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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkThresholdPoints.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.

=========================================================================*/
// .NAME vtkThresholdPoints - extracts points whose scalar value satisfies threshold criterion
// .SECTION Description
// vtkThresholdPoints is a filter that extracts points from a dataset that 
// satisfy a threshold criterion. The criterion can take three forms:
// 1) greater than a particular value; 2) less than a particular value; or
// 3) between a particular value. The output of the filter is polygonal data.
// .SECTION See Also
// vtkThreshold

#ifndef __vtkThresholdPoints_h
#define __vtkThresholdPoints_h

#include "vtkPolyDataAlgorithm.h"

class VTK_GRAPHICS_EXPORT vtkThresholdPoints : public vtkPolyDataAlgorithm
{
public:
  static vtkThresholdPoints *New();
  vtkTypeRevisionMacro(vtkThresholdPoints,vtkPolyDataAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent);
  
  // Description:
  // Criterion is cells whose scalars are less or equal to lower threshold.
  void ThresholdByLower(double lower);

  // Description:
  // Criterion is cells whose scalars are greater or equal to upper threshold.
  void ThresholdByUpper(double upper);

  // Description:
  // Criterion is cells whose scalars are between lower and upper thresholds
  // (inclusive of the end values).
  void ThresholdBetween(double lower, double upper);

  // Description:
  // Get the upper and lower thresholds.
  vtkGetMacro(UpperThreshold,double);
  vtkGetMacro(LowerThreshold,double);

protected:
  vtkThresholdPoints();
  ~vtkThresholdPoints() {};

  // Usual data generation method
  virtual int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *);

  virtual int FillInputPortInformation(int port, vtkInformation *info);

  double LowerThreshold;
  double UpperThreshold;

  //BTX
  int (vtkThresholdPoints::*ThresholdFunction)(double s);
  //ETX

  int Lower(double s) {return ( s <= this->LowerThreshold ? 1 : 0 );};
  int Upper(double s) {return ( s >= this->UpperThreshold ? 1 : 0 );};
  int Between(double s) {return ( s >= this->LowerThreshold ? 
                               ( s <= this->UpperThreshold ? 1 : 0 ) : 0 );};
private:
  vtkThresholdPoints(const vtkThresholdPoints&);  // Not implemented.
  void operator=(const vtkThresholdPoints&);  // Not implemented.
};

#endif
