<!doctype html>
<meta charset=utf-8>
<title>CSSTransition.currentTime</title>
<!-- TODO: Add a more specific link for this once it is specified. -->
<link rel="help" href="https://drafts.csswg.org/css-transitions-2/#csstransition">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/helper.js"></script>
<div id="log"></div>
<script>
'use strict';
const marginLeft = div => parseFloat(getComputedStyle(div).marginLeft);
promise_test(async t => {
const div = addDiv(t, {
style: 'margin-left: 100px; transition: margin-left 100s linear 100s',
});
getComputedStyle(div).marginLeft;
div.style.marginLeft = '200px';
const animation = div.getAnimations()[0];
assert_equals(
animation.currentTime,
0,
'currentTime should initially be zero'
);
await animation.ready;
const seekTime = 150 * MS_PER_SEC;
animation.currentTime = seekTime;
assert_time_equals_literal(
animation.currentTime,
seekTime,
'currentTime is updated'
);
assert_equals(getComputedStyle(div).marginLeft, '150px');
}, 'currentTime can be used to seek a CSS transition');
promise_test(async t => {
const div = addDiv(t, {
style: 'margin-left: 100px; transition: margin-left 100s linear 100s',
});
const eventWatcher = new EventWatcher(t, div, 'transitionend');
getComputedStyle(div).marginLeft;
div.style.marginLeft = '200px';
const animation = div.getAnimations()[0];
await animation.ready;
const marginLeft = () => parseFloat(getComputedStyle(div).marginLeft);
assert_equals(marginLeft(div), 100);
animation.currentTime = 100 * MS_PER_SEC;
assert_equals(marginLeft(div), 100);
animation.currentTime = 150 * MS_PER_SEC;
assert_equals(marginLeft(div), 150);
animation.currentTime = 200 * MS_PER_SEC;
await eventWatcher.wait_for('transitionend');
assert_equals(marginLeft(div), 200);
}, 'Skipping forwards through transition');
promise_test(async t => {
const div = addDiv(t, {
style: 'margin-left: 100px; transition: margin-left 100s linear 100s',
});
const eventWatcher = new EventWatcher(t, div, 'transitionend');
getComputedStyle(div).marginLeft;
div.style.marginLeft = '200px';
const animation = div.getAnimations()[0];
await animation.ready;
// Unlike in the case of CSS animations, we cannot skip to the end and skip
// backwards since when we reach the end the transition effect is removed and
// changes to the Animation object no longer affect the element. For
// this reason we only skip forwards as far as the 50% through point.
animation.currentTime = 150 * MS_PER_SEC;
assert_equals(marginLeft(div), 150);
animation.currentTime = 100 * MS_PER_SEC;
assert_equals(marginLeft(div), 100);
}, 'Skipping backwards through transition');
promise_test(async t => {
const div = addDiv(t, {
style: 'margin-left: 100px; transition: margin-left 100s linear 100s',
});
getComputedStyle(div).marginLeft;
div.style.marginLeft = '200px';
const animation = div.getAnimations()[0];
await animation.ready;
assert_throws_js(
TypeError,
() => {
animation.currentTime = null;
},
'Expect TypeError exception on trying to set Animation.currentTime to null'
);
}, 'Setting currentTime to null on a CSS transition throws');
test(t => {
const div = addDiv(t);
div.style.left = '0px';
getComputedStyle(div).transitionProperty;
div.style.transition = 'left 100s ease-in';
div.style.left = '100px';
const transition = div.getAnimations()[0];
// Seek to the middle. Note, this is not equivalent to 50% progress since the
// timing-function is non-linear.
transition.currentTime = 50 * MS_PER_SEC;
const portion = transition.effect.getComputedTiming().progress;
// Reverse the transition.
div.style.left = '0px';
const reversedTransition = div.getAnimations()[0];
// If the transition reversing behavior does not advance the previous
// transition to the time set by currentTime, start and end values will both
// be 0px and no transition will be produced.
assert_not_equals(reversedTransition, undefined,
"A reversed transition is produced");
const expectedDuration = 100 * MS_PER_SEC * portion;
assert_approx_equals(
reversedTransition.effect.getComputedTiming().activeDuration,
expectedDuration,
1,
"The reversed transition has correctly reduced duration"
);
}, "Transition reversing behavior respects currentTime and uses the " +
"transition's current position.");
</script>