<!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 supports animation as a repeatable list">

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

<style>
.parent {
  background-position: 60px 60px;
}
.target {
  width: 120px;
  height: 120px;
  display: inline-block;
  border: 2px solid black;
  background-repeat: no-repeat;
  background-image: radial-gradient(20px circle at 20px 20px, red 18px, transparent),
                    radial-gradient(20px circle at 20px 20px, yellow 18px, transparent),
                    radial-gradient(20px circle at 20px 20px, lime 18px, transparent),
                    radial-gradient(20px circle at 20px 20px, blue 18px, transparent);
  background-position: 40px 40px;
}
.expected {
  margin-right: 10px;
}
</style>

<body></body>

<script>
test_interpolation({
  property: 'background-position',
  from: neutralKeyframe,
  to: '80px 80px, 80px 80px, 80px 80px, 80px 80px',
}, [
  {at: -0.25, expect: '30px 30px, 30px 30px, 30px 30px, 30px 30px'},
  {at: 0, expect:     '40px 40px, 40px 40px, 40px 40px, 40px 40px'},
  {at: 0.25, expect:  '50px 50px, 50px 50px, 50px 50px, 50px 50px'},
  {at: 0.5, expect:   '60px 60px, 60px 60px, 60px 60px, 60px 60px'},
  {at: 0.75, expect:  '70px 70px, 70px 70px, 70px 70px, 70px 70px'},
  {at: 1, expect:     '80px 80px, 80px 80px, 80px 80px, 80px 80px'},
  {at: 1.25, expect:  '90px 90px, 90px 90px, 90px 90px, 90px 90px'},
]);

// background-position's initial value is 0% 0%, and calcs involving percentages
// are never resolved by the calc spec (even when the percentage is 0%).
test_interpolation({
  property: 'background-position',
  from: 'initial',
  to: '80px 80px, 80px 80px, 80px 80px, 80px 80px',
}, [
  {at: -0.25, expect: 'calc(0% - 20px)  calc(0% - 20px),  calc(0% - 20px)  calc(0% - 20px),  calc(0% - 20px)  calc(0% - 20px),  calc(0% - 20px)  calc(0% - 20px)'},
  {at: 0, expect:     '0% 0%, 0% 0%, 0% 0%, 0% 0%'},
  {at: 0.25, expect:  'calc(0% + 20px)  calc(0% + 20px),  calc(0% + 20px)  calc(0% + 20px),  calc(0% + 20px)  calc(0% + 20px),  calc(0% + 20px)  calc(0% + 20px)'},
  {at: 0.5, expect:   'calc(0% + 40px)  calc(0% + 40px),  calc(0% + 40px)  calc(0% + 40px),  calc(0% + 40px)  calc(0% + 40px),  calc(0% + 40px)  calc(0% + 40px)'},
  {at: 0.75, expect:  'calc(0% + 60px)  calc(0% + 60px),  calc(0% + 60px)  calc(0% + 60px),  calc(0% + 60px)  calc(0% + 60px),  calc(0% + 60px)  calc(0% + 60px)'},
  {at: 1, expect:     'calc(0% + 80px)  calc(0% + 80px),  calc(0% + 80px)  calc(0% + 80px),  calc(0% + 80px)  calc(0% + 80px),  calc(0% + 80px)  calc(0% + 80px)'},
  {at: 1.25, expect:  'calc(0% + 100px) calc(0% + 100px), calc(0% + 100px) calc(0% + 100px), calc(0% + 100px) calc(0% + 100px), calc(0% + 100px) calc(0% + 100px)'},
]);

test_interpolation({
  property: 'background-position',
  from: 'inherit',
  to: '80px 80px, 80px 80px, 80px 80px, 80px 80px',
}, [
  {at: -0.25, expect: '55px 55px, 55px 55px, 55px 55px, 55px 55px'},
  {at: 0, expect:     '60px 60px, 60px 60px, 60px 60px, 60px 60px'},
  {at: 0.25, expect:  '65px 65px, 65px 65px, 65px 65px, 65px 65px'},
  {at: 0.5, expect:   '70px 70px, 70px 70px, 70px 70px, 70px 70px'},
  {at: 0.75, expect:  '75px 75px, 75px 75px, 75px 75px, 75px 75px'},
  {at: 1, expect:     '80px 80px, 80px 80px, 80px 80px, 80px 80px'},
  {at: 1.25, expect:  '85px 85px, 85px 85px, 85px 85px, 85px 85px'},
]);

// background-position is not inherited, so 'unset' is equivalent to initial.
test_interpolation({
  property: 'background-position',
  from: 'unset',
  to: '80px 80px, 80px 80px, 80px 80px, 80px 80px',
}, [
  {at: -0.25, expect: 'calc(0% - 20px)  calc(0% - 20px),  calc(0% - 20px)  calc(0% - 20px),  calc(0% - 20px)  calc(0% - 20px),  calc(0% - 20px)  calc(0% - 20px)'},
  {at: 0, expect:     '0% 0%, 0% 0%, 0% 0%, 0% 0%'},
  {at: 0.25, expect:  'calc(0% + 20px)  calc(0% + 20px),  calc(0% + 20px)  calc(0% + 20px),  calc(0% + 20px)  calc(0% + 20px),  calc(0% + 20px)  calc(0% + 20px)'},
  {at: 0.5, expect:   'calc(0% + 40px)  calc(0% + 40px),  calc(0% + 40px)  calc(0% + 40px),  calc(0% + 40px)  calc(0% + 40px),  calc(0% + 40px)  calc(0% + 40px)'},
  {at: 0.75, expect:  'calc(0% + 60px)  calc(0% + 60px),  calc(0% + 60px)  calc(0% + 60px),  calc(0% + 60px)  calc(0% + 60px),  calc(0% + 60px)  calc(0% + 60px)'},
  {at: 1, expect:     'calc(0% + 80px)  calc(0% + 80px),  calc(0% + 80px)  calc(0% + 80px),  calc(0% + 80px)  calc(0% + 80px),  calc(0% + 80px)  calc(0% + 80px)'},
  {at: 1.25, expect:  'calc(0% + 100px) calc(0% + 100px), calc(0% + 100px) calc(0% + 100px), calc(0% + 100px) calc(0% + 100px), calc(0% + 100px) calc(0% + 100px)'},
]);

// Test equal number of position values as background images.
test_interpolation({
  property: 'background-position',
  from: '0px 0px, 0px 0px, 0px 0px, 0px 0px',
  to: '80px 80px, 80px 80px, 80px 80px, 80px 80px',
}, [
  {at: -0.25, expect: '-20px -20px, -20px -20px, -20px -20px, -20px -20px'},
  {at: 0, expect:     '  0px   0px,   0px   0px,   0px   0px,   0px   0px'},
  {at: 0.25, expect:  ' 20px  20px,  20px  20px,  20px  20px,  20px  20px'},
  {at: 0.5, expect:   ' 40px  40px,  40px  40px,  40px  40px,  40px  40px'},
  {at: 0.75, expect:  ' 60px  60px,  60px  60px,  60px  60px,  60px  60px'},
  {at: 1, expect:     ' 80px  80px,  80px  80px,  80px  80px,  80px  80px'},
  {at: 1.25, expect:  '100px 100px, 100px 100px, 100px 100px, 100px 100px'},
]);

// Test single position value repeated over background images.
test_interpolation({
  property: 'background-position',
  from: 'top 0px left 0px',
  to: 'left 80px top 80px',
}, [
  {at: -0.25, expect: '-20px -20px, -20px -20px, -20px -20px, -20px -20px'},
  {at: 0, expect:     '  0px   0px,   0px   0px,   0px   0px,   0px   0px'},
  {at: 0.25, expect:  ' 20px  20px,  20px  20px,  20px  20px,  20px  20px'},
  {at: 0.5, expect:   ' 40px  40px,  40px  40px,  40px  40px,  40px  40px'},
  {at: 0.75, expect:  ' 60px  60px,  60px  60px,  60px  60px,  60px  60px'},
  {at: 1, expect:     ' 80px  80px,  80px  80px,  80px  80px,  80px  80px'},
  {at: 1.25, expect:  '100px 100px, 100px 100px, 100px 100px, 100px 100px'},
]);

// Test mismatched numbers of position values.
test_interpolation({
  property: 'background-position',
  from: '0px 0px, 80px 0px',
  to: '40px 40px, 80px 80px, 0px 80px',
}, [
  {at: -0.25, expect: '-10px -10px, 80px -20px, 0px -20px, 90px -10px'},
  {at: 0, expect:     '  0px   0px, 80px   0px, 0px   0px, 80px   0px'},
  {at: 0.25, expect:  ' 10px  10px, 80px  20px, 0px  20px, 70px  10px'},
  {at: 0.5, expect:   ' 20px  20px, 80px  40px, 0px  40px, 60px  20px'},
  {at: 0.75, expect:  ' 30px  30px, 80px  60px, 0px  60px, 50px  30px'},
  {at: 1, expect:     ' 40px  40px, 80px  80px, 0px  80px, 40px  40px'},
  {at: 1.25, expect:  ' 50px  50px, 80px 100px, 0px 100px, 30px  50px'},
]);
</script>
