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/*
* Copyright (C) 2011 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.
*/
#ifndef ScrollElasticityController_h
#define ScrollElasticityController_h
#if ENABLE(RUBBER_BANDING)
#include "FloatPoint.h"
#include "FloatSize.h"
#include "ScrollTypes.h"
#include <wtf/Noncopyable.h>
namespace WebCore {
class PlatformWheelEvent;
class ScrollElasticityControllerClient {
protected:
virtual ~ScrollElasticityControllerClient() { }
public:
virtual bool allowsHorizontalStretching() = 0;
virtual bool allowsVerticalStretching() = 0;
virtual IntSize stretchAmount() = 0;
virtual bool pinnedInDirection(const FloatSize&) = 0;
virtual bool canScrollHorizontally() = 0;
virtual bool canScrollVertically() = 0;
virtual bool shouldRubberBandInDirection(ScrollDirection) = 0;
// Return the absolute scroll position, not relative to the scroll origin.
virtual WebCore::IntPoint absoluteScrollPosition() = 0;
virtual void immediateScrollBy(const FloatSize&) = 0;
virtual void immediateScrollByWithoutContentEdgeConstraints(const FloatSize&) = 0;
virtual void startSnapRubberbandTimer() = 0;
virtual void stopSnapRubberbandTimer() = 0;
};
class ScrollElasticityController {
WTF_MAKE_NONCOPYABLE(ScrollElasticityController);
public:
explicit ScrollElasticityController(ScrollElasticityControllerClient*);
bool handleWheelEvent(const PlatformWheelEvent&);
void snapRubberBandTimerFired();
bool isRubberBandInProgress() const;
private:
void stopSnapRubberbandTimer();
void snapRubberBand();
bool shouldRubberBandInHorizontalDirection(const PlatformWheelEvent&);
ScrollElasticityControllerClient* m_client;
bool m_inScrollGesture;
bool m_momentumScrollInProgress;
bool m_ignoreMomentumScrolls;
CFTimeInterval m_lastMomentumScrollTimestamp;
FloatSize m_overflowScrollDelta;
FloatSize m_stretchScrollForce;
FloatSize m_momentumVelocity;
// Rubber band state.
CFTimeInterval m_startTime;
FloatSize m_startStretch;
FloatPoint m_origOrigin;
FloatSize m_origVelocity;
bool m_snapRubberbandTimerIsActive;
};
} // namespace WebCore
#endif // ENABLE(RUBBER_BANDING)
#endif // ScrollElasticityController_h
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