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

  Program:   Visualization Toolkit
  Module:    vtkImageDifference.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   vtkImageDifference
 * @brief   Compares images for regression tests.
 *
 * vtkImageDifference takes two rgb unsigned char images and compares them.
 * It allows the images to be slightly different.  If AllowShift is on,
 * then each pixel can be shifted by two pixels. Threshold is the allowable
 * error for each pixel.
 *
 * This is a symmetric filter and the difference computed is symmetric.
 * The resulting value is the maximum error of the two directions
 * A->B and B->A
 */

#ifndef vtkImageDifference_h
#define vtkImageDifference_h

#include "vtkImagingCoreModule.h" // For export macro
#include "vtkSmartPointer.h"      // For smart pointer
#include "vtkThreadedImageAlgorithm.h"

class vtkImageDifferenceThreadData;
class vtkImageDifferenceSMPThreadLocal;

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

  ///@{
  /**
   * Specify the Image to compare the input to.
   */
  void SetImageConnection(vtkAlgorithmOutput* output) { this->SetInputConnection(1, output); }
  void SetImageData(vtkDataObject* image) { this->SetInputData(1, image); }
  vtkImageData* GetImage();
  ///@}

  /**
   * Return the total error in comparing the two images.
   */
  double GetError() { return this->Error; }
  void GetError(double* e) { *e = this->GetError(); }

  /**
   * Return the total thresholded error in comparing the two images.
   * The thresholded error is the error for a given pixel minus the
   * threshold and clamped at a minimum of zero.
   */
  double GetThresholdedError() { return this->ThresholdedError; }
  void GetThresholdedError(double* e) { *e = this->GetThresholdedError(); }

  ///@{
  /**
   * Specify a threshold tolerance for pixel differences.
   */
  vtkSetMacro(Threshold, int);
  vtkGetMacro(Threshold, int);
  ///@}

  ///@{
  /**
   * Specify whether the comparison will allow a shift of two
   * pixels between the images.  If set, then the minimum difference
   * between input images will be used to determine the difference.
   * Otherwise, the difference is computed directly between pixels
   * of identical row/column values.
   */
  vtkSetMacro(AllowShift, bool);
  vtkGetMacro(AllowShift, bool);
  vtkBooleanMacro(AllowShift, bool);
  ///@}

  ///@{
  /**
   * Specify whether the comparison will include comparison of
   * averaged 3x3 data between the images. For graphics renderings
   * you normally would leave this on. For imaging operations it
   * should be off.
   */
  vtkSetMacro(Averaging, bool);
  vtkGetMacro(Averaging, bool);
  vtkBooleanMacro(Averaging, bool);
  ///@}

  ///@{
  /**
   * When doing Averaging, adjust the threshold for the average
   * by this factor. Defaults to 0.5 requiring a better match
   */
  vtkSetMacro(AverageThresholdFactor, double);
  vtkGetMacro(AverageThresholdFactor, double);
  ///@}

protected:
  vtkImageDifference();
  ~vtkImageDifference() override = default;

  // Parameters
  // ideally threshold * averageThresholdFactor should be < 255/9
  // to capture one pixel errors or 510/9 to capture 2 pixel errors
  bool AllowShift = true;
  bool Averaging = true;
  int Threshold = 105;
  double AverageThresholdFactor = 0.65;

  // Outputs
  const char* ErrorMessage = nullptr;
  double Error = 0.;
  double ThresholdedError = 0.;

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

  void ThreadedRequestData(vtkInformation* request, vtkInformationVector** inputVector,
    vtkInformationVector* outputVector, vtkImageData*** inData, vtkImageData** outData,
    int outExt[6], int threadId) override;

  void GrowExtent(int* uExt, int* wholeExtent);
  int ComputeSumedValue(unsigned char* values, vtkIdType* indices, int comp);

  // Used for vtkMultiThreader operation.
  vtkImageDifferenceThreadData* ThreadData;

  // Used for vtkSMPTools operation.
  vtkImageDifferenceSMPThreadLocal* SMPThreadData = nullptr;

private:
  vtkImageDifference(const vtkImageDifference&) = delete;
  void operator=(const vtkImageDifference&) = delete;

  friend class vtkImageDifferenceSMPFunctor;
};

#endif