/*

* 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 _GESTURERECOGNISER_H_

#define _GESTURERECOGNISER_H_

#include <e32std.h>

#include <gestureobserver.h>

struct TPointerEvent;

namespace GestureHelper

{

class TPointArray;

/**

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

 * easier to replace it with a heavier implementation

 */

NONSHARABLE_CLASS( TGestureRecogniser )

    {

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 aAxis Axis to filter the points

     * @return recognised gesture id or EUnknownGesture

     */

    TGestureCode GestureCode( const TPointArray& aPoints, MGestureEvent::TAxis aRelevantAxis ) const;

    /** 

     * Translates 2 sequences of points into a multitouch gesture code

     * @param aPoints Points that represent the first touch point variations. Client is not required 

     *                to pass in repeated points (sequential points that are 

     *                almost in the same place)

     * @param aSecondaryPoints Points that represent the second touch point variations.

     * @param aPreviousDistance distance between the two points when the pinch was recognized the last time.

     * @param aisFirstPinch, Is this the first pinch of teh current gesture. Required to decide which tolerance to use

     * @return recognised gesture id or EUnknownGesture if its not a valid multi touch gesture

     */

    TGestureCode MultiTouchGestureCode( const TPointArray& aPoints, const TPointArray& aSecondaryPoints, TInt aPreviousDistance,

            TBool aIsFirstPinch ) const;

    /** 

     * Validate the points to decide its a drag or not

     * @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 aAxis Axis to filter the points

     * @return EGestureDrag if valid else returns EUnknownGesture

     */    

    TGestureCode ValidateDrag( const TPointArray& aPoints, MGestureEvent::TAxis aRelevantAxis ) const;

    /** 

     * Validate the points to decide its a drag or not

     * @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 aAxis Axis to filter the points

     * @return EGestureDrag if valid else returns EUnknownGesture

     */    

    TInt Length( const TPoint aPoint, const TPoint aSecondaryPoint ) const;

    /** 

     * Return the pointer number from the given event

	 *

     * @param aEvent, event for which the pointer number needs to be fetched

     * 

	 * This function is added here only for simulating multiple pointer events

	 * for testing UT, For simulation purpose we will have a custom implemetation

	 * which will override this method and return our own pointer numbers

	 * So that we can simulate multiple pointer event.

     * @return TInt pointer number

     */       

    TInt PointerNumber( const TPointerEvent& aEvent);

    };

} // namespace GestureHelper

#endif // _GESTURERECOGNISER_H_