DisplayMethod.h

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//# DisplayMethod.h: Base class for drawing data in the Display Library
//# Copyright (C) 1996,1997,1998,1999,2000,2001,2002
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library is distributed in the hope that it will be useful, but WITHOUT
//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//#        Internet email: aips2-request@nrao.edu.
//#        Postal address: AIPS++ Project Office
//#                        National Radio Astronomy Observatory
//#                        520 Edgemont Road
//#                        Charlottesville, VA 22903-2475 USA
//#
//# $Id$

#ifndef TRIALDISPLAY_DISPLAYMETHOD_H
#define TRIALDISPLAY_DISPLAYMETHOD_H

//# aips includes:
#include <casa/aips.h>

//# display library includes:
#include <display/Display/DisplayEnums.h>
#include <display/Display/AttributeBuffer.h>

namespace casa { //# NAMESPACE CASA - BEGIN

//# forwards:
class WorldCanvasHolder;
class Attribute;
class DisplayData;

// <summary>
// Base class for drawing a particular element (view) of a DisplayData.
// </summary>
//
// <synopsis> 
// This base class defines an interface for drawing a single view of a
// DisplayData object.  The fundamental idea is that a DisplayData
// class will manage one or more DisplayMethod objects, and request
// the individual objects to draw as necessary.
// </synopsis>

class DisplayMethod {
 public:

  // Constructor.  DisplayMethods need to know who their parent
  // DisplayData is.
  DisplayMethod(DisplayData *parentDisplayData);

  // Destructor.
  virtual ~DisplayMethod();

  // Draw on the provided WorldCanvasHolder.
  virtual void draw(Display::RefreshReason reason,
                    WorldCanvasHolder &wcHolder) = 0;

  // clear drawlist state.
  // dk note 11/03:  Only used by the PrincipleAxesDM branch, where the
  // implementation has been moved.  Implementation should remain null
  // on the CachingDD/DM branch, which uses different interface (purgeCache)
  // and state for this.
  virtual void cleanup();

  // Set & remove restrictions
  // <group>
  void addRestriction(Attribute& newAt, Bool permanent);
  void addRestrictions(AttributeBuffer& newBuf);
  void setRestriction(Attribute& newAt);
  void setRestrictions(AttributeBuffer& newBuf);
  void removeRestriction(const String& name);
  Bool existRestriction(const String& name);
  void clearRestrictions();
  // </group>

  // match restriction
  // <group>
  Bool matches(Attribute& at);
  Bool matches(AttributeBuffer& atBuf);
  // </group>


  // Allow DisplayData objects to find out about restrictions in
  // DisplayMethod elements...
  friend class DisplayData;

 protected:

  AttributeBuffer  restrictions;

  // (Required) default constructor.
  DisplayMethod();

  // (Required) copy constructor.
  DisplayMethod(const DisplayMethod &other);

  // (Required) copy assignment.
  void operator=(const DisplayMethod &other);
  
  // Return the parent DisplayData.
  DisplayData *parentDisplayData() 
    { return itsParentDisplayData; }

 private:

  DisplayData *itsParentDisplayData;

};


} //# NAMESPACE CASA - END

#endif