CImageDecoder Class Reference

#include <imageconversion.h>

class CImageDecoder : public CBase

Inherits from

CImageDecoder

Public Member Enumerations
enum	TImageType { EImageTypeThumbnail, EImageTypeMain }
enum	TOptions { EOptionNone, EOptionNoDither, EOptionAlwaysThread, EOptionAllowZeroFrameOpen, ..., EOptionAutoRotate }

Public Member Functions
virtual	~CImageDecoder()
IMPORT_C TImageConvStreamedDecode *	BlockStreamerL()
IMPORT_C void	Cancel()
virtual IMPORT_C void	ContinueConvert(TRequestStatus *)
IMPORT_C void	ContinueProcessingHeaderL()
virtual IMPORT_C void	Convert(TRequestStatus *, CFbsBitmap &, TInt)
virtual IMPORT_C void	Convert(TRequestStatus *, CFbsBitmap &, CFbsBitmap &, TInt)
IMPORT_C CImageDecoder *	DataNewL(RFs &, const TDesC8 &, const TDesC8 &, const TOptions)
IMPORT_C CImageDecoder *	DataNewL(RFs &, const TDesC8 &, const TOptions, const TUid, const TUid, const TUid)
IMPORT_C CImageDecoder *	FileNewL(RFs &, const TDesC &, const TDesC8 &, const TOptions)
IMPORT_C CImageDecoder *	FileNewL(RFs &, const TDesC &, const TOptions, const TUid, const TUid, const TUid)
IMPORT_C CImageDecoder *	FileNewL(RFs &, const TDesC &, const TDesC8 &, ContentAccess::TIntent, const TOptions)
IMPORT_C CImageDecoder *	FileNewL(RFs &, const TDesC &, ContentAccess::TIntent, const TOptions, const TUid, const TUid, const TUid)
IMPORT_C CImageDecoder *	FileNewL(RFile &, const TDesC8 &, ContentAccess::TIntent, const TOptions)
IMPORT_C CImageDecoder *	FileNewL(RFile &, ContentAccess::TIntent, const TOptions, const TUid, const TUid, const TUid)
IMPORT_C CImageDecoder *	FileNewL(RFs &, const TMMSource &, const TDesC8 &, const TOptions)
IMPORT_C CImageDecoder *	FileNewL(RFs &, const TMMSource &, const TOptions, const TUid, const TUid, const TUid)
IMPORT_C HBufC *	FrameCommentL(TInt, TInt)
IMPORT_C TInt	FrameCount()
IMPORT_C const CFrameImageData &	FrameData(TInt)
IMPORT_C const TFrameInfo &	FrameInfo(TInt)
IMPORT_C CFrameInfoStrings *	FrameInfoStringsL(TInt)
IMPORT_C CFrameInfoStrings *	FrameInfoStringsLC(TInt)
IMPORT_C TInt	GetDestinationSize(TSize &, TInt)
IMPORT_C void	GetFileTypesL(RFileExtensionMIMETypeArray &)
IMPORT_C void	GetImageSubTypesL(const TUid, RImageTypeDescriptionArray &)
IMPORT_C void	GetImageTypesL(RImageTypeDescriptionArray &)
IMPORT_C CImplementationInformationType *	GetImplementationInformationL(TUid)
IMPORT_C void	GetInterfaceImplementationsL(const RUidDataArray &, RUidDataArray &)
IMPORT_C void	GetInterfaceImplementationsL(const TUid *, const TInt, RUidDataArray &)
IMPORT_C void	GetMimeTypeDataL(const TDesC8 &, TDes8 &)
IMPORT_C void	GetMimeTypeFileL(RFs &, const TDesC &, TDes8 &)
IMPORT_C void	GetPluginPropertiesL(const TUid, RUidDataArray &)
IMPORT_C HBufC *	ImageCommentL(TInt)
IMPORT_C void	ImageType(TInt, TUid &, TUid &)
IMPORT_C TUid	ImplementationUid()
IMPORT_C TBool	IsImageHeaderProcessingComplete()
IMPORT_C TInt	NumberOfFrameComments(TInt)
IMPORT_C TInt	NumberOfImageComments()
IMPORT_C TImageConvOperation *	OperationL()
IMPORT_C void	Prepare(TRequestStatus *)
IMPORT_C TInt	ReducedSize(const TSize &, TInt, TSize &)
IMPORT_C TInt	ReductionFactor(const TSize &, const TSize &)
IMPORT_C TImageConvScaler *	ScalerL()
IMPORT_C TInt	SetAgentProperty(ContentAccess::TAgentProperty, TInt)
IMPORT_C void	SetClippingRectL(const TRect *)
IMPORT_C TInt	SetDecoderThreadPriority(TThreadPriority)
IMPORT_C void	SetImageTypeL(TInt)

Protected Member Functions
	CImageDecoder()
IMPORT_C void	CustomAsync(TRequestStatus *, TInt)
IMPORT_C void	CustomSyncL(TInt)
IMPORT_C CImageDecoderPlugin *	Plugin()

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()

Detailed Description

Provides access to the Image Conversion Library decoders.

This class provides functions to decode images held in files or descriptors. To decode buffered images use the buffered version of this class CBufferedImageDecoder.

Regarding DRM: Note that intent is evaluated when a CImageDecoder instance is being constructed by one of the FileNewL() methods. It is executed after at least one frame of the image has been successfully decoded. Subsequent converts using the same CImageDecoder instance will not execute intent.

Member Enumeration Documentation

Enum TImageType

Flags to control which image is decoded. This can be used when the source file or descriptor contains multiple distinct image sources.

Enumerator	Value	Description
EImageTypeThumbnail	0x01	Use the thumbnail as source image
EImageTypeMain	0x02	Use the main image

Enum TOptions

Flags to control how the image is decoded. These can be combined using an OR operation.

Enumerator	Value	Description
EOptionNone	0x00	No flag set
EOptionNoDither	0x01	Do not dither the decoded image
EOptionAlwaysThread	0x02	Perform the decoding in a separate thread
EOptionAllowZeroFrameOpen	0x04	Allow Opens to complete with no error if there is less than one frame available. This should be set for streaming.
EAllowGeneratedMask	0x08	Setting this flag requests that the plugin generate a mask during decoding. Note: This option is only relevant to image formats that do not already contain mask information. The client must check that TFrameInfo::ETransparencyPossible is set before attempting to obtain the mask, because not all plugins support mask generation.
EPreferFastDecode	0x10	Use the highest possible image decoding speed; this may result in lower image quality. This flag is more applicable to formats which use "lossy" compression algorithms, such as JPEG. Decoders that do not support fast decoding will ignore it.
EOptionMngSubframesNoLoops	0x20	Prevent MNG ImageDecoder from unwinding all the loops
EOptionUseFrameSizeInPixels	0x40	Setting this flag requests that the plugin use the frame size rather than the overall size when calculating its reduction factor
EOptionIgnoreExifMetaData	0x80	When specified, this flag indicates that the decoder must ignore the EXIF meta-data, if present. In this case, the ExifMetaData() should return NULL. This option value is also used to indicate the requirement to ignore the EXIF meta-data when doing the image transformation.
EOptionExtCrop	0x0100	Codec must support crop.
EOptionExtStream	0x0200	Codec must support block streaming extension.
EOptionExtRotation	0x0400	Codec must support rotation through the operation extension.
EOptionExtMirrorHorizontalAxis	0x0800	Codec must support horizontal mirror through the operation extension.
EOptionExtMirrorVerticalAxis	0x1000	Codec must support vertical mirror through the operation extension.
EOptionExtScaling	0x2000	Codec must support the scaling extension.
EOptionExtReserved7	0x4000	Reserved.
EOptionExtReserved8	0x8000	Reserved.
EOptionPngMissingiENDFail	0x010000	Requests that decode always fails for Png images without an iEND chunk.
EOptionWmfIgnoreViewportMetaData	0x020000	Allows WMF codec to ignore any SETVIEWPORTORG, SETVIEWPORTEXT, SCALEVIEWPORTEXT or OFFSETVIEWPORTORG commands in the metafile and allows scaling to destination bitmap.
EOptionAutoRotate	0x040000	Requests that codec applies the auto rotation when decoding according to the orientation tag in the image Exif header.

Constructor & Destructor Documentation

CImageDecoder ( )

IMPORT_C

CImageDecoder

(

)

[protected]

Constructor for this class.

~CImageDecoder ( )

IMPORT_C

~CImageDecoder

(

)

[virtual]

Destructor for this class.

If using a local file session, it closes it. It also informs ECom that has finished with the decoder instance.

Frees all resources owned by the object prior to its destruction.

Member Function Documentation

BlockStreamerL ( )

IMPORT_C TImageConvStreamedDecode *

BlockStreamerL

(

)

Get the extension interface for block streaming on the image.

Cancel ( )

IMPORT_C void

Cancel

(

)

Cancels any conversions currently in progress (Cancel is synchronous).

ContinueConvert ( TRequestStatus * )

IMPORT_C void

ContinueConvert

(

TRequestStatus *

aRequestStatus

)

[virtual]

Continue decoding a frame and/or mask after new image data was added to the source file or descriptor and a previous call to Convert() or ContinueConvert() returned KErrUnderflow.

Parameter	Description
aRequestStatus	Request status. On completion contains an error code. KErrNone if frame was decoded successfully, KErrUnderflow if the frame was partially decoded otherwise another of the system-wide error codes.

ContinueProcessingHeaderL ( )

IMPORT_C void

ContinueProcessingHeaderL

(

)

Continue processing image headers after new image data was added to the source file or descriptor.

Convert ( TRequestStatus *, CFbsBitmap &, TInt )

IMPORT_C void	Convert	(	TRequestStatus *	aRequestStatus,
			CFbsBitmap &	aDestination,
			TInt	aFrameNumber = 0
		)	[virtual]

Start decoding an image frame asynchronously.

Pre-condition: The destination bitmap aDestination, must be created before the call to Convert() is made. aDestination must be large enough to contain the frame and be set to the required display mode. FrameInfo() can be used to obtain the size and display mode of the frame.

When the conversion is complete, successfully or otherwise, the status is returned in aRequestStatus.

If the operations completes with KErrUnderflow, then there is insufficient information in the descriptor. In this situation, ContinueConvert() should be called repeatedly until the descriptor has accumulated enough information for ContinueConvert() to complete with KErrNone.It is the responsibility of the caller to ensure that the original data source used to create this decoder object gets enough information. If there is no data available then a caller can ignore this error code and use partially decoded image.

Note:

As most codec plugins support downscaling the image but not upscaling, the standard behaviour (i.e. no requested transformations) for codecs begins with the size of the destination bitmap passed to CImageDecoder::Convert being inspected, and:

1. If the destination size matches the frame size of the image then the image is decoded full size into the destination bitmap.
2. If the destination size is larger than the frame size of the image then the image is decoded full size into the destination bitmap with no upscaling. The image origin is aligned with the top left corner of the bitmap and any area in the bitmap to the bottom and right of image is left in its initialised state.
3. If the destination size is smaller than the frame size of the image then a reduction factor is calculated and the image is scaled down (1/2, 1/4, 1/8 size) whilst maintaining the aspect ratio of the image. The size is the next smallest size that will fit in the destination bitmap. The use case for this is when the client wants to pass in the screen size of device and have the image scaled to fill as much of the screen as possible. However, if the extension interfaces (clipping, scale, operation) are used then the additional behaviour below applies.
4. If the extension interfaces for clipping rectangle and/or operation are applied, but not scaling, then the size of the destination bitmap for an unscaled image can be obtained via CImageDecoder::GetDestinationSize. Lets call that SizeA. The same rules apply as given in 1, 2, 3 above resulting in a down-scaled destination if the destination bitmap is smaller than SizeA.
5. If the extension interface for scaling is called via one of the two TImageConvScaler::SetScalingL(.. functions then it is required that the destination size is obtained through CImageDecoder::GetDestinationSize and that a destination bitmap of that size is passed to CImageDecoder::Convert. Failure to do this will cause the decoder to fail with KErrArgument. This rule holds if clipping and/or operation is applied as well as scaling.

Parameter	Description
aRequestStatus	Request status. On completion contains an error code. KErrNone if frame was decoded successfully, KErrUnderflow if the frame was partially decoded otherwise another of the system-wide error codes.
aDestination	A bitmap that will contain the decoded frame.
aFrameNumber	The frame in a multi-frame image to decode (optional, defaults to zero).

Convert ( TRequestStatus *, CFbsBitmap &, CFbsBitmap &, TInt )

IMPORT_C void	Convert	(	TRequestStatus *	aRequestStatus,
			CFbsBitmap &	aDestination,
			CFbsBitmap &	aDestinationMask,
			TInt	aFrameNumber = 0
		)	[virtual]

Start decoding an image frame and mask asynchronously.

Pre-condition: The destination bitmap aDestination, must be created before the call to Convert() is made. aDestination must be large enough to contain the frame and be set to the required display mode. FrameInfo() can be used to obtain the size and display mode of the frame. The destination mask aDestinationMask must be created before the call to Convert() is made and must be large enough for the mask. The display mode must be EGray2 or EGray256 and must be EGray256 if the image contains alpha-blending information. This information can be obtained from the iFlags property of TFrameInfo obtained from a FrameInfo() call.

When the conversion is complete, successfully or otherwise, the status is returned in aRequestStatus.

CustomAsync ( TRequestStatus *, TInt )

IMPORT_C void	CustomAsync	(	TRequestStatus *	aRequestStatus,
			TInt	aParam
		)	[protected]

Sets up background convert cycle, bypassing Convert(). A call to this will result in a call to the associated CImageDecoderPlugin::InitCustomAsyncL(aParam), which if successful will start background processing. This function uses the same mechanism as Convert(), and therefore cannot be used concurrently. Cancel() etc work as expected.

Note: This function is intended for use by plugin writers only.

Parameter	Description
aRequestStatus	Request status. On completion contains an error code. KErrNone if the bitmap was successfully decoded, otherwise another of the system-wide error codes.
aParam	Interpretation dependent on plugin.

CustomSyncL ( TInt )

IMPORT_C void

CustomSyncL

(

TInt

aParam

)

[protected]

Calls CImageDecoderPlugin::HandleCustomSyncL(aParam) that executes user defined plugin specific functions. Subsequent behaviour depends on the CImageDecoderPlugin class.

This function is part of the support for extended codecs for use within classes derived from CImageDecoder.

Note: This function is intended for use by plugin writers only.

Parameter	Description
aParam	Interpretation dependent on plugin.

DataNewL ( RFs &, const TDesC8 &, const TDesC8 &, const TOptions )

IMPORT_C CImageDecoder *	DataNewL	(	RFs &	aFs,
			const TDesC8 &	aSourceData,
			const TDesC8 &	aMIMEType,
			const TOptions	aOptions = EOptionNone
		)	[static]

Create a decoder for the image in the source buffer. The client supplies a MIME type which will be used to try and select an appropriate plugin decoder. If a decoder is found it is created and then used to scan the beginning of the image file.

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

leave: KErrNotFound No appropriate plugin decoder for this image has been found.

See also: TOptions

Parameter	Description
aFs	A reference to a file server session for the decoder to use.
aSourceData	The buffer containing the image to be decoded. Note that the framework doesn't take a copy of the actual data, therefore both the descriptor object and the data must persist during decoding.
aMIMEType	The MIME type of the image in the file(used to determine the plugin to create).
aOptions	The decoder options to use. Specifying one of more extension options (for example EOptionExtCrop) can be used to cause the to cause a plugin to load which supports the image type and supports the requested extensions.

Returns: Returns a pointer to the newly created decoder.

DataNewL ( RFs &, const TDesC8 &, const TOptions, const TUid, const TUid, const TUid )

IMPORT_C CImageDecoder *	DataNewL	(	RFs &	aFs,
			const TDesC8 &	aSourceData,
			const TOptions	aOptions = EOptionNone,
			const TUid	aImageType = KNullUid,
			const TUid	aImageSubType = KNullUid,
			const TUid	aDecoderUid = KNullUid
		)	[static]

Creates a decoder for the image in the source buffer.

If the client supplies an image type (and sub-type, if applicable) or decoder UID, these will be used to try and select an appropriate plugin decoder. If not, then the selection will be done by matching the image header from the buffer. If it finds a decoder, it is created and then used to scan the beginning of the image buffer.

See also: KUidICLJpegEXIFInterface KUidICLJpegImageFrameInterface

leave: KErrUnderflow Not enough data in descriptor to identify which plugin decoder to use.

leave: KErrNotFound No appropriate plugin decoder for this image has been found.

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

panic: ImageConversion 19 No base type given for sub-type.

See also: TOptions

Parameter	Description
aFs	A reference to a file server session for the decoder to use.
aSourceData	The buffer containing the image to be decoded. Note that the framework doesn't take a copy of the actual data, therefore both the descriptor object and the data must persist during decoding.
aOptions	Decoder options to use.
aImageType	The image type of the image in the file (optional, defaults to KNullUid).
aImageSubType	The image sub-type of the image in the file (optional, defaults to KNullUid).
aDecoderUid	The implementation UID for a specific codec or a decoder/encoder class UID (optional, defaults to KNullUid). If this option is selected for a specific codec the image type and image sub type for the displayer must be supplied. When loading plugins by class UID the image type and image subtype are not mandatory and the first valid plugin from the list of available plugins with the specified class UID will be loaded.

Returns: Returns a pointer to the newly created decoder.

FileNewL ( RFs &, const TDesC &, const TDesC8 &, const TOptions )

IMPORT_C CImageDecoder *	FileNewL	(	RFs &	aFs,
			const TDesC &	aSourceFilename,
			const TDesC8 &	aMIMEType,
			const TOptions	aOptions = EOptionNone
		)	[static]

Create a decoder for the image in the named file. The client supplies a MIME type which will be used to try and select an appropriate plugin decoder. If it finds a decoder it creates it and then goes on to use that decoder to scan the beginning of the image file.

If any file related errors are encountered opening the specified file, this function leaves with an appropriate file related leave code.

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

leave: KErrNotFound Either the specific plugin decoder for this file hasn't been found, or the file itself is missing.

See also: TOptions

Parameter	Description
aFs	A reference to a file server session for the decoder to use.
aSourceFilename	The name of the file to be decoded.
aMIMEType	The MIME type of the image in the file.
aOptions	Decoder options to use.

Returns: Returns a pointer to the newly created decoder.

FileNewL ( RFs &, const TDesC &, const TOptions, const TUid, const TUid, const TUid )

IMPORT_C CImageDecoder *	FileNewL	(	RFs &	aFs,
			const TDesC &	aSourceFilename,
			const TOptions	aOptions = EOptionNone,
			const TUid	aImageType = KNullUid,
			const TUid	aImageSubType = KNullUid,
			const TUid	aDecoderUid = KNullUid
		)	[static]

Create a decoder for the image in the named file.

If the client supplies an image type (and sub-type, if applicable) or decoder UID, these will be used to try and select an appropriate plugin decoder. If not, then the selection will be done by matching the image header in the file. If it finds a decoder, it will be created and then used to scan the beginning of the image file.

Note: Every image format has two IDs, known as the type and the sub-type (although generally the sub-type is KNullUid). To retrieve a list of supported types and sub-types that can be decoded, use the static functions GetImageTypesL() and GetImageSubTypesL().

See also: KUidICLJpegEXIFInterface KUidICLJpegImageFrameInterface

leave: KErrUnderflow Not enough data in file to identify which plugin decoder to use.

leave: KErrNotFound Either the appropriate plugin decoder for this file hasn't been found, or the file itself is missing.

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

panic: ImageConversion 19 No base type given for sub-type.

See also: TOptions

Parameter	Description
aFs	A reference to a file server session for the decoder to use.
aSourceFilename	The name of the file to be decoded.
aOptions	Decoder options to use.
aImageType	The image type of the image in the file (optional, defaults to KNullUid).
aImageSubType	The image sub-type of the image in the file (optional, defaults to KNullUid).
aDecoderUid	The implementation UID for a specific codec or a decoder/encoder class UID (optional, defaults to KNullUid). If this option is selected for a specific codec the image type and image sub type for the displayer must be supplied. When loading plugins by class UID the image type and image subtype are not mandatory and the first valid plugin from the list of available plugins with the specified class UID will be loaded.

Returns: Returns a pointer to the newly created decoder.

FileNewL ( RFs &, const TDesC &, const TDesC8 &, ContentAccess::TIntent, const TOptions )

IMPORT_C CImageDecoder *	FileNewL	(	RFs &	aFs,
			const TDesC &	aSourceFilename,
			const TDesC8 &	aMIMEType,
			ContentAccess::TIntent	aIntent,
			const TOptions	aOptions = EOptionNone
		)	[static]

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

leave: KErrNotFound Either the specific plugin decoder for this file hasn't been found, or the file itself is missing.

Parameter	Description
aFs	A reference to a file server session for the decoder to use.
aSourceFilename	The name of the file to be decoded.
aMIMEType	The MIME type of the image in the file.
aIntent	The DRM Intent for image conversion.
aOptions	The decoder options to use.

Returns: A pointer to the newly created decoder.

FileNewL ( RFs &, const TDesC &, ContentAccess::TIntent, const TOptions, const TUid, const TUid, const TUid )

IMPORT_C CImageDecoder *	FileNewL	(	RFs &	aFs,
			const TDesC &	aSourceFilename,
			ContentAccess::TIntent	aIntent,
			const TOptions	aOptions = EOptionNone,
			const TUid	aImageType = KNullUid,
			const TUid	aImageSubType = KNullUid,
			const TUid	aDecoderUid = KNullUid
		)	[static]

Creates a decoder for the image in the named file. If the client supplies an image type (and sub-type, if applicable) or decoder UID, these will be used to try and select an appropriate plugin decoder. If not, then the selection will be done by matching the image header in the file. If it finds a decoder it creates it and then goes on to use that decoder to scan the beginning of the image file.

See also: KUidICLJpegEXIFInterface KUidICLJpegImageFrameInterface

leave: KErrUnderflow Not enough data in file to identify which plugin decoder to use.

leave: KErrNotFound Either the appropriate plugin decoder for this file hasn't been found, or the file itself is missing.

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

panic: ImageConversion 19 No base type given for sub-type.

See also: TOptions

Parameter	Description
aFs	A reference to a file server session for the decoder to use.
aSourceFilename	The name of the file to be decoded.
aIntent	The DRM Intent for image conversion.
aOptions	The decoder options to use. See TOptions.
aImageType	The image type of the image in the file (optional, defaults to KNullUid).
aImageSubType	The image sub-type of the image in the file (optional, defaults to KNullUid).
aDecoderUid	The implementation UID for a specific codec or a decoder/encoder class UID (optional, defaults to KNullUid). If this option is selected for a specific codec the image type and image sub type for the displayer must be supplied. When loading plugins by class UID the image type and image subtype are not mandatory and the first valid plugin from the list of available plugins with the specified class UID will be loaded.

Returns: A pointer to the newly created decoder.

FileNewL ( RFile &, const TDesC8 &, ContentAccess::TIntent, const TOptions )

IMPORT_C CImageDecoder *	FileNewL	(	RFile &	aFile,
			const TDesC8 &	aMIMEType,
			ContentAccess::TIntent	aIntent,
			const TOptions	aOptions = EOptionNone
		)	[static]

If any file related errors are encountered opening the specified file, this function leaves with an appropriate file related leave code.

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

leave: KErrNotFound Either the appropriate plugin decoder for this file hasn't been found, or the file itself is missing.

See also: TOptions

Parameter	Description
aFile	The handle of the file to decode
aMIMEType	The MIME type of the image in the file.
aIntent	The DRM Intent to open the file with
aOptions	Decoder options to use.

Returns: Returns a pointer to the newly created decoder.

FileNewL ( RFile &, ContentAccess::TIntent, const TOptions, const TUid, const TUid, const TUid )

IMPORT_C CImageDecoder *	FileNewL	(	RFile &	aFile,
			ContentAccess::TIntent	aIntent,
			const TOptions	aOptions = EOptionNone,
			const TUid	aImageType = KNullUid,
			const TUid	aImageSubType = KNullUid,
			const TUid	aDecoderUid = KNullUid
		)	[static]

See also: KUidICLJpegEXIFInterface KUidICLJpegImageFrameInterface

leave: KErrUnderflow Not enough data in file to identify which plugin decoder to use.

leave: KErrNotFound Either the appropriate plugin decoder for this file hasn't been found, or the file itself is missing.

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

panic: ImageConversion 19 No base type given for sub-type.

See also: TOptions

Parameter	Description
aFile	The handle of the file to decode
aIntent	The DRM Intent for image conversion.
aOptions	The decoder options to use. See TOptions.
aImageType	The image type of the image in the file (optional, defaults to KNullUid).
aImageSubType	The image sub-type of the image in the file (optional, defaults to KNullUid).
aDecoderUid	The implementation UID for a specific codec or a decoder/encoder class UID (optional, defaults to KNullUid). If this option is selected for a specific codec the image type and image sub type for the displayer must be supplied. When loading plugins by class UID the image type and image subtype are not mandatory and the first valid plugin from the list of available plugins with the specified class UID will be loaded.

Returns: A pointer to the newly created decoder.

FileNewL ( RFs &, const TMMSource &, const TDesC8 &, const TOptions )

IMPORT_C CImageDecoder *	FileNewL	(	RFs &	aFs,
			const TMMSource &	aFileSource,
			const TDesC8 &	aMIMEType,
			const TOptions	aOptions = EOptionNone
		)	[static]

leave: KErrNotSupported A matching decoder could not be found for the MIME type.

leave: KErrNotFound Either the specific plugin decoder for this source image hasn't been found, or the source image itself is missing, or a plugin with the requested extensions cannot be found.

Parameter	Description
aFs	A reference to a file server session for the decoder to use.
aFileSource	An interface between filename based and file handle.
aMIMEType	The MIME type of the image in the file.
aOptions	The decoder options to use. Specifying one of more extension options (for example EOptionExtCrop) can be used to cause the to cause a plugin to load which supports the image type and supports the requested extensions.

Returns: A pointer to the newly created decoder.

FileNewL ( RFs &, const TMMSource &, const TOptions, const TUid, const TUid, const TUid )

IMPORT_C CImageDecoder *	FileNewL	(	RFs &	aFs,
			const TMMSource &	aFileSource,
			const TOptions	aOptions = EOptionNone,
			const TUid	aImageType = KNullUid,
			const TUid	aImageSubType = KNullUid,
			const TUid	aDecoderUid = KNullUid
		)	[static]

Create a decoder for the image in the named source.

See also: KUidICLJpegEXIFInterface KUidICLJpegImageFrameInterface

leave: KErrNotSupported A matching decoder could not be found for the MIME type.

leave: KErrNotFound Either the specific plugin decoder for this source image hasn't been found, or the source image itself is missing.

leave: KEComErrNoInterfaceIdentified ECom could not find the specified interface.

panic: ImageConversion 19 No base type given for sub-type.

Parameter	Description
aFs	A reference to a file server session for the decoder to use.
aFileSource	An interface between filename based and file handle.
aOptions	The decoder options to use. Specifying one of more extension options (for example EOptionExtCrop) can be used to cause the to cause a plugin to load which supports the image type and supports the requested extensions.
aImageType	The image type of the image in the file.
aImageSubType	The image sub-type of the image in the file.
aDecoderUid	The implementation UID for a specific codec or a decoder/encoder class UID.

Returns: A pointer to the newly created decoder.

FrameCommentL ( TInt, TInt )

IMPORT_C HBufC *	FrameCommentL	(	TInt	aFrameNumber,
			TInt	aCommentNumber
		)	const

Return a particular comment attached to a given frame of the image.

The desired order of calling methods should be FrameCount(),NumberOfFrameComments() and then FrameCommentL().

Use FrameCount() to retrieve the number of frames in the image to ensure that a valid aFrameNumber is used.

Use NumberOfFrameComments() to retrieve the number of comments attached to a given frame of the image (as opposed to the whole image),to ensure that a valid aCommentNumber is used.

Ownership of the returned buffer is transferred to the caller.

For further informantion on panic categories, please see the note in CImageDecoder::IsImageHeaderProcessingComplete().

panic: ImageConversion 10 aFrameNumber is not valid. See CImageDecoder::FrameCount().

panic: ImageConversion 13 Header processing has not completed. See CImageDecoder::IsImageHeaderProcessingComplete().

panic: ImageConversion 14 aCommentNumber is not valid. See CImageDecoder::NumberOfFrameComments().

Parameter	Description
aFrameNumber	The frame number within the image from which to retrieve the specified comment.
aCommentNumber	The comment number to retrieve from the specified frame.

Returns: A buffer containing the specified comment.

FrameCount ( )

IMPORT_C TInt

FrameCount

(

)

const

Return the number of frames in the image being decoded.

This function can be called immediately after the call to create the decoder, thus enabling the caller to know how many frames need to be converted. Client may have to call IsImageHeaderProcessingComplete() & ContinueProcessingHeaders() to ensure all all data is available.

Returns: The number of frames in the source image.

FrameData ( TInt )

IMPORT_C const CFrameImageData &

FrameData

(

TInt

aFrameNumber = 0

)

const

Returns additional plugin specific information on a specified frame.

The plugin specific information usually covers advanced image features such as image quality, advanced colour settings and so on.

Use FrameCount() to determine how many frames are contained in the image before using this function.

panic: ImageConversion 10 Frame number outside the range 0 to FrameCount()-1. See CImageDecoder::FrameCount().

FrameInfo ( TInt )

IMPORT_C const TFrameInfo &

FrameInfo

(

TInt

aFrameNumber = 0

)

const

Return the frame info for a specified frame of the image.

This function can be called immediately after the call to create the decoder, thus enabling the caller to know about each frame in advance of converting it.

The returned information contains details of the size of the image, the dimensions of the frame, its colour depth and so on. More advanced information may be available for the image using FrameData().

Use FrameCount() to determine how many frames are contained in the image before using this function.

panic: ImageConversion 10 Frame number outside the range 0 to FrameCount()-1. See CImageDecoder::FrameCount().

FrameInfoStringsL ( TInt )

IMPORT_C CFrameInfoStrings *

FrameInfoStringsL

(

TInt

aFrameNumber = 0

)

Return the formatted frame information strings for a specific frame. Ownership is transferred to the caller.

Parameter	Description
aFrameNumber	The frame number from which to retrieve the formatted information string.

Returns: The formatted frame information strings.

FrameInfoStringsLC ( TInt )

IMPORT_C CFrameInfoStrings *

FrameInfoStringsLC

(

TInt

aFrameNumber = 0

)

Return the formatted frame information strings for a specific frame and leave it on the cleanup stack.

Ownership is transferred to the caller.

Parameter	Description
aFrameNumber	The frame number from which to retrieve the formatted information string.

Returns: The formatted frame information strings.

GetDestinationSize ( TSize &, TInt )

IMPORT_C TInt	GetDestinationSize	(	TSize &	aSize,
			TInt	aFrameNumber = 0
		)

Get the size of the decoded image for the given frame. The calculation will account for any clipping rectangle set, scaling applied through the TImageConvScaler extension and any operation applied through TImageConvOperation. If TImageConvScaler::SetScalingL(.. has been called then the size of the bitmap passed to CImageDecoder::Convert must match the size returned from this function.

Parameter	Description
aSize	Returns the size of the decoded image.
aFrameNumber	The frame number.

Returns: KErrArgument if an error in calculation is detected e.g. if clipping rectangle is outside of the overall frame boundary. Other system wide errors.

GetFileTypesL ( RFileExtensionMIMETypeArray & )

IMPORT_C void

GetFileTypesL

(

RFileExtensionMIMETypeArray &

aFileExtensionArray

)

[static]

Get a list of the file extensions that can be decoded and their corresponding MIME types, based on the currently available decoder plugins.

Ownership of the array is passed to the caller so, before the array goes out of scope in the client, the caller must call ResetAndDestroy() on it to free the entries.

Parameter	Description
aFileExtensionArray	An empty array, into which this function will put a list of entries. Each entry will consist of a file extension string for which a decoder plugin has been found, accompanied by the primary MIME type and then any secondary MIME types (if present).

GetImageSubTypesL ( const TUid, RImageTypeDescriptionArray & )

IMPORT_C void	GetImageSubTypesL	(	const TUid	aImageType,
			RImageTypeDescriptionArray &	aSubTypeArray
		)	[static]

For a given basic image type, get a list of the sub image types that can be decoded, based on the currently available decoder plugins.

Ownership of the array is passed to the caller so, before the array goes out of scope in the client, the caller must call ResetAndDestroy() on it to free the entries.

Parameter	Description
aImageType	The basic image type for which you want a list of sub-types.
aSubTypeArray	An empty array, into which this function will put a list of entries. Each entry will consist of the "display string" from the registry entry for a plugin that has been found and that is a decoder for a sub-type of the given basic image type, accompanied by the Uids for the sub type. The first Uid, for the basic type, will always correspond to aImageType.

GetImageTypesL ( RImageTypeDescriptionArray & )

IMPORT_C void

GetImageTypesL

(

RImageTypeDescriptionArray &

aImageTypeArray

)

[static]

Get a list of the basic image types that can be decoded, based on the currently available decoder plugins.

Ownership of the array is passed to the caller so, before the array goes out of scope in the client, the caller must call ResetAndDestroy() on it to free the entries.

Parameter	Description
aImageTypeArray	An empty array, into which this function will put a list of entries. Each entry will consist of the "display string" from the registry entry for a plugin that has been found and that is a decoder for a basic image type, accompanied by the Uids for that image type. Since we asked for basic types the second Uid, for the image sub-type, will always be zero.

GetImplementationInformationL ( TUid )

IMPORT_C CImplementationInformationType *

GetImplementationInformationL

(

TUid

aImplementationUid

)

[static]

Gets the implementation information for a specific decoder plugin

Ownership of the implementation information is passed to the caller.

Parameter	Description
aImplementationUid	The decoder implementation UID for which to retrieve implementation information

Returns: A pointer to the implementation information.

GetInterfaceImplementationsL ( const RUidDataArray &, RUidDataArray & )

IMPORT_C void	GetInterfaceImplementationsL	(	const RUidDataArray &	aRequiredUids,
			RUidDataArray &	aImplArray
		)	[static]

Gets a list of decoder implementations UIDs which have a set of specific capabilities defined by UIDs.

Parameter	Description
aRequiredUids	The array containing the required UIDs (properties, image type, image sub-type or class UIDs).
aImplArray	The array containing the implementation UIDs of the available decoder plugins with the required UIDs. The caller has the ownership of the array.

GetInterfaceImplementationsL ( const TUid *, const TInt, RUidDataArray & )

IMPORT_C void	GetInterfaceImplementationsL	(	const TUid *	aRequiredUids,
			const TInt	aLength,
			RUidDataArray &	aImplArray
		)	[static]

Gets a list of decoder implementations UIDs which have a set of specific capabilities defined by UIDs.

Parameter	Description
aRequiredUids	The array containing the required UIDs (properties, image type, image sub-type or class UIDs).
aLength	The length of aRequiredUids (number of required UIDs).
aImplArray	The array containing the implementation UIDs of the available decoder plugins with the required UIDs. The caller has the ownership of the array.

GetMimeTypeDataL ( const TDesC8 &, TDes8 & )

IMPORT_C void	GetMimeTypeDataL	(	const TDesC8 &	aImageData,
			TDes8 &	aMimeType
		)	[static]

Get the primary MIME type of the decoder that will be used to decode a descriptor. Some file types (like OTA or WBPM), which do not have unique pattern in their header may not be recognised. Such files are not supported by this API

Parameter	Description
aImageData	A descriptor containing the image data for which a MIME type has to be determined.
aMimeType	An empty descriptor in which the MIME type assosiated with the file will be returned. Ownership is passed to the caller.

GetMimeTypeFileL ( RFs &, const TDesC &, TDes8 & )

IMPORT_C void	GetMimeTypeFileL	(	RFs &	aFs,
			const TDesC &	aFileName,
			TDes8 &	aMimeType
		)	[static]

Get the primary MIME type of the decoder that will be used to decode a file. Some file types (like OTA or WBPM), which do not have unique pattern in their header may not be recognised, in case when the source file name doesn't have extension or, extension is not common to that file type. Such files are not supported by this API.

Parameter	Description
aFs	A reference to a file server session to use.
aFileName	The name of the file for which a MIME type has to be determined
aMimeType	An empty descriptor in which the MIME type assosiated with the file will be returned. Ownership is passed to the caller.

GetPluginPropertiesL ( const TUid, RUidDataArray & )

IMPORT_C void	GetPluginPropertiesL	(	const TUid	aImplementationUid,
			RUidDataArray &	aPropertiesArray
		)	[static]

Gets a list of the properties of a specific decoder plugin.

Parameter	Description
aImplementationUid	The decoder implementation UID for which the plugin properties need to be retrieved.
aPropertiesArray	The array of plugin properties owned by the specified decoder. The caller has the ownership of the array.

ImageCommentL ( TInt )

IMPORT_C HBufC *

ImageCommentL

(

TInt

aCommentNumber

)

const

Return a particular comment attached to the image.

Ownership of the returned buffer is transferred to the caller. Use NumberOfImageComments() to determine how many (if any) comments are contained within the image.

For further informantion on panic categories, please see the note in CImageDecoder::IsImageHeaderProcessingComplete().

panic: ImageConversion 12 Comments are not supported. See CImageDecoder::NumberOfImageComments().

panic: ImageConversion 13 Header processing has not completed. See CImageDecoder::IsImageHeaderProcessingComplete().

panic: ImageConversion 14 aCommentNumber is not valid. See CImageDecoder::NumberOfImageComments().

Parameter	Description
aCommentNumber	The comment number.

Returns: A buffer containing the comment.

ImageType ( TInt, TUid &, TUid & )

IMPORT_C void	ImageType	(	TInt	aFrameNumber,
			TUid &	aImageType,
			TUid &	aImageSubType
		)	const

Retrieves the image type and sub-type for a given frame of the image that has just been decoded.

For further informantion on panic categories, please see the note in CImageDecoder::IsImageHeaderProcessingComplete().

panic: ImageConversion 10 aFrameNumber is not valid. See CImageDecoder::FrameCount().

Parameter	Description
aFrameNumber	The frame number for which type information should be retreived.
aImageType	On return contains the image type UID for the specified frame.
aImageSubType	On return contains the image sub-type UID if there is one (or KNullUid if there is not).

ImplementationUid ( )

IMPORT_C TUid

ImplementationUid

(

)

const

Return the implementation UID of the decoder being used to decode the image.

Returns: The implementation UID of the decoder.

IsImageHeaderProcessingComplete ( )

IMPORT_C TBool

IsImageHeaderProcessingComplete

(

)

const

Return the status of the image.

If the image is incomplete EFalse will be returned. The client should continue to supply more data and call ContinueProcessingHeaders() until ETrue is returned.

Panic categories: Many CImageDecoder functions are dependent upon this function returning ETrue before they can successfully be called. If the client calls one of these dependent functions, then that function call may panic with either the 'ImageConversion' panic category or a decoder plugin specific panic category, for example: 'BMPConvertPlugin', 'GIFConvertPlugin', 'ICOConvertPlugin', 'JPEGConvertPlugin', 'MBMConvertPlugin', 'OTAConvertPlugin', 'PNGConvertPlugin', 'TIFFConvertPlugin', 'WBMPConvertPlugin', 'WMFConvertPlugin'.

Returns: Image status.

NumberOfFrameComments ( TInt )

IMPORT_C TInt

NumberOfFrameComments

(

TInt

aFrameNumber

)

const

Return the number of comments attached to a given frame of the image (as opposed to the whole image).

Use FrameCount() to retrieve the number of frames in the image to ensure that a valid aFrameNumber is used.

For further informantion on panic categories, please see the note in CImageDecoder::IsImageHeaderProcessingComplete().

panic: ImageConversion 10 aFrameNumber is not valid. See CImageDecoder::FrameCount().

panic: ImageConversion 13 Header processing has not completed. See CImageDecoder::IsImageHeaderProcessingComplete().

Parameter	Description
aFrameNumber	The frame number.

Returns: The number of comments attached to a given frame of the image.

NumberOfImageComments ( )

IMPORT_C TInt

NumberOfImageComments

(

)

const

Return the number of comments attached to the image (as opposed to a particular frame).

For further informantion on panic categories, please see the note in CImageDecoder::IsImageHeaderProcessingComplete().

panic: ImageConversion 13 Header processing has not completed. See CImageDecoder::IsImageHeaderProcessingComplete().

Returns: The number of comments attached to the image.

OperationL ( )

IMPORT_C TImageConvOperation *

OperationL

(

)

Get the extension interface for operations on the image.

leave: KErrNotSupported if loaded codec plugin does not support this optional extension.

leave: Other system wide errors

Note:

The order of post processing operations when applied for decoding is

1. Clip the image
2. Scale the image
3. Operate on the image

Returns: Interface to image conversion operations.

Plugin ( )

IMPORT_C CImageDecoderPlugin *

Plugin

(

)

const [protected]

Returns associated CImageDecoderPlugin.

Allows the extended CImageDecoder object to talk to its CImageDecoderPlugin equivalent.

Note: This function is intendend for use by plugin writers only.

Returns: A pointer to the related CImageDecoderPlugin instance.

Prepare ( TRequestStatus * )

IMPORT_C void

Prepare

(

TRequestStatus *

aRequestStatus

)

Optional call from client which may be made on the decoder to allow analysis of image prior to calling Convert.

Should be called once decode is fully set up e.g. clipping rectangle set.

ReducedSize ( const TSize &, TInt, TSize & )

IMPORT_C TInt	ReducedSize	(	const TSize &	aOriginalSize,
			TInt	aReductionFactor,
			TSize &	aReducedSize
		)	const

Calculates reduced size of the decoded bitmap based on the input parameters and updates aReducedSize with this value.

Parameter	Description
aOriginalSize	A reference to the original size of an image.
aReductionFactor	The Reduction Factor to be applied
aReducedSize	A reference to the new size of the image.

Returns: An error code indicating if the function call was successful. KErrNone on success, otherwise KErrArgument.

ReductionFactor ( const TSize &, const TSize & )

IMPORT_C TInt	ReductionFactor	(	const TSize &	aOriginalSize,
			const TSize &	aReducedSize
		)	const

Function to calculate the reduction factor based on the input parameters.

Parameter	Description
aOriginalSize	A reference to the original size of an image.
aReducedSize	A reference to the new size of an image.

Returns: The reduction factor.

ScalerL ( )

IMPORT_C TImageConvScaler *

ScalerL

(

)

Get the extension interface for scaling the image.

SetAgentProperty ( ContentAccess::TAgentProperty, TInt )

IMPORT_C TInt	SetAgentProperty	(	ContentAccess::TAgentProperty	aProperty,
			TInt	aValue
		)

Sets the properties for the Image decoder.

Parameter	Description
aProperty	The property to set.
aValue	The value of the property.

Returns: KErrNone if successful, otherwise one of the system-wide errors.

SetClippingRectL ( const TRect * )

IMPORT_C void

SetClippingRectL

(

const TRect *

aClipRect

)

Sets the area of interest of the image to be decoded. This function can leave with any of the system-wide error codes.

leave: KErrNotSupported This function is not supported.

leave: KErrArgument Returned if the clipping rectangle: a) is empty (i.e. IsEmpty() returns ETrue) b) is not normalised (i.e. IsNormalized() returns EFalse) c) has coordinates that are not located within, or on, the coodinates of at least one frame of the original image. d) has a width or a height of 0

Parameter	Description
aClipRect	A pointer to a TRect that specifies the location and size of the region to be decoded. This rectangle must have positive width and height values as per TRect::IsNormalized() and TRect::Normalize(). Passing in a NULL value will clear the clipping rectangle. Note that a clipping rectangle may not be valid for all frames of an image.

SetDecoderThreadPriority ( TThreadPriority )

IMPORT_C TInt

SetDecoderThreadPriority

(

TThreadPriority

aPriority

)

Set the decoder worker thread priority

SetImageTypeL ( TInt )

IMPORT_C void

SetImageTypeL

(

TInt

aImageType

)

Set the source image type, this can be any value from TImageType. It can leave with a system wide error. Typical leaves are documented below.

leave: KErrNotFound If the image for the type specified is not found.

leave: KErrCorrupt For a corrupt image. In the case of failing to change the source image from a valid EImageTypeMain image to a corrupt EImageTypeThumbnail, the decoder resets the image type back to the valid EImageTypeMain.

Parameter	Description
aImageType	An image type from TImageType to denote source image that the decoder should use.