diff --git a/css/css-transforms/animation/support/transform-interpolation-reftests.js b/css/css-transforms/animation/support/transform-interpolation-reftests.js
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+'use strict';
+
+// Each test is an array of [endpoint, midpoint, endpoint] and tests
+// whether the endpoints interpolate to the same visual state as the midpoint
+const transformTests = {
+ translate: [
+ ['translateX(0px)', 'translateX(25px)', 'translateX(50px)'],
+ ['translateY(0px)', 'translateY(25px)', 'translateY(50px)'],
+ ['translateX(0%)', 'translateX(25%)', 'translateX(50%)'],
+ ['translateY(0%)', 'translateY(25%)', 'translateY(50%)'],
+ ['translateX(50%)', 'translate(25%, 25%)', 'translateY(50%)'],
+ ['translateX(50%)', 'translate(25%, 25px)', 'translateY(50px)'],
+ ['translateX(50px)', 'translateX(calc(25px + 25%))', 'translateX(50%)']
+ ],
+ translateEm: [
+ ['translateX(0em)', 'translateX(2em)', 'translateX(4em)'],
+ ['translateX(-50px)', 'translateX(calc(2em - 25px))', 'translateX(4em)'],
+ ['translateX(50%)', 'translateX(calc(25% - 2em))', 'translateX(-4em)']
+ ],
+ rotate: [
+ ['rotate(0deg)', 'rotate(45deg)', 'rotate(90deg)'],
+ ['rotateX(0deg)', 'rotateX(45deg)', 'rotateX(90deg)'],
+ ['rotateY(0deg)', 'rotateY(45deg)', 'rotateY(90deg)'],
+ ['rotate(0deg)', 'rotate(180deg)', 'rotate(360deg)'],
+ ['rotate3d(7, 8, 9, 0deg)', 'rotate3d(7, 8, 9, 45deg)', 'rotate3d(7, 8, 9, 90deg)'],
+ // First endpoint is the same rotation as rotateZ(0deg) but triggers SLERP
+ ['rotateX(360deg)', 'rotateZ(45deg)', 'rotateZ(90deg)']
+ ],
+ scale: [
+ ['scaleX(0.5)', 'scaleX(0.75)', 'scaleX(1)'],
+ ['scaleY(0.5)', 'scaleY(0.75)', 'scaleY(1)'],
+ ['scale(0.5)', 'scale(0.75)', 'scale(1)'],
+ ['scaleX(0.5)', 'scale(0.75)', 'scaleY(0.5)'],
+ ['scale3d(0.5, 1, 2)', 'scale3d(0.75, 0.75, 3)', 'scale3d(1, 0.5, 4)']
+ ],
+ skew: [
+ ['skewX(0deg)', 'skewX(30deg)', 'skewX(60deg)'],
+ ['skewY(0deg)', 'skewY(30deg)', 'skewY(60deg)'],
+ ['skew(60deg, 0deg)', 'skew(30deg, 30deg)', 'skew(0deg, 60deg)'],
+ ['skewX(0deg) rotate(0deg)', 'skewX(0deg) rotate(180deg)', 'skewX(0deg) rotate(360deg)'],
+ ['skewX(0deg) rotate(0deg)', 'matrix(1, 0, 0, 1, 0, 0)', 'skewY(0deg) rotate(360deg)']
+ ],
+ matrix: [
+ // matched matrix parameters do not collapse the values after them
+ ['matrix(1,0,0,1,0,0) rotate(0deg)', 'matrix(1.5,0,0,1.5,0,0) rotate(180deg)', 'matrix(2,0,0,2,0,0) rotate(360deg)']
+ ]
+}
+
+// Initial setup, which includes properties that will be overridden to
+// test invalidation.
+function initialStyle(div) {
+ div.style.width = '180px';
+ div.style.height = '150px';
+ div.style.margin = '50px';
+ div.style.borderLeft = 'solid 40px blue';
+ div.style.backgroundColor = 'green';
+ div.style.willChange = 'transform';
+ div.style.fontSize = '30px';
+}
+
+function finalStyle(div) {
+ div.style.width = '80px';
+ div.style.height = '80px';
+ div.style.fontSize = '15px';
+}
+
+function styleBody(){
+ let body = document.body;
+ body.style.display = 'flex';
+ body.style.flexDirection = 'row';
+ body.style.flexWrap = 'wrap';
+}
+
+// Simulate a static image at 50% progeress with a running animation.
+// The easing curve has zero slope and curvature at its midpoint of 50% -> 50%.
+// The timing values are chosen so as so that a delay of up to 10s will not
+// cause a visual change.
+const easing = 'cubic-bezier(0,1,1,0)';
+const duration = 1e9;
+const delay = -duration/2;
+
+// Indices to unpack a test case, which is in the format
+// [start, midpoint, end]
+const startIndex = 0;
+const midIndex = 1;
+const endIndex = 2;
+
+async function createTests(tests) {
+ styleBody();
+ for (const test of tests) {
+ let div = document.createElement('div');
+ document.body.appendChild(div);
+ initialStyle(div);
+ var anim = div.animate(
+ {transform: [test[startIndex], test[endIndex]]},
+ {duration: duration, delay: delay, easing: easing});
+ await anim.ready;
+ finalStyle(div); // Change size to test invalidation.
+ }
+
+ await new Promise(requestAnimationFrame);
+ await new Promise(requestAnimationFrame);
+ takeScreenshot();
+}
+
+// Create references using an animation with identical keyframes for start
+// and end so as to avoid rounding and anti-aliasing differences between
+// animated and non-animated pathways.
+async function createRefs(tests) {
+ styleBody();
+ for (const test of tests) {
+ let div = document.createElement('div');
+ document.body.appendChild(div);
+ initialStyle(div);
+ finalStyle(div);
+ var anim = div.animate(
+ {transform: [test[midIndex], test[midIndex]]},
+ {duration: duration, delay: delay, easing: easing});
+ await anim.ready;
+ }
+
+ await new Promise(requestAnimationFrame);
+ await new Promise(requestAnimationFrame);
+ takeScreenshot();
+}
+
diff --git a/css/css-transforms/animation/transform-interpolation-animated-ref.html b/css/css-transforms/animation/transform-interpolation-animated-ref.html
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+++ b/css/css-transforms/animation/transform-interpolation-animated-ref.html
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+
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diff --git a/css/css-transforms/animation/transform-interpolation-matrix.html b/css/css-transforms/animation/transform-interpolation-matrix.html
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index 00000000000000..b5f9c3cd308402
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+++ b/css/css-transforms/animation/transform-interpolation-matrix.html
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+
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diff --git a/css/css-transforms/animation/transform-interpolation-ref.html b/css/css-transforms/animation/transform-interpolation-ref.html
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+++ b/css/css-transforms/animation/transform-interpolation-ref.html
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diff --git a/css/css-transforms/animation/transform-interpolation-rotate.html b/css/css-transforms/animation/transform-interpolation-rotate.html
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+++ b/css/css-transforms/animation/transform-interpolation-rotate.html
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diff --git a/css/css-transforms/animation/transform-interpolation-scale.html b/css/css-transforms/animation/transform-interpolation-scale.html
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+++ b/css/css-transforms/animation/transform-interpolation-scale.html
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diff --git a/css/css-transforms/animation/transform-interpolation-skew.html b/css/css-transforms/animation/transform-interpolation-skew.html
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+++ b/css/css-transforms/animation/transform-interpolation-skew.html
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diff --git a/css/css-transforms/animation/transform-interpolation-translate-em.html b/css/css-transforms/animation/transform-interpolation-translate-em.html
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index 00000000000000..aff613ab09c3c6
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+++ b/css/css-transforms/animation/transform-interpolation-translate-em.html
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diff --git a/css/css-transforms/animation/transform-interpolation-translate.html b/css/css-transforms/animation/transform-interpolation-translate.html
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index 00000000000000..5abeb240932957
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+++ b/css/css-transforms/animation/transform-interpolation-translate.html
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