<!DOCTYPE html>
<meta charset="UTF-8">
<style>
.parent {
  -webkit-mask-image: url(../resources/blue-20.png);
}
.target {
  width: 20px;
  height: 20px;
  display: inline-block;
  background-color: black;
  -webkit-mask-image: url(../resources/stripes-20.png);
}
.expected {
  background-color: green;
  margin-right: 10px;
}
</style>
<body>
<script src="resources/interpolation-test.js"></script>
<script>
function assertCrossfadeInterpolation(options) {
  var fromComputed = options.fromComputed || options.from;
  assertInterpolation({
    property: '-webkit-mask-image',
    from: options.from,
    to: options.to,
  }, [
    {at: -0.3, is: fromComputed},
    {at: 0, is: fromComputed},
    {at: 0.3, is: '-webkit-cross-fade(' + fromComputed + ', ' + options.to + ', 0.3)'},
    {at: 0.5, is: '-webkit-cross-fade(' + fromComputed + ', ' + options.to + ', 0.5)'},
    {at: 0.6, is: '-webkit-cross-fade(' + fromComputed + ', ' + options.to + ', 0.6)'},
    {at: 1, is: options.to},
    {at: 1.5, is: options.to},
  ]);
}

// neutral
assertCrossfadeInterpolation({
  from: neutralKeyframe,
  fromComputed: 'url(../resources/stripes-20.png)',
  to: 'url(../resources/green-20.png)',
});

// initial
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'initial',
  to: 'url(../resources/green-20.png)',
});

// inherit
assertCrossfadeInterpolation({
  from: 'inherit',
  fromComputed: 'url(../resources/blue-20.png)',
  to: 'url(../resources/green-20.png)',
});

// unset
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'unset',
  to: 'url(../resources/stripes-20.png)',
});

// Image to image
assertCrossfadeInterpolation({
  from: 'url(../resources/stripes-20.png)',
  to: 'url(../resources/blue-20.png)',
});

// Image to gradient
assertCrossfadeInterpolation({
  from: 'url(../resources/stripes-20.png)',
  to: 'linear-gradient(45deg, blue, transparent)',
});

// Gradient to gradient
assertCrossfadeInterpolation({
  from: 'linear-gradient(-45deg, blue, transparent)',
  to: 'linear-gradient(45deg, blue, transparent)',
});

// Keyword to image
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'none',
  to: 'url(../resources/blue-20.png)',
});

// Multiple to multiple
var fromA = 'url(../resources/stripes-20.png)';
var fromB = 'linear-gradient(-45deg, blue, transparent)';
var toA = 'url(../resources/blue-20.png)';
var toB = 'url(../resources/stripes-20.png)';
var from = fromA + ', ' + fromB;
var to = toA + ', ' + toB;
assertInterpolation({
  property: '-webkit-mask-image',
  from: from,
  to: to,
}, [
  // The interpolation of different numbers of -webkit-mask-images looks a bit strange here.
  // Animating -webkit-mask-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, is: from},
  {at: 0, is: from},
  {at: 0.3, is: '-webkit-cross-fade(' + fromA + ', ' + toA + ', 0.3), -webkit-cross-fade(' + fromB + ', ' + toB + ', 0.3)'},
  {at: 0.6, is: '-webkit-cross-fade(' + fromA + ', ' + toA + ', 0.6), -webkit-cross-fade(' + fromB + ', ' + toB + ', 0.6)'},
  {at: 1, is: to},
  {at: 1.5, is: to},
]);

// Single to multiple
from = 'url(../resources/blue-20.png)';
toA = 'url(../resources/stripes-20.png)';
toB = 'url(../resources/blue-20.png)';
to = toA + ', ' + toB;
assertInterpolation({
  property: '-webkit-mask-image',
  from: from,
  to: to,
}, [
  {at: -0.3, is: from + ', ' + from},
  {at: 0, is: from},
  {at: 0.3, is: '-webkit-cross-fade(' + from + ', ' + toA + ', 0.3), -webkit-cross-fade(' + from + ', ' + toB + ', 0.3)'},
  {at: 0.6, is: '-webkit-cross-fade(' + from + ', ' + toA + ', 0.6), -webkit-cross-fade(' + from + ', ' + toB + ', 0.6)'},
  {at: 1, is: to},
  {at: 1.5, is: to},
]);

// Multiple mismatched types
assertNoInterpolation({
  property: '-webkit-mask-image',
  from: 'url(../resources/blue-20.png), none',
  to: 'url(../resources/stripes-20.png), url(../resources/blue-20.png)',
});
</script>
</body>