Location:
ImageConversion.h
Link against: imageconversion.lib
class CBufferedImageDecoder : public CBase;
Buffered image conversion library.
Provides a wrapper arround CImageDecoder
that enables you to decode multiple images without having to recreate the CBufferedImageDecoder object each time. One of
the key features of this class is the ability to append image data to the decoder object as it becomes available; this is
done using AppendDataL()
.
CBase
- Base class for all classes to be instantiated on the heap
CBufferedImageDecoder
- Buffered image conversion library
Defined in CBufferedImageDecoder
:
AppendDataL()
, Cancel()
, ContinueConvert()
, ContinueOpenL()
, ContinueProcessingHeaderL()
, Convert()
, Convert()
, FrameCommentL()
, FrameCount()
, FrameData()
, FrameInfo()
, FrameInfoStringsL()
, FrameInfoStringsLC()
, ImageCommentL()
, ImplementationUid()
, IsImageHeaderProcessingComplete()
, NewL()
, NumberOfFrameComments()
, NumberOfImageComments()
, OpenL()
, OpenL()
, Reset()
, ValidDecoder()
, ~CBufferedImageDecoder()
Inherited from CBase
:
Delete()
,
Extension_()
,
operator new()
static IMPORT_C CBufferedImageDecoder *NewL(RFs &aFs);
Creates a buffered decoder.
The function leaves if the decoder object cannot be created or initialised.
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virtual IMPORT_C ~CBufferedImageDecoder();
Destructor for this class.
Stops decoding if it is in progress and frees all resources owned by the object prior to its destruction.
IMPORT_C void OpenL(const TDesC8 &aSourceData, const TDesC8 &aMIMEType, const CImageDecoder::TOptions aOptions=CImageDecoder::EOptionNone);
Creates 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 it finds a decoder it creates it and then goes on to use that decoder to scan the beginning of the image file.
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IMPORT_C void OpenL(const TDesC8 &aSourceData, const CImageDecoder::TOptions aOptions=CImageDecoder::EOptionNone, const TUid
aImageType=TUid::Null(), const TUid aImageSubType=TUid::Null(), const TUid aDecoderUid=TUid::Null());
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 creates it and then goes on to use that decoder to scan the beginning of the image buffer. If a decoder could
not be created append data using AppendDataL()
and call ContinueOpenL()
.
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IMPORT_C void ContinueOpenL();
Call this function to retry to create a decoder after OpenL()
returned with KErrUnderFlow and extra data was added to the descriptor using AppendDataL()
. This function can be recalled until ValidDecoder()
return ETrue.
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IMPORT_C void ContinueProcessingHeaderL();
Continues processing image headers after new image data was appended.
This function can be called until IsImageHeaderProcessingComplete()
return ETrue.
IMPORT_C TBool IsImageHeaderProcessingComplete() const;
Returns the status of the image.
If the image is incomplete or not terminated correctly EFalse will be returned
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IMPORT_C void Convert(TRequestStatus *aRequestStatus, CFbsBitmap &aDestination, TInt aFrameNumber=0);
Starts decoding an image frame asynchronously.
When converting the operation can complete with KErrUnderflow, if 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.
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IMPORT_C void Convert(TRequestStatus *aRequestStatus, CFbsBitmap &aDestination, CFbsBitmap &aDestinationMask, TInt aFrameNumber=0);
Starts decoding an image frame and mask asynchronously.
When converting the operation can complete with KErrUnderflow, if 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.
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IMPORT_C void ContinueConvert(TRequestStatus *aRequestStatus);
Continues 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.
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IMPORT_C void Cancel();
Requests an asynchronous decode to terminate.
Cancels any conversions currently in progress.
IMPORT_C void Reset();
Reset the decoder for reuse.
Follow this call with OpenL()
and new source data.
IMPORT_C void AppendDataL(const TDesC8 &aData);
Adds new image data.
A copy of the data is held internally, and the caller does not need to retain the data.
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IMPORT_C TInt FrameCount() const;
Returns 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.
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IMPORT_C const TFrameInfo &FrameInfo(TInt aFrameNumber=0) const;
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 converting it.
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IMPORT_C const CFrameImageData &FrameData(TInt aFrameNumber=0) const;
Returns the image data for a specific frame.
Use FrameCount()
to determine how many frames are contained in the image before using this function.
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IMPORT_C TInt NumberOfImageComments() const;
Returns the number of comments attached to the image (as opposed to a particular frame).
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IMPORT_C HBufC *ImageCommentL(TInt aCommentNumber) const;
Returns 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.
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IMPORT_C TInt NumberOfFrameComments(TInt aFrameNumber) const;
Returns 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 the value you use for aFrameNumber is valid.
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IMPORT_C HBufC *FrameCommentL(TInt aFrameNumber, TInt aCommentNumber) const;
Returns a particular comment attached to a given frame of the image. Ownership of the returned buffer is transferred to the caller.
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IMPORT_C CFrameInfoStrings *FrameInfoStringsLC(TInt aFrameNumber=0);
Returns the formatted frame information strings for a specific frame and leave it on the cleanup stack.
Ownership is transferred to the caller.
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IMPORT_C CFrameInfoStrings *FrameInfoStringsL(TInt aFrameNumber=0);
Returns the formatted frame information strings for a specific frame.
Ownership is transferred to the caller.
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IMPORT_C TUid ImplementationUid() const;
Returns the implementation UID of the decoder being used to decode the image.
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IMPORT_C TBool ValidDecoder() const;
Determine if enough data was available to determine which plugin decoder to use. If this return EFalse append extra data using
AppendDataL()
and and call ContinueOpenL()
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