Class: TCanvasSelectionFilter

Declaration: CanvasConvenienceFilters.h

Taxonomy Categories:

Member Functions:

Interface Category:

API.

Inherits From:

TCanvasGraphicFilter

Inherited By:

TCanvasTopSelectionDrawingFilter TCanvasTopSelectionHitDetectionFilter

Purpose:

This class is an abstract derived class of TCanvasGraphicFilter, designed to provide a default implementation of three virtual member functions that manage a default feedbacker (TSRTFeedbacker). The two main member functions that are of interest to derived classes are GetCanvasFeedbacker and GetGraphicFeedbacker. This filter can hold on to a generic feedbacker (called the canvas feedbacker) that can be used for all canvas graphics that choose not to provide one of their own. When iterating through a filter, (in the First and Next member functions) GetGraphicFeedbacker is called. If no feedbacker is returned, then GetCanvasFeedbacker is called to provide a default feedback mechanism.

Instantiation:

Allocate on the heap or the stack.

Deriving Classes:

This class is used as the base class for other filter classes that are interested in feedbackers (notably, TCanvasTopSelectionHitDetectionFilter and TCanvasTopSelectionDrawingFilter).

Concurrency:

Not multithread safe.

Resource Use:

No special requirements.

Other Considerations:

None.

Member Function: TCanvasSelectionFilter::TCanvasSelectionFilter

TCanvasSelectionFilter (TSRTFeedbacker * defaultFeedbacker =NIL)

Interface Category:

API.

Purpose:

Constructor.

Calling Context:

Called to create a new object.

Parameters:

TSRTFeedbacker * defaultFeedbacker =NIL -If this pointer is NIL, a new standard TSRTBoxFeedbacker feedbacker is created.

Return Value:

None.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TCanvasSelectionFilter::~TCanvasSelectionFilter

virtual ~ TCanvasSelectionFilter ()

Interface Category:

API.

Purpose:

Destructor.

Calling Context:

Called to destroy an object.

Parameters:

Takes no parameters.

Return Value:

None.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TCanvasSelectionFilter::First

virtual const MCanvasGraphic * First ()

Interface Category:

API.

Purpose:

Returns the first graphic in a representation.

Calling Context:

Typically called from an implementation of EnumerateGraphics.

Parameters:

Takes no parameters.

Return Value:

const MCanvasGraphic * -The first graphic.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TCanvasSelectionFilter::Next

virtual const MCanvasGraphic * Next ()

Interface Category:

API.

Purpose:

Returns the next graphic in the representation.

Calling Context:

Typically called from an implementation of EnumerateGraphics.

Parameters:

Takes no parameters.

Return Value:

const MCanvasGraphic * -The next graphic.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TCanvasSelectionFilter::SetCanvasFeedbacker

virtual void SetCanvasFeedbacker (const TSRTFeedbacker &)

Interface Category:

API.

Purpose:

Sets the feedbacker for the given canvas.

Calling Context:

This member function is called by a client (such as an implementation of EnumerateGraphics) who desires that their filter provide a particular feedbacker other than the default TSRTBoxFeedbacker. This feedbacker is then provided as the generic feedbacker for all canvas graphics that do not supply their own (by implementing the MCanvasGraphic::GetFeedbacker member function).

Parameters:

const TSRTFeedbacker & -The feedbacker object to set to. Note that a copy of this is made (this is not adopted).

Return Value:

None.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TCanvasSelectionFilter::GetCanvasFeedbacker

virtual MCanvasGraphic * GetCanvasFeedbacker (const MCanvasGraphic &)

Interface Category:

API.

Purpose:

Returns a pointer to the default feedbacker for a given canvas.

Calling Context:

Typically called from an implementation of EnumerateGraphics.

Parameters:

const MCanvasGraphic & -The graphic desiring the feedbacker. This is necessary because before returning the feedbacker, SetGraphic is called on it, resizing the feedbacker to fit this particular canvas graphic.

Return Value:

MCanvasGraphic * -A pointer to the feedbacker for the canvas. If none has been established, then a default of type TSRTBoxFeedbacker is created.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Member Function: TCanvasSelectionFilter::GetGraphicFeedbacker

virtual MCanvasGraphic * GetGraphicFeedbacker (const MCanvasGraphic &)

Interface Category:

API.

Purpose:

Gets the feedbacker for the specified graphic. This is accomplished by calling the MCanvasGraphic::GetFeedbacker of the canvas graphic passed in.

Calling Context:

Typically called from an implementation of EnumerateGraphics.

Parameters:

const MCanvasGraphic & -The graphic whose feedbacker is being accessed.

Return Value:

MCanvasGraphic * -A pointer to the feedbacker for the graphic.

Exceptions:

Throws no exceptions, passes all exceptions through.

Concurrency:

Not multithread safe.

Other Considerations:

None.

Click the icon to mail questions or corrections about this material to Taligent personnel.