imageconverterengine.h

这个源代码是symbian下实现图片旋转及缩放的例子代码。对图片处理时有帮助。

/*
* ============================================================================
*  Name     : CImageConverterEngine from ImageConverterEngine.h
*  Part of  : ImageConverter
*  Created  : May 14, 2006 by Forum Nokia
*  Implementation notes:
*     Handles all ICL interaction. Implemented as a separate class/engine
*     for the sake of clarity of the example.
*  Version  : 2.0
*  Copyright: Nokia Corporation
* ============================================================================
*/

#ifndef __IMAGECONVERTER_H__
#define __IMAGECONVERTER_H__

#include <e32std.h>
#include <e32base.h>
#include <f32file.h>
#include <ImageConversion.h>

class CFbsBitmap;
class CBitmapRotator;
class CBitmapScaler;

class MConverterController
    {
    public:
        virtual void NotifyCompletion( TInt aErr, const TDesC& aMsg ) = 0;
    };

class CImageConverterEngine : public CActive
    {
    // states for this engine
    enum TState 
        {
        EIdle = 0,
        EDecoding,
        EEncoding,
        ERotating,
        EScaling
        };

    public:
        // rotation directions
        enum TDirection 
            {
            EClockwise90 = 0,
            EAntiClockwise90 
            };

        public: // contructors/destructors

        /*
        * NewL
        *  
        * Create a CImageConverterEngine object and return a pointer to it.
        *
        * Params: 
        *		aController Pointer to a MConverterController interface.
        *      The engine uses NotifyCompletion callback from this interface
        *      to notify the controller about completions of coding or 
        *      encoding requests.
        *		 
        * Returns:
        * 		A pointer to the created engine
        *
        */	
        static CImageConverterEngine* NewL( MConverterController* aController );
	
        ~CImageConverterEngine();
        
    public: // interface methods

        /*
        * StartToDecodeL
        *  
        * Starts to decode an image from a file. When completed calls 
        * NotifyCompletion, from iController.
        *
        * Params: 
        *		aFileName Full path and filename of the image to be decoded.
        *		 
        * Returns:
        * 		Nothing
        */
        void StartToDecodeL( TFileName& aFileName );

        /*
        * StartToEncodeL
        *  
        * Starts to encode an image to a file. When completed calls 
        * NotifyCompletion, from iController.
        *
        * Params: 
        *		aFileName Full path and filename to the image to be encoded.
        *		 
        * Returns:
        * 		Nothing
        */
        void StartToEncodeL( TFileName& aFileName, 
            TUid aImageType, TUid aImageSubType );

        /*
        * GetImageInfoL
        *  
        * Gets frame 0 info strings. An image has to be decoded before 
        * call to this method, otherwise will return NULL.
        * 
        * Params: 
        *		None
        *		 
        * Returns:
        * 		CFrameInfoStrings* See Symbian OS documentation for 
        *		reference.
        */
        CFrameInfoStrings* GetImageInfoL();

		/*
        * GetEncoderImageTypesL
        *  
        * Gets descriptions of supported (encoding) image types. 
		*
        * Params: 
        *		aImageTypeArray Reference to an array to be filled.
        *		See Symbian OS documentation for reference.
        *
        * Returns:
        * 		Nothing 
        */
        static void GetEncoderImageTypesL( 
            RImageTypeDescriptionArray& aImageTypeArray );
    
        /*
        * Rotate
        *  
        * Rotates the image to the given direction.
        *
        * Params: 
        *		aDirection The direction to rotate to.
        *
        * Returns:
        * 		Nothing 
        */
        void Rotate( TDirection aDirection );

        /*
        * Scale
        *  
        * Scales the image to the given percentage of the current size.
        *
        * Params: 
        *		aPercent The new size relative to the current size 
        * 		(e.g. 110 will increase the size by 10 %).
        *
        * Returns:
        * 		Nothing 
        */
        void Scale( TInt aPercent );
	
        /*
        * GetBitmap
        *  
        * Returns a pointer to the decoded image.
        *
        * Params: 
        *		None
        *
        * Returns:
        * 		A pointer to the encoded image  
        */
        CFbsBitmap* GetBitmap();


    protected: // implementation of CActive
        void DoCancel();
        void RunL();
        TInt RunError(TInt aError);

    private: // internal methods
        CImageConverterEngine( MConverterController* aController ); 
        void ConstructL();	        

    private: // internal data
        /*
        * Access to the decoded image,
        * images are also encoded from this bitmap.
        */
        CFbsBitmap* iBitmap; // decoded image

        MConverterController* iController; // ui controller
	
        RFs iFs; // for opening/saving images from/to files
		
        CImageDecoder* iImageDecoder; // decoder from ICL API
        CImageEncoder* iImageEncoder; // encoder from ICL API
		
        CBitmapRotator* iRotator;
        CBitmapScaler* iScaler;
	
        TState iState;
    };

#endif // #ifndef __IMAGECONVERTER_H__