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

  Program:   Visualization Toolkit
  Module:    vtkImageDifference.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$


Copyright (c) 1993-2000 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

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modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=========================================================================*/
// .NAME vtkImageDifference - Compares images for regression tests.
// .SECTION Description
// 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 one pixel. Threshold is the allowable
// error for each pixel.

#ifndef __vtkImageDifference_h
#define __vtkImageDifference_h

#include "vtkImageTwoInputFilter.h"

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

  // Description:
  // Specify the Image to compare the input to.
  void SetImage(vtkImageData *image) {this->SetInput2(image);}
  vtkImageData *GetImage() {return this->GetInput2();}

  // Description:
  // Specify the Input for comparison.
  void SetInput(vtkImageData *input) {this->SetInput1(input);}
  void SetInput(int num, vtkImageData *input)
    { this->vtkImageMultipleInputFilter::SetInput(num, input); };
  
  // Description:
  // Return the total error in comparing the two images.
  float GetError(void);
  void GetError(float *e) { *e = this->GetError(); };
  
  // Description:
  // 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. 
  float GetThresholdedError(void);
  void GetThresholdedError(float *e) { *e = this->GetThresholdedError(); };


  // Description:
  // Specify a threshold tolorance for pixel differences.
  vtkSetMacro(Threshold,int);
  vtkGetMacro(Threshold,int);

  // Description:
  // Specify whether the comparison will allow a shift of one
  // pixel 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,int);
  vtkGetMacro(AllowShift,int);
  vtkBooleanMacro(AllowShift,int);

  // Description:
  // 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,int);
  vtkGetMacro(Averaging,int);
  vtkBooleanMacro(Averaging,int);

protected:
  vtkImageDifference();
  ~vtkImageDifference() {};
  vtkImageDifference(const vtkImageDifference&) {};
  void operator=(const vtkImageDifference&) {};

  float ErrorPerThread[VTK_MAX_THREADS];
  float ThresholdedErrorPerThread[VTK_MAX_THREADS];
  int AllowShift;
  int Threshold;
  int Averaging;
  
  void ExecuteInformation(vtkImageData **inputs, vtkImageData *output); 
  void ComputeInputUpdateExtent(int inExt[6], int outExt[6],
				int whichInput);
  void ExecuteInformation(){this->vtkImageTwoInputFilter::ExecuteInformation();};
  void ThreadedExecute(vtkImageData **inDatas, vtkImageData *outData,
		       int extent[6], int id);  
  
};

#endif


