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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkScalarToRGBPixelFunctor.h,v $
  Language:  C++
  Date:      $Date: 2006/02/06 22:01:58 $
  Version:   $Revision: 1.5 $

  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 __itkScalarToRGBPixelFunctor_h
#define __itkScalarToRGBPixelFunctor_h

#include "itkRGBPixel.h"

namespace itk {

namespace Functor {  

/**
 * \class ScalarToRGBPixelFunctor
 * \brief Function object which maps a scalar value into an RGB pixel value.
 *
 *  This class is useful for visualizing labeled images which cannot be mapped
 *  succefully into grayscale images.  Images of unsigned long integers, for
 *  example may have too many graylevels to visualize effectively.
 * 
 *  The hashing scheme used is designed to spread close scalar values very
 *  different colors by using the least significant bits (fastest changing) of
 *  the scalar type to determine the color.  Because labeled images may
 *  typically use sequential values, it is desirable that those values result
 *  in easily discernable colors.
 *
 */
template< class TScalar >
class ITK_EXPORT ScalarToRGBPixelFunctor
{
public:
  ScalarToRGBPixelFunctor();
  ~ScalarToRGBPixelFunctor() {};

  typedef unsigned char               RGBComponentType;
  typedef RGBPixel<RGBComponentType>  RGBPixelType;
  typedef TScalar                     ScalarType;
  
  RGBPixelType operator()( const TScalar &) const;

  void SetLittleEndian()
  {
    m_IsBigEndian = false;
  }
  void SetBigEndian()
  {
    m_IsBigEndian = true;
  }
  
private:
  bool m_IsBigEndian;
  ::size_t m_Index[3];
  
};
  
} // end namespace functor

} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkScalarToRGBPixelFunctor.txx"
#endif

#endif
