<!DOCTYPE html>
<meta charset="utf-8">
<title> perspective composition</title>
<link rel="help" href="https://drafts.csswg.org/css-transforms-2/#propdef-perspective">
<meta name="assert" content="perspective supports animation">

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

<body>
<script>
test_composition({
  property: 'perspective',
  underlying: '50px',
  addFrom: '100px',
  addTo: '200px',
}, [
  {at: -0.3, expect: '120px'},
  {at: 0, expect: '150px'},
  {at: 0.5, expect: '200px'},
  {at: 1, expect: '250px'},
  {at: 1.5, expect: '300px'},
]);

test_composition({
  property: 'perspective',
  underlying: '100px',
  addFrom: '10px',
  addTo: '2px',
}, [
  {at: -0.5, expect: '114px'},
  {at: 0, expect: '110px'},
  {at: 0.5, expect: '106px'},
  {at: 1, expect: '102px'},
  {at: 1.5, expect: '98px'}, // Value clamping should happen after composition.
]);

test_composition({
  property: 'perspective',
  underlying: '50px',
  addFrom: '100px',
  replaceTo: '200px',
}, [
  {at: -0.3, expect: '135px'},
  {at: 0, expect: '150px'},
  {at: 0.5, expect: '175px'},
  {at: 1, expect: '200px'},
  {at: 1.5, expect: '225px'},
]);

test_composition({
  property: 'perspective',
  underlying: '100px',
  addFrom: '100px',
  addTo: 'none',
}, [
  {at: -0.3, expect: '200px'},
  {at: 0, expect: '200px'},
  {at: 0.5, expect: 'none'},
  {at: 1, expect: 'none'},
  {at: 1.5, expect: 'none'},
]);
</script>
</body>