Class CGraphicsAccelerator

class CGraphicsAccelerator : public CBase;

Description

Abstract base class for 2D graphics accelerators.

This class can be derived from to provide accelerated implementations of some common 2D graphics algorithms. Support for accelerated 2D graphics has been integrated into existing classes in the Graphics API for instance CFbsBitGc, so that existing code does not need to be altered, but a graphics accelerator can be used directly by applications. The accelerated 2D graphics operations may be implemented in software, hardware, or both.

Derivation

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

• CGraphicsAccelerator - Abstract base class for 2D graphics accelerators

Members

Defined in CGraphicsAccelerator:
Capabilities(), Operation(), Operation(), Operation(), Operation(), Reserved_1(), Reserved_2(), Reserved_3(), Reserved_4()

Inherited from CBase:
Delete(), Extension_(), operator new()

virtual const TGraphicsAcceleratorCaps *Capabilities()=0;

Description

Returns the capabilities of the graphics accelerator.

Return value

const TGraphicsAcceleratorCaps * The capabilities of the accelerator.

virtual TInt Operation(const TGraphicsOperation &aOperation)=0;

Description

Requests the graphics accelerator to perform a single graphics operation.

Parameters

const TGraphicsOperation &aOperation An instance of a TGraphicsOperation-derived class that identifies the graphics operation to be performed.

Return value

TInt KErrNone if successful, otherwise one of the system error codes. The function should return KErrNotSupported if the accelerator does not support the requested operation.

virtual TInt Operation(const TGraphicsOperation &aOperation, TInt aNumClipRects, TRect *aClipRects)=0;

Description

Requests the graphics accelerator perform a single graphics operation within a clipping region. This version is of Operation() is only usable if the accelerator capabilities returned by Capabilities() indicate that clipping to a region is supported.

Parameters

const TGraphicsOperation &aOperation An instance of a TGraphicsOperation-derived class that identifies the graphics operation to be performed. TInt aNumClipRects The number of rectangles in the clipping region. TRect *aClipRects A pointer to the first rectangle in the clipping region.

Return value

TInt KErrNone if successful, otherwise one of the system error codes. The function should return KErrNotSupported if the accelerator does not support the requested operation.

See also:

• TGraphicsAcceleratorCaps::iClipping

virtual TInt Operation(TDes8 &aBuffer)=0;

Description

Requests the graphics accelerator perform one or more graphics operations contained in a buffer.

The underlying implementation may be able to process a group of graphics operations more efficiently than if Operation() was called for each individually.

This function should be implemented as if Operation() was called in turn for each operation contained in the buffer. Each operation should be carried out immediately after the one preceding it. If a method returns an error, the length of aBuffer should be set to indicate the number of operations that have been successfully processed. In this case, the operation in which the error occurred will be indicated by the memory address &aBuffer[aBuffer.Length()].

Parameters

TDes8 &aBuffer A descriptor which holds a concatenation of graphics operations (TGraphicsOperation-derived objects).

Return value

TInt KErrNone if successful, otherwise one of the system error codes. The function should return KErrNotSupported if the accelerator does not support any of the requested operations.

virtual TInt Operation(TDes8 &aBuffer, TInt aNumClipRects, TRect *aClipRects)=0;

Description

Requests the graphics accelerator perform one or more graphics operations within a clipping region. This version is of Operation() is only usable if the accelerator capabilities returned by Capabilities() indicate that clipping to a region is supported.

The underlying implementation may be able to process a group of graphics operations more efficiently than if Operation() was called for each individually.

This function should be implemented as if Operation() was called in turn for each operation contained in the buffer. Each operation should be carried out immediately after the one preceding it. If a method returns an error, the length of aBuffer should be set to indicate the number of operations that have been successfully processed. In this case, the operation in which the error occurred will be indicated by the memory address &aBuffer[aBuffer.Length()].

Parameters

TDes8 &aBuffer A descriptor which holds a concatenation of graphics operations (TGraphicsOperation objects). TInt aNumClipRects The number of rectangles in the clipping region. TRect *aClipRects A pointer to the first rectangle in the clipping region.

Return value

TInt KErrNone if successful, otherwise one of the system error codes. The function should return KErrNotSupported if the accelerator does not support any of the requested operations.

See also:

• TGraphicsAcceleratorCaps::iClipping

virtual void Reserved_1()=0;

Description

virtual void Reserved_2()=0;

Description

virtual void Reserved_3()=0;

Description

virtual void Reserved_4()=0;

Description