Class CMdaImageUtility

class CMdaImageUtility : public CActive, private MMdaObjectStateChangeObserver;

Description

Defines the public interface to image conversion.

This class has been deprecated in 7.0s, it's functionality is now part of the Image Converter Library. For more information see CImageEncoder and CImageDecoder.

Clients of the concrete conversion classes call the functions provided by this interface to perform the conversion. The implementation of these functions is provided either by the concrete conversion classes themselves or by private implementation classes.

Derivation

• MMdaObjectStateChangeObserver - No description.

• CBase - Base class for all classes to be instantiated on the heap

• CActive - The core class of the active object abstraction

• CMdaImageUtility - Defines the public interface to image conversion

Members

Defined in CMdaImageUtility:
CancelConvertL(), Close(), ConvertL(), ConvertL(), DoCancel(), DoClose(), FrameCount(), FrameInfo(), ImageUtil_Reserved1(), ImageUtil_Reserved2(), ImageUtil_Reserved3(), ImageUtil_Reserved4(), MoscoStateChangeEvent(), ~CMdaImageUtility()

Inherited from CActive:
Cancel(), Deque(), EPriorityHigh, EPriorityIdle, EPriorityLow, EPriorityStandard, EPriorityUserInput, Extension_(), IsActive(), IsAdded(), Priority(), RunError(), RunL(), SetActive(), SetPriority(), TPriority, iStatus

Inherited from CBase:
Delete(), operator new()

See also:

• CImageEncoder
• CImageDecoder

virtual ~CMdaImageUtility();

Description

virtual IMPORT_C void Close();

Description

Closes the open file-based or descriptor-based image.

Any conversion operation in progress is cancelled.

virtual void ConvertL(CFbsBitmap &aBitmap, TInt aFrameNumber=0)=0;

Description

Begins the image conversion operation for the specified frame overloaded function.

The operation is asynchronous. When the conversion operation is complete, successfully or otherwise, the callback function MMdaImageUtilObserver::MiuoConvertComplete() is called.When converting from a file or descriptor to a bitmap, the operation can complete with KErrUnderflow, if there is insufficient information in the file or descriptor. Typically, this occurs when using the file or descriptor as a cache. In this situation, the conversion operation should be performed repeatedly until the file or descriptor has accumulated enough information for the operation to complete with KErrNone. As much of the image as is present is converted and written to the target bitmap at each call to this function.

Parameters

CFbsBitmap &aBitmap A reference to a bitmap. This may be a source or a target for the conversion process, depending on the concrete conversion class utility being used. TInt aFrameNumber The frame number. This value is relative to zero. For those concrete conversion classes which perform conversion from a bitmap, this value must always be zero. For those concrete conversion classes which perform conversion to a bitmap, this value must be less than the number of frames in the image.

virtual void ConvertL(CFbsBitmap &aBitmap, CFbsBitmap &aMaskBitmap, TInt aFrameNumber=0)=0;

Description

Begins the image conversion operation for the specified frame overloaded function.

The operation is asynchronous. When the conversion operation is complete, successfully or otherwise, the callback function MMdaImageUtilObserver::MiuoConvertComplete() is called.When converting from a file or descriptor to a bitmap, the operation can complete with KErrUnderflow, if there is insufficient information in the file or descriptor. Typically, this occurs when using the file or descriptor as a cache. In this situation, the conversion operation should be performed repeatedly until the file or descriptor has accumulated enough information for the operation to complete with KErrNone. As much of the image as is present is converted and written to the target bitmap at each call to this function.

Parameters

CFbsBitmap &aBitmap A reference to a bitmap. This may be a source or a target for the conversion process, depending on the concrete conversion class utility being used. CFbsBitmap &aMaskBitmap A source or target mask bitmap, if present. TInt aFrameNumber The frame number. This value is relative to zero. For those concrete conversion classes which perform conversion from a bitmap, this value must always be zero. For those concrete conversion classes which perform conversion to a bitmap, this value must be less than the number of frames in the image.

See also:

• CFbsBitmap
• TInt

virtual void CancelConvertL()=0;

Description

Cancels the conversion operation.

The callback function MMdaImageUtilObserver::MiuoConvertComplete() is not called.

virtual IMPORT_C void FrameInfo(TInt aFrame, TFrameInfo &aInfo) const;

Description

Retrieves information about the specified frame.

This function should only be called after an existing image has been successfully opened or a new image successfully created.

Parameters

TInt aFrame The frame number. This value is relative to zero. The value must be less than the total number of frames in the image, otherwise the function raises a USER 0 panic TFrameInfo &aInfo A reference to the frame information.

virtual IMPORT_C TInt FrameCount() const;

Description

Returns the number of frames in the image, counting from the first frame in the image, to the next frame to be decoded.

Note: The image conversion utilities do not scan all the image data on calling OpenL(), just the header. Therefore, if, as in the case of an animated gif, there is no frame count in the header, then until all the frames in the image have been decoded, the total frame count is unknown. Initially therefore, FrameCount() returns 1, but this increments as each frame is decoded, and the utility reads the next frame's header. Once the last frame has been decoded, all frames are available for access as the information about each frame is stored.

Return value

TInt The number of frames in the image

virtual void ImageUtil_Reserved1();

Description

virtual void ImageUtil_Reserved2();

Description

virtual void ImageUtil_Reserved3();

Description

virtual void ImageUtil_Reserved4();

Description

protected: virtual void DoClose();

Description

protected: virtual void MoscoStateChangeEvent(CBase *aObject, TInt aPreviousState, TInt aCurrentState, TInt aErrorCode);

Description

Parameters

CBase *aObject TInt aPreviousState TInt aCurrentState TInt aErrorCode

protected: virtual void DoCancel();

Description

Implements cancellation of an outstanding request.

This function is called as part of the active object's Cancel().

It must call the appropriate cancel function offered by the active object's asynchronous service provider. The asynchronous service provider's cancel is expected to act immediately.

DoCancel() must not wait for event completion; this is handled by Cancel().