// $Revision: 1.3 $
// Copyright (C) 1994 Taligent, Inc. All rights reserved.

#ifndef Taligent_CANVASCONVENIENCEFILTERS
#define Taligent_CANVASCONVENIENCEFILTERS

#ifndef Taligent_GRAFEDIT
#include <Taligent/GrafEdit.h>
#endif
#ifndef Taligent_CANVASGRAPHICMANIPULATION
#include <Taligent/CanvasGraphicManipulation.h>
#endif


// Classes defined in this file:

class TCanvasSelectionFilter;
class TCanvasTopSelectionDrawingFilter;
class TCanvasTopSelectionHitDetectionFilter;

// Classes defined elsewhere (but needed here):

class TSRTFeedbacker;

// ********************************************************************************
// class			TCanvasSelectionFilter
//
// description		TCanvasGraphicFilter abstract subclass that is used by filters wishing
//					to deal with selections.  For instance, the TCanvasTopSelectionDrawingFilter
//					and the TCanvasTopSelectionHitDetectionFilter subclass from this
//					class.  The main functionality provided by this level of abstraction
// 					are the two virtual CreateFeedbacker methods.
//
// ********************************************************************************

class TCanvasSelectionFilter : public TCanvasGraphicFilter 
{
	public:
		TCanvasSelectionFilter (TSRTFeedbacker* defaultFeedbacker = NIL);
								
		virtual							~TCanvasSelectionFilter ();
				
		//=========================================
		// Unidirectional Iteration 
		//=========================================
		virtual const MCanvasGraphic*	First () = 0;
		virtual const MCanvasGraphic* 	Next () = 0;
		
		virtual void					SetCanvasFeedbacker (const TSRTFeedbacker&); 

	protected:
		virtual MCanvasGraphic*			GetCanvasFeedbacker (const MCanvasGraphic&);
		virtual MCanvasGraphic*			GetGraphicFeedbacker (const MCanvasGraphic&);

#ifndef NO_Internal		
	private:
		void*							fExtension;
		TSRTFeedbacker*					fCanvasFeedbacker;
#endif

};


// ********************************************************************************
// class			TCanvasTopSelectionDrawingFilter
//
// description		This class is provided to demonstrate the basic flavor of
//					using filters and funnels to accomplish various selection
//					strategies.  Filters will be changed to support linking
//					and a set of linkable filters for managing direction, selection
//					strategies, filtering out unwanted graphics, etc. will be
//					provided.
//
// ********************************************************************************

class TCanvasTopSelectionDrawingFilter : public TCanvasSelectionFilter
{
	public:

		TCanvasTopSelectionDrawingFilter (const MCanvasSelection* referenceSelection);
		virtual							~TCanvasTopSelectionDrawingFilter ();
		
		// ========================================
		// Iteration from back to front
		// ========================================
		
		virtual const MCanvasGraphic*	First ();
		virtual const MCanvasGraphic* 	Next ();

#ifndef NO_Internal		
	private:
		void*							fExtension;
		const MCanvasSelection*			fSelection;			// not owned
		bool							fSelectionPass;
		MCanvasGraphic*					fCurrentFeedbacker; // not owned 
#endif

};


// ********************************************************************************
// class			TCanvasTopSelectionHitDetectionFilter
//
// description		This class is provided to demonstrate the basic flavor of
//					using filters and funnels to accomplish various selection
//					strategies.  Filters will be changed to support linking
//					and a set of linkable filters for managing direction, selection
//					strategies, filtering out unwanted graphics, etc. will be
//					provided.
//
// ********************************************************************************

class TCanvasTopSelectionHitDetectionFilter : public TCanvasSelectionFilter
{
	public:

		TCanvasTopSelectionHitDetectionFilter (const MCanvasSelection* referenceSelection);
		virtual							~TCanvasTopSelectionHitDetectionFilter ();
		
		// ========================================
		// Iteration from back to front
		// ========================================
		
		virtual const MCanvasGraphic*	First ();
		virtual const MCanvasGraphic* 	Next ();

#ifndef NO_Internal		
	private:
		void*							fExtension;
		const MCanvasSelection*			fSelection;			// not owned
		bool							fSelectionPass;
		MCanvasGraphic*					fCurrentFeedbacker; // not owned 
#endif

};


#endif // Taligent_CANVASCONVENIENCEFILTERS