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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 TimedItemCalculations_h
     32 #define TimedItemCalculations_h
     33 
     34 #include "core/animation/TimedItem.h"
     35 #include "core/animation/Timing.h"
     36 #include "core/platform/animation/AnimationUtilities.h"
     37 #include "wtf/MathExtras.h"
     38 
     39 namespace WebCore {
     40 
     41 static inline TimedItem::Phase calculatePhase(double activeDuration, double localTime, const Timing& specified)
     42 {
     43     ASSERT(activeDuration >= 0);
     44     if (isNull(localTime))
     45         return TimedItem::PhaseNone;
     46     if (localTime < specified.startDelay)
     47         return TimedItem::PhaseBefore;
     48     if (localTime >= specified.startDelay + activeDuration)
     49         return TimedItem::PhaseAfter;
     50     return TimedItem::PhaseActive;
     51 }
     52 
     53 static inline bool isActiveInParentPhase(TimedItem::Phase parentPhase, Timing::FillMode fillMode)
     54 {
     55     switch (parentPhase) {
     56     case TimedItem::PhaseBefore:
     57         return fillMode == Timing::FillModeBackwards || fillMode == Timing::FillModeBoth;
     58     case TimedItem::PhaseActive:
     59         return true;
     60     case TimedItem::PhaseAfter:
     61         return fillMode == Timing::FillModeForwards || fillMode == Timing::FillModeBoth;
     62     default:
     63         ASSERT_NOT_REACHED();
     64         return false;
     65     }
     66 }
     67 
     68 static inline double calculateActiveTime(double activeDuration, double localTime, TimedItem::Phase parentPhase, TimedItem::Phase phase, const Timing& specified)
     69 {
     70     ASSERT(activeDuration >= 0);
     71     ASSERT(phase == calculatePhase(activeDuration, localTime, specified));
     72 
     73     switch (phase) {
     74     case TimedItem::PhaseBefore:
     75         if (specified.fillMode == Timing::FillModeBackwards || specified.fillMode == Timing::FillModeBoth)
     76             return 0;
     77         return nullValue();
     78     case TimedItem::PhaseActive:
     79         if (isActiveInParentPhase(parentPhase, specified.fillMode))
     80             return localTime - specified.startDelay;
     81         return nullValue();
     82     case TimedItem::PhaseAfter:
     83         if (specified.fillMode == Timing::FillModeForwards || specified.fillMode == Timing::FillModeBoth)
     84             return activeDuration;
     85         return nullValue();
     86     case TimedItem::PhaseNone:
     87         ASSERT(isNull(localTime));
     88         return nullValue();
     89     default:
     90         ASSERT_NOT_REACHED();
     91         return nullValue();
     92     }
     93 }
     94 
     95 static inline double calculateScaledActiveTime(double activeDuration, double activeTime, double startOffset, const Timing& specified)
     96 {
     97     ASSERT(activeDuration >= 0);
     98     ASSERT(startOffset >= 0);
     99 
    100     if (isNull(activeTime))
    101         return nullValue();
    102 
    103     ASSERT(activeTime >= 0);
    104 
    105     return (specified.playbackRate < 0 ? activeTime - activeDuration : activeTime) * specified.playbackRate + startOffset;
    106 }
    107 
    108 static inline bool endsOnIterationBoundary(double iterationCount, double iterationStart)
    109 {
    110     return !fmod(iterationCount + iterationStart, 1);
    111 }
    112 
    113 static inline double calculateIterationTime(double iterationDuration, double repeatedDuration, double scaledActiveTime, double startOffset, const Timing& specified)
    114 {
    115     ASSERT(iterationDuration >= 0);
    116     ASSERT(repeatedDuration == iterationDuration * specified.iterationCount);
    117 
    118     if (isNull(scaledActiveTime))
    119         return nullValue();
    120 
    121     ASSERT(scaledActiveTime >= 0);
    122     ASSERT(scaledActiveTime <= repeatedDuration + startOffset);
    123 
    124     if (!iterationDuration)
    125         return 0;
    126 
    127     if (scaledActiveTime - startOffset == repeatedDuration && specified.iterationCount && endsOnIterationBoundary(specified.iterationCount, specified.iterationStart))
    128         return iterationDuration;
    129 
    130     return fmod(scaledActiveTime, iterationDuration);
    131 }
    132 
    133 static inline double calculateCurrentIteration(double iterationDuration, double iterationTime, double scaledActiveTime, const Timing& specified)
    134 {
    135     ASSERT(iterationDuration >= 0);
    136     ASSERT(isNull(iterationTime) || iterationTime >= 0);
    137 
    138     if (isNull(scaledActiveTime))
    139         return nullValue();
    140 
    141     ASSERT(iterationTime >= 0);
    142     ASSERT(iterationTime <= iterationDuration);
    143     ASSERT(scaledActiveTime >= 0);
    144 
    145     if (!scaledActiveTime)
    146         return 0;
    147 
    148     if (!iterationDuration)
    149         return floor(specified.iterationStart + specified.iterationCount);
    150 
    151     if (iterationTime == iterationDuration)
    152         return specified.iterationStart + specified.iterationCount - 1;
    153 
    154     return floor(scaledActiveTime / iterationDuration);
    155 }
    156 
    157 static inline double calculateDirectedTime(double currentIteration, double iterationDuration, double iterationTime, const Timing& specified)
    158 {
    159     ASSERT(isNull(currentIteration) || currentIteration >= 0);
    160     ASSERT(iterationDuration > 0);
    161 
    162     if (isNull(iterationTime))
    163         return nullValue();
    164 
    165     ASSERT(currentIteration >= 0);
    166     ASSERT(iterationTime >= 0);
    167     ASSERT(iterationTime <= iterationDuration);
    168 
    169     const bool currentIterationIsOdd = fmod(currentIteration, 2) >= 1;
    170     const bool currentDirectionIsForwards = specified.direction == Timing::PlaybackDirectionNormal
    171         || (specified.direction == Timing::PlaybackDirectionAlternate && !currentIterationIsOdd)
    172         || (specified.direction == Timing::PlaybackDirectionAlternateReverse && currentIterationIsOdd);
    173 
    174     return currentDirectionIsForwards ? iterationTime : iterationDuration - iterationTime;
    175 }
    176 
    177 static inline double calculateTransformedTime(double currentIteration, double iterationDuration, double iterationTime, const Timing& specified)
    178 {
    179     ASSERT(isNull(currentIteration) || currentIteration >= 0);
    180     ASSERT(iterationDuration > 0);
    181     ASSERT(isNull(iterationTime) || (iterationTime >= 0 && iterationTime <= iterationDuration));
    182 
    183     double directedTime = calculateDirectedTime(currentIteration, iterationDuration, iterationTime, specified);
    184     if (isNull(directedTime))
    185         return nullValue();
    186     return specified.timingFunction ?
    187         iterationDuration * specified.timingFunction->evaluate(directedTime / iterationDuration, accuracyForDuration(iterationDuration)) :
    188         directedTime;
    189 }
    190 
    191 } // namespace WebCore
    192 
    193 #endif
    194