Class CMdaImageDataReadUtility

class CMdaImageDataReadUtility : public CMdaImageUtility;

Description

Base class used in the derivation of CMdaImageDescToBitmapUtility and CMdaImageFileToBitmapUtility.

It has no user accessible functions.

Replaced by Image Conversion library - see CImageDecoder

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

• CMdaImageDataReadUtility - Base class used in the derivation of CMdaImageDescToBitmapUtility and CMdaImageFileToBitmapUtility

Members

Defined in CMdaImageDataReadUtility:
CancelConvertL(), ConvertL(), ConvertL(), DoCancel(), DoClose(), FrameCommentL(), ImageReadUtil_Reserved2(), ImageReadUtil_Reserved3(), ImageReadUtil_Reserved4(), RunL(), ~CMdaImageDataReadUtility()

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

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

Inherited from CMdaImageUtility:
Close(), FrameCount(), FrameInfo(), ImageUtil_Reserved1(), ImageUtil_Reserved2(), ImageUtil_Reserved3(), ImageUtil_Reserved4(), MoscoStateChangeEvent()

See also:

• CImageDecoder

virtual ~CMdaImageDataReadUtility();

Description

Default destructor.

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

Description

Cancels the conversion operation.

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

virtual void RunL();

Description

Handles an active object's request completion event.

A derived class must provide an implementation to handle the completed request. If appropriate, it may issue another request.

The function is called by the active scheduler when a request completion event occurs, i.e. after the active scheduler's WaitForAnyRequest() function completes.

Before calling this active object's RunL() function, the active scheduler has:

1. decided that this is the highest priority active object with a completed request

2. marked this active object's request as complete (i.e. the request is no longer outstanding)

RunL() runs under a trap harness in the active scheduler. If it leaves, then the active scheduler calls RunError() to handle the leave.

Note that once the active scheduler's Start() function has been called, all user code is run under one of the program's active object's RunL() or RunError() functions.

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().

virtual IMPORT_C const TDesC &FrameCommentL(TInt aFrameNumber);

Description

Returns a particular comment attached to a given frame of the image This function has been superceded by the parallel one in CImageDecoder, as this assumes that each frame has a comment within it, which is not always the case.

Parameters

TInt aFrameNumber The Frame Number within the image from which to retrieve the specified comment

Return value

const TDesC & The specified comment

virtual void ImageReadUtil_Reserved2();

Description

virtual void ImageReadUtil_Reserved3();

Description

virtual void ImageReadUtil_Reserved4();

Description

protected: virtual void DoClose();

Description