/*

* Copyright (c) 2008-2009 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:     Declaration of Maths Engine

*

*/

#ifndef GLXZOOMMATHSENGINE_H_

#define GLXZOOMMATHSENGINE_H_

// INCLUDE FILES

#include <e32base.h>

#include <glxzoomview.hrh>

NONSHARABLE_CLASS( TGlxZoomAndPanMathsEngine )

    {

public:

    /**

     * Starts panning with keys

     *@ param aOffset:Specifies the offset value with which image has to be shifted/panned

     */              

    void Pan(TPoint aOffset, 

            TPoint& aViewPortTopLeft,

            TGlxPanIncrementType aPanIncrement,

            TBool* aThresholdReached = NULL);

    /**

     */              

    TInt Zoom( TZoomMode aZoomMode,         // Ignored when aExpectedZoomRatio has a value 

                TInt aExpectedZoomRatio,    // only for slider based zoom. = 0 for key based zoom. 

                TPoint& aViewPortTopLeft, 

                TSize& aViewPortDimension,

                TBool* apThresholdReached = NULL,

                TPoint* apZoomFocus = NULL, 

                TInt aRelativeZoomFactor = 0);

    void Initialize(TPoint& aCenter, 

            TSize& aScreenSize, 

            TSize& aImageSize,

            TSize& aOriginalZoomedDimensions, 

            TUint8 aInitialZoomRatio);

    // this can have a more generic name. but now it informs only abt screen orientation changes. and hence the name 

    void OrientationChanged(const TRect& aNewScreenRect);

    TSize ImageVirtualSize();

    TSize ScreenSize();

            TBool *aLimitReached = NULL) ;

    void SetupPanOperation();

    TPoint LastPanOffset();

private:

    /**

     * Get the next Zoomlevel on the basis of Zoom In/Out

     *  @ param aZoomMode:Specifies the zoomode,whether it is Zoom In/Out

     *  

     *  We ignore aZoommode and aRelativeZoomFactor if we have a aExpectedZoomRatio.

     *  We ignore aZoommode if we have a aRelativeZoomFactor.

     *  

     */          

    TInt NewZoomRatio( 

            TInt aExpectedZoomRatio,

            TInt aRelativeZoomFactor,

            TZoomMode aZoomMode,

            TBool *aThresholdReached = NULL) ;

    TPoint          iCenter             ;

    TSize           iScreenSize         ;

    TSize           iImageVirtualSize   ;

    TSize           iActualImageSize    ;

    // The Purpose of this Variable is to set the No:of pixels, by which it should Pan,

    // when the Key is held for long time.

    TUint8          iPanFactor          ;       

    // No of continuous pan operations that have happened. This is used in calculating the pan factor  

    TInt            iContinuousPanOperations;

    // These are the thresholds

    TUint8          iMaxZoomRatio;

    // This is what our current zoom ratio is in percentage

    TPoint          iLastPanOffset;     //  Pixels Panned during the last pan operation.

    // [TODO]:Tsize might not be an exact match for this. using this only since it has exactly all the parameters that are required.   

    TSize           iBorderWidth;

    };

#endif //GLXZOOMMATHSENGINE