1 /*

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

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

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

     6 * which accompanies this distribution, and is available

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

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:  Algorithm to recognise gesture from a stream of points

    15 *

    16 */

    17 

    18 #ifndef _GESTURERECOGNISER_H_

    19 #define _GESTURERECOGNISER_H_

    20 

    21 #include <e32std.h>

    22 #include <gestureobserver.h>

    23 

    24 struct TPointerEvent;

    25 

    26 namespace GestureHelper

    27 {

    28 

    29 class TPointArray;

    30 

    31 /**

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

    33  * easier to replace it with a heavier implementation

    34  */

    35 NONSHARABLE_CLASS( TGestureRecogniser )

    36     {

    37 public:

    38     /** 

    39      * Translates points into a gesture code

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

    41      *                to pass in repeated points (sequential points that are 

    42      *                almost in the same place)

    43      * @param aAxis Axis to filter the points

    44      * @return recognised gesture id or EUnknownGesture

    45      */

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

    47 

    48     /** 

    49      * Translates 2 sequences of points into a multitouch gesture code

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

    51      *                to pass in repeated points (sequential points that are 

    52      *                almost in the same place)

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

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

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

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

    57      */

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

    59             TBool aIsFirstPinch ) const;

    60     

    61     /** 

    62      * Validate the points to decide its a drag or not

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

    64      *                to pass in repeated points (sequential points that are 

    65      *                almost in the same place)

    66      * @param aAxis Axis to filter the points

    67      * @return EGestureDrag if valid else returns EUnknownGesture

    68      */    

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

    70     

    71     /** 

    72      * Validate the points to decide its a drag or not

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

    74      *                to pass in repeated points (sequential points that are 

    75      *                almost in the same place)

    76      * @param aAxis Axis to filter the points

    77      * @return EGestureDrag if valid else returns EUnknownGesture

    78      */    

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

    80 

    81     /** 

    82      * Return the pointer number from the given event

    83 	 *

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

    85      * 

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

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

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

    89 	 * So that we can simulate multiple pointer event.

    90      * @return TInt pointer number

    91      */       

    92     TInt PointerNumber( const TPointerEvent& aEvent);

    93     

    94     };

    95     

    96 } // namespace GestureHelper

    97 

    98 #endif // _GESTURERECOGNISER_H_