<!DOCTYPE html>
<meta charset="UTF-8">
<link rel="help" href="https://drafts.csswg.org/css-backgrounds-3/#background-image">
<meta name="test" content="background-image supports animation">

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

<style>
.parent {
  background-image: url(../resources/blue-100.png);
  background-size: 0 0;
}
.target {
  width: 100px;
  height: 100px;
  display: inline-block;
  border: 10px solid black;
  background-repeat: no-repeat;
  background-image: url(../resources/blue-100.png);
}
.expected {
  border-color: green;
  margin-right: 2px;
}
</style>

<body>
<script>
// Neutral to image
var from = 'url(../resources/blue-100.png)';
var to = 'url(../resources/green-100.png)';
test_interpolation({
  property: 'background-image',
  from: neutralKeyframe,
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// initial to image
to = 'url(../resources/green-100.png)';
test_interpolation({
  property: 'background-image',
  from: 'initial',
  to: to,
}, [
  {at: -0.3, expect: 'none'},
  {at: 0, expect: 'none'},
  {at: 0.3, expect: 'none'},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// inherit to image
from = 'url(../resources/blue-100.png)';
to = 'url(../resources/green-100.png)';
test_interpolation({
  property: 'background-image',
  from: 'inherit',
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// unset to image
test_interpolation({
  property: 'background-image',
  from: 'unset',
  to: to,
}, [
  {at: -0.3, expect: 'none'},
  {at: 0, expect: 'none'},
  {at: 0.3, expect: 'none'},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// Image to image
from = 'url(../resources/blue-100.png)';
to = 'url(../resources/green-100.png)';
test_interpolation({
  property: 'background-image',
  from: from,
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// Image to gradient
from = 'url(../resources/blue-100.png)';
to = 'linear-gradient(45deg, blue, orange)';
test_interpolation({
  property: 'background-image',
  from: from,
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// Image to crossfade
from = 'url(../resources/blue-100.png)';
to = 'cross-fade(url(../resources/green-100.png), url(../resources/stripes-100.png), 0.5)';
test_interpolation({
  property: 'background-image',
  from: from,
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// Gradient to gradient
from = 'linear-gradient(-45deg, red, yellow)';
to = 'linear-gradient(45deg, blue, orange)';
test_interpolation({
  property: 'background-image',
  from: from,
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// Keyword to image
from = 'none';
to = 'url(../resources/green-100.png)';
test_interpolation({
  property: 'background-image',
  from: from,
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// Multiple to multiple
var fromA = 'url(../resources/stripes-100.png)';
var fromB = 'url(../resources/blue-100.png)';
var toA = 'url(../resources/blue-100.png)';
var toB = 'url(../resources/stripes-100.png)';
from = fromA + ', ' + fromB;
to = toA + ', ' + toB;
test_interpolation({
  property: 'background-image',
  from: from,
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// Single to multiple
from = 'url(../resources/blue-100.png)';
var toA = 'url(../resources/stripes-100.png)';
var toB = 'url(../resources/green-100.png)';
to = toA + ', ' + toB;
test_interpolation({
  property: 'background-image',
  from: from,
  to: to,
}, [
  // The interpolation of different numbers of background-images looks a bit strange here.
  // Animating background-image is not specified to be possible however we do it for backwards compatibility.
  // With this in mind we kept the implementation simple at the expense of this corner case because there is
  // no official specification to support.
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);

// Multiple mismatched types
from = 'url(../resources/blue-100.png), none';
to = 'url(../resources/stripes-100.png), url(../resources/green-100.png)';
test_interpolation({
  property: 'background-image',
  from: from,
  to: to,
}, [
  {at: -0.3, expect: from},
  {at: 0, expect: from},
  {at: 0.3, expect: from},
  {at: 0.6, expect: to},
  {at: 1, expect: to},
  {at: 1.5, expect: to},
]);
</script>
</body>
