/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkWidgetSet.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// .NAME vtkWidgetSet - Synchronize a collection on vtkWidgets drawn on different renderwindows using the Callback - Dispatch Action mechanism.
// 
// .SECTION Description
// The class synchronizes a set of vtkAbstractWidget(s). Widgets typically
// invoke "Actions" that drive the geometry/behaviour of their representations
// in response to interactor events. Interactor interactions on a render window
// are mapped into "Callbacks" by the widget, from which "Actions" are 
// dispatched to the entire set. This architecture allows us to tie widgets
// existing in different render windows together. For instance a HandleWidget
// might exist on the sagittal view. Moving it around should update the 
// representations of the corresponding handle widget that lies on the axial 
// and coronal and volume views as well. 
//
// .SECTION User API
// A user would use this class as follows.
// \code
// vtkWidgetSet *set = vtkWidgetSet::New();
// vtkParallelopipedWidget *w1 = vtkParallelopipedWidget::New();
// set->AddWidget(w1);
// w1->SetInteractor(axialRenderWindow->GetInteractor());
// vtkParallelopipedWidget *w2 = vtkParallelopipedWidget::New();
// set->AddWidget(w2);
// w2->SetInteractor(coronalRenderWindow->GetInteractor());
// vtkParallelopipedWidget *w3 = vtkParallelopipedWidget::New();
// set->AddWidget(w3);
// w3->SetInteractor(sagittalRenderWindow->GetInteractor());
// set->SetEnabled(1);
// \endcode
//
// .SECTION Motivation
// The motivation for this class is really to provide a usable API to tie 
// together multiple widgets of the same kind. To enable this, subclasses
// of vtkAbstractWidget, must be written as follows:
//   They will generally have callback methods mapped to some user 
// interaction such as:
// \code
// this->CallbackMapper->SetCallbackMethod(vtkCommand::LeftButtonPressEvent,
//                         vtkEvent::NoModifier, 0, 0, NULL, 
//                         vtkPaintbrushWidget::BeginDrawStrokeEvent,
//                         this, vtkPaintbrushWidget::BeginDrawCallback);
// \endcode
//   The callback invoked when the left button is pressed looks like: 
// \code
// void vtkPaintbrushWidget::BeginDrawCallback(vtkAbstractWidget *w)
// {
//   vtkPaintbrushWidget *self = vtkPaintbrushWidget::SafeDownCast(w);
//   self->WidgetSet->DispatchAction(self, &vtkPaintbrushWidget::BeginDrawAction);
// }
// \endcode
//   The actual code for handling the drawing is written in the BeginDrawAction 
// method.
// \code
// void vtkPaintbrushWidget::BeginDrawAction( vtkPaintbrushWidget *dispatcher)
// {
// // Do stuff to draw... 
// // Here dispatcher is the widget that was interacted with, the one that
// // dispatched an action to all the other widgets in its group. You may, if
// // necessary find it helpful to get parameters from it.
// //   For instance for a ResizeAction:
// //     if (this != dispatcher)
// //       {
// //       double *newsize = dispatcher->GetRepresentation()->GetSize();
// //       this->WidgetRep->SetSize(newsize);
// //       }
// //     else
// //       {
// //       this->WidgetRep->IncrementSizeByDelta();
// //       }
// }
// \endcode
// 
// .SECTION Caveats
// Actions are always dispatched first to the activeWidget, the one calling
// the set, and then to the other widgets in the set.
// 
#ifndef __vtkWidgetSet_h
#define __vtkWidgetSet_h

#include "vtkObject.h"
#include <vector> // Required for vector

class vtkAbstractWidget;

//BTX
// Pointer to a member function that takes a vtkAbstractWidget (the active
// child) and another vtkAbstractWidget (the widget to dispatch an action)
// to. All "Action" functions in a widget must conform to this signature.
template< class TWidget > struct ActionFunction
{
  typedef void (TWidget::*TActionFunctionPointer)(TWidget *dispatcher);
};
//ETX

class VTK_WIDGETS_EXPORT vtkWidgetSet : public vtkObject
{
public:
  // Description:
  // Instantiate this class.
  static vtkWidgetSet *New();

  // Description:
  // Standard methods for a VTK class.
  vtkTypeMacro(vtkWidgetSet,vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Method for activating and deactivating all widgets in the group.
  virtual void SetEnabled(int);
  vtkBooleanMacro(Enabled, int);

  // Description:
  // Add a widget to the set.
  void AddWidget(vtkAbstractWidget *);

  // Description:
  // Remove a widget from the set
  void RemoveWidget(vtkAbstractWidget *);

  // Description:
  // Get number of widgets in the set.
  unsigned int GetNumberOfWidgets();

  // Description:
  // Get the Nth widget in the set.
  vtkAbstractWidget *GetNthWidget( unsigned int );

  //BTX
  // TODO: Move this to the protected section. The class vtkAbstractWidget 
  //       should be a friend of this class. 
  typedef std::vector< vtkAbstractWidget * >   WidgetContainerType;
  typedef WidgetContainerType::iterator           WidgetIteratorType;
  typedef WidgetContainerType::const_iterator     WidgetConstIteratorType;
  WidgetContainerType                             Widget;
 
  // Description:
  // Dispatch an "Action" to every widget in this set. This is meant to be 
  // invoked from a "Callback" in a widget.
  template < class TWidget >
  void DispatchAction(TWidget *caller, 
                      typename ActionFunction< TWidget >::TActionFunctionPointer action)
    {
    // Dispatch action to the caller first.
    for (WidgetIteratorType it  = this->Widget.begin(); 
                            it != this->Widget.end()  ; ++it)
      {
      TWidget *w = static_cast<TWidget *>(*it);
      if (caller == w)
        {
        ((*w).*(action))(caller); 
        break;
        }
      }
    
    // Dispatch action to all other widgets
    for (WidgetIteratorType it  = this->Widget.begin(); 
                            it != this->Widget.end()  ; ++it)
      {
      TWidget *w = static_cast<TWidget *>(*it);
      if (caller != w) ((*w).*(action))(caller);
      }
    }
  //ETX

protected:
  vtkWidgetSet();
  ~vtkWidgetSet();

private:
  vtkWidgetSet(const vtkWidgetSet&);  //Not implemented
  void operator=(const vtkWidgetSet&);  //Not implemented
};

#endif

