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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    itkMultiplyByConstantImageFilter.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$

  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 __itkMultiplyByConstantImageFilter_h
#define __itkMultiplyByConstantImageFilter_h

#include <itkUnaryFunctorImageFilter.h>
#include <itkNumericTraits.h>

namespace itk
{
  
/** \class MultiplyByConstantImageFilter
 *
 * \brief Multiply input pixels by a constant.
 *
 * This filter is templated over the input image type
 * and the output image type.
 *
 * \author Tom Vercauteren, INRIA & Mauna Kea Technologies
 *
 * 
 * This implementation was taken from the Insight Journal paper:
 * http://hdl.handle.net/1926/510
 *
 * \ingroup IntensityImageFilters  Multithreaded
 * \sa UnaryFunctorImageFilter
 */
namespace Functor {  
  
template< class TInput, class TConstant, class TOutput>
class MultiplyByConstant
{
public:
  MultiplyByConstant() : m_Constant(NumericTraits<TConstant>::One) {};
  ~MultiplyByConstant() {};
  bool operator!=( const MultiplyByConstant & other ) const
    {
    return !(*this == other);
    }
  bool operator==( const MultiplyByConstant & 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 cte is not 0;
    return static_cast<TOutput>( A * m_Constant );
    }
  void SetConstant(TConstant ct) {this->m_Constant = ct; }
  const TConstant & GetConstant() const { return m_Constant; }
  
  TConstant m_Constant;
};
}

template <class TInputImage, class TConstant, class TOutputImage>
class ITK_EXPORT MultiplyByConstantImageFilter :
      public
UnaryFunctorImageFilter<TInputImage,TOutputImage, 
                        Functor::MultiplyByConstant< 
   typename TInputImage::PixelType, TConstant,
   typename TOutputImage::PixelType> >
{
public:
  /** Standard class typedefs. */
  typedef MultiplyByConstantImageFilter                 Self;
  typedef UnaryFunctorImageFilter<
    TInputImage,TOutputImage, 
    Functor::MultiplyByConstant< 
      typename TInputImage::PixelType, TConstant,
      typename TOutputImage::PixelType>   >             Superclass;
  typedef SmartPointer<Self>                            Pointer;
  typedef SmartPointer<const Self>                      ConstPointer;

  /** Method for creation through the object factory. */
  itkNewMacro(Self);

  /** Run-time type information (and related methods). */
  itkTypeMacro(MultiplyByConstantImageFilter, UnaryFunctorImageFilter);

  
  /** Set the constant that will be used to multiply all the image pixels */
  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
  /** Begin concept checking */
  itkConceptMacro(InputConvertibleToOutputCheck,
                  (Concept::Convertible<typename TInputImage::PixelType,
                   typename TOutputImage::PixelType>));
  itkConceptMacro(Input1Input2OutputMultiplyOperatorCheck,
                  (Concept::MultiplyOperator<typename TInputImage::PixelType,
                   TConstant,
                   typename TOutputImage::PixelType>));
  /** End concept checking */
#endif

protected:
  MultiplyByConstantImageFilter() {};
  virtual ~MultiplyByConstantImageFilter() {};
   
  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:
  MultiplyByConstantImageFilter(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented

};


} // end namespace itk

#endif
