CImageEncoderPlugin Class Reference

class CImageEncoderPlugin : public CBase

The plugin API for Image Converter Library encoder plugins.

Intended for use by plugin writers only.

Inherits from

Public Member Functions
~CImageEncoderPlugin ()
IMPORT_C void GetExtensionL ( TUid , MImageConvExtension *&)
Protected Member Functions
CImageEncoderPlugin ()
IMPORT_C TBool AmInThread ()
IMPORT_C void Cleanup ()
IMPORT_C TInt CurrentImageSizeL ()
IMPORT_C TBufPtr8 & DestinationData ()
IMPORT_C void DoConvert ()
IMPORT_C CImageEncoder::TOptions EncoderOptions ()
IMPORT_C void FinishConvertL ()
IMPORT_C const TSize & FrameInfoOverallSizeInPixels ()
IMPORT_C void HandleCustomSyncL ( TInt )
IMPORT_C void HandleProcessFrameResult ( TInt , TFrameState )
IMPORT_C CImageWriteCodec * ImageWriteCodec ()
IMPORT_C void InitConvertL ()
IMPORT_C void InitCustomAsyncL ( TInt )
IMPORT_C void NotifyComplete ()
IMPORT_C TInt & Position ()
void PrepareEncoderL (const CFrameImageData *)
IMPORT_C void RequestComplete ( TInt )
IMPORT_C void RequestInitL ()
IMPORT_C void SelfComplete ( TInt )
IMPORT_C void SetImageWriteCodec ( CImageWriteCodec *)
IMPORT_C void SetSelfPending ()
IMPORT_C TBool ShouldAbort ()
IMPORT_C const CFbsBitmap & Source ()
IMPORT_C TInt & StartPosition ()
void UpdateHeaderL ()
IMPORT_C TBool ValidSource ()
IMPORT_C void WriteDataL ( TInt , const TDesC8 &)
IMPORT_C void WriteDataPositionIncL ( TInt , const TDesC8 &)
Private Member Functions
IMPORT_C void ReservedVirtual1 ()
IMPORT_C void ReservedVirtual2 ()
IMPORT_C void ReservedVirtual3 ()
IMPORT_C void SetThumbnail ( TBool )
TBool ValidProperties ()
IMPORT_C void WriteExifDataL ( TRequestStatus *&)
IMPORT_C void WriteThumbnailL ()
Inherited Functions
CBase::CBase()
CBase::Delete(CBase *)
CBase::Extension_(TUint,TAny *&,TAny *)
CBase::operator new(TUint)
CBase::operator new(TUint,TAny *)
CBase::operator new(TUint,TLeave)
CBase::operator new(TUint,TLeave,TUint)
CBase::operator new(TUint,TUint)
CBase::~CBase()
Private Attributes
CImageEncoderPriv * iProperties

Constructor & Destructor Documentation

CImageEncoderPlugin()

IMPORT_C CImageEncoderPlugin ( ) [protected]

Constructor for this class.

~CImageEncoderPlugin()

IMPORT_C ~CImageEncoderPlugin ( )

Destructor for this class.

Member Functions Documentation

AmInThread()

IMPORT_C TBool AmInThread ( ) const [protected]

Indicates if this encoder is running in a separate thread.

Cleanup()

IMPORT_C void Cleanup ( ) [protected, virtual]

Called when the plugin is destroyed or an encode is cancelled to perform cleanup functions.

This function may be overriden in derived classes in which case the derived class should ensure it calls this version after performing any plugin specific cleanup.

CurrentImageSizeL()

IMPORT_C TInt CurrentImageSizeL ( ) const [protected]

Returns the current size of the encoded image in bytes.

DestinationData()

IMPORT_C TBufPtr8 & DestinationData ( ) [protected]

Returns the value to be fed to CImageWriteCodec::ProcessFrameL() , and will be used by codecs that fully override DoConvert() .

DoConvert()

IMPORT_C void DoConvert ( ) [protected, virtual]

Performs the encoding process.

This call may be overriden in derived classes. If this is not the case and a custom decode is not performed, the derived class should ensure that this base class's version is called.

EncoderOptions()

IMPORT_C CImageEncoder::TOptions EncoderOptions ( ) const [protected]

Enables getting set of options which has been passed by client during encoder object creation. Plugins should ignore unknown options.

FinishConvertL()

IMPORT_C void FinishConvertL ( ) [protected]

Notifies the framework that the main frame encoding is complete, so it can tidy up. This results in a call to UpdateHeaderL() and then either the descriptor is copied across or the file is closed.

Note: This function is only used if a decoder replaces the DoConvert() call - the default version does this as part of its processing.

FrameInfoOverallSizeInPixels()

IMPORT_C const TSize & FrameInfoOverallSizeInPixels ( ) const [protected]

Returns the overall size of the image frame in pixels.

GetExtensionL(TUid, MImageConvExtension *&)

IMPORT_C void GetExtensionL ( TUid aExtUid,
MImageConvExtension *& aExtPtr
) [virtual]

Called by the framework to obtain a pointer to a codec implemented extension.

icl_uids.hrh .

Parameters

TUid aExtUid Extension UID normally prefixed KUidImageConv.
MImageConvExtension *& aExtPtr

HandleCustomSyncL(TInt)

IMPORT_C void HandleCustomSyncL ( TInt aParam ) [protected, virtual]

Called as a result of the associated CImageEncoder::CustomSyncL() function being called. Plugins may override this to provide extended commands in CImageEncoder . Default version leaves with KErrNotSupported.

Parameters

TInt aParam Interpretation dependent on plugin.

HandleProcessFrameResult(TInt, TFrameState)

IMPORT_C void HandleProcessFrameResult ( TInt aErrCode,
TFrameState aCodecState
) [protected]

Deals with the result from ProcessFrameL().

This processes the results of the standard ProcessFrameL() call, feeding in the resultant error code from its TRAP and the status result. It will call RequestComplete() or SelfComplete() as appropriate. Note that if no data was created by ProcessFrameL(), HandleProcessFrameResult() assumes that the encoding process is complete. If this is not appropriate, an overloaded DoConvert() should be used to handle it.

Parameters

TInt aErrCode The error result of TRAP around ProcessFrameL().
TFrameState aCodecState The result of ProcessFrameL() itself.

ImageWriteCodec()

IMPORT_C CImageWriteCodec * ImageWriteCodec ( ) const [protected]

Returns the plugin's write codec.

InitConvertL()

IMPORT_C void InitConvertL ( ) [protected, virtual]

Initialises data structures prior to encoding a frame.

This may be overriden in derived classes in which case the derived class should ensure it calls this version after performing any plugin initialisation.

InitCustomAsyncL(TInt)

IMPORT_C void InitCustomAsyncL ( TInt aParam ) [protected, virtual]

Called as a result of the associated CImageEncoder::CustomAsync() function being called. If this function finishes normally, then a convert cycle is started - so that DoConvert() will be subsequently started in the background - otherwise, if this function leaves then the error result is immediately signalled back to the caller of CustomAsync().

The default version leaves with KErrNotSupported unless overridden to change this behaviour. Plugins may override this to provide extended commands in CImageEncoder .

Parameters

TInt aParam Interpretation dependent on plugin.

NotifyComplete()

IMPORT_C void NotifyComplete ( ) [protected, virtual]

Plugin defined actions resulting from a call by RequestComplete() .

This function is called when a RequestComplete() is issued indicating that an asynchronous command has finished. Plugins can extend this function to clear any custom command flags.

Position()

IMPORT_C TInt & Position ( ) const [protected]

Returns the current position within the internal data buffer that is being written to.

WriteDataPositionIncL(TInt aPosition,const TDesC8& aDes) WriteDataL(TInt aPosition,const TDesC8& aDes)

PrepareEncoderL(const CFrameImageData *)

void PrepareEncoderL ( const CFrameImageData * aFrameImageData ) [protected, pure virtual]

Allocates the specific codec used for the encoding and passes ownership to the plugin.

This is a pure virtual function that each individual plugin must implement.

Parameters

const CFrameImageData * aFrameImageData The parameters which can be passed on to the encoding algorithm. This data might be used to determine the exact codec created.

RequestComplete(TInt)

IMPORT_C void RequestComplete ( TInt aReason ) [protected]

This function must be called on completion of encoding the image data.

CImageEncoderPlugin::SelfComplete(TInt aReason)

Parameters

TInt aReason The error code giving the reason for completion, or KErrNone if no error occurred.

RequestInitL()

IMPORT_C void RequestInitL ( ) [protected]

Forces initialization of data structures prior to decoding a frame.

ReservedVirtual1()

IMPORT_C void ReservedVirtual1 ( ) [private, virtual]

Intended for future proofing - will panic if called.

panic
EReservedCall

ReservedVirtual2()

IMPORT_C void ReservedVirtual2 ( ) [private, virtual]

Intended for future proofing - will panic if called.

panic
EReservedCall

ReservedVirtual3()

IMPORT_C void ReservedVirtual3 ( ) [private, virtual]

Intended for future proofing - will panic if called.

panic
EReservedCall

SelfComplete(TInt)

IMPORT_C void SelfComplete ( TInt aReason ) [protected]

Must be called at the end of a slice of encoding. If called with KErrNone will cause a repeat call to DoConvert() .

CImageEncoderPlugin::RequestComplete(TInt aReason)

Parameters

TInt aReason The error code giving the reason for completion, or KErrNone if no error occurred.

SetImageWriteCodec(CImageWriteCodec *)

IMPORT_C void SetImageWriteCodec ( CImageWriteCodec * aImageWriteCodec ) const [protected]

Sets the plugin's write codec.

Ownership of the codec is transferred to the plugin.

Parameters

CImageWriteCodec * aImageWriteCodec A pointer to the codec.

SetSelfPending()

IMPORT_C void SetSelfPending ( ) [protected]

May be called at the start of a slice of encoding if the encoding is expected to complete asynchronously. This sets the AO in CImageEncoderPriv to active, but does not complete the request.

When the encoding of the slice is complete, there must be a call to SelfComplete()

CImageEncoderPlugin::SelfComplete(TInt aReason)

SetThumbnail(TBool)

IMPORT_C void SetThumbnail ( TBool aDoGenerateThumbnail ) [private, virtual]

Tells the encoder to generate the thumbnail

THis is used only for Exif format. If aDoGenerateThumbnail=EFalse, the thumbnail is not generated. The default value is ETrue

Parameters

TBool aDoGenerateThumbnail

ShouldAbort()

IMPORT_C TBool ShouldAbort ( ) const [protected]

Indicates if an encode should abort early (ie. following a Cancel).

Note: This function always returns EFalse unless the encoder is running in its own thread.

Source()

IMPORT_C const CFbsBitmap & Source ( ) const [protected]

Returns the bitmap which is being encoded.

StartPosition()

IMPORT_C TInt & StartPosition ( ) const [protected]

Returns the starting position of the internal data buffer of the encoded image that is being written to.

UpdateHeaderL()

void UpdateHeaderL ( ) [protected, pure virtual]

May be used to fill in additional fields at the end of the encoding process, which it may not have been possible to do earlier.

This is a pure virtual function that each individual plugin must implement.

ValidProperties()

TBool ValidProperties ( ) const [private]

Checks that the constructed encoder is valid.

ValidSource()

IMPORT_C TBool ValidSource ( ) const [protected]

Checks the validity of the bitmap which is being encoded. Returns ETrue if the bitmap is valid, otherwise EFalse.

WriteDataL(TInt, const TDesC8 &)

IMPORT_C void WriteDataL ( TInt aPosition,
const TDesC8 & aDes
) [protected]

Writes a descriptor to the internal data buffer of the encoded image without incrementing the position in the buffer, and therefore a call to Position() will return the same value before or after a call to this function.

Position()

Parameters

TInt aPosition The start position in the internal data buffer of the encoded image from which point the data in aDes is written.
const TDesC8 & aDes The descriptor containing the data to be written to the internal data buffer of the encoded image.

WriteDataPositionIncL(TInt, const TDesC8 &)

IMPORT_C void WriteDataPositionIncL ( TInt aPosition,
const TDesC8 & aDes
) [protected]

Writes a descriptor to the internal data buffer of the encoded image. In addition, the position in the buffer that is written to (obtained with Position() ) will be incremented returning aPosition + aDes.Length().

Position()

Parameters

TInt aPosition The start position in the internal data buffer of the encoded image from which point the data in aDes is written.
const TDesC8 & aDes The descriptor containing the data to be written to the internal data buffer of the encoded image.

WriteExifDataL(TRequestStatus *&)

IMPORT_C void WriteExifDataL ( TRequestStatus *& aScaleCompletionStatus ) [private, virtual]

Originally only used by the jpeg codec, but now in use as a generic pre-convert async step

Intended for future proofing - will panic if called

panic
EReservedCall

Parameters

TRequestStatus *& aScaleCompletionStatus

WriteThumbnailL()

IMPORT_C void WriteThumbnailL ( ) [private, virtual]

Sets the thumbnail in the encoded file

panic
EReservedCall

Member Data Documentation

CImageEncoderPriv * iProperties

CImageEncoderPriv * iProperties [private]