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

#ifndef __cpExtensions__Algorithms__RGBToSingleChannelFunctor__h__
#define __cpExtensions__Algorithms__RGBToSingleChannelFunctor__h__

#include <itkFunctionBase.h>
#include <itkRGBPixel.h>

namespace cpExtensions
{
  namespace Algorithms
  {
    /**
     */
    template< class _TScalar >
    class RGBToSingleChannelFunctor
      : public itk::FunctionBase< itk::RGBPixel< _TScalar >, _TScalar >
    {
    public:
      typedef _TScalar                             TScalar;
      typedef itk::RGBPixel< _TScalar >            TPixel;
      typedef RGBToSingleChannelFunctor            Self;
      typedef itk::FunctionBase< TPixel, TScalar > Superclass;
      typedef itk::SmartPointer< Self >            Pointer;
      typedef itk::SmartPointer< const Self >      ConstPointer;

      enum ChannelType
      {
        Red = 0,
        Green,
        Blue,
        Hue,
        Saturation,
        Value
      };

    public:
      itkNewMacro( Self );
      itkTypeMacro( RGBToSingleChannelFunctor, itkFunctionBase );

      itkGetConstMacro( Channel, ChannelType );
      itkSetMacro( Channel, ChannelType );

    public:
      bool IsChannelRed( ) const;
      bool IsChannelGreen( ) const;
      bool IsChannelBlue( ) const;
      bool IsChannelHue( ) const;
      bool IsChannelSaturation( ) const;
      bool IsChannelValue( ) const;

      void SetChannelToRed( );
      void SetChannelToGreen( );
      void SetChannelToBlue( );
      void SetChannelToHue( );
      void SetChannelToSaturation( );
      void SetChannelToValue( );

      virtual TScalar Evaluate( const TPixel& pixel ) const override;

    protected:
      RGBToSingleChannelFunctor( );
      virtual ~RGBToSingleChannelFunctor( );

    private:
      // Purposely not implemented.
      RGBToSingleChannelFunctor( const Self& );
      void operator=( const Self& );

    protected:
      ChannelType m_Channel;
    };

  } // ecapseman

} // ecapseman

#ifndef ITK_MANUAL_INSTANTIATION
#  include <cpExtensions/Algorithms/RGBToSingleChannelFunctor.hxx>
#endif // ITK_MANUAL_INSTANTIATION

#endif // __cpExtensions__Algorithms__RGBToSingleChannelFunctor__h__

// eof - $RCSfile$