/*

* Copyright (c) 2007-2010 Sebastian Brannstrom, Lars Persson, EmbedDev AB

*

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "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:

* EmbedDev AB - initial contribution.

*

* Contributors:

* Example code from OcrExample Copyright (c) 2006 Nokia Corporation.

* Description:

*

*/

#ifndef IMAGEHANDLER_H

#define IMAGEHANDLER_H

#include <f32file.h>

#include <ImageConversion.h>

#include <BitmapTransforms.h>

/**

 * Listener interface that can be used to listen for image loading operation

 * completion events from CImageHandler.

 *

 * The class is intended to be implemented by a client class that observes the

 * loading operation of image handler. The methods in this class

 * are called by the image handler (class CImageHandler) when it loads

 * an image.

 *

 * Reference to implementations of this listener interface can be passed as

 * a parameter to the constructor of the image handler (class CImageHandler).

 */

class MImageHandlerCallback

    {

public:

   /**

    * Called by CImageHandler when an image has been loaded.

    * @param aError Error code given by the CImageHandler or 0 (zero) if the

    *   image was loaded successfully.

    */

    virtual void ImageOperationCompleteL(TInt aError, TUint aHandle) = 0;

    };

// ============================================================================

class TImageStruct

	{

public:

	CFbsBitmap* iScaledImage;

	TSize iScaledSize;

	MImageHandlerCallback* iCallBack;

	TFileName iFileName;

	TUint iHandle;

	};

/**

*  CImageHandler

*  Image loader and scaler class.

*/

class CImageHandler : public CActive

    {

    public: // Constructors and destructor

       /**

        * Factory method that constructs a CImageHandler by using the NewLC method

        * and then cleans the cleanup stack.

        * @param aBitmap Bitmap where the image data is loaded to.

        * @param aScaledBitmap Bitmap where the scaled image data is loaded to.

        * @param aFs File server reference that is used to load the image data.

        * @param aCallback Listener interface implementation that is notified

        *  when an image has been loaded.

        * @return pointer to created CImageHandler-object

        */

        IMPORT_C static CImageHandler* NewL(RFs& aFs);

       /**

        * Factory method that constructs a CImageHandler and leaves it to the

        * cleanup stack.

        * @param aBitmap Bitmap where the image data is loaded to.

        * @param aScaledBitmap Bitmap where the scaled image data is loaded to.

        * @param aFs File server reference that is used to load the image data.

        * @param aCallback Listener interface implementation that is notified

        *  when an image has been loaded.

        * @return pointer to created CImageHandler-object

        */

        IMPORT_C static CImageHandler* NewLC(RFs& aFs);

       /**

        * Desctructor. Destroys the CImageDecoder used by the image handler.

        */

        IMPORT_C virtual ~CImageHandler();

        IMPORT_C CFbsBitmap* ScaledBitmap();

    public: // New functions      

        /**

         * Loads a the given frame from the given file and scale it to the

         * specified size

         * @param aFileName Filename wherefrom the bitmap data is loaded.

         * @param aSize the target size for the scaling

         * @param aSelectedFrame A single frame index in a multi-frame file.

         *  If not given the first frame is loaded.

         */

    	IMPORT_C void LoadFileAndScaleL(CFbsBitmap* aScaledBitmap, 

							   const TFileName& aFileName,

                               const TSize &aSize,

                               MImageHandlerCallback& aCallback,

                               TUint aHandle,

                               TInt aSelectedFrame = 0);

        /**

         * Returns the current frame information.

         * @return Current frame information.

         */

        const TFrameInfo& FrameInfo() const;     

    private:

        /**

         * Loads a the given frame from the given file.

         * @param aFileName Filename wherefrom the bitmap data is loaded.

         * @param aSelectedFrame A single frame index in a multi-frame file. If not given the first frame is loaded.

         */

        void LoadFileL(const TFileName& aFileName, TInt aSelectedFrame = 0);

       /**

        * Scales a loaded image

        * Scales a loaded image to the target size (given in LoadFileAndScaleL or

        * FitToScreenL). The scaled image is stored into iScaledBitmap.

        */

        void ScaleL();

    private: // Functions from base classes

        /**

         * CActive::RunL() implementation. Called on image load success/failure.

         */

        void RunL();

        /**

         * CActive::Cancel() implementation. Stops decoding.

         */

        void DoCancel();

    protected:

        /**

         * C++ default constructor. Just stores the given parameters to

         * corresponding attributes.      

         * @param aScaledBitmap Bitmap where the scaled image data is loaded to.

         * @param aFs File server reference that is used to load the image data.

         * @param aCallback Listener interface implementation that is notified

         *  when an image has been loaded.

         */

        CImageHandler(RFs& aFs);

        /**

         * 2nd phase constructor. Adds this object to the active scheduler.

         */

        void ConstructL();

    private: // Data

        /** Image decoder that is used to load the image data from file. */

        CImageDecoder           *iDecoder;

        /** Image scaler that is used to scale the image */

        CBitmapScaler           *iScaler;

        /** Listener that is notified when an image has been loaded. */

        MImageHandlerCallback *  iCallback;

        /** Bitmap (owned by the user of this class) where the loaded image is put */

        CFbsBitmap              *iBitmap;

        /** Bitmap (owned by the user of this class) where the SCALED image is put */

        CFbsBitmap              *iScaledBitmap;

        /** File server session (owned by the user of this class) */

        RFs                     &iFs;

        /** Current image frame information. */

        TFrameInfo              iFrameInfo;

        /** target size for scaled image */

        TSize                   iSize;

        RArray<TImageStruct> iCallbackQue;  

        /* Handle passed back to caller */

        TUint iHandle;

    };

#endif