/*

* 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:  Algorithm to recognise gesture from a stream of points

*

*/

#ifndef _XNGESTURERECOGNISER_H_

#define _XNGESTURERECOGNISER_H_

// System includes

#include <e32std.h>

/**

 * XnGestureHelper namespace

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

 * Point array

 */

namespace XnGestureHelper

    {

    // Forward declarations

    class TXnPointArray;

    /**

     * flag that indicates gesture code is a holding code

     * clients should use MGestureEvent::IsHolding

     */

    const TInt EFlagHold = 0x10000000;

    /**

     * Gesture codes and states

     */

    enum TXnGestureCode

        {

        // states

        /** gesture just started (user pressed stylus down)*/ 

        EGestureStart = 0x00000001, 

        /** user moved stylus (may be holding or not holding) */

        EGestureDrag = 0x00000002, 

        /** user lifted stylus while user was holding */

        EGestureReleased = 0x00000003, 

        // gestures  

        /** gesture was not recognised */

        EGestureUnknown = 0x00000005, 

        /** these codes are sent when user lifts stylus 

         * (if holding not started)

         */

        EGestureTap = 0x00000006,

        /** first tap emits EGestureTap */

        EGestureDoubleTap = 0x00000007, 

        /** swipe left */

        EGestureSwipeLeft = 0x00000008,

        /** swipe right */

        EGestureSwipeRight = 0x00000009,

        /** swipe up */

        EGestureSwipeUp = 0x0000000A,

        /** swipe down */

        EGestureSwipeDown = 0x0000000B,

        /** 

         * these codes are sent when user initiates holding by keeping stylus 

         * in same place for a longer duration

         */

        EGestureHoldLeft = EGestureSwipeLeft | EFlagHold,

        EGestureHoldRight = EGestureSwipeRight | EFlagHold,

        EGestureHoldUp = EGestureSwipeUp | EFlagHold,

        EGestureHoldDown = EGestureSwipeDown | EFlagHold

        };

    //Class declaration

    /**

     *  Set of algorithms to recognise gesture from a stream of points

     *  Note: Not a static class or a function pointer, just to make it 

     *  sligthly easier to replace it with a heavier implementation

     *

     *  @ingroup group_xnlayoutengine

     */

    NONSHARABLE_CLASS( TXnGestureRecogniser )

        {

    public:

        /** 

         * Translates points into a gesture code

         * @param aPoints Points that form the gestures. Client is not 

         *        required to pass in repeated points (sequential 

         *        points that are almost in the same place)

         * @param aIsHolding ETrue if gesture was ended at pointer being held 

         *        down at same position

         *        EFalse if gesture ended at pointer being released 

         * @return recognised gesture id or EUnknownGesture

         */

        TXnGestureCode GestureCode( const TXnPointArray& aPoints ) const;

        };

    } // namespace XnGestureHelper

#endif // _XNGESTURERECOGNISER_H_