text: /*=========================================================================
  
    Program:   Visualization Toolkit
    Module:    vtkObserverMediator.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 vtkObserverMediator - manage contention for cursors and other resources
  // .SECTION Description
  // The vtkObserverMediator is a helper class that manages requests for
  // cursor changes from multiple interactor observers (e.g. widgets). It keeps
  // a list of widgets (and their priorities) and their current requests for
  // cursor shape. It then satisfies requests based on widget priority and the
  // relative importance of the request (e.g., a lower priority widget
  // requesting a particular cursor shape will overrule a higher priority
  // widget requesting a default shape).
  
  // .SECTION See Also
  // vtkAbstractWidget vtkWidgetRepresentation
  
  
  #ifndef vtkObserverMediator_h
  #define vtkObserverMediator_h
  
  #include "vtkRenderingCoreModule.h" // For export macro
  #include "vtkObject.h"
  
  class vtkRenderWindowInteractor;
  class vtkInteractorObserver;
  class vtkObserverMap;
  
  
  class VTKRENDERINGCORE_EXPORT vtkObserverMediator : public vtkObject
  {
  public:
    // Description:
    // Instantiate the class.
    static vtkObserverMediator *New();
  
    // Description:
    // Standard macros.
    vtkTypeMacro(vtkObserverMediator,vtkObject);
    void PrintSelf(ostream& os, vtkIndent indent);
  
    // Description:
    // Specify the instance of vtkRenderWindow whose cursor shape is
    // to be managed.
    void SetInteractor(vtkRenderWindowInteractor* iren);
    vtkGetObjectMacro(Interactor, vtkRenderWindowInteractor);
  
    // Description:
    // Method used to request a cursor shape. Note that the shape is specified
    // using one of the integral values determined in vtkRenderWindow.h. The
    // method returns a non-zero value if the shape was successfully changed.
    int RequestCursorShape(vtkInteractorObserver*, int cursorShape);
  
    // Description:
    // Remove all requests for cursor shape from a given interactor.
    void RemoveAllCursorShapeRequests(vtkInteractorObserver*);
  
  protected:
    vtkObserverMediator();
    ~vtkObserverMediator();
  
    // The render window whose cursor we are controlling
    vtkRenderWindowInteractor *Interactor;
  
    // A map whose key is the observer*, and whose data value is a cursor
    // request. Note that a special compare function is used to sort the
    // widgets based on the observer's priority.
    vtkObserverMap *ObserverMap; //given a widget*, return its data
  
    // The current observer and cursor shape
    vtkInteractorObserver *CurrentObserver;
    int                    CurrentCursorShape;
  
  private:
    vtkObserverMediator(const vtkObserverMediator&);  //Not implemented
    void operator=(const vtkObserverMediator&);  //Not implemented
  };
  
  #endif
  