1 /*

     2 * Copyright (c) 2008 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 the License "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:Pinch Gesture Recognizer

    15 *

    16 */

    17 

    18 #ifndef PINCHGESTURERECOGNISER_H_

    19 #define PINCHGESTURERECOGNISER_H_

    20 

    21 #include "rt_gestureengineif.h"

    22 #include <rt_gestureif.h>

    23 #include <rt_gesturelistener.h>

    24 

    25 class CCoeControl ;

    26 

    27 namespace stmGesture

    28 {

    29 /*!

    30  * Recognise pinching gesture. !!! very experimental !!!

    31  * It seems that in capacitive touch in Symbian 9.4 touching with two

    32  * fingers causes fast EDrag events which are far from each other.

    33  * This gesture recogniser tries to use that feature

    34  * to determine when the gestures looks like a pinch.

    35  * Would requires a lot of tuning to be really useful, if at all possible.

    36  * With current implementation it is easy to zoom in but

    37  * almost impossible to zoom out.

    38  */

    39 NONSHARABLE_CLASS( CPinchGestureRecogniser ): public CGestureRecogniser

    40 {

    41 public:

    42     static const TGestureUid KUid = EGestureUidPinch;

    43 

    44     static CPinchGestureRecogniser* NewL(MGestureListener* aListener);

    45 

    46     virtual ~CPinchGestureRecogniser();

    47     /*!

    48      * MGestureRecogniserIf methods

    49      */

    50     virtual TGestureRecognitionState recognise(int numOfActiveStreams, MGestureEngineIf* ge) ;

    51     virtual void release(MGestureEngineIf* ge) ;

    52 

    53     virtual TGestureUid gestureUid() const

    54         {

    55         return KUid;

    56         }

    57 

    58     /* define the pinch triggering as speed value */

    59     /* after EHold has been seen, then any move which is faster than this will enter pinch gesture */

    60     /* note that the value varies depending on techology, speed is measured as pixels / ms */

    61     void setPinchingSpeed(float aSpeed) __SOFTFP;

    62 

    63 private:

    64     CPinchGestureRecogniser(MGestureListener* aListener) ;

    65 

    66     void calculateZoomingLine() ;

    67     float calculateDistance() ;

    68     int adjustPinchMove(float& aPreviousDistance, float aNewDistance) ;

    69 

    70 private:

    71     bool m_pinching ;

    72     float m_pinchingspeed ;

    73     TPoint m_pinchstart ;

    74     TPoint m_pinchend ;

    75 

    76     float m_m ;

    77     float m_b ;

    78 

    79     float m_ddistance ;

    80     bool m_holdseen ;

    81     TPoint m_holdseenAtPos ;

    82     TTime m_holdseenAtTime ;

    83 };

    84 

    85 }

    86 

    87 #endif /* PINCHGESTURERECOGNISER_H_ */