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

  Program:   Visualization Toolkit
  Module:    vtkDijkstraImageContourLineInterpolator.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 vtkDijkstraImageContourLineInterpolator - Contour interpolator for placing points on an image.
//
// .SECTION Description 
// vtkDijkstraImageContourLineInterpolator interpolates and places
// contour points on images. The class interpolates nodes by
// computing a graph lying on the image data. By graph, we mean 
// that the line interpolating the two end points traverses along 
// pixels so as to form a shortest path. A Dijkstra algorithm is 
// used to compute the path.
// 
// The class is meant to be used in conjunction with 
// vtkImageActorPointPlacer. One reason for this coupling is a 
// performance issue: both classes need to perform a cell pick, and 
// coupling avoids multiple cell picks (cell picks are slow).  Another
// issue is that the interpolator may need to set the image input to 
// its vtkDijkstraImageGeodesicPath ivar.
//
// .SECTION See Also
// vtkContourWidget vtkContourLineInterpolator vtkDijkstraImageGeodesicPath


#ifndef __vtkDijkstraImageContourLineInterpolator_h
#define __vtkDijkstraImageContourLineInterpolator_h

#include "vtkContourLineInterpolator.h"

class vtkDijkstraImageGeodesicPath;
class vtkImageData;

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

  static vtkDijkstraImageContourLineInterpolator *New();

  // Description:
  // Subclasses that wish to interpolate a line segment must implement this.
  // For instance vtkBezierContourLineInterpolator adds nodes between idx1
  // and idx2, that allow the contour to adhere to a bezier curve.
  virtual int InterpolateLine( vtkRenderer *ren,
                               vtkContourRepresentation *rep,
                               int idx1, int idx2 );

  // Description:
  // Set the image data for the vtkDijkstraImageGeodesicPath.
  // If not set, the interpolator uses the image data input to the image actor.
  // The image actor is obtained from the expected vtkImageActorPointPlacer.
  virtual void SetCostImage( vtkImageData* );
  vtkGetObjectMacro( CostImage, vtkImageData );

  // Description:
  // access to the internal dijkstra path
  vtkGetObjectMacro( DijkstraImageGeodesicPath, vtkDijkstraImageGeodesicPath );

protected:
  vtkDijkstraImageContourLineInterpolator();
  ~vtkDijkstraImageContourLineInterpolator();

  vtkImageData *CostImage;
  vtkDijkstraImageGeodesicPath *DijkstraImageGeodesicPath;

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

#endif
