Calculating the iteration progress now follows the spec

All stages between active time and iteration progress have been re-written to match the spec. https://w3c.github.io/web-animations/#calculating-the-iteration-progress
web-animations · Jul 29, 2016 · b85f9a3 · b85f9a3
1 parent 46f41d1
commit b85f9a3
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Showing 8 changed files with 81 additions and 176 deletions.
diff --git a/src/effect-callback.js b/src/effect-callback.js
@@ -31,7 +31,7 @@
     var callback = function() {
       var t = callback._animation ? callback._animation.currentTime : null;
       if (t !== null) {
-        t = shared.calculateTimeFraction(shared.calculateActiveDuration(timing), t, timing);
+        t = shared.calculateIterationProgress(shared.calculateActiveDuration(timing), t, timing);
         if (isNaN(t))
           t = null;
       }

diff --git a/src/group-constructors.js b/src/group-constructors.js
@@ -168,13 +168,13 @@
 
       // If the group has a negative playback rate and is not fill backwards/both, then it should go
       // out of effect when it reaches the start of its active interval (tf == 0). If it is fill
-      // backwards/both then it should stay in effect. calculateTimeFraction will return 0 in the
+      // backwards/both then it should stay in effect. calculateIterationProgress will return 0 in the
       // backwards-filling case, and null otherwise.
       if (tf == 0 && animation.playbackRate < 0) {
         if (!timing) {
           timing = shared.normalizeTimingInput(animation.effect.timing);
         }
-        tf = shared.calculateTimeFraction(shared.calculateActiveDuration(timing), -1, timing);
+        tf = shared.calculateIterationProgress(shared.calculateActiveDuration(timing), -1, timing);
         if (isNaN(tf) || tf == null) {
           animation._forEachChild(function(child) {
             child.currentTime = -1;

diff --git a/src/keyframe-effect.js b/src/keyframe-effect.js
@@ -18,7 +18,7 @@
     var timeFraction = 0;
     var activeDuration = shared.calculateActiveDuration(timing);
     var effectTime = function(localTime) {
-      return shared.calculateTimeFraction(activeDuration, localTime, timing);
+      return shared.calculateIterationProgress(activeDuration, localTime, timing);
     };
     effectTime._totalDuration = timing.delay + activeDuration + timing.endDelay;
     return effectTime;

diff --git a/src/timing-utilities.js b/src/timing-utilities.js
@@ -264,6 +264,10 @@
   }
 
   function repeatedDuration(timing) {
+    // https://w3c.github.io/web-animations/#calculating-the-active-duration
+    if (timing.duration === 0 || timing.iterations === 0) {
+      return 0;
+    }
     return timing.duration * timing.iterations;
   }
 
@@ -273,19 +277,24 @@
   var PhaseActive = 3;
 
   function calculatePhase(activeDuration, localTime, timing) {
+    // https://w3c.github.io/web-animations/#animation-effect-phases-and-states
     if (localTime == null) {
       return PhaseNone;
     }
-    if (localTime < timing.delay) {
+
+    var endTime = timing.delay + activeDuration + timing.endDelay;
+    if (localTime < Math.min(timing.delay, endTime)) {
       return PhaseBefore;
     }
-    if (localTime >= timing.delay + activeDuration) {
+    if (localTime >= Math.min(timing.delay + activeDuration, endTime)) {
       return PhaseAfter;
     }
+
     return PhaseActive;
   }
 
   function calculateActiveTime(activeDuration, fillMode, localTime, phase, delay) {
+    // https://w3c.github.io/web-animations/#calculating-the-active-time
     switch (phase) {
       case PhaseBefore:
         if (fillMode == 'backwards' || fillMode == 'both')
@@ -302,56 +311,82 @@
     }
   }
 
-  function calculateScaledActiveTime(activeDuration, activeTime, startOffset, timing) {
-    return (timing.playbackRate < 0 ? activeTime - activeDuration : activeTime) * timing.playbackRate + startOffset;
+  function calculateOverallProgress(iterationDuration, phase, iterations, activeTime, iterationStart) {
+    // https://w3c.github.io/web-animations/#calculating-the-overall-progress
+    var overallProgress = iterationStart;
+    if (iterationDuration === 0) {
+      if (phase !== PhaseBefore) {
+        overallProgress += iterations;
+      }
+    } else {
+      overallProgress += activeTime / iterationDuration;
+    }
+    return overallProgress;
   }
 
-  function calculateIterationTime(iterationDuration, repeatedDuration, scaledActiveTime, startOffset, timing) {
-    if (scaledActiveTime === Infinity || scaledActiveTime === -Infinity || (scaledActiveTime - startOffset == repeatedDuration && timing.iterations && ((timing.iterations + timing.iterationStart) % 1 == 0))) {
-      return iterationDuration;
-    }
+  function calculateSimpleIterationProgress(overallProgress, iterationStart, phase, iterations, activeTime, iterationDuration) {
+    // https://w3c.github.io/web-animations/#calculating-the-simple-iteration-progress
 
-    return scaledActiveTime % iterationDuration;
+    var simpleIterationProgress = (overallProgress === Infinity) ? iterationStart % 1 : overallProgress % 1;
+    if (simpleIterationProgress === 0 && phase === PhaseAfter && iterations !== 0 &&
+        (activeTime !== 0 || iterationDuration === 0)) {
+      simpleIterationProgress = 1;
+    }
+    return simpleIterationProgress;
   }
 
-  function calculateCurrentIteration(iterationDuration, iterationTime, scaledActiveTime, timing) {
-    if (scaledActiveTime === 0) {
-      return 0;
+  function calculateCurrentIteration(phase, iterations, simpleIterationProgress, overallProgress) {
+    // https://w3c.github.io/web-animations/#calculating-the-current-iteration
+    if (phase === PhaseAfter && iterations === Infinity) {
+      return Infinity;
     }
-    if (iterationTime == iterationDuration) {
-      return timing.iterationStart + timing.iterations - 1;
+    if (simpleIterationProgress === 1) {
+      return Math.floor(overallProgress) - 1;
     }
-    return Math.floor(scaledActiveTime / iterationDuration);
+    return Math.floor(overallProgress);
   }
 
-  function calculateTransformedTime(currentIteration, iterationDuration, iterationTime, timing) {
-    var currentIterationIsOdd = currentIteration % 2 >= 1;
-    var currentDirectionIsForwards = timing.direction == 'normal' || timing.direction == (currentIterationIsOdd ? 'alternate-reverse' : 'alternate');
-    var directedTime = currentDirectionIsForwards ? iterationTime : iterationDuration - iterationTime;
-    var timeFraction = directedTime / iterationDuration;
-    return iterationDuration * timing._easingFunction(timeFraction);
+  function calculateDirectedProgress(playbackDirection, currentIteration, simpleIterationProgress) {
+    // https://w3c.github.io/web-animations/#calculating-the-directed-progress
+    var currentDirection = playbackDirection;
+    if (playbackDirection !== 'normal' && playbackDirection !== 'reverse') {
+      var d = currentIteration;
+      if (playbackDirection === 'alternate-reverse') {
+        d += 1;
+      }
+      currentDirection = 'normal';
+      if (d !== Infinity && d % 2 !== 0) {
+        currentDirection = 'reverse';
+      }
+    }
+    if (currentDirection === 'normal') {
+      return simpleIterationProgress;
+    }
+    return 1 - simpleIterationProgress;
   }
 
-  function calculateTimeFraction(activeDuration, localTime, timing) {
+  function calculateIterationProgress(activeDuration, localTime, timing) {
     var phase = calculatePhase(activeDuration, localTime, timing);
     var activeTime = calculateActiveTime(activeDuration, timing.fill, localTime, phase, timing.delay);
     if (activeTime === null)
       return null;
-    if (activeDuration === 0)
-      return phase === PhaseBefore ? 0 : 1;
-    var startOffset = timing.iterationStart * timing.duration;
-    var scaledActiveTime = calculateScaledActiveTime(activeDuration, activeTime, startOffset, timing);
-    var iterationTime = calculateIterationTime(timing.duration, repeatedDuration(timing), scaledActiveTime, startOffset, timing);
-    var currentIteration = calculateCurrentIteration(timing.duration, iterationTime, scaledActiveTime, timing);
-    return calculateTransformedTime(currentIteration, timing.duration, iterationTime, timing) / timing.duration;
+
+    var overallProgress = calculateOverallProgress(timing.duration, phase, timing.iterations, activeTime, timing.iterationStart);
+    var simpleIterationProgress = calculateSimpleIterationProgress(overallProgress, timing.iterationStart, phase, timing.iterations, activeTime, timing.duration);
+    var currentIteration = calculateCurrentIteration(phase, timing.iterations, simpleIterationProgress, overallProgress);
+    var directedProgress = calculateDirectedProgress(timing.direction, currentIteration, simpleIterationProgress);
+
+    // https://w3c.github.io/web-animations/#calculating-the-transformed-progress
+    // https://w3c.github.io/web-animations/#calculating-the-iteration-progress
+    return timing._easingFunction(directedProgress);
   }
 
   shared.cloneTimingInput = cloneTimingInput;
   shared.makeTiming = makeTiming;
   shared.numericTimingToObject = numericTimingToObject;
   shared.normalizeTimingInput = normalizeTimingInput;
   shared.calculateActiveDuration = calculateActiveDuration;
-  shared.calculateTimeFraction = calculateTimeFraction;
+  shared.calculateIterationProgress = calculateIterationProgress;
   shared.calculatePhase = calculatePhase;
   shared.normalizeEasing = normalizeEasing;
   shared.parseEasingFunction = parseEasingFunction;
@@ -366,11 +401,6 @@
     testing.PhaseBefore = PhaseBefore;
     testing.PhaseActive = PhaseActive;
     testing.PhaseAfter = PhaseAfter;
-    testing.calculateActiveTime = calculateActiveTime;
-    testing.calculateScaledActiveTime = calculateScaledActiveTime;
-    testing.calculateIterationTime = calculateIterationTime;
-    testing.calculateCurrentIteration = calculateCurrentIteration;
-    testing.calculateTransformedTime = calculateTransformedTime;
   }
 
 })(webAnimationsShared, webAnimationsTesting);
diff --git a/src/web-animations-next-animation.js b/src/web-animations-next-animation.js
@@ -368,7 +368,7 @@
       var timing = this.effect._timing;
       var t = this.currentTime;
       if (t !== null)
-        t = shared.calculateTimeFraction(shared.calculateActiveDuration(timing), t, timing);
+        t = shared.calculateIterationProgress(shared.calculateActiveDuration(timing), t, timing);
       if (t == null || isNaN(t))
         this._removeChildAnimations();
     },

diff --git a/test/js/group-animation.js b/test/js/group-animation.js
@@ -1093,7 +1093,7 @@ suite('group-animation', function() {
     tick(102);
     assert.equal(getComputedStyle(this.target).marginLeft, '2px');
     tick(103);
-    assert.equal(getComputedStyle(this.target).marginLeft, '3px');
+    assert.equal(getComputedStyle(this.target).marginLeft, '0px');
     tick(104);
   });
 

diff --git a/test/js/timing-utilities.js b/test/js/timing-utilities.js
@@ -56,72 +56,27 @@ suite('timing-utilities', function() {
     assert.equal(f(0.1), 0.1);
     assert.equal(f(0.25), 0.2);
   });
-  test('calculating phase', function() {
-    // calculatePhase(activeDuration, localTime, timing);
-    assert.equal(calculatePhase(1000, 100, {delay: 0}), PhaseActive);
-    assert.equal(calculatePhase(1000, 100, {delay: 200}), PhaseBefore);
-    assert.equal(calculatePhase(1000, 2000, {delay: 200}), PhaseAfter);
-    assert.equal(calculatePhase(1000, null, {delay: 200}), PhaseNone);
-  });
-  test('calculating active time', function() {
-    // calculateActiveTime(activeDuration, fillMode, localTime, phase, delay);
-    assert.equal(calculateActiveTime(1000, 'forwards', 100, PhaseActive, 0), 100);
-    assert.equal(calculateActiveTime(1000, 'forwards', 100, PhaseBefore, 200), null);
-    assert.equal(calculateActiveTime(1000, 'both', 100, PhaseBefore, 200), 0);
-    assert.equal(calculateActiveTime(1000, 'forwards', 500, PhaseActive, 200), 300);
-    assert.equal(calculateActiveTime(1000, 'forwards', 1100, PhaseAfter, 200), 1000);
-    assert.equal(calculateActiveTime(1000, 'none', 1100, PhaseAfter, 200), null);
-    assert.equal(calculateActiveTime(Infinity, 'both', 5000000, PhaseActive, 2000000), 3000000);
-    assert.equal(calculateActiveTime(Infinity, 'both', 50000, PhaseBefore, 2000000), 0);
-  });
-  test('calculating scaled active time', function() {
-    // calculateScaledActiveTime(activeDuration, activeTime, startOffset, timingInput);
-    assert.equal(calculateScaledActiveTime(1000, 200, 300, {playbackRate: 1.5}), 600);
-    assert.equal(calculateScaledActiveTime(1000, 200, 300, {playbackRate: -4}), 3500);
-    assert.equal(calculateScaledActiveTime(Infinity, 400, 200, {playbackRate: 1}), 600);
-    assert.equal(calculateScaledActiveTime(Infinity, 400, 200, {playbackRate: -4}), Infinity);
-  });
-  test('calculating iteration time', function() {
-    // calculateIterationTime(iterationDuration, repeatedDuration, scaledActiveTime, startOffset, timingInput);
-    assert.equal(calculateIterationTime(500, 5000, 600, 100, {iterations: 10, iterationStart: 0}), 100);
-    assert.equal(calculateIterationTime(500, 5000, Infinity, 100, {iterations: 10, iterationStart: 0}), 500);
-    assert.equal(calculateIterationTime(500, 5000, 5100, 100, {iterations: 3.2, iterationStart: 0.8}), 500);
-  });
-  test('calculating current iteration', function() {
-    // calculateCurrentIteration(iterationDuration, iterationTime, scaledActiveTime, timingInput);
-    assert.equal(calculateCurrentIteration(1000, 400, 4400, {iterations: 50, iterationStart: 0.8}), 4);
-    assert.equal(calculateCurrentIteration(1000, 1000, 4400, {iterations: 50.2, iterationStart: 0.8}), 50);
-  });
-  test('calculating transformed time', function() {
-    // calculateTransformedTime(currentIteration, iterationDuration, iterationTime, timingInput);
-    assert.equal(calculateTransformedTime(4, 1000, 200, {_easingFunction: function(x) { return x; }, direction: 'normal'}), 200);
-    assert.equal(calculateTransformedTime(4, 1000, 200, {_easingFunction: function(x) { return x; }, direction: 'reverse'}), 800);
-    assert.closeTo(calculateTransformedTime(4, 1000, 200, {_easingFunction: function(x) { return x * x; }, direction: 'reverse'}), 640, 0.0001);
-    assert.closeTo(calculateTransformedTime(4, 1000, 600, {_easingFunction: function(x) { return x * x; }, direction: 'alternate'}), 360, 0.0001);
-    assert.closeTo(calculateTransformedTime(3, 1000, 600, {_easingFunction: function(x) { return x * x; }, direction: 'alternate'}), 160, 0.0001);
-    assert.closeTo(calculateTransformedTime(4, 1000, 600, {_easingFunction: function(x) { return x * x; }, direction: 'alternate-reverse'}), 160, 0.0001);
-    assert.closeTo(calculateTransformedTime(3, 1000, 600, {_easingFunction: function(x) { return x * x; }, direction: 'alternate-reverse'}), 360, 0.0001);
-  });
   test('EffectTime', function() {
     var timing = normalizeTimingInput({duration: 1000, iterations: 4, iterationStart: 0.5, easing: 'linear', direction: 'alternate', delay: 100, fill: 'forwards'});
     var timing2 = normalizeTimingInput({duration: 1000, iterations: 4, iterationStart: 0.5, easing: 'ease', direction: 'alternate', delay: 100, fill: 'forwards'});
     var effectTF = effectTime(timing);
     var effectTF2 = effectTime(timing2);
+    var epsilon = 0.005;
     assert.equal(effectTF(0), null);
     assert.equal(effectTF(100), 0.5);
-    assert.closeTo(effectTF2(100), 0.8, 0.005);
+    assert.closeTo(effectTF2(100), 0.8, epsilon);
     assert.equal(effectTF(600), 1);
-    assert.closeTo(effectTF2(600), 1, 0.005);
-    assert.equal(effectTF(700), 0.9);
-    assert.closeTo(effectTF2(700), 0.99, 0.005);
+    assert.closeTo(effectTF2(600), 1, epsilon);
+    assert.closeTo(effectTF(700), 0.9, epsilon);
+    assert.closeTo(effectTF2(700), 0.99, epsilon);
     assert.equal(effectTF(1600), 0);
-    assert.closeTo(effectTF2(1600), 0, 0.005);
-    assert.equal(effectTF(4000), 0.4);
-    assert.closeTo(effectTF2(4000), 0.68, 0.005);
+    assert.closeTo(effectTF2(1600), 0, epsilon);
+    assert.closeTo(effectTF(4000), 0.4, epsilon);
+    assert.closeTo(effectTF2(4000), 0.68, epsilon);
     assert.equal(effectTF(4100), 0.5);
-    assert.closeTo(effectTF2(4100), 0.8, 0.005);
+    assert.closeTo(effectTF2(4100), 0.8, epsilon);
     assert.equal(effectTF(6000), 0.5);
-    assert.closeTo(effectTF2(6000), 0.8, 0.005);
+    assert.closeTo(effectTF2(6000), 0.8, epsilon);
   });
   test('TypeErrors', function() {
     var timing = normalizeTimingInput({