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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

CImageEncoderPlugin
- CBase

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]