CImageDecoderPlugin Class Reference

Constructor for this class.

Destructor for this class.

Indicates if this decoder is running in a separate thread.

Appends a new image data data block to the end of the internally held array.

Appends a new image data buffer to the end of the internally held array

Called when the plugin is destroyed or a decode is cancelled. This may be overriden in derived classes.

Note: Derived classes must call this version after performing any plugin specific cleanup.

Returns the maximum number of bytes of data that can be decoded.

Returns the decoding options specified by the client when it created the CImageDecoder object.

Returns the destination bitmap.

Returns the destination bitmap mask.

Performs a decode step. This effectively forms the RunL() call of the decoder.

This call may be overriden in derived classes. However, if this the case, then if the custom decode is not performed and the derived class should either ensure that this base class's version is called or should completely replace the base class's version calling PrepareForProcessFrameL(), ProcessFrameL() and HandleProcessFrameResult() as appropriate. Unlike the standard version, an override instance may choose to spread these calls over several RunL() instances.

Returns the block size used in the specified frame. Always returns 4096 regardless of the frame number specified. Should be overriden by codecs that use larger blocks.

Returns a particular comment attatched to a given frame of the image.

Ownership of the returned buffer is transferred to the caller.

Returns the frame data for a specified frame of the image.

Returns the block size used in the specified frame's header. Always returns 4096 regardless of the frame number specified. Should be overriden by codecs that use larger blocks.

Returns 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 decoding it.

Returns the codec specific frame information stored in resource files.

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

Called by framework on plugin to get the size of decoded image.

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.

Gets the size of the destination CFbsBitmap needed prior to a call to Convert(). Essential when using the ICL Framework Extensions such as SetClippingRectL() or codec extensions obtained through the OperationL(), ScalerL() and BlockStreamerL() calls.

See also: CImageDecoder::OperationL() CImageDecoder::ScalerL() CImageDecoder::BlockStreamerL() CImageDecoder::SetClippingRectL() CImageDecoder::Convert()

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

See also: icl_uids.hrh .

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

Deals with result from ProcessFrameL(). This function 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 consumed by ProcessFrameL(), HandleProcessFrameResult() assumes that it requires more data and calls RequestComplete(KErrUnderflow). If this is not appropriate, an overloaded DoConvert() should be made to handle it.

Returns a particular comment attatched to the image. Ownership of the returned buffer is transferred to the caller.

Returns the image data block for the specified index.

Returns the number of image data blocks present in the image data.

Returns image information such as colour depth, scaling support etc.

Returns the plugin's read codec.

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

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

Initialises data structures prior to decoding a frame.

This function may be overriden in derived classes. Any override should also call this version after performing any plugin initialistion.

Called as a result of the associated CImageDecoder::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().

Plugins may override this to provide extended commands in CImageDecoder.Users of CImageEncoder can then use the extended encoder functions by calling CustomAsync, rather than CImageEncoder::Convert().

By default this function leaves with KErrNotSupported unless overriden.

Inserts an image data block into the internally held array at the specified position.

Returns the status of header processing. If the processing is incomplete or not terminated correctly EFalse will be returned

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.

Returns the number of comments attatched to a given frame of the image.

Use NumberOfImageComments() for the image equivalent.

Returns the number of frames to be decoded.

Returns the number of comments attatched to the image.

Some image formats allow comments to be attached to the entire image, others allow comments to be attached to individual frames within the image. Use this function to retrieve the number of comments in the image. Use NumberOfFrameComments() for the frame equivalent.

Locates the extra resource file for the decoder aUid_extra.rsc, opens the resource file and pushes it on the cleanup stack.

If the resource file is not found the method leaves with KErrNotFound. If more than one resource file is found, only the first one is opened.

Returns the current position within the data.

Initialises system for ProcessFrameL(). This reads in a new buffer for ProcessFrameL().

Reads a block of data into an internal buffer.

A block of data of size aLength is read from the position specified by aPosition to an internal data buffer. After a successful read, aReadBuffer is set to point to the internal buffer.

If an attempt is made to read past the end of data, all available data is read and the descriptors length will indicate the actual number of bytes read.

Invokes the ReadFrameHeadersL method of the supplied plugin which should process the frame headers contained within the image.

Removes a specified image data block from the internally held array.

Must be called on completion of decoding the image data.

See also: CImageDecoderPlugin::SelfComplete(TInt aReason)

Forces initialization of data structures prior to decoding a frame.

Invokes the ReadFrameHeadersL() method of the supplied plugin.

The plugin's version of ReadFrameHeadersL() should read the image header information, create the required codec and read the frame headers.

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

Must be called at the end of a slice of decoding.

If successful specify KErrNone that results in a repeat call to DoConvert().

See also: CImageDecoderPlugin::RequestComplete(TInt aReason)

Called by the framework on the plugin to apply a clipping rectangle to the image.

Sets the area of interest of the image to be decoded.

See also: TRect::IsEmpty() TRect::IsNormalized() TRect::Normalize()

Sets the maximum number of bytes of data that can be decoded.

Sets the image information.

Sets the plugin's read codec. Ownership of the codec is transferred to the plugin.

Sets the current position in the data.

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

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

See also: CImageDecoderPlugin::SelfComplete(TInt aReason)

Sets the starting position of the frame to be decoded.

Passes a pointer to a descriptor containing the thumbnail from the plugin to the framework. The framework then owns this descriptor.

Indicates if the decoder should abort early ie. following a call to Cancel().

Note: This function always returns false unless the decoder is running in its own thread.

Value to be fed to CImageReadCodec::ProcessFrameL().

This value is setup by PrepareForProcessFrameL() - it returns the value that will be fed to CImageReadCodec::ProcessFrameL(), and will be used by codecs that fully override DoConvert().

Returns the length of the source data in bytes.

Returns the starting position of the frame to be decoded.

Returns the validity of the destination bitmap.

Indicates if the destination bitmap mask is valid.