<!DOCTYPE html>
<meta charset=utf-8>
<title>The effect value of a keyframe effect: Overlapping keyframes</title>
<link rel="help" href="https://drafts.csswg.org/web-animations/#the-effect-value-of-a-keyframe-animation-effect">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../../testcommon.js"></script>
<body>
<div id="log"></div>
<div id="target"></div>
<script>
'use strict';
function assert_opacity_value(opacity, expected, description) {
return assert_approx_equals(parseFloat(opacity), expected, 0.0001, description);
}
test(t => {
const div = createDiv(t);
const anim = div.animate([ { offset: 0, opacity: 0 },
{ offset: 0, opacity: 0.1 },
{ offset: 0, opacity: 0.2 },
{ offset: 1, opacity: 0.8 },
{ offset: 1, opacity: 0.9 },
{ offset: 1, opacity: 1 } ],
{ duration: 1000,
easing: 'cubic-bezier(0.5, -0.5, 0.5, 1.5)' });
assert_opacity_value(getComputedStyle(div).opacity, 0.2,
'When progress is zero the last keyframe with offset 0 should'
+ ' be used');
// http://cubic-bezier.com/#.5,-0.5,.5,1.5
// At t=0.15, the progress should be negative
anim.currentTime = 150;
assert_equals(getComputedStyle(div).opacity, '0',
'When progress is negative, the first keyframe with a 0 offset'
+ ' should be used');
// At t=0.71, the progress should be just less than 1
anim.currentTime = 710;
assert_approx_equals(parseFloat(getComputedStyle(div).opacity), 0.8, 0.01,
'When progress is just less than 1, the first keyframe with an'
+ ' offset of 1 should be used as the interval endpoint');
// At t=0.85, the progress should be > 1
anim.currentTime = 850;
assert_equals(getComputedStyle(div).opacity, '1',
'When progress is greater than 1.0, the last keyframe with a 1'
+ ' offset should be used');
anim.finish();
assert_equals(getComputedStyle(div).opacity, '1',
'When progress is equal to 1.0, the last keyframe with a 1'
+ ' offset should be used');
}, 'Overlapping keyframes at 0 and 1 use the appropriate value when the'
+ ' progress is outside the range [0, 1]');
test(t => {
const div = createDiv(t);
const anim = div.animate([ { offset: 0, opacity: 0 },
{ offset: 0.5, opacity: 0.3 },
{ offset: 0.5, opacity: 0.5 },
{ offset: 0.5, opacity: 0.7 },
{ offset: 1, opacity: 1 } ], 1000);
anim.currentTime = 250;
assert_opacity_value(getComputedStyle(div).opacity, 0.15,
'Before the overlap point, the first keyframe from the'
+ ' overlap point should be used as interval endpoint');
anim.currentTime = 500;
assert_opacity_value(getComputedStyle(div).opacity, 0.7,
'At the overlap point, the last keyframe from the'
+ ' overlap point should be used as interval startpoint');
anim.currentTime = 750;
assert_opacity_value(getComputedStyle(div).opacity, 0.85,
'After the overlap point, the last keyframe from the'
+ ' overlap point should be used as interval startpoint');
}, 'Overlapping keyframes between 0 and 1 use the appropriate value on each'
+ ' side of the overlap point');
</script>
</body>
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