flutter_flutter/engine/core/animation/Animation.cpp

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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#include "sky/engine/core/animation/Animation.h"

#include "sky/engine/bindings/exception_state.h"
#include "sky/engine/core/animation/ActiveAnimations.h"
#include "sky/engine/core/animation/AnimationHelpers.h"
#include "sky/engine/core/animation/AnimationPlayer.h"
#include "sky/engine/core/animation/AnimationTimeline.h"
#include "sky/engine/core/animation/Interpolation.h"
#include "sky/engine/core/animation/KeyframeEffectModel.h"
#include "sky/engine/core/dom/Element.h"
#include "sky/engine/core/rendering/RenderLayer.h"

namespace blink {

PassRefPtr<Animation> Animation::create(Element* target, PassRefPtr<AnimationEffect> effect, const Timing& timing, Priority priority, PassOwnPtr<EventDelegate> eventDelegate)
{
    return adoptRef(new Animation(target, effect, timing, priority, eventDelegate));
}

PassRefPtr<Animation> Animation::create(Element* element, double duration, ExceptionState&)
{
    return create(element, PassRefPtr<AnimationEffect>(), TimingInput::convert(duration));
}
PassRefPtr<Animation> Animation::create(Element* element, ExceptionState& es)
{
    return create(element, 0.0, es);
}

Animation::Animation(Element* target, PassRefPtr<AnimationEffect> effect, const Timing& timing, Priority priority, PassOwnPtr<EventDelegate> eventDelegate)
    : AnimationNode(timing, eventDelegate)
    , m_target(target)
    , m_effect(effect)
    , m_sampledEffect(nullptr)
    , m_priority(priority)
{
    if (m_target)
        m_target->ensureActiveAnimations().addAnimation(this);
}

Animation::~Animation()
{
    if (m_target)
        m_target->activeAnimations()->notifyAnimationDestroyed(this);
}

void Animation::attach(AnimationPlayer* player)
{
    if (m_target) {
        m_target->ensureActiveAnimations().players().add(player);
        m_target->setNeedsAnimationStyleRecalc();
    }
    AnimationNode::attach(player);
}

void Animation::detach()
{
    if (m_target)
        m_target->activeAnimations()->players().remove(player());
    if (m_sampledEffect)
        clearEffects();
    AnimationNode::detach();
}

void Animation::specifiedTimingChanged()
{
    if (player()) {
        // FIXME: Needs to consider groups when added.
        ASSERT(player()->source() == this);
        player()->setPending();
    }
}

static AnimationStack& ensureAnimationStack(Element* element)
{
    return element->ensureActiveAnimations().defaultStack();
}

void Animation::applyEffects()
{
    ASSERT(isInEffect());
    ASSERT(player());
    if (!m_target || !m_effect)
        return;

    double iteration = currentIteration();
    ASSERT(iteration >= 0);
    // FIXME: Handle iteration values which overflow int.
    OwnPtr<Vector<RefPtr<Interpolation> > > interpolations = m_effect->sample(static_cast<int>(iteration), timeFraction(), iterationDuration());
    if (m_sampledEffect) {
        m_sampledEffect->setInterpolations(interpolations.release());
    } else if (!interpolations->isEmpty()) {
        OwnPtr<SampledEffect> sampledEffect = SampledEffect::create(this, interpolations.release());
        m_sampledEffect = sampledEffect.get();
        ensureAnimationStack(m_target).add(sampledEffect.release());
    } else {
        return;
    }

    m_target->setNeedsAnimationStyleRecalc();
}

void Animation::clearEffects()
{
    ASSERT(player());
    ASSERT(m_sampledEffect);

    m_sampledEffect->clear();
    m_sampledEffect = nullptr;
    m_target->setNeedsAnimationStyleRecalc();
    invalidate();
}

void Animation::updateChildrenAndEffects() const
{
    if (!m_effect)
        return;
    if (isInEffect())
        const_cast<Animation*>(this)->applyEffects();
    else if (m_sampledEffect)
        const_cast<Animation*>(this)->clearEffects();
}

double Animation::calculateTimeToEffectChange(bool forwards, double localTime, double timeToNextIteration) const
{
    const double start = startTimeInternal() + specifiedTiming().startDelay;
    const double end = start + activeDurationInternal();

    switch (phase()) {
    case PhaseBefore:
        ASSERT(start >= localTime);
        return forwards
            ? start - localTime
            : std::numeric_limits<double>::infinity();
    case PhaseActive:
        return 0;
    case PhaseAfter:
        ASSERT(localTime >= end);
        // If this Animation is still in effect then it will need to update
        // when its parent goes out of effect. We have no way of knowing when
        // that will be, however, so the parent will need to supply it.
        return forwards
            ? std::numeric_limits<double>::infinity()
            : localTime - end;
    default:
        ASSERT_NOT_REACHED();
        return std::numeric_limits<double>::infinity();
    }
}

void Animation::notifySampledEffectRemovedFromAnimationStack()
{
    ASSERT(m_sampledEffect);
    m_sampledEffect = nullptr;
}

void Animation::notifyElementDestroyed()
{
    // If our player is kept alive just by the sampledEffect, we might get our
    // destructor called when we call SampledEffect::clear(), so we need to
    // clear m_sampledEffect first.
    m_target = nullptr;
    clearEventDelegate();
    SampledEffect* sampledEffect = m_sampledEffect;
    m_sampledEffect = nullptr;
    if (sampledEffect)
        sampledEffect->clear();
}

} // namespace blink