/*

* 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 to store physics related data in forms.

*

*/

#ifndef C_CAKNFORMPHYSICS_H

#define C_CAKNFORMPHYSICS_H

#include <e32base.h>

#include <aknphysicsobserveriface.h>

class CAknPhysics;

class CEikDialogPage;

class CAknRecordingGc;

/**

 */

NONSHARABLE_CLASS( CAknFormPhysics ) : public CBase, public MAknPhysicsObserver

    {

public:

    /**

    * Two-phased constructor.

    */

    static CAknFormPhysics* NewL( CEikDialogPage& aParent, CAknRecordingGc& aRecordingGc );

    /**

    * Destructor.

    */

    virtual ~CAknFormPhysics();

    /**

    * Initializes physics engine.

    *

    * @since S60 v5.0

    * @param aWorldSize Collected size of all form items.

    * @param aViewSize View's size i.e. size of form's rect.

    * @param aViewCenter View center's initial position.

    */

    void InitPhysicsL( const TSize& aWorldSize, const TSize& aViewSize, const TPoint& aViewCenter );

    /**

    * Stops the physics engine.

    *

    * @since S60 v5.0

    */

    void Stop();

    /**

    * Starts the physics engine.

    *

    * @since S60 v5.0

    * @param aLength Length of the flick on display (in pixels).

    * @param aStartTime Flick's start time.

    * @return ETrue if flicking was started.

    */

    TBool StartFlick( const TPoint& aLength, const TTime& aStartTime );

    /**

    * Returns highlight timeout. Tapped item should be activated only after a small delay.

    *

    * @since S60 v5.0

    * @return Highlight delay.

    */

    TInt HighlightDelay() const;

    /**

    * Return drag event's treshold.

    *

    * @since S60 v5.0

    * @return Drag treshold in pixels.

    */

    TInt DragThreshold() const;

    /**

    * Returns current view size.

    *

    * @since S60 v5.0

    * @return View size.

    */

    TSize ViewSize() const;

    /**

    * Registers panning position to physics.

    *

    * @since S60 v5.0

    * @aPosition Position delta.

    */

    void SetPanningPosition( const TPoint& aDelta );

public: // From base class MAknPhysicsObserver.

    /**

     * Called when view position changes.

     *

     * @param  aNewPosition  The new position of the view.

     * @param  aDrawNow      @c ETrue if the screen is to be redrawn,

     *                       otherwise @c EFalse.

     * @param  aFlags        Additional flags, not used currently.

     */

    virtual void ViewPositionChanged( const TPoint& aNewPosition,

                                      TBool aDrawNow = ETrue,

                                      TUint aFlags = 0 );

    /**

     * Physics emulation has stopped moving the view.

     *

     * @since S60 v5.0

     */

    virtual void PhysicEmulationEnded();        

    /**

     * Returns the observer's view position.

     *

     * @since S60 v5.0

     *

     * @return Physics observer's view position.

     */

    virtual TPoint ViewPosition() const;

public: // New methods

    /**

     * Checks whether the physics engine can be stopped.

     *

     * @since S60 v5.0

     * @return ETrue if the physics engine can be stopped.

     */

    TBool CanBeStopped() const;

    /**

     * Returns CAknPhysics action code i.e. which action CAknPhysics 

     * is currently performing.

     *

     * @since S60 v5.2

     * @return TAknPhysicsAction type action code.

     */

    TInt OngoingPhysicsAction() const;

    /**

     * Returns view's top y coordinate.

     * 

     * @since S60 v5.0

     * @return View's top y coordinate in pixels, relative to 0. 

     */

    TInt ViewTopY() const;

    /**

     * Returns distance from view's top to its center. In other words,

     * ViewPosition() == ViewTopY() + ViewDistance().

     * 

     * @since S60 v5.0

     * @return Distance from view's top y to its center.

     */

    TInt ViewCenterDistance() const;

    /**

     * Sets view center position.

     * 

     * @since S60 v5.0

     */

    void SetViewCenter( const TPoint& aPosition );

    /**

     * Return view center position.

     * 

     * @since S60 v5.0

     * @return View center.

     */

    TPoint ViewCenter() const;

private:

    /**

    * Constructor.

    */

    CAknFormPhysics( CEikDialogPage& aParent, CAknRecordingGc& aRecordingGc );

    /**

    * Second stage constructor.

    */

    void ConstructL();

private: // data

    /**

    * Center of the "view" (the visible window to the whole form i.e. form's

    * virtual rect).

    */

    TPoint iViewCenter;

    /**

     * Interface to the physics engine.

     * Own.

     */

    CAknPhysics* iPhysics;

    /**

    * Dialog page whose scrolling is controlled by this class.

    */

    CEikDialogPage& iParent;

    /**

    * Graphics context used to cache drawing commands.

    */

    CAknRecordingGc& iRecordingGc;

    /**

    * Size of the "world".

    */

    TSize iWorldSize;

    /**

    * View size.

    */

    TSize iViewSize;

    };

#endif // C_CAKNFORMPHYSICS_H