#include <ImageCodec.h>
Link against: imageconversion.lib

Class `CImageReadCodec`

class CImageReadCodec : public CBase;

Description

Provides read related processing functions for bitmaps.

Note: For use by plugin writers only.

Derivation

CBase - Base class for all classes to be instantiated on the heap.

CImageReadCodec - Provides read related processing functions for bitmaps.

Members

Defined in CImageReadCodec:

CImageReadCodec()Default constructor.
ClearBitmapL(CFbsBitmap &,TRgb)Paints the entire bitmap aBitmap with the color supplied as aColor.
Complete()Processes/displays converted image data.
ConstructL()Second phase constructor.
CurrentFrame()constReturn the current frame number
GetNewDataPosition(TInt &,TInt &)Returns a new position and number of bytes to read for the data stream.
InitFrameHeader(TFrameInfo &,CFrameImageData &)Used to initialise the frame header data structures.
InitFrameL(TFrameInfo &,CFrameImageData &,TBool,CFbsBitmap &,CFbsBitmap *)Performs initial processing of image data and mask bitmaps.
ProcessFrameHeaderL(TBufPtr8 &)Processes the header for one frame.
ProcessFrameL(TBufPtr8 &)Processes the frame data contained in aSrc.
ReducedSize(const TSize &,TInt,TSize &)constCalculates reduced size of the decoded bitmap based on the input parameters and ...
ReductionFactor(const TSize &,const TSize &)constCalculates reduction factor based on the input parameters. The default Implement...
ReservedVirtual1()Intended for future proofing - will panic if called
ReservedVirtual2()Intended for future proofing - will panic if called
ReservedVirtual3()Intended for future proofing - will panic if called
ReservedVirtual4()Intended for future proofing - will panic if called
~CImageReadCodec()Destructor.

Inherited from CBase:

Delete(CBase *)Deletes the specified object.
Extension_(TUint,TAny *&,TAny *)Extension function
operator new(TUint)Allocates the object from the heap and then initialises its contents to binary z...
operator new(TUint,TAny *)Initialises the object to binary zeroes.
operator new(TUint,TLeave)Allocates the object from the heap and then initialises its contents to binary z...
operator new(TUint,TLeave,TUint)Allocates the object from the heap and then initialises its contents to binary z...
operator new(TUint,TUint)Allocates the object from the heap and then initialises its contents to binary z...

Construction and destruction

`~CImageReadCodec()`

IMPORT_C ~CImageReadCodec();

Description

Destructor.

`CImageReadCodec()`

protected: IMPORT_C CImageReadCodec();

Description

Default constructor.

`ConstructL()`

protected: IMPORT_C void ConstructL();

Description

Second phase constructor.

Member functions

`InitFrameL(TFrameInfo &,CFrameImageData &,TBool,CFbsBitmap &,CFbsBitmap *)`

virtual void InitFrameL(TFrameInfo &aFrameInfo, CFrameImageData &aFrameImageData, TBool aDisableErrorDiffusion, CFbsBitmap &aDestination, CFbsBitmap *aDestinationMask)=0;

Description

Performs initial processing of image data and mask bitmaps.

This function processes the image frame using data supplied in aFrameInfo, aFrameImageData and using the flag aDisableErrorDiffusion. Not all codecs are expected to make use of all fields.

This is a virtual function that each derived class must implement.

Parameters

`TFrameInfo &aFrameInfo`	A reference to a `TFrameInfo` object.
`CFrameImageData &aFrameImageData`	A reference to a `CFrameImageData` object.
`TBool aDisableErrorDiffusion`	A flag indicating whether error diffusion should be disabled.
`CFbsBitmap &aDestination`	The destination bitmap.
`CFbsBitmap *aDestinationMask`	The destination mask bitmap.

`InitFrameHeader(TFrameInfo &,CFrameImageData &)`

IMPORT_C virtual void InitFrameHeader(TFrameInfo &aFrameInfo, CFrameImageData &aFrameData);

Description

Used to initialise the frame header data structures.

The default version of this function does nothing. It should be implemented by the codec to at least update the appropriate processing state of the current frame using its TFrameInfo structure.

Parameters

`TFrameInfo &aFrameInfo`	A reference to a `TFrameInfo` object which will contain the current frame's header info
`CFrameImageData &aFrameData`	A reference to a `TFrameInfo` object which will contain the current frame's header data

`ProcessFrameHeaderL(TBufPtr8 &)`

IMPORT_C virtual TFrameState ProcessFrameHeaderL(TBufPtr8 &aData);

Description

Processes the header for one frame.

The default version of this function and simply returns EFrameComplete. It should be implemented by the codec to at least update the appropriate processing state of the current frame using its TFrameInfo structure.

Parameters


                                 						TBufPtr8 &aData

A reference to a TBufPtr8 that contains the frame data.

Return value

TFrameState

The completion status of this frame's processing

`Complete()`

IMPORT_C virtual void Complete();

Description

Processes/displays converted image data.

This function is called on frame completion and on underflow. The default version of this function does nothing. It should be implemented by the codec if required.

If it is called on underflow for example, it can enable display of a partially decoded image. In such cases this function could display all the image data up to the point of the underflow.

`GetNewDataPosition(TInt &,TInt &)`

IMPORT_C virtual void GetNewDataPosition(TInt &aPosition, TInt &aLength);

Description

Returns a new position and number of bytes to read for the data stream.

The default version of this function does nothing. It should be implemented by the codec, if required.

Parameters

`TInt &aPosition`	A reference to the returned new position.
`TInt &aLength`	A reference to the number of bytes to read.

`ProcessFrameL(TBufPtr8 &)`

virtual TFrameState ProcessFrameL(TBufPtr8 &aSrc)=0;

Description

Processes the frame data contained in aSrc.

This is a pure virtual function that each derived class must implement.

Parameters


                                 						TBufPtr8 &aSrc

A reference to the buffer containing the frame data.

Return value

TFrameState

The current frame state after processing.

`ReductionFactor(const TSize &,const TSize &)const`

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

Description

Calculates reduction factor based on the input parameters. The default Implementation is given here. It should be implemented by the Codecs, If required.

Parameters

`const TSize &aOriginalSize`	A reference to the original size of an image.
`const TSize &aReducedSize`	A reference to the new size of an image.

Return value

TInt

The reduction factor.

`ReducedSize(const TSize &,TInt,TSize &)const`

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

Description

Calculates reduced size of the decoded bitmap based on the input parameters and updates aReducedSize with this value. The default Implementation is given here. It should be implemented by the Codecs, If required.

Parameters

`const TSize &aOriginalSize`	A reference to the original size of an image.
`TInt aReductionFactor`
`TSize &aReducedSize`	A reference to the new size of an image.

Return value

TInt

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

`ClearBitmapL(CFbsBitmap &,TRgb)`

protected: IMPORT_C void ClearBitmapL(CFbsBitmap &aBitmap, TRgb aColor);

Description

Paints the entire bitmap aBitmap with the color supplied as aColor.

Parameters

`CFbsBitmap &aBitmap`	A reference to a fully constructed bitmap.
`TRgb aColor`	The color to use for painting.

`CurrentFrame()const`

protected: IMPORT_C TInt CurrentFrame() const;

Description

Return the current frame number

Return value

TInt

The current frame number

`ReservedVirtual1()`

private: IMPORT_C virtual void ReservedVirtual1();

Description

Intended for future proofing - will panic if called

Panic codes

EReservedCall

`ReservedVirtual2()`

private: IMPORT_C virtual void ReservedVirtual2();

Description

Intended for future proofing - will panic if called

Panic codes

EReservedCall

`ReservedVirtual3()`

private: IMPORT_C virtual void ReservedVirtual3();

Description

Intended for future proofing - will panic if called

Panic codes

EReservedCall

`ReservedVirtual4()`

private: IMPORT_C virtual void ReservedVirtual4();

Description

Intended for future proofing - will panic if called

Panic codes

EReservedCall

Class CImageReadCodec

Description

Derivation

Members

Construction and destruction

~CImageReadCodec()

Description

CImageReadCodec()

Description

ConstructL()

Description

Member functions

InitFrameL(TFrameInfo &,CFrameImageData &,TBool,CFbsBitmap &,CFbsBitmap *)

Description

Parameters

InitFrameHeader(TFrameInfo &,CFrameImageData &)

Description

Parameters

ProcessFrameHeaderL(TBufPtr8 &)

Description

Parameters

Return value

Complete()

Description

GetNewDataPosition(TInt &,TInt &)

Description

Parameters

ProcessFrameL(TBufPtr8 &)

Description

Parameters

Return value

ReductionFactor(const TSize &,const TSize &)const

Description

Parameters

Return value

ReducedSize(const TSize &,TInt,TSize &)const

Description

Parameters

Return value

ClearBitmapL(CFbsBitmap &,TRgb)

Description

Parameters

CurrentFrame()const

Description

Return value

ReservedVirtual1()

Description

Panic codes

ReservedVirtual2()

Description

Panic codes

ReservedVirtual3()

Description

Panic codes

ReservedVirtual4()

Description

Panic codes

Class `CImageReadCodec`

`~CImageReadCodec()`

`CImageReadCodec()`

`ConstructL()`

`InitFrameL(TFrameInfo &,CFrameImageData &,TBool,CFbsBitmap &,CFbsBitmap *)`

`InitFrameHeader(TFrameInfo &,CFrameImageData &)`

`ProcessFrameHeaderL(TBufPtr8 &)`

`Complete()`

`GetNewDataPosition(TInt &,TInt &)`

`ProcessFrameL(TBufPtr8 &)`

`ReductionFactor(const TSize &,const TSize &)const`

`ReducedSize(const TSize &,TInt,TSize &)const`

`ClearBitmapL(CFbsBitmap &,TRgb)`

`CurrentFrame()const`

`ReservedVirtual1()`

`ReservedVirtual2()`

`ReservedVirtual3()`

`ReservedVirtual4()`