<!DOCTYPE html>
<meta charset="UTF-8">
<title>font-size interpolation</title>
<link rel="help" href="https://drafts.csswg.org/css-fonts-3/#propdef-font-size">
<meta name="assert" content="font-size supports animation as length">

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

<style>
.container {
  font-stretch: ultra-expanded;
}
.container2 {
  font-stretch: ultra-condensed;
}
.target {
  display: inline-block;
  font: 100px sans-serif;
  font-stretch: normal;
}
.expected {
  color: green;
  margin-right: 30px;
}
</style>

<body>
<template id="target-template">
  <span class="container">
    <div class="target">TT</div>
  </span>
</template>

<span id="inv-container" class="container">
  <div id="inv-target" class="target">TT</div>
</span>
</body>

<script>
test_interpolation({
  property: 'font-stretch',
  from: '100%',
  to: '200%'
}, [
  {at: -2, expect: '0%'},  // CSS font-stretch can't be negative.
  {at: -0.25, expect: '75%'},
  {at: 0, expect: '100%'},
  {at: 0.3, expect: '130%'},
  {at: 0.6, expect: '160%'},
  {at: 1, expect: '200%'},
  {at: 1.5, expect: '250%'},
]);

test_interpolation({
  property: 'font-stretch',
  from: neutralKeyframe,
  to: '200%'
}, [
  {at: -2, expect: '0%'},
  {at: -0.25, expect: '75%'},
  {at: 0, expect: '100%'},
  {at: 0.3, expect: '130%'},
  {at: 0.6, expect: '160%'},
  {at: 1, expect: '200%'},
  {at: 1.5, expect: '250%'},
]);

test_interpolation({
  property: 'font-stretch',
  from: 'initial',
  to: 'inherit'
}, [
  {at: -2, expect: '0%'},
  {at: -0.25, expect: '75%'},
  {at: 0, expect: '100%'},
  {at: 0.3, expect: '130%'},
  {at: 0.6, expect: '160%'},
  {at: 1, expect: '200%'},
  {at: 1.5, expect: '250%'},
]);

// Test interpolation from keywords.
test_interpolation({
  property: 'font-stretch',
  from: 'normal',
  to: 'ultra-expanded'
}, [
  {at: -0.25, expect: '75%'},
  {at: 0, expect: '100%'},
  {at: 0.125, expect: '112.5%'},
  {at: 0.25, expect: '125%'},
  {at: 0.5, expect: '150%'},
  {at: 0.75, expect: '175%'},
  {at: 1, expect: '200%'},
]);

test_interpolation({
  property: 'font-stretch',
  from: 'ultra-condensed',
  to: 'condensed'
}, [
  {at: 0, expect: '50%'},
  {at: 0.5, expect: '62.5%'},
  {at: 1, expect: '75%'},
]);

test_interpolation({
  property: 'font-stretch',
  from: 'extra-condensed',
  to: 'semi-condensed'
}, [
  {at: 0, expect: '62.5%'},
  {at: 0.5, expect: '75%'},
  {at: 1, expect: '87.5%'},
]);

test_interpolation({
  property: 'font-stretch',
  from: 'condensed',
  to: 'expanded'
}, [
  {at: 0, expect: '75%'},
  {at: 0.25, expect: '87.5%'},
  {at: 0.5, expect: '100%'},
  {at: 0.75, expect: '112.5%'},
  {at: 1, expect: '125%'},
]);

test_interpolation({
  property: 'font-stretch',
  from: 'semi-condensed',
  to: 'semi-expanded'
}, [
  {at: 0, expect: '87.5%'},
  {at: 0.5, expect: '100%'},
  {at: 1, expect: '112.5%'},
]);

test_interpolation({
  property: 'font-stretch',
  from: 'normal',
  to: 'extra-expanded'
}, [
  {at: 0, expect: '100%'},
  {at: 0.25, expect: '112.5%'},
  {at: 0.5, expect: '125%'},
  {at: 1, expect: '150%'},
]);

test(t => {
  var container = document.getElementById('inv-container');
  var target = document.getElementById('inv-target');
  var anim = target.animate({fontStretch: ['normal', 'inherit']}, 1000);
  anim.pause();
  anim.currentTime = 500;
  assert_equals(getComputedStyle(target).fontStretch, '150%');

  container.setAttribute('class', 'container2');
  assert_equals(getComputedStyle(target).fontStretch, '75%');
}, "An interpolation to inherit updates correctly on a parent style change.");

</script>
