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- This WPT test may be referenced by the following Test IDs:
- /css/css-easing/linear-timing-functions-output.tentative.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<meta charset=utf-8>
<meta name="assert" content="This test checks the output of linear timing functions" />
<title>Tests for the output of linear timing functions</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/util.js"></script>
<script src="testcommon.js"></script>
<body>
<div id="log"></div>
<script>
'use strict';
function assert_style_left_at(animation, time, expected_y) {
animation.currentTime = time;
assert_approx_equals(pxToNum(getComputedStyle(animation.effect.target).left),
expected_y * 100,
0.01,
'The left of the animation should be approximately ' +
expected_y * 100 + ' at ' + time + 'ms');
}
function assert_animations_equal_at(actual_animation, expected_animation, time) {
actual_animation.currentTime = time;
var actual_left = pxToNum(getComputedStyle(actual_animation.effect.target).left);
expected_animation.currentTime = time;
var expected_left = pxToNum(getComputedStyle(expected_animation.effect.target).left);
assert_approx_equals(actual_left,
expected_left,
0.01,
'The left of the animation should be approximately ' +
expected_left + ' at ' + time + 'ms');
}
function create_animated_div(t, easing_function) {
var target = createDiv(t);
target.style.position = 'absolute';
return target.animate(
[ { left: '0px' },
{ left: '100px' } ],
{ duration: 1000,
fill: 'forwards',
easing: easing_function });
}
test(function(t) {
var anim = create_animated_div(t, 'linear(0, 1.5, 1)');
assert_style_left_at(anim, 0, 0.0);
assert_style_left_at(anim, 250, 0.75);
assert_style_left_at(anim, 500, 1.5);
assert_style_left_at(anim, 750, 1.25);
assert_style_left_at(anim, 1000, 1.00);
}, 'linear function easing with output greater than 1');
test(function(t) {
var anim = create_animated_div(t, 'linear(1, -0.5, 0)');
assert_style_left_at(anim, 0, 1.0);
assert_style_left_at(anim, 250, 0.25);
assert_style_left_at(anim, 500, -0.5);
assert_style_left_at(anim, 750, -0.25);
assert_style_left_at(anim, 1000, 0.00);
}, 'linear function easing with output less than 1');
test(function(t) {
var anim = create_animated_div(t, 'linear(0.2 0% 20%, 0.4 20% 40%, 0.6 40% 60%, 0.8 60% 80%, 1.0 80% 100%)');
var equiv = create_animated_div(t, 'steps(5, jump-start)');
assert_animations_equal_at(anim, equiv, 0);
assert_animations_equal_at(anim, equiv, 200);
assert_animations_equal_at(anim, equiv, 400);
assert_animations_equal_at(anim, equiv, 600);
assert_animations_equal_at(anim, equiv, 800);
assert_animations_equal_at(anim, equiv, 1000);
}, 'linear function easing, steps equivalent');
test(function(t) {
var anim = create_animated_div(t, 'linear(0, 0.1 -10%, 1)');
var equiv = create_animated_div(t, 'linear(0, 0.1 0%, 1)');
assert_animations_equal_at(anim, equiv, 0);
assert_animations_equal_at(anim, equiv, 100);
assert_animations_equal_at(anim, equiv, 550);
assert_animations_equal_at(anim, equiv, 1000);
}, 'linear function easing, input value being unspecified in the first entry implies zero');
test(function(t) {
var anim = create_animated_div(t, 'linear(0, 0.9 110%, 1)');
var equiv = create_animated_div(t, 'linear(0, 0.9 110%, 1 110%)');
assert_animations_equal_at(anim, equiv, 0);
assert_animations_equal_at(anim, equiv, 450);
assert_animations_equal_at(anim, equiv, 900);
assert_animations_equal_at(anim, equiv, 950);
assert_animations_equal_at(anim, equiv, 1000);
}, 'linear function easing, input value being unspecified in the last entry implies max input value');
</script>
</body>