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      1 /*
      2  * Copyright (C) 2013 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef TimingCalculations_h
     32 #define TimingCalculations_h
     33 
     34 #include "core/animation/AnimationNode.h"
     35 #include "core/animation/Timing.h"
     36 #include "platform/animation/AnimationUtilities.h"
     37 #include "wtf/MathExtras.h"
     38 
     39 namespace blink {
     40 
     41 static inline double multiplyZeroAlwaysGivesZero(double x, double y)
     42 {
     43     ASSERT(!isNull(x));
     44     ASSERT(!isNull(y));
     45     return x && y ? x * y : 0;
     46 }
     47 
     48 static inline AnimationNode::Phase calculatePhase(double activeDuration, double localTime, const Timing& specified)
     49 {
     50     ASSERT(activeDuration >= 0);
     51     if (isNull(localTime))
     52         return AnimationNode::PhaseNone;
     53     if (localTime < specified.startDelay)
     54         return AnimationNode::PhaseBefore;
     55     if (localTime >= specified.startDelay + activeDuration)
     56         return AnimationNode::PhaseAfter;
     57     return AnimationNode::PhaseActive;
     58 }
     59 
     60 static inline bool isActiveInParentPhase(AnimationNode::Phase parentPhase, Timing::FillMode fillMode)
     61 {
     62     switch (parentPhase) {
     63     case AnimationNode::PhaseBefore:
     64         return fillMode == Timing::FillModeBackwards || fillMode == Timing::FillModeBoth;
     65     case AnimationNode::PhaseActive:
     66         return true;
     67     case AnimationNode::PhaseAfter:
     68         return fillMode == Timing::FillModeForwards || fillMode == Timing::FillModeBoth;
     69     default:
     70         ASSERT_NOT_REACHED();
     71         return false;
     72     }
     73 }
     74 
     75 static inline double calculateActiveTime(double activeDuration, Timing::FillMode fillMode, double localTime, AnimationNode::Phase parentPhase, AnimationNode::Phase phase, const Timing& specified)
     76 {
     77     ASSERT(activeDuration >= 0);
     78     ASSERT(phase == calculatePhase(activeDuration, localTime, specified));
     79 
     80     switch (phase) {
     81     case AnimationNode::PhaseBefore:
     82         if (fillMode == Timing::FillModeBackwards || fillMode == Timing::FillModeBoth)
     83             return 0;
     84         return nullValue();
     85     case AnimationNode::PhaseActive:
     86         if (isActiveInParentPhase(parentPhase, fillMode))
     87             return localTime - specified.startDelay;
     88         return nullValue();
     89     case AnimationNode::PhaseAfter:
     90         if (fillMode == Timing::FillModeForwards || fillMode == Timing::FillModeBoth)
     91             return activeDuration;
     92         return nullValue();
     93     case AnimationNode::PhaseNone:
     94         ASSERT(isNull(localTime));
     95         return nullValue();
     96     default:
     97         ASSERT_NOT_REACHED();
     98         return nullValue();
     99     }
    100 }
    101 
    102 static inline double calculateScaledActiveTime(double activeDuration, double activeTime, double startOffset, const Timing& specified)
    103 {
    104     ASSERT(activeDuration >= 0);
    105     ASSERT(startOffset >= 0);
    106 
    107     if (isNull(activeTime))
    108         return nullValue();
    109 
    110     ASSERT(activeTime >= 0 && activeTime <= activeDuration);
    111     return multiplyZeroAlwaysGivesZero(specified.playbackRate < 0 ? activeTime - activeDuration : activeTime, specified.playbackRate) + startOffset;
    112 }
    113 
    114 static inline bool endsOnIterationBoundary(double iterationCount, double iterationStart)
    115 {
    116     ASSERT(std::isfinite(iterationCount));
    117     return !fmod(iterationCount + iterationStart, 1);
    118 }
    119 
    120 static inline double calculateIterationTime(double iterationDuration, double repeatedDuration, double scaledActiveTime, double startOffset, const Timing& specified)
    121 {
    122     ASSERT(iterationDuration > 0);
    123     ASSERT(repeatedDuration == multiplyZeroAlwaysGivesZero(iterationDuration, specified.iterationCount));
    124 
    125     if (isNull(scaledActiveTime))
    126         return nullValue();
    127 
    128     ASSERT(scaledActiveTime >= 0);
    129     ASSERT(scaledActiveTime <= repeatedDuration + startOffset);
    130 
    131     if (!std::isfinite(scaledActiveTime)
    132         || (scaledActiveTime - startOffset == repeatedDuration && specified.iterationCount && endsOnIterationBoundary(specified.iterationCount, specified.iterationStart)))
    133         return iterationDuration;
    134 
    135     ASSERT(std::isfinite(scaledActiveTime));
    136     return fmod(scaledActiveTime, iterationDuration);
    137 }
    138 
    139 static inline double calculateCurrentIteration(double iterationDuration, double iterationTime, double scaledActiveTime, const Timing& specified)
    140 {
    141     ASSERT(iterationDuration > 0);
    142     ASSERT(isNull(iterationTime) || iterationTime >= 0);
    143 
    144     if (isNull(scaledActiveTime))
    145         return nullValue();
    146 
    147     ASSERT(iterationTime >= 0);
    148     ASSERT(iterationTime <= iterationDuration);
    149     ASSERT(scaledActiveTime >= 0);
    150 
    151     if (!scaledActiveTime)
    152         return 0;
    153 
    154     if (iterationTime == iterationDuration)
    155         return specified.iterationStart + specified.iterationCount - 1;
    156 
    157     return floor(scaledActiveTime / iterationDuration);
    158 }
    159 
    160 static inline double calculateDirectedTime(double currentIteration, double iterationDuration, double iterationTime, const Timing& specified)
    161 {
    162     ASSERT(isNull(currentIteration) || currentIteration >= 0);
    163     ASSERT(iterationDuration > 0);
    164 
    165     if (isNull(iterationTime))
    166         return nullValue();
    167 
    168     ASSERT(currentIteration >= 0);
    169     ASSERT(iterationTime >= 0);
    170     ASSERT(iterationTime <= iterationDuration);
    171 
    172     const bool currentIterationIsOdd = fmod(currentIteration, 2) >= 1;
    173     const bool currentDirectionIsForwards = specified.direction == Timing::PlaybackDirectionNormal
    174         || (specified.direction == Timing::PlaybackDirectionAlternate && !currentIterationIsOdd)
    175         || (specified.direction == Timing::PlaybackDirectionAlternateReverse && currentIterationIsOdd);
    176 
    177     return currentDirectionIsForwards ? iterationTime : iterationDuration - iterationTime;
    178 }
    179 
    180 static inline double calculateTransformedTime(double currentIteration, double iterationDuration, double iterationTime, const Timing& specified)
    181 {
    182     ASSERT(isNull(currentIteration) || currentIteration >= 0);
    183     ASSERT(iterationDuration > 0);
    184     ASSERT(isNull(iterationTime) || (iterationTime >= 0 && iterationTime <= iterationDuration));
    185 
    186     double directedTime = calculateDirectedTime(currentIteration, iterationDuration, iterationTime, specified);
    187     if (isNull(directedTime))
    188         return nullValue();
    189     if (!std::isfinite(iterationDuration))
    190         return directedTime;
    191     double timeFraction = directedTime / iterationDuration;
    192     ASSERT(timeFraction >= 0 && timeFraction <= 1);
    193     return multiplyZeroAlwaysGivesZero(iterationDuration, specified.timingFunction->evaluate(timeFraction, accuracyForDuration(iterationDuration)));
    194 }
    195 
    196 } // namespace blink
    197 
    198 #endif
    199