PassiveCachingDD.h

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//# PassiveCachingDD.h: passive implementation of a CachingDisplayData
//# Copyright (C) 1999,2000,2001,2002,2003
//# 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_PASSIVECACHINGDD_H
#define TRIALDISPLAY_PASSIVECACHINGDD_H

#include <casa/aips.h>
#include <casa/Arrays/IPosition.h>
#include <display/DisplayDatas/CachingDisplayData.h>

namespace casa { //# NAMESPACE CASA - BEGIN

// <summary>
// Class providing passive behaviour for CachingDisplayDatas.
// </summary>

// <synopsis> 
// A "passive" DisplayData is one which can only be used in
// conjunction with another non-passive DisplayData.  As such, it will
// not negotiate coordinates on a WorldCanvas, nor will it provide
// coordinate conversion capabilities.
// </synopsis>

class PassiveCachingDD : public CachingDisplayData {

 public:

  // Constructor.
  PassiveCachingDD();

  // Destructor.
  virtual ~PassiveCachingDD();

    // Coordinate transformation handlers, called by WorldCanvasHolder.
  // These functions simply return False because this DisplayData is
  // passive.
  // <group>
  virtual Bool linToWorld(Vector<Double> &world, const Vector<Double> &lin);
  virtual Bool worldToLin(Vector<Double> &lin, const Vector<Double> &world);
  // </group>

  // Format a string containing coordinate or value information at the
  // given world coordinate.  They simply return empty Strings because
  // this DisplayData is passive.
  // <group>
  virtual String showPosition(const Vector<Double> &world, 
                              const Bool &displayAxesOnly = False);
  virtual String showValue(const Vector<Double> &world);
  // </group>

  
  // World axis information suppliers.
  // <group>
  virtual Vector<String> worldAxisNames() const;
  virtual Vector<String> worldAxisUnits() const;
  // </group>
  
  const Unit dataUnit() const { return Unit("_"); }
  const IPosition dataShape() const { return IPosition( ); }
  const uInt dataDim() const { return 0; }
  std::vector<int> displayAxes( ) const { return std::vector<int>( ); }

  // Return the number of display elements (ie. drawable images) in
  // this DisplayData.
  // <group>
  virtual const uInt nelements(const WorldCanvasHolder &wcHolder) const;
  virtual const uInt nelements() const;
  // </group>

  // Install the default options for this DisplayData.
  virtual void setDefaultOptions();

  // Apply options stored in <src>rec</src> to the DisplayData.  A
  // return value of <src>True</src> means a refresh is needed.
  // <src>recOut</src> contains any fields which were implicitly 
  // changed as a result of the call to this function.
  virtual Bool setOptions(Record &rec, Record &recOut);

  // Retrieve the current and default options and parameter types.
  virtual Record getOptions();

  // Negotiatiate WorldCanvas linear coordinate system when asked to
  // do so by the WorldCanvasHolder.  In this implementation, simply
  // return False to indicate that this DisplayData will not negotiate
  // coordinates: it is a passive DisplayData.

  virtual void refreshEH(const WCRefreshEvent &ev);
  virtual Bool sizeControl(WorldCanvasHolder &/*wcHolder*/,
                           AttributeBuffer &/*holderBuf*/)
    { return False; }

  // Tidy up the elements of this DisplayData.
  virtual void cleanup();  

 protected:

  // Return the current options of this DisplayData as an
  // AttributeBuffer.  The caller must delete the returned buffer.
  virtual AttributeBuffer optionsAsAttributes();

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

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

};


} //# NAMESPACE CASA - END

#endif