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

  Program:   Visualization Toolkit
  Module:    vtkImageGradient.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.

=========================================================================*/
/**
 * @class   vtkImageGradient
 * @brief   Computes the gradient vector.
 *
 * vtkImageGradient computes the gradient vector of an image.  The
 * vector results are stored as scalar components. The Dimensionality
 * determines whether to perform a 2d or 3d gradient. The default is
 * two dimensional XY gradient.  OutputScalarType is always
 * double. Gradient is computed using central differences.
*/

#ifndef vtkImageGradient_h
#define vtkImageGradient_h

#include "vtkImagingGeneralModule.h" // For export macro
#include "vtkThreadedImageAlgorithm.h"

class VTKIMAGINGGENERAL_EXPORT vtkImageGradient : public vtkThreadedImageAlgorithm
{
public:
  static vtkImageGradient *New();
  vtkTypeMacro(vtkImageGradient,vtkThreadedImageAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  //@{
  /**
   * Determines how the input is interpreted (set of 2d slices ...)
   */
  vtkSetClampMacro(Dimensionality,int,2,3);
  vtkGetMacro(Dimensionality,int);
  //@}

  //@{
  /**
   * Get/Set whether to handle boundaries.  If enabled, boundary
   * pixels are treated as duplicated so that central differencing
   * works for the boundary pixels.  If disabled, the output whole
   * extent of the image is reduced by one pixel.
   */
  vtkSetMacro(HandleBoundaries, int);
  vtkGetMacro(HandleBoundaries, int);
  vtkBooleanMacro(HandleBoundaries, int);
  //@}

protected:
  vtkImageGradient();
  ~vtkImageGradient() override {}

  int HandleBoundaries;
  int Dimensionality;

  int RequestInformation (vtkInformation*,
                                  vtkInformationVector**,
                                  vtkInformationVector*) override;
  int RequestUpdateExtent(vtkInformation*,
                                  vtkInformationVector**,
                                  vtkInformationVector*) override;
  int RequestData(vtkInformation*,
                          vtkInformationVector**,
                          vtkInformationVector*) override;

  void ThreadedRequestData(vtkInformation*,
                           vtkInformationVector**,
                           vtkInformationVector*,
                           vtkImageData*** inData,
                           vtkImageData** outData,
                           int outExt[6],
                           int threadId) override;
private:
  vtkImageGradient(const vtkImageGradient&) = delete;
  void operator=(const vtkImageGradient&) = delete;
};

#endif



