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/*
* Copyright (C) 2014-2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "FloatPoint.h"
#include "FloatSize.h"
#include "LayoutPoint.h"
#include "PlatformWheelEvent.h"
#include "ScrollSnapOffsetsInfo.h"
#include "ScrollTypes.h"
#include "ScrollingMomentumCalculator.h"
#include <wtf/MonotonicTime.h>
namespace WTF {
class TextStream;
}
namespace WebCore {
enum class ScrollSnapState {
Snapping,
Gliding,
DestinationReached,
UserInteraction
};
class ScrollSnapAnimatorState {
WTF_MAKE_FAST_ALLOCATED;
public:
const Vector<SnapOffset<LayoutUnit>>& snapOffsetsForAxis(ScrollEventAxis axis) const
{
return axis == ScrollEventAxis::Horizontal ? m_snapOffsetsInfo.horizontalSnapOffsets : m_snapOffsetsInfo.verticalSnapOffsets;
}
const LayoutScrollSnapOffsetsInfo& snapOffsetInfo() const { return m_snapOffsetsInfo; }
void setSnapOffsetInfo(const LayoutScrollSnapOffsetsInfo& newInfo) { m_snapOffsetsInfo = newInfo; }
ScrollSnapState currentState() const { return m_currentState; }
std::optional<unsigned> activeSnapIndexForAxis(ScrollEventAxis axis) const
{
return axis == ScrollEventAxis::Horizontal ? m_activeSnapIndexX : m_activeSnapIndexY;
}
void setActiveSnapIndexForAxis(ScrollEventAxis axis, std::optional<unsigned> index)
{
if (axis == ScrollEventAxis::Horizontal)
m_activeSnapIndexX = index;
else
m_activeSnapIndexY = index;
}
FloatPoint currentAnimatedScrollOffset(MonotonicTime, bool& isAnimationComplete) const;
// State transition helpers.
void transitionToSnapAnimationState(const FloatSize& contentSize, const FloatSize& viewportSize, float pageScale, const FloatPoint& initialOffset);
void transitionToGlideAnimationState(const FloatSize& contentSize, const FloatSize& viewportSize, float pageScale, const FloatPoint& initialOffset, const FloatSize& initialVelocity, const FloatSize& initialDelta);
void transitionToUserInteractionState();
void transitionToDestinationReachedState();
private:
std::pair<float, std::optional<unsigned>> targetOffsetForStartOffset(ScrollEventAxis, const FloatSize& viewportSize, float maxScrollOffset, float startOffset, FloatPoint predictedOffset, float pageScale, float initialDelta) const;
void teardownAnimationForState(ScrollSnapState);
void setupAnimationForState(ScrollSnapState, const FloatSize& contentSize, const FloatSize& viewportSize, float pageScale, const FloatPoint& initialOffset, const FloatSize& initialVelocity, const FloatSize& initialDelta);
ScrollSnapState m_currentState { ScrollSnapState::UserInteraction };
LayoutScrollSnapOffsetsInfo m_snapOffsetsInfo;
std::optional<unsigned> m_activeSnapIndexX;
std::optional<unsigned> m_activeSnapIndexY;
MonotonicTime m_startTime;
std::unique_ptr<ScrollingMomentumCalculator> m_momentumCalculator;
};
WTF::TextStream& operator<<(WTF::TextStream&, const ScrollSnapAnimatorState&);
} // namespace WebCore
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