PCTool.h

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//# PCTool.h: base class for PixelCanvas event-based tools
//# Copyright (C) 1999,2000
//# 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_PCTOOL_H
#define TRIALDISPLAY_PCTOOL_H

#include <casa/aips.h>
#include <display/DisplayEvents/PCPositionEH.h>
#include <display/DisplayEvents/PCMotionEH.h>
#include <display/DisplayEvents/PCRefreshEH.h>

namespace casa { //# NAMESPACE CASA - BEGIN

class PCTool;
class PixelCanvas;

// <summary>
// PixelCanvas position event handler for PCTool.
// </summary>
//
// <synopsis>
// This class is a simple implementation of a PCPositionEH which 
// passes PixelCanvas position events on to a single PCTool.
// </synopsis>

class PCToolPosEH : public PCPositionEH {
 public:
  PCToolPosEH(PCTool *tool);
  virtual ~PCToolPosEH(){};
  virtual void operator()(const PCPositionEvent& ev);
 private:
  PCTool *itsTool;
};

// <summary>
// PixelCanvas motion event handler for PCTool.
// </summary>
//
// <synopsis>
// This class is a simple implementation of a PCMotionEH which 
// passes PixelCanvas motion events on to a single PCTool.
// </synopsis>

class PCToolMotEH : public PCMotionEH {
 public:
  PCToolMotEH(PCTool *tool);
  virtual ~PCToolMotEH(){};
  virtual void operator()(const PCMotionEvent& ev);
 private:
  PCTool *itsTool;
};

// <summary>
// PixelCanvas refresh event handler for PCTool.
// </summary>
//
// <synopsis>
// This class is a simple implementation of a PCRefreshEH which 
// passes PixelCanvas refresh events on to a single PCTool.
// </synopsis>

class PCToolRefEH : public PCRefreshEH {
 public:
  PCToolRefEH(PCTool *tool);
  virtual ~PCToolRefEH(){};
  virtual void operator()(const PCRefreshEvent& ev);
 private:
  PCTool *itsTool;
};

// <summary>
// Base class for PixelCanvas event-based tools.
// </summary>

// <use visibility=export>

// <reviewed reviewer="" date="yyyy/mm/dd" tests="" demos="">
// </reviewed>

// <prerequisites>
//   <li> PCPositionEH
//   <li> PCMotionEH
//   <li> PCRefreshEH
// </prerequisites>

// <etymology>
// PCTool stands for PixelCanvas Tool.
// </etymology>

// <synopsis>
// This class is a base class upon which tools which respond to 
// various events on a PixelCanvas can be built.  It wraps up
// the position, motion and refresh events so that the programmer
// sees them all coming into one class, where they can be dealt
// with in a unified manner.  PCTool is not actually abstract,
// so the programmer need only write handlers for the events in
// which they are interested.
// </synopsis>

// <example>
// </example>

// <motivation>
// The majority of tools written for the PixelCanvas will fall 
// into the category that this class serves: they respond to a 
// single key or mouse button, and they potentially need to 
// respond to position, motion and refresh events.
// </motivation>

// <todo asof="1999/10/09">
//   <li> Nothing known
// </todo>

class PCTool {
  
 public:
  
  // Constructor.  A PixelCanvas to attach to must be specified,
  // and normally a key to respond to as well.
  PCTool(PixelCanvas *pcanvas,
         Display::KeySym keysym = Display::K_Pointer_Button1);
  
  // Destructor.
  virtual ~PCTool();
  
  // Switch the tool on/off.  This simply registers or unregisters the
  // event handlers.
  // <group>
  virtual void enable();
  virtual void disable();
  // </group>
  
  // Required operators for event handling.  These are called when
  // events occur, and distribute the events to the "user-level"
  // methods.
  // <group>
  virtual void operator()(const PCPositionEvent& ev);
  virtual void operator()(const PCMotionEvent& ev);
  virtual void operator()(const PCRefreshEvent& ev);
  // </group>

  // Functions called by the local event handling operators.  By
  // default they do nothing, so a derived class needs only implement
  // the events it cares about.
  // <group>
  virtual void keyPressed(const PCPositionEvent &ev);
  virtual void keyReleased(const PCPositionEvent &ev);
  virtual void otherKeyPressed(const PCPositionEvent &ev);
  virtual void otherKeyReleased(const PCPositionEvent &ev);
  virtual void moved(const PCMotionEvent &ev);
  virtual void refresh(const PCRefreshEvent &ev);
  // </group>

  // Get the PixelCanvas to which this Tool is attached.
  virtual PixelCanvas *pixelCanvas() const 
    { return itsPixelCanvas; }

  // Set/get which key to catch.
  // <group>
  virtual void setKey(const Display::KeySym &keysym);
  virtual Display::KeySym getKey() const
    { return itsKeySym; }
  // </group>

 protected:

  // Indicate whether key is presently pressed.
  virtual Bool keyPresentlyDown(const PCMotionEvent &ev);

 private:

  // The PixelCanvas to which this is connected.
  PixelCanvas *itsPixelCanvas;

  // The key to handle.
  Display::KeySym itsKeySym;

  // The modifier mask for the key.
  Display::KeyModifier itsKeyModifier;

  // Whether the event handlers are currently registered.
  Bool itsEventHandlersRegistered;

  // The event handlers.
  PCToolPosEH *itsPositionEH;
  PCToolMotEH *itsMotionEH;
  PCToolRefEH *itsRefreshEH;

};


} //# NAMESPACE CASA - END

#endif