CachingDisplayMethod.h

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//# CachingDisplayMethod.h: assistance for auto-caching DisplayData objects
//# Copyright (C) 1999,2000,2001
//# 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
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//#
//# $Id$

#ifndef TRIALDISPLAY_CACHINGDISPLAYMETHOD_H
#define TRIALDISPLAY_CACHINGDISPLAYMETHOD_H

#include <casa/aips.h>
#include <display/Display/DisplayEnums.h>
#include <display/DisplayDatas/DisplayMethod.h>

namespace casa { //# NAMESPACE CASA - BEGIN

        class AttributeBuffer;
        class WorldCanvas;
        class WorldCanvasHolder;
        class CachingDisplayData;

// <summary>
// Assistance class for auto-caching of DisplayData objects.
// </summary>

// <use visibility=export>

// <reviewed reviewer="" data="" tests="" demos="">
// </reviewed>

// <prerequisite>
// <li> <linkto class=DisplayMethod> DisplayMethod </linkto>
// <li> <linkto class=CachingDisplayData> CachingDisplayData </linkto>
// </prerequisite>

// <etymology>
// "CachingDisplayMethod" is an implementation of a <linkto
// class=DisplayMethod> DisplayMethod </linkto> which provides a
// single element in a cache of individual depictions of some data.
// </etymology>

// <synopsis>
// </synopsis>


        class CachingDisplayMethod : public DisplayMethod {

        public:

                // Constructor.  A single instance of a CachingDisplayMethod is
                // setup to draw on a particular WorldCanvas, and only when
                // particular conditions, as stored in the provided
                // AttributeBuffers, are met.  The parent DisplayData is given
                // in <src>parentDisplayData</src>.
                CachingDisplayMethod(WorldCanvas *worldCanvas,
                                     AttributeBuffer *wchAttributes,
                                     AttributeBuffer *ddAttributes,
                                     CachingDisplayData *parentDisplayData);

                // Destructor.
                virtual ~CachingDisplayMethod();

                // Return the WorldCanvas recorded in this CachingDisplayMethod.
                virtual WorldCanvas *worldCanvas() {
                        return itsWorldCanvas;
                }

                // Draw this slice of data on the supplied WorldCanvasHolder.
                virtual void draw(Display::RefreshReason reason,
                                  WorldCanvasHolder &wcHolder);

        protected:

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

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

                // (Required) copy assignment.
                void operator=(const CachingDisplayMethod &other);

                // Draw into a cached drawing list, called by draw function.
                // The return value is set false if the DM could not draw or
                // does not wish a drawlist to be saved.
                virtual casacore::Bool drawIntoList(Display::RefreshReason reason,
                                          WorldCanvasHolder &wcHolder) = 0;

        private:

                // Store for the WorldCanvas which this has previously drawn upon.
                WorldCanvas *itsWorldCanvas;

                // Store for WorldCanvasHolder- and DisplayData-specific
                // AttributeBuffers.
                AttributeBuffer *itsWCHAttributes, *itsDDAttributes;

                // Do we have a cached drawing list?
                casacore::Bool itsHasList;

                // Store for cached drawing list number.
                casacore::uInt itsCachedDrawingList;

        };


} //# NAMESPACE CASA - END

#endif