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

  Program:   Visualization Toolkit
  Module:    vtkPointPlacer.h,v

  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.

=========================================================================*/
/**
 * @class   vtkPointPlacer
 * @brief   Abstract interface to translate 2D display positions to world coordinates
 *
 * Most widgets in VTK have a need to translate of 2D display coordinates (as
 * reported by the RenderWindowInteractor) to 3D world coordinates. This class
 * is an abstraction of this functionality. A few subclasses are listed below:
 * <p>1) vtkFocalPlanePointPlacer: This class converts 2D display positions to
 * world positions such that they lie on the focal plane.
 * <p>2) vtkPolygonalSurfacePointPlacer: Converts 2D display positions to
 * world positions such that they lie on the surface of one or more specified
 * polydatas.
 * <p>3) vtkImageActorPointPlacer: Converts 2D display positions to world
 * positions such that they lie on an ImageActor
 * <p>4) vtkBoundedPlanePointPlacer: Converts 2D display positions to world
 * positions such that they lie within a set of specified bounding planes.
 * <p>5) vtkTerrainDataPointPlacer: Converts 2D display positions to world
 * positions such that they lie on a height field.
 * <p> Point placers provide an extensible framework to specify constraints on
 * points. The methods ComputeWorldPosition, ValidateDisplayPosition and
 * ValidateWorldPosition may be overridden to dictate whether a world or
 * display position is allowed. These classes are currently used by the
 * HandleWidget and the ContourWidget to allow various constraints to be
 * enforced on the placement of their handles.
*/

#ifndef vtkPointPlacer_h
#define vtkPointPlacer_h

#include "vtkInteractionWidgetsModule.h" // For export macro
#include "vtkObject.h"

class vtkRenderer;

class VTKINTERACTIONWIDGETS_EXPORT vtkPointPlacer : public vtkObject
{
public:
  /**
   * Instantiate this class.
   */
  static vtkPointPlacer *New();

  //@{
  /**
   * Standard methods for instances of this class.
   */
  vtkTypeMacro(vtkPointPlacer,vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) VTK_OVERRIDE;
  //@}

  /**
   * Given a renderer and a display position in pixel coordinates,
   * compute the world position and orientation where this point
   * will be placed. This method is typically used by the
   * representation to place the point initially. A return value of 1
   * indicates that constraints of the placer are met.
   */
  virtual int ComputeWorldPosition( vtkRenderer *ren,
                                    double displayPos[2],
                                    double worldPos[3],
                                    double worldOrient[9] );

  /**
   * Given a renderer, a display position, and a reference world
   * position, compute the new world position and orientation
   * of this point. This method is typically used by the
   * representation to move the point. A return value of 1 indicates that
   * constraints of the placer are met.
   */
  virtual int ComputeWorldPosition( vtkRenderer *ren,
                                    double displayPos[2],
                                    double refWorldPos[3],
                                    double worldPos[3],
                                    double worldOrient[9] );

  /**
   * Given a world position check the validity of this
   * position according to the constraints of the placer.
   */
  virtual int ValidateWorldPosition( double worldPos[3] );

  /**
   * Given a display position, check the validity of this position.
   */
  virtual int ValidateDisplayPosition( vtkRenderer *, double displayPos[2] );

  /**
   * Given a world position and a world orientation,
   * validate it according to the constraints of the placer.
   */
  virtual int ValidateWorldPosition( double worldPos[3],
                                     double worldOrient[9] );

  /**
   * Given a current renderer, world position and orientation,
   * update them according to the constraints of the placer.
   * This method is typically used when UpdateContour is called
   * on the representation, which must be called after changes
   * are made to the constraints in the placer. A return
   * value of 1 indicates that the point has been updated. A
   * return value of 0 indicates that the point could not
   * be updated and was left alone. By default this is a no-op -
   * leaving the point as is.
   */
  virtual int UpdateWorldPosition( vtkRenderer *ren,
                                   double worldPos[3],
                                   double worldOrient[9] );

  /**
   * Give the placer a chance to update the node information, if any. Most
   * placers do not maintain any cached node information.
   * vtkPolygonalSurfacePointPlacer is one that does. It stores the point
   * id (id on the surface mesh) on which its drawn. The second argument
   * may be used to pass that in.
   * Update world position
   */
  virtual int UpdateNodeWorldPosition(
      double worldPos[3], vtkIdType nodePointId);

  /**
   * Called by the representation to give the placer a chance
   * to update itself.
   */
  virtual int UpdateInternalState() {return 0;}

  //@{
  /**
   * Set/get the tolerance used when performing computations
   * in display coordinates.
   */
  vtkSetClampMacro(PixelTolerance,int,1,100);
  vtkGetMacro(PixelTolerance,int);
  //@}

  //@{
  /**
   * Set/get the tolerance used when performing computations
   * in world coordinates.
   */
  vtkSetClampMacro(WorldTolerance, double, 0.0, VTK_DOUBLE_MAX);
  vtkGetMacro(WorldTolerance, double);
  //@}

protected:
  vtkPointPlacer();
  ~vtkPointPlacer() VTK_OVERRIDE;

  int          PixelTolerance;
  double       WorldTolerance;

private:
  vtkPointPlacer(const vtkPointPlacer&) VTK_DELETE_FUNCTION;
  void operator=(const vtkPointPlacer&) VTK_DELETE_FUNCTION;
};

#endif





