/*

* Copyright (c) 2009 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: Class for tracing the direction in which pointer

*              is being dragged.

*

*/

#ifndef C_AKNTOUCHGESTUREFWDRAGTRACER_H

#define C_AKNTOUCHGESTUREFWDRAGTRACER_H

#include <e32base.h>

namespace AknTouchGestureFw

{

/**

 * Traces the direction in which pointer is being dragged.

 */

NONSHARABLE_CLASS( CAknTouchGestureFwDragTracer ) : public CBase

    {

public:

    /**

     * Values used to represent horizontal and vertical direction.

     */

    enum TDirection

        {

        EDirectionNone,     ///< No change in position.

        EDirectionForward,  ///< Movement towards right or down.

        EDirectionBackward  ///< Movement towards left or up.

        };

    /**

     * Two-phased constructor.

     */

    static CAknTouchGestureFwDragTracer* NewL();

    /**

     * Two-phased constructor.

     */

    static CAknTouchGestureFwDragTracer* NewLC();

    /**

     * Destructor.

     */

    virtual ~CAknTouchGestureFwDragTracer();

    /**

     * Initializes tracer.

     *

     * @param  aStartPosition  Start coordinate.

     */

    void Initialize( const TPoint& aStartPosition );

    /**

     * Checks if dragging direction has changed with new position.

     *

     * @param  aPosition     New position.

     * @param  aSensitivity  Tells how many points can be dragged to reversed

     *                       direction before direction is changed.

     *

     * @return @c ETrue if direction has changed

     */

    TBool IsDirectionChanged( const TPoint& aPosition, TInt aSensitivity );

private:

    /**

     * C++ constructor.

     */

    CAknTouchGestureFwDragTracer();

    /**

     * Checks if dragging direction has changed horizontally or vertically

     * with new position. Only horizontal or vertical direction can be checked

     * with single call.

     *

     * @param  aCurrentCoordinate  Current X- or Y-coordinate

     * @param  aPrevCoordinate     Previous X- or Y-coordinate

     * @param  aDirection          Current direction, will be updated within

     *                             this call.

     * @param  aCounter            Counter of coordinates that are dragged

     *                             to reversed direction, will be updated

     *                             within this call.

     * @param  aSensitivity        Tells how many points can be dragged to

     *                             reversed direction before direction is

     *                             changed.

     *

     * @return @c ETrue if direction has changed

     */

    TBool IsDirectionChanged( TInt aCurrentCoordinate,

                              TInt aPrevCoordinate,

                              TDirection& aDirection,

                              TInt& aCounter,

                              TInt aSensitivity );

private: // data

    /**

     * Current horizontal direction

     */

    TDirection iHorizDirection;

    /**

     * Current vertical direction

     */

    TDirection iVertDirection;

    /**

     * Counter for points which are to reversed horizontal direction

     * compared to current direction.

     */

    TInt iHorizCounter;

    /**

     * Counter for points which are to reversed vertical direction

     * compared to current direction.

     */

    TInt iVertCounter;

    /**

     * Current position.

     */

    TPoint iPosition;

    };

} // namespace AknTouchGestureFw

#endif // C_AKNTOUCHGESTUREFWDRAGTRACER_H