.scrollTo(100, 150);
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assert_equals(scroller.scrollLeft, 200);
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assert_equals(scroller.scrollTop, 200);
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scroller.scrollTo(300, 300);
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assert_equals(scroller.scrollLeft, 200);
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assert_equals(scroller.scrollTop, 250);
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scroller.scrollTo(200, 100);
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assert_equals(scroller.scrollLeft, 200);
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assert_equals(scroller.scrollTop, 200);
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}, 'Snap to points of combinations of two different elements');
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</script>
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