<!doctype html>
<meta charset="utf-8">
<link rel="help" href="https://drafts.csswg.org/css-backgrounds-3/#background-position">
<meta name="test" content="background-position animation handles origin parameters">

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/css/support/interpolation-testcommon.js"></script>

<style>
.parent {
  background-position: 80px 80px;
}
.target {
  border: 3px solid skyblue;
  width: 100px;
  height: 100px;
  background-image: linear-gradient(to right, green, green);
  background-size: 20px 20px;
  background-repeat: no-repeat;
  background-position: 10px 10px;
  display: inline-block;
}

.actual {
  background-image: linear-gradient(to right, red, red);
}
.expected {
  margin-left: -106px;
}
</style>

<body></body>

<script>
// neutral
test_interpolation({
  property: 'background-position',
  from: neutralKeyframe,
  to: 'left 20px top 20px',
}, [
  {at: 0, expect: '10px 10px'},
  {at: 0.25, expect: '12.5px 12.5px'},
  {at: 0.5, expect: '15px 15px'},
  {at: 0.75, expect: '17.5px 17.5px'},
  {at: 1, expect: '20px 20px'},
]);

// initial
test_interpolation({
  property: 'background-position',
  from: 'initial',
  to: 'left 20px top 20px',
}, [
  {at: 0, expect: '0% 0%'},
  {at: 0.25, expect: 'calc(0% + 5px) calc(0% + 5px)'},
  {at: 0.5, expect: 'calc(0% + 10px) calc(0% + 10px)'},
  {at: 0.75, expect: 'calc(0% + 15px) calc(0% + 15px)'},
  {at: 1, expect: 'calc(0% + 20px) calc(0% + 20px)'},
]);

// inherit
test_interpolation({
  property: 'background-position',
  from: 'inherit',
  to: 'left 20px top 20px',
}, [
  {at: 0, expect: '80px 80px'},
  {at: 0.25, expect: '65px 65px'},
  {at: 0.5, expect: '50px 50px'},
  {at: 0.75, expect: '35px 35px'},
  {at: 1, expect: '20px 20px'},
]);

// unset
test_interpolation({
  property: 'background-position',
  from: 'unset',
  to: 'left 20px top 20px',
}, [
  {at: 0, expect: '0% 0%'},
  {at: 0.25, expect: 'calc(0% + 5px) calc(0% + 5px)'},
  {at: 0.5, expect: 'calc(0% + 10px) calc(0% + 10px)'},
  {at: 0.75, expect: 'calc(0% + 15px) calc(0% + 15px)'},
  {at: 1, expect: 'calc(0% + 20px) calc(0% + 20px)'},
]);

// left-top
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'left 20px top 20px',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: 'calc(5px + 37.5%) calc(5px + 37.5%)'},
  {at: 0.5, expect: 'calc(10px + 25%) calc(10px + 25%)'},
  {at: 0.75, expect: 'calc(15px + 12.5%) calc(15px + 12.5%)'},
  {at: 1, expect: 'calc(0% + 20px) calc(0% + 20px)'},
]);

// center-top
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'center top 20px',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: '50% calc(5px + 37.5%)'},
  {at: 0.5, expect: '50% calc(10px + 25%)'},
  {at: 0.75, expect: '50% calc(15px + 12.5%)'},
  {at: 1, expect: '50% calc(0% + 20px)'},
]);

// right-top
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'right 20px top 20px',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: 'calc(-5px + 62.5%) calc(5px + 37.5%)'},
  {at: 0.5, expect: 'calc(-10px + 75%) calc(10px + 25%)'},
  {at: 0.75, expect: 'calc(-15px + 87.5%) calc(15px + 12.5%)'},
  {at: 1, expect: 'calc(-20px + 100%) calc(0% + 20px)'},
]);

// left-center
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'left 20px center',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: 'calc(5px + 37.5%) 50%'},
  {at: 0.5, expect: 'calc(10px + 25%) 50%'},
  {at: 0.75, expect: 'calc(15px + 12.5%) 50%'},
  {at: 1, expect: 'calc(0% + 20px) 50%'},
]);

// center-center
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'center center',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: '50% 50%'},
  {at: 0.5, expect: '50% 50%'},
  {at: 0.75, expect: '50% 50%'},
  {at: 1, expect: '50% 50%'},
]);

// right-center
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'right 20px center',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: 'calc(-5px + 62.5%) 50%'},
  {at: 0.5, expect: 'calc(-10px + 75%) 50%'},
  {at: 0.75, expect: 'calc(-15px + 87.5%) 50%'},
  {at: 1, expect: 'calc(-20px + 100%) 50%'},
]);

// left-bottom
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'left 20px bottom 20px',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: 'calc(5px + 37.5%) calc(-5px + 62.5%)'},
  {at: 0.5, expect: 'calc(10px + 25%) calc(-10px + 75%)'},
  {at: 0.75, expect: 'calc(15px + 12.5%) calc(-15px + 87.5%)'},
  {at: 1, expect: 'calc(0% + 20px) calc(-20px + 100%)'},
]);

// center-bottom
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'center bottom 20px',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: '50% calc(-5px + 62.5%)'},
  {at: 0.5, expect: '50% calc(-10px + 75%)'},
  {at: 0.75, expect: '50% calc(-15px + 87.5%)'},
  {at: 1, expect: '50% calc(-20px + 100%)'},
]);

// right-bottom
test_interpolation({
  property: 'background-position',
  from: 'center center',
  to: 'right 20px bottom 20px',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: 'calc(-5px + 62.5%) calc(-5px + 62.5%)'},
  {at: 0.5, expect: 'calc(-10px + 75%) calc(-10px + 75%)'},
  {at: 0.75, expect: 'calc(-15px + 87.5%) calc(-15px + 87.5%)'},
  {at: 1, expect: 'calc(-20px + 100%) calc(-20px + 100%)'},
]);

// Single values
test_interpolation({
  property: 'background-position',
  from: 'center',
  to: 'bottom',
}, [
  {at: 0, expect: '50% 50%'},
  {at: 0.25, expect: '50% 62.5%'},
  {at: 0.5, expect: '50% 75%'},
  {at: 0.75, expect: '50% 87.5%'},
  {at: 1, expect: '50% 100%'},
]);
</script>
