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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkAddImageFilter.h,v $
  Language:  C++
  Date:      $Date: 2007/08/30 15:01:08 $
  Version:   $Revision: 1.12 $

  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 __itkAddImageFilter_h
#define __itkAddImageFilter_h

#include "itkBinaryFunctorImageFilter.h"
#include "itkNumericTraits.h"


namespace itk
{
  
/** \class AddImageFilter
 * \brief Implements an operator for pixel-wise addition of two images.
 *
 * This class is parametrized over the types of the two 
 * input images and the type of the output image. 
 * Numeric conversions (castings) are done by the C++ defaults.
 *
 * The pixel type of the input 1 image must have a valid defintion of
 * the operator+ with a pixel type of the image 2. This condition is 
 * required because internally this filter will perform the operation
 *
 *        pixel_from_image_1 + pixel_from_image_2
 *
 * Additionally the type resulting from the sum, will be cast to
 * the pixel type of the output image.
 * 
 * The total operation over one pixel will be
 *
 *  output_pixel = static_cast<OutputPixelType>( input1_pixel + input2_pixel )
 *
 * For example, this filter could be used directly for adding images whose
 * pixels are vectors of the same dimension, and to store the resulting vector
 * in an output image of vector pixels.
 *
 * \warning No numeric overflow checking is performed in this filter.
 *
 * \ingroup IntensityImageFilters  Multithreaded
 */
namespace Functor {  
  
template< class TInput1, class TInput2=TInput1, class TOutput=TInput1>
class Add2
{
public:
  typedef typename NumericTraits< TInput1 >::AccumulateType AccumulatorType;
  Add2() {};
  ~Add2() {};
  bool operator!=( const Add2 & ) const
  {
    return false;
  }
  bool operator==( const Add2 & other ) const
  {
    return !(*this != other);
  }
  inline TOutput operator()( const TInput1 & A, const TInput2 & B)
  {
    const AccumulatorType sum = A;
    return static_cast<TOutput>( sum + B );
  }
}; 

}
template <class TInputImage1, class TInputImage2=TInputImage1, class TOutputImage=TInputImage1>
class ITK_EXPORT AddImageFilter :
    public
BinaryFunctorImageFilter<TInputImage1,TInputImage2,TOutputImage, 
                         Functor::Add2< 
  typename TInputImage1::PixelType, 
  typename TInputImage2::PixelType,
  typename TOutputImage::PixelType>   >


{
public:
  /** Standard class typedefs. */
  typedef AddImageFilter  Self;
  typedef BinaryFunctorImageFilter<TInputImage1,TInputImage2,TOutputImage, 
                                   Functor::Add2< 
    typename TInputImage1::PixelType, 
    typename TInputImage2::PixelType,
    typename TOutputImage::PixelType>   
  >  Superclass;
  typedef SmartPointer<Self>   Pointer;
  typedef SmartPointer<const Self>  ConstPointer;

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

#ifdef ITK_USE_CONCEPT_CHECKING
  /** Begin concept checking */
  itkConceptMacro(Input1Input2OutputAdditiveOperatorsCheck,
    (Concept::AdditiveOperators<typename TInputImage1::PixelType,
                                typename TInputImage2::PixelType,
                                typename TOutputImage::PixelType>));
  /** End concept checking */
#endif

protected:
  AddImageFilter() {}
  virtual ~AddImageFilter() {}

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

};

} // end namespace itk


#endif
