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/*
* Copyright (C) 2021 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
#if ENABLE(MOMENTUM_EVENT_DISPATCHER)
#include <WebCore/FloatSize.h>
#include <wtf/text/WTFString.h>
namespace IPC {
class Decoder;
class Encoder;
}
namespace WebKit {
class NativeWebWheelEvent;
class ScrollingAccelerationCurve {
public:
constexpr ScrollingAccelerationCurve(float gainLinear, float gainParabolic, float gainCubic, float gainQuartic, float tangentSpeedLinear, float tangentSpeedParabolicRoot, float resolution, float frameRate);
static std::optional<ScrollingAccelerationCurve> fromNativeWheelEvent(const NativeWebWheelEvent&);
static ScrollingAccelerationCurve interpolate(const ScrollingAccelerationCurve& from, const ScrollingAccelerationCurve& to, float amount);
float gainLinear() const { return m_parameters.gainLinear; }
float gainParabolic() const { return m_parameters.gainParabolic; }
float gainCubic() const { return m_parameters.gainCubic; }
float gainQuartic() const { return m_parameters.gainQuartic; }
float tangentSpeedLinear() const { return m_parameters.tangentSpeedLinear; };
float tangentSpeedParabolicRoot() const { return m_parameters.tangentSpeedParabolicRoot; };
float resolution() const { return m_parameters.resolution; }
float frameRate() const { return m_parameters.frameRate; }
float accelerationFactor(float);
friend bool operator==(const ScrollingAccelerationCurve& a, const ScrollingAccelerationCurve& b)
{
// Does not check m_intermediates.
return a.m_parameters == b.m_parameters;
}
static constexpr std::optional<ScrollingAccelerationCurve> fallbackCurve();
private:
friend TextStream& operator<<(TextStream&, const ScrollingAccelerationCurve&);
void computeIntermediateValuesIfNeeded();
float evaluateQuartic(float) const;
struct Parameters {
float gainLinear { 0 };
float gainParabolic { 0 };
float gainCubic { 0 };
float gainQuartic { 0 };
float tangentSpeedLinear { 0 };
float tangentSpeedParabolicRoot { 0 };
// FIXME: Resolution and frame rate are not technically properties
// of the curve, just required to use it; they should be plumbed separately.
float resolution { 0 };
float frameRate { 0 };
friend bool operator==(const Parameters&, const Parameters&) = default;
};
Parameters m_parameters;
struct ComputedIntermediateValues {
float tangentStartX { 0 };
float tangentSlope { 0 };
float tangentIntercept { 0 };
float falloffStartX { 0 };
float falloffSlope { 0 };
float falloffIntercept { 0 };
};
std::optional<ComputedIntermediateValues> m_intermediates;
};
constexpr ScrollingAccelerationCurve::ScrollingAccelerationCurve(float gainLinear, float gainParabolic, float gainCubic, float gainQuartic, float tangentSpeedLinear, float tangentSpeedParabolicRoot, float resolution, float frameRate)
: m_parameters { gainLinear, gainParabolic, gainCubic, gainQuartic, tangentSpeedLinear, tangentSpeedParabolicRoot, resolution, frameRate }
{
}
constexpr std::optional<ScrollingAccelerationCurve> ScrollingAccelerationCurve::fallbackCurve()
{
#if ENABLE(MOMENTUM_EVENT_DISPATCHER) && PLATFORM(MAC)
return ScrollingAccelerationCurve {
0.924995422,
0.75,
0,
0,
6.29999542,
12,
400,
60,
};
#else
return std::nullopt;
#endif
};
TextStream& operator<<(TextStream&, const ScrollingAccelerationCurve&);
} // namespace WebKit
#endif // ENABLE(MOMENTUM_EVENT_DISPATCHER)
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