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

  Program:   Visualization Toolkit
  Module:    vtkWidgetRepresentation.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 vtkWidgetRepresentation - abstract class defines interface between the widget and widget representation classes
// .SECTION Description
// This class is used to define the API for, and partially implement, a
// representation for different types of widgets. Note that the widget
// representation (i.e., subclasses of vtkWidgetRepresentation) are a type of
// vtkProp; meaning that they can be associated with a vtkRenderer end
// embedded in a scene like any other vtkActor. However,
// vtkWidgetRepresentation also defines an API that enables it to be paired
// with a subclass vtkAbstractWidget, meaning that it can be driven by a
// widget, serving to represent the widget as the widget responds to
// registered events. 
//
// The API defined here should be regarded as a guideline for implementing
// widgets and widget representations. Widget behavior is complex, as is the
// way the representation responds to the registered widget events, so the API
// may vary from widget to widget to reflect this complexity.

// .SECTION Caveats
// The separation of the widget event handling and representation enables
// users and developers to create new appearances for the widget. It also
// facilitates parallel processing, where the client application handles
// events, and remote representations of the widget are slaves to the 
// client (and do not handle events).


#ifndef __vtkWidgetRepresentation_h
#define __vtkWidgetRepresentation_h

#include "vtkProp.h"

class vtkRenderer;


class VTK_WIDGETS_EXPORT vtkWidgetRepresentation : public vtkProp
{
public:
  // Description:
  // Standard methods for instances of this class.
  vtkTypeMacro(vtkWidgetRepresentation,vtkProp);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Subclasses of vtkWidgetRepresentation must implement these methods. This is
  // considered the minimum API for a widget representation.
  // <pre>
  // SetRenderer() - the renderer in which the widget is to appear must be set.
  // BuildRepresentation() - update the geometry of the widget based on its
  //                         current state.
  // </pre>
  // WARNING: The renderer is NOT reference counted by the representation,
  // in order to avoid reference loops.  Be sure that the representation
  // lifetime does not extend beyond the renderer lifetime.
  virtual void SetRenderer(vtkRenderer *ren);
  vtkGetObjectMacro(Renderer,vtkRenderer);
  virtual void BuildRepresentation() = 0;

  // Description:
  // The following is a suggested API for widget representations. These methods
  // define the communication between the widget and its representation. These
  // methods are only suggestions because widgets take on so many different
  // forms that a universal API is not deemed practical. However, these methods
  // should be implemented when possible to insure that the VTK widget hierarchy
  // remains self-consistent.
  // <pre>
  // PlaceWidget() - given a bounding box (xmin,xmax,ymin,ymax,zmin,zmax), place 
  //                 the widget inside of it. The current orientation of the widget 
  //                 is preserved, only scaling and translation is performed.
  // StartWidgetInteraction() - generally corresponds to a initial event (e.g.,
  //                            mouse down) that starts the interaction process
  //                            with the widget.
  // WidgetInteraction() - invoked when an event causes the widget to change 
  //                       appearance.
  // EndWidgetInteraction() - generally corresponds to a final event (e.g., mouse up)
  //                          and completes the interaction sequence.
  // ComputeInteractionState() - given (X,Y) display coordinates in a renderer, with a
  //                             possible flag that modifies the computation,
  //                             what is the state of the widget?
  // GetInteractionState() - return the current state of the widget. Note that the
  //                         value of "0" typically refers to "outside". The 
  //                         interaction state is strictly a function of the
  //                         representation, and the widget/represent must agree
  //                         on what they mean.
  // Highlight() - turn on or off any highlights associated with the widget.
  //               Highlights are generally turned on when the widget is selected.
  // </pre>
  // Note that subclasses may ignore some of these methods and implement their own
  // depending on the specifics of the widget.
  virtual void PlaceWidget(double* vtkNotUsed(bounds[6])) {}
  virtual void StartWidgetInteraction(double eventPos[2]) { (void)eventPos; }
  virtual void WidgetInteraction(double newEventPos[2]) { (void)newEventPos; }
  virtual void EndWidgetInteraction(double newEventPos[2]) { (void)newEventPos; }
  virtual int ComputeInteractionState(int X, int Y, int modify=0);
  virtual int GetInteractionState()
    {return this->InteractionState;}
  virtual void Highlight(int vtkNotUsed(highlightOn)) {}

  // Description:
  // Set/Get a factor representing the scaling of the widget upon placement
  // (via the PlaceWidget() method). Normally the widget is placed so that
  // it just fits within the bounding box defined in PlaceWidget(bounds).
  // The PlaceFactor will make the widget larger (PlaceFactor > 1) or smaller
  // (PlaceFactor < 1). By default, PlaceFactor is set to 0.5.
  vtkSetClampMacro(PlaceFactor,double,0.01,VTK_DOUBLE_MAX);
  vtkGetMacro(PlaceFactor,double);

  // Description:
  // Set/Get the factor that controls the size of the handles that appear as
  // part of the widget (if any). These handles (like spheres, etc.)  are
  // used to manipulate the widget. The HandleSize data member allows you
  // to change the relative size of the handles. Note that while the handle
  // size is typically expressed in pixels, some subclasses may use a relative size
  // with respect to the viewport. (As a corollary, the value of this ivar is often
  // set by subclasses of this class during instance instantiation.)
  vtkSetClampMacro(HandleSize,double,0.001,1000);
  vtkGetMacro(HandleSize,double);

  // Description:
  // Some subclasses use this data member to keep track of whether to render
  // or not (i.e., to minimize the total number of renders).
  vtkGetMacro( NeedToRender, int );
  vtkSetClampMacro( NeedToRender, int, 0, 1 );
  vtkBooleanMacro( NeedToRender, int );
  
  // Description:
  // Methods to make this class behave as a vtkProp. They are repeated here (from the
  // vtkProp superclass) as a reminder to the widget implementor. Failure to implement
  // these methods properly may result in the representation not appearing in the scene
  // (i.e., not implementing the Render() methods properly) or leaking graphics resources
  // (i.e., not implementing ReleaseGraphicsResources() properly).
  virtual double *GetBounds() {return NULL;}
  virtual void ShallowCopy(vtkProp *prop);
  virtual void GetActors(vtkPropCollection *) {}
  virtual void GetActors2D(vtkPropCollection *) {}
  virtual void GetVolumes(vtkPropCollection *) {}
  virtual void ReleaseGraphicsResources(vtkWindow *) {}
  virtual int RenderOverlay(vtkViewport *vtkNotUsed(viewport)) {return 0;}
  virtual int RenderOpaqueGeometry(vtkViewport *vtkNotUsed(viewport)) {return 0;}
  virtual int RenderTranslucentPolygonalGeometry(vtkViewport *vtkNotUsed(viewport)) {return 0;}
  virtual int RenderVolumetricGeometry(vtkViewport *vtkNotUsed(viewport)) {return 0;}
  virtual int HasTranslucentPolygonalGeometry() { return 0; }
  
protected:
  vtkWidgetRepresentation();
  ~vtkWidgetRepresentation();

  // The renderer in which this widget is placed
  vtkRenderer *Renderer;

  // The state of this representation based on a recent event
  int InteractionState;

  // These are used to track the beginning of interaction with the representation
  // It's dimensioned [3] because some events re processed in 3D.
  double StartEventPosition[3];

  // Instance variable and members supporting suclasses
  double PlaceFactor; // Used to control how widget is placed around bounding box
  int    Placed; // Indicate whether widget has been placed
  void   AdjustBounds(double bounds[6], double newBounds[6], double center[3]);
  double InitialBounds[6]; //initial bounds on place widget (valid after PlaceWidget)
  double InitialLength; //initial length on place widget

  // Sizing handles is tricky because the procedure requires information
  // relative to the last pick, as well as a live renderer to perform
  // coordinate conversions. In some cases, a pick is never made so handle
  // sizing has to follow a different path. The following ivars help with
  // this process.
  int    ValidPick; //indicate when valid picks are made

  // Members use to control handle size. The two methods return a "radius"
  // in world coordinates. Note that the HandleSize data member is used
  // internal to the SizeHandles__() methods.
  double HandleSize; //controlling relative size of widget handles
  double SizeHandlesRelativeToViewport(double factor, double pos[3]);
  double SizeHandlesInPixels(double factor,double pos[3]);
  
  // Try and reduce multiple renders
  int NeedToRender;
  
  // This is the time that the representation was built. This data member
  // can be used to reduce the time spent building the widget.
  vtkTimeStamp  BuildTime;

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

#endif
