86 lines
3.7 KiB
C++
86 lines
3.7 KiB
C++
/*
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* Copyright (C) 2016 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include "PlatformWheelEvent.h"
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#include "ScrollTypes.h"
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#include <wtf/Seconds.h>
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namespace WebCore {
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class FloatPoint;
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class FloatSize;
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class ScrollingMomentumCalculator {
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WTF_MAKE_FAST_ALLOCATED;
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public:
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ScrollingMomentumCalculator(const FloatSize& viewportSize, const FloatSize& contentSize, const FloatPoint& initialOffset, const FloatSize& initialDelta, const FloatSize& initialVelocity);
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static std::unique_ptr<ScrollingMomentumCalculator> create(const FloatSize& viewportSize, const FloatSize& contentSize, const FloatPoint& initialOffset, const FloatSize& initialDelta, const FloatSize& initialVelocity);
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WEBCORE_EXPORT static void setPlatformMomentumScrollingPredictionEnabled(bool);
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virtual ~ScrollingMomentumCalculator() = default;
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virtual FloatPoint scrollOffsetAfterElapsedTime(Seconds) = 0;
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virtual Seconds animationDuration() = 0;
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virtual FloatSize predictedDestinationOffset();
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void setRetargetedScrollOffset(const FloatSize&);
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protected:
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const FloatSize& retargetedScrollOffset() const { return m_retargetedScrollOffset.value(); }
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virtual void retargetedScrollOffsetDidChange() { }
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FloatSize m_initialDelta;
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FloatSize m_initialVelocity;
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FloatSize m_initialScrollOffset;
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FloatSize m_viewportSize;
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FloatSize m_contentSize;
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private:
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std::optional<FloatSize> m_retargetedScrollOffset;
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};
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class BasicScrollingMomentumCalculator final : public ScrollingMomentumCalculator {
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public:
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BasicScrollingMomentumCalculator(const FloatSize& viewportSize, const FloatSize& contentSize, const FloatPoint& initialOffset, const FloatSize& initialDelta, const FloatSize& initialVelocity);
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private:
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FloatPoint scrollOffsetAfterElapsedTime(Seconds) final;
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Seconds animationDuration() final;
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void initializeInterpolationCoefficientsIfNecessary();
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void initializeSnapProgressCurve();
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float animationProgressAfterElapsedTime(Seconds) const;
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FloatSize linearlyInterpolatedOffsetAtProgress(float progress);
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FloatSize cubicallyInterpolatedOffsetAtProgress(float progress) const;
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float m_snapAnimationCurveMagnitude { 0 };
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float m_snapAnimationDecayFactor { 0 };
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FloatSize m_snapAnimationCurveCoefficients[4] { };
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bool m_forceLinearAnimationCurve { false };
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bool m_momentumCalculatorRequiresInitialization { true };
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std::optional<FloatSize> m_predictedDestinationOffset;
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};
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} // namespace WebCore
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