/*

* Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "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:  Gesture helper implementation

*

*/

#ifndef _XNGESTUREHELPER_H_

#define _XNGESTUREHELPER_H_

// System includes

#include <e32base.h>

// Forward declarations

class CXnNode;

struct TPointerEvent;

/**

 * Swipe directions (left, right, none)

 */

enum TSwipeResult

    {

    ESwipeNone = 0,

    ESwipeLeft,

    ESwipeRight

    };

/**

 * XnGestureHelper namespace

 * Used for the whole gesture family - Gesture recognizer, gesture helper, 

 * Point array

 */

namespace XnGestureHelper

    {

    // Forward declarations

    class CHoldingTimer;

    class CXnGesture;

    // Constants

    const TReal32 KGestureMinSpeedX = 300;

    const TInt KGestureMinLengthX = 100;

    const TInt KGestureMaxDeltaY = 100;

    /**

     *  Implementation of CGestureHelper interface

     *

     *  @ingroup group_xnlayoutengine

     */

    NONSHARABLE_CLASS( CXnGestureHelper ) : public CBase

        {

        /** private implementation class */

        friend class CHoldingTimer;

    public:

        /** 2-phase constructor */

        static CXnGestureHelper* NewL( CXnNode& aNode );

        /** Destructor */

        ~CXnGestureHelper();

        /** 

         * See GestureHelper, SetHoldingEnabled function

         * 

         * @see CGestureHelper::SetHoldingEnabled 

         */

        void SetHoldingEnabled( TBool aEnabled );

        /** 

         * See Gesturehelper, IsHoldingEnabled function

         * 

         * @see CGestureHelper::IsHoldingEnabled 

         */

        TBool IsHoldingEnabled() const;

        /** 

         * Gets the owner

         * 

         * @return Owner

         */                

        CXnNode* Owner() const;

        /** 

         * Sets destination

         * 

         * @aParam Destination

         */        

        void SetDestination( CXnNode* aDestination );

        /** 

         * Gets destination

         * 

         * @return Destination

         */                         

        CXnNode* Destination() const;

        /** 

         * See GestureHelper Handlepointervent

         * 

         * @see CGestureHelper::HandlePointerEventL 

         */ 

        TSwipeResult HandlePointerEventL( const TPointerEvent& aEvent );

        /** Reset helper state */

        void Reset();

    private:

        /** Constructor */

        CXnGestureHelper( CXnNode& aNode );

        /** 

         * Returns if the helper is processing

         *         

         * @return ETrue if the helper has not started processing a gesture

         */

        inline TBool IsIdle() const; 

        /** 

         * Add a point to the sequence of points that make up the gesture 

         */

        inline void AddPointL( const TPointerEvent& aEvent );

        /** 

         * Add a point to the sequence of points that make up the gesture

         * 

         * @return                    

         */

        inline TInt AddPoint( const TPointerEvent& aEvent );

        /** 

         * Activates holding and notifies observer that holding has been 

         * started 

         */

        void StartHoldingL();

        /** 

         * Check if swipe if between defined values 

         * 

         * @return Swiping left/right/none 

         */

        TSwipeResult ValidSwipe();

    private:

        /** 

         * Gesture owner, Not owned.

         */        

        CXnNode& iOwner;        

        /** 

         * Gesture is the logical representation of a sequence of points 

         * arriving at certain times

         */ 

        CXnGesture* iGesture;

        /** 

         * holding is activated when user keeps pointer down in the same place 

         * for a longer period. the holding timer activates off when enough 

         * time has passed.

         */

        CHoldingTimer* iHoldingTimer;

        /** 

         * Gesture destination, Not owned.

         */        

        CXnNode* iDestination;        

        };

    } // GestureHelper

#endif // _XNGESTUREHELPER_H_