/*

* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:Pinch Gesture Recognizer

*

*/

#ifndef PINCHGESTURERECOGNISER_H_

#define PINCHGESTURERECOGNISER_H_

#include "rt_gestureengineif.h"

#include <rt_gestureif.h>

#include <rt_gesturelistener.h>

class CCoeControl ;

namespace stmGesture

{

/*!

 * Recognise pinching gesture. !!! very experimental !!!

 * It seems that in capacitive touch in Symbian 9.4 touching with two

 * fingers causes fast EDrag events which are far from each other.

 * This gesture recogniser tries to use that feature

 * to determine when the gestures looks like a pinch.

 * Would requires a lot of tuning to be really useful, if at all possible.

 * With current implementation it is easy to zoom in but

 * almost impossible to zoom out.

 */

NONSHARABLE_CLASS( CPinchGestureRecogniser ): public CGestureRecogniser

{

public:

    static const TGestureUid KUid = EGestureUidPinch;

    static CPinchGestureRecogniser* NewL(MGestureListener* aListener);

    virtual ~CPinchGestureRecogniser();

    /*!

     * MGestureRecogniserIf methods

     */

    virtual TGestureRecognitionState recognise(int numOfActiveStreams, MGestureEngineIf* ge) ;

    virtual void release(MGestureEngineIf* ge) ;

    virtual TGestureUid gestureUid() const

        {

        return KUid;

        }

    /* define the pinch triggering as speed value */

    /* after EHold has been seen, then any move which is faster than this will enter pinch gesture */

    /* note that the value varies depending on techology, speed is measured as pixels / ms */

    void setPinchingSpeed(float aSpeed) __SOFTFP;

private:

    CPinchGestureRecogniser(MGestureListener* aListener) ;

    void calculateZoomingLine() ;

    float calculateDistance() ;

    int adjustPinchMove(float& aPreviousDistance, float aNewDistance) ;

private:

    bool m_pinching ;

    float m_pinchingspeed ;

    TPoint m_pinchstart ;

    TPoint m_pinchend ;

    float m_m ;

    float m_b ;

    float m_ddistance ;

    bool m_holdseen ;

    TPoint m_holdseenAtPos ;

    TTime m_holdseenAtTime ;

};

}

#endif /* PINCHGESTURERECOGNISER_H_ */