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<meta charset="UTF-8">
<title>transform-scale composition</title>
<link rel="help" href="https://drafts.csswg.org/css-transforms/#two-d-transform-functions">
<meta name="assert" content="transform-scale supports animation as a transform list">

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

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<script>
// Addition (aka concatenation) of scale functions results in multiplying their
// values (scale(2) scale(3) == scale(6)), whereas accumulation does a 1-based
// sum of the components (accumulate(scale(2), scale(3)) == scale(2 + 3 - 1) ==
// scale(4)).

// ------------ Addition tests --------------

test_composition({
  property: 'transform',
  underlying: 'scaleX(2)',
  addFrom: 'scaleX(3)',
  addTo: 'scaleX(4)',
}, [
  {at: -0.5, expect: 'scaleX(5)'},
  {at: 0, expect: 'scaleX(6)'},
  {at: 0.25, expect: 'scaleX(6.5)'},
  {at: 0.5, expect: 'scaleX(7)'},
  {at: 0.75, expect: 'scaleX(7.5)'},
  {at: 1, expect: 'scaleX(8)'},
  {at: 1.5, expect: 'scaleX(9)'},
]);

test_composition({
  property: 'transform',
  underlying: 'scaleY(2)',
  addFrom: 'scaleY(3)',
  addTo: 'scaleY(4)',
}, [
  {at: -0.5, expect: 'scaleY(5)'},
  {at: 0, expect: 'scaleY(6)'},
  {at: 0.25, expect: 'scaleY(6.5)'},
  {at: 0.5, expect: 'scaleY(7)'},
  {at: 0.75, expect: 'scaleY(7.5)'},
  {at: 1, expect: 'scaleY(8)'},
  {at: 1.5, expect: 'scaleY(9)'},
]);

test_composition({
  property: 'transform',
  underlying: 'scaleZ(2)',
  addFrom: 'scaleZ(3)',
  addTo: 'scaleZ(4)',
}, [
  {at: -0.5, expect: 'scaleZ(5)'},
  {at: 0, expect: 'scaleZ(6)'},
  {at: 0.25, expect: 'scaleZ(6.5)'},
  {at: 0.5, expect: 'scaleZ(7)'},
  {at: 0.75, expect: 'scaleZ(7.5)'},
  {at: 1, expect: 'scaleZ(8)'},
  {at: 1.5, expect: 'scaleZ(9)'},
]);

// ------------ Accumulation tests --------------

test_composition({
  property: 'transform',
  underlying: 'scaleX(2)',
  accumulateFrom: 'scaleX(3)',
  accumulateTo: 'scaleX(4)',
}, [
  {at: -0.5, expect: 'scaleX(3.5)'},
  {at: 0, expect: 'scaleX(4)'},
  {at: 0.25, expect: 'scaleX(4.25)'},
  {at: 0.5, expect: 'scaleX(4.5)'},
  {at: 0.75, expect: 'scaleX(4.75)'},
  {at: 1, expect: 'scaleX(5)'},
  {at: 1.5, expect: 'scaleX(5.5)'},
]);

test_composition({
  property: 'transform',
  underlying: 'scaleY(2)',
  accumulateFrom: 'scaleY(3)',
  accumulateTo: 'scaleY(4)',
}, [
  {at: -0.5, expect: 'scaleY(3.5)'},
  {at: 0, expect: 'scaleY(4)'},
  {at: 0.25, expect: 'scaleY(4.25)'},
  {at: 0.5, expect: 'scaleY(4.5)'},
  {at: 0.75, expect: 'scaleY(4.75)'},
  {at: 1, expect: 'scaleY(5)'},
  {at: 1.5, expect: 'scaleY(5.5)'},
]);

test_composition({
  property: 'transform',
  underlying: 'scaleZ(2)',
  accumulateFrom: 'scaleZ(3)',
  accumulateTo: 'scaleZ(4)',
}, [
  {at: -0.5, expect: 'scaleZ(3.5)'},
  {at: 0, expect: 'scaleZ(4)'},
  {at: 0.25, expect: 'scaleZ(4.25)'},
  {at: 0.5, expect: 'scaleZ(4.5)'},
  {at: 0.75, expect: 'scaleZ(4.75)'},
  {at: 1, expect: 'scaleZ(5)'},
  {at: 1.5, expect: 'scaleZ(5.5)'},
]);

// The scale functions all share the same primitive type (scale3d), so can be
// accumulated between.
test_composition({
  property: 'transform',
  underlying: 'scale(2, 4)',
  accumulateFrom: 'scaleZ(3)',
  accumulateTo: 'scaleZ(4)',
}, [
  {at: -0.5, expect: 'scale3d(2, 4, 2.5)'},
  {at: 0, expect: 'scale3d(2, 4, 3)'},
  {at: 0.25, expect: 'scale3d(2, 4, 3.25)'},
  {at: 0.5, expect: 'scale3d(2, 4, 3.5)'},
  {at: 0.75, expect: 'scale3d(2, 4, 3.75)'},
  {at: 1, expect: 'scale3d(2, 4, 4)'},
  {at: 1.5, expect: 'scale3d(2, 4, 4.5)'},
]);
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