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TImageConvStreamedDecode Class Reference

class TImageConvStreamedDecode

'Block' streaming extension for Image Conversion Library decoder.

Public Member Functions
IMPORT_C void	GetBlocks ( TRequestStatus &, CImageFrame &, TInt , TInt , TInt &)
IMPORT_C TInt	GetBufferSize ( TUid , TSize &, TInt )
IMPORT_C void	GetCapabilities ( TUid , TInt , TDecodeStreamCaps &)
IMPORT_C void	GetNextBlocks ( TRequestStatus &, CImageFrame &, TInt , TInt &, TBool &)
IMPORT_C void	GetSupportedFormatsL ( RArray < TUid > &, TUid &)
IMPORT_C void	InitFrameL ( TUid , TInt , TDecodeStreamCaps::TNavigation )

Private Member Functions
	TImageConvStreamedDecode ()
void	SetExtension ( MImageConvExtension *)

Private Attributes
MImageConvStreamedDecode *	iExtension
TInt	iReserved

Constructor & Destructor Documentation

TImageConvStreamedDecode()

IMPORT_C

TImageConvStreamedDecode

(

)

[private]

Member Functions Documentation

GetBlocks(TRequestStatus &, CImageFrame &, TInt, TInt, TInt &)

IMPORT_C void	GetBlocks	(	TRequestStatus &	aStatus,
			CImageFrame &	aFrame,
			TInt	aSeqPosition,
			TInt	aNumBlocksToGet,
			TInt &	aNumBlocksRead
		)

Start asynchronous call to return random blocks from the stream

Note:

use CImageDecoder::Cancel() to cancel this request.

Parameters

TRequestStatus & aStatus	request status
CImageFrame & aFrame	An image frame wrapper a memory buffer to hold the returned block(s) of pixel data. This can be 'uninitialised' or given specific format which must match that specified in the InitFrameL call.
TInt aSeqPosition	block number starting at top left 0 ... TDecodeStreamCaps::StreamSizeInBlocks()
TInt aNumBlocksToGet	number of blocks requested
TInt & aNumBlocksRead	number of blocks which will be returned when the request completes

GetBufferSize(TUid, TSize &, TInt)

IMPORT_C TInt	GetBufferSize	(	TUid	aFormat,
			TSize &	aBlockSizeInPixels,
			TInt	aNumBlocks
		)	const

Get the size of the memory buffer to hold the returned data.

Parameters

TUid aFormat	the required format
TSize & aBlockSizeInPixels	returns the size in pixels of the block returned from the stream when aNumBlocks of minimum block size are requested.
TInt aNumBlocks	the number of blocks of size TDecodeStreamCaps::MinBlockSizeInPixels() to be returned by one request

GetCapabilities(TUid, TInt, TDecodeStreamCaps &)

IMPORT_C void	GetCapabilities	(	TUid	aFormat,
			TInt	aFrameNumber,
			TDecodeStreamCaps &	aCaps
		)	const

Returns the capabilities of the codec plugin for a specific format and for a specific frame.

Parameters

TUid aFormat	The format.
TInt aFrameNumber	frame to stream
TDecodeStreamCaps & aCaps	The capabilities for the format given.

GetNextBlocks(TRequestStatus &, CImageFrame &, TInt, TInt &, TBool &)

IMPORT_C void	GetNextBlocks	(	TRequestStatus &	aStatus,
			CImageFrame &	aFrame,
			TInt	aNumBlocksToGet,
			TInt &	aNumBlocksRead,
			TBool &	aHaveMoreBlocks
		)

Start asynchronous call to return blocks sequentially from the stream. Blocks are returned from the first block until the last in the stream.

Note:

use CImageDecoder::Cancel() to cancel this request.

Parameters

TRequestStatus & aStatus	request status
CImageFrame & aFrame	An image frame wrapper a memory buffer to hold the returned block(s) of pixel data. This can be 'uninitialised' or given specific format which must match that specified in the InitFrameL call.
TInt aNumBlocksToGet	number of blocks requested
TInt & aNumBlocksRead	number of blocks which will be returned when the request completes
TBool & aHaveMoreBlocks

GetSupportedFormatsL(RArray< TUid > &, TUid &)

IMPORT_C void	GetSupportedFormatsL	(	RArray < TUid > &	aFormats,
			TUid &	aOptimalFormat
		)	const

Returns a list of supported formats and the optimal format to be used. imageframeconst.h for a list of format uids.

Parameters

RArray < TUid > & aFormats	Returns an array of format uids
TUid & aOptimalFormat	The 'best' uid to use.

InitFrameL(TUid, TInt, TDecodeStreamCaps::TNavigation)

IMPORT_C void	InitFrameL	(	TUid	aFormat,
			TInt	aFrameNumber,
			TDecodeStreamCaps::TNavigation	aNavigation
		)

Initialise the stream.

leave: System wide error if for example the format is not supported.

Note:

must call InitFrameL before GetBlocks or GetNextBlocks. Failure to do so completes request with KErrNotReady

Parameters

TUid aFormat	the format to use
TInt aFrameNumber	frame to stream
TDecodeStreamCaps::TNavigation aNavigation	indication to stream of the way that the stream will be navigated. Allows codec to optimise it's behaviour.

SetExtension(MImageConvExtension *)

void

SetExtension

(

MImageConvExtension *

aExtension

)

[private]

Parameters

MImageConvExtension * aExtension

Member Data Documentation

MImageConvStreamedDecode * iExtension

MImageConvStreamedDecode *

iExtension

[private]

TInt iReserved

TInt

iReserved

[private]