itkDivideByConstantImageFilter.h

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkDivideByConstantImageFilter.h,v $
  Language:  C++
  Date:      $Date: 2009-02-24 19:03:15 $
  Version:   $Revision: 1.4 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/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 notices for more information.

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

#ifndef __itkDivideByConstantImageFilter_h
#define __itkDivideByConstantImageFilter_h

#include "itkUnaryFunctorImageFilter.h"
#include "itkNumericTraits.h"

namespace itk
{
  
namespace Functor {  
  
template< class TInput, class TConstant, class TOutput>
class DivideByConstant
{
public:
  DivideByConstant() : m_Constant(NumericTraits<TConstant>::One) {};
  ~DivideByConstant() {};
  bool operator!=( const DivideByConstant & other ) const
    {
    return !(*this == other);
    }
  bool operator==( const DivideByConstant & other ) const
    {
    return other.m_Constant == m_Constant;
    }
  inline TOutput operator()( const TInput & A ) const
    {
    // Because the user has to specify the constant we don't
    // check if the constant is not too small (i.e. almost equal to zero);
    return static_cast<TOutput>( A / m_Constant );
    }
  void SetConstant(TConstant ct)
    {
    if( ct == NumericTraits<TConstant>::Zero )
      {
      itkGenericExceptionMacro(
        <<"The constant value used as denominator should not be set to zero");
      }

    this->m_Constant = ct;
    }
  const TConstant & GetConstant() const { return m_Constant; }
   
  TConstant m_Constant;
};
}

template <class TInputImage, class TConstant, class TOutputImage>
class ITK_EXPORT DivideByConstantImageFilter :
      public
UnaryFunctorImageFilter<TInputImage,TOutputImage, 
                        Functor::DivideByConstant< 
   typename TInputImage::PixelType, TConstant,
   typename TOutputImage::PixelType> >
{
public:
  typedef DivideByConstantImageFilter                        Self;
  typedef UnaryFunctorImageFilter<
    TInputImage,TOutputImage, Functor::DivideByConstant< 
      typename TInputImage::PixelType, TConstant,
      typename TOutputImage::PixelType>   >                  Superclass;
  typedef SmartPointer<Self>                                 Pointer;
  typedef SmartPointer<const Self>                           ConstPointer;

  itkNewMacro(Self);

  itkTypeMacro(DivideByConstantImageFilter, UnaryFunctorImageFilter);

  void SetConstant(TConstant ct)
    {
    if( ct != this->GetFunctor().GetConstant() )
      {
      this->GetFunctor().SetConstant(ct);
      this->Modified();
      }
    }
  const TConstant & GetConstant() const
    {
    return this->GetFunctor().GetConstant();
    }


#ifdef ITK_USE_CONCEPT_CHECKING

  itkConceptMacro(InputConvertibleToOutputCheck,
                   (Concept::Convertible<typename TInputImage::PixelType,
                    typename TOutputImage::PixelType>));
  // The following concept check doesn't seem to work with vector immages
  //itkConceptMacro(Input1Input2OutputDivisionOperatorsCheck,
  //                (Concept::DivisionOperators<typename TInputImage::PixelType,
  //                 TConstant,
  //                 typename TOutputImage::PixelType>));

#endif

protected:
  DivideByConstantImageFilter() {};
  virtual ~DivideByConstantImageFilter() {};
   
  void PrintSelf(std::ostream &os, Indent indent) const
    {
    Superclass::PrintSelf(os, indent);
    os << indent << "Constant: " 
       << static_cast<typename NumericTraits<TConstant>::PrintType>(this->GetConstant())
       << std::endl;
    }

private:
  DivideByConstantImageFilter(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented

};


} // end namespace itk

#endif