// -------------------------------------------------------------------------
// @author Leonardo Florez-Valencia (florez-l@javeriana.edu.co)
// -------------------------------------------------------------------------

#ifndef __CPEXTENSIONS__ALGORITHMS__LIGHTCOMPENSATIONFILTER__HXX__
#define __CPEXTENSIONS__ALGORITHMS__LIGHTCOMPENSATIONFILTER__HXX__

#include <itkImageRegionIterator.h>
#include <itkImageRegionConstIterator.h>
#include <itkNumericTraits.h>

// -------------------------------------------------------------------------
template< class I >
cpExtensions::Algorithms::LightCompensationFilter< I >::
LightCompensationFilter( )
  : Superclass( )
{
  this->SetNumberOfRequiredInputs( 1 );
  this->InPlaceOff( );
}

// -------------------------------------------------------------------------
template< class I >
cpExtensions::Algorithms::LightCompensationFilter< I >::
~LightCompensationFilter( )
{
}

// -------------------------------------------------------------------------
template< class I >
void cpExtensions::Algorithms::LightCompensationFilter< I >::
BeforeThreadedGenerateData( )
{
  this->Superclass::BeforeThreadedGenerateData( );

  I* input = const_cast< I* >( this->GetInput( ) );

  typename TMeanCalculator::Pointer mc = TMeanCalculator::New( );
  mc->Execute( input, input->GetRequestedRegion( ) );
  this->m_Mean = mc->GetMean( );

  double gm = this->m_Mean[ 0 ] + this->m_Mean[ 1 ] + this->m_Mean[ 2 ];
  gm /= double( 3 );
  this->m_Coefficient = this->m_Mean;
  this->m_Coefficient.Fill( gm );
  this->m_Coefficient[ 0 ] /= this->m_Mean[ 0 ];
  this->m_Coefficient[ 1 ] /= this->m_Mean[ 1 ];
  this->m_Coefficient[ 2 ] /= this->m_Mean[ 2 ];
}

// -------------------------------------------------------------------------
template< class I >
void cpExtensions::Algorithms::LightCompensationFilter< I >::
ThreadedGenerateData( const TRegion& region, itk::ThreadIdType id )
{
  typedef itk::NumericTraits< typename I::PixelType > _TPixelTraits;
  typedef typename _TPixelTraits::ValueType           _TPixelChannel;
  typedef itk::NumericTraits< _TPixelChannel >        _TChannelTraits;
  static const double max_value = double( _TChannelTraits::max( ) );

  itk::ImageRegionConstIterator< I > iIt( this->GetInput( ), region );
  itk::ImageRegionIterator< I > oIt( this->GetOutput( ), region );

  iIt.GoToBegin( );
  oIt.GoToBegin( );
  for( ; !iIt.IsAtEnd( ); ++iIt, ++oIt )
  {
    double r = double( iIt.Get( )[ 0 ] ) * this->m_Coefficient[ 0 ];
    double g = double( iIt.Get( )[ 1 ] ) * this->m_Coefficient[ 1 ];
    double b = double( iIt.Get( )[ 2 ] ) * this->m_Coefficient[ 2 ];

    if( r > max_value ) r = max_value;
    if( g > max_value ) g = max_value;
    if( b > max_value ) b = max_value;

    typename I::PixelType pix;
    pix.SetRed( _TPixelChannel( r ) );
    pix.SetGreen( _TPixelChannel( g ) );
    pix.SetBlue( _TPixelChannel( b ) );

    oIt.Set( pix );

  } // rof
}

// -------------------------------------------------------------------------
template< class I >
void cpExtensions::Algorithms::LightCompensationFilter< I >::
AfterThreadedGenerateData( )
{
  this->Superclass::AfterThreadedGenerateData( );
}

#endif // __CPEXTENSIONS__ALGORITHMS__LIGHTCOMPENSATIONFILTER__HXX__

// eof - $RCSfile$