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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkColormapFunctor.h,v $
  Language:  C++
  Date:      $Date: 2008/10/18 00:20:04 $
  Version:   $Revision: 1.1.1.1 $

  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 __itkColormapFunctor_h
#define __itkColormapFunctor_h

#include "itkLightObject.h"
#include "itkNumericTraits.h"
#include "itkRGBPixel.h"

namespace itk {

namespace Functor {

/**
 * \class ColormapFunctor
 * \brief Function object which maps a scalar value into an RGB colormap value.
 *
 */
template< class TScalar, class TRGBPixel >
class ITK_EXPORT ColormapFunctor
: public LightObject
{
public:

  ColormapFunctor() :
    m_MinimumInputValue( NumericTraits<TScalar>::min() ),
    m_MaximumInputValue( NumericTraits<TScalar>::max() ),
    m_MinimumRGBComponentValue( 
      NumericTraits<typename TRGBPixel::ComponentType>::min() ),
    m_MaximumRGBComponentValue( 
      NumericTraits<typename TRGBPixel::ComponentType>::max() ) {};
  ~ColormapFunctor() {};

  typedef ColormapFunctor                               Self;
  typedef LightObject                                   Superclass;
  typedef SmartPointer<Self>                            Pointer;
  typedef SmartPointer<const Self>                      ConstPointer;

  typedef TRGBPixel                                     RGBPixelType;
  typedef typename TRGBPixel::ComponentType             RGBComponentType;
  typedef TScalar                                       ScalarType;
  typedef typename NumericTraits<ScalarType>::RealType  RealType;

  void SetMinimumRGBComponentValue( RGBComponentType min )
    {
    this->m_MinimumRGBComponentValue = min;
    }
  RGBComponentType GetMinimumRGBComponentValue()
    {
    return this->m_MinimumRGBComponentValue;
    }
  void SetMaximumRGBComponentValue( RGBComponentType max )
    {
    this->m_MaximumRGBComponentValue = max;
    }
  RGBComponentType GetMaximumRGBComponentValue()
    {
    return this->m_MaximumRGBComponentValue;
    }

  void SetMinimumInputValue( ScalarType min )
    {
    this->m_MinimumInputValue = min;
    }
  ScalarType GetMinimumInputValue()
    {
    return this->m_MinimumInputValue;
    }
  void SetMaximumInputValue( ScalarType max )
    {
    this->m_MaximumInputValue = max;
    }
  ScalarType GetMaximumInputValue()
    {
    return this->m_MaximumInputValue;
    }

  virtual bool operator!=( const ColormapFunctor & ) const
    {
    return false;
    }
  virtual bool operator==( const ColormapFunctor & other ) const
    {
    return !(*this != other);
    }

  virtual RGBPixelType operator()( const ScalarType & ) const = 0;

protected:

  /**
   * Map [min, max] input values to [0, 1].
   */
  RealType RescaleInputValue( ScalarType v ) const
    {
    RealType d = static_cast<RealType>( this->m_MaximumInputValue
      - this->m_MinimumInputValue );
    RealType value = ( static_cast<RealType>( v )
      - static_cast<RealType>( this->m_MinimumInputValue ) ) / d;
    value = vnl_math_max( 0.0, value );
    value = vnl_math_min( 1.0, value );
    return value;
    }

  /**
   * Map [0, 1] value to [min, max] rgb component values.
   */
  RGBComponentType RescaleRGBComponentValue( RealType v ) const
    {
    RealType d = static_cast<RealType>( m_MaximumRGBComponentValue
      - m_MinimumRGBComponentValue );
    return static_cast<RGBComponentType>( d * v ) 
      + this->m_MinimumRGBComponentValue;
    }

protected:

  ScalarType                            m_MinimumInputValue;
  ScalarType                            m_MaximumInputValue;

  typename RGBPixelType::ComponentType  m_MinimumRGBComponentValue;
  typename RGBPixelType::ComponentType  m_MaximumRGBComponentValue;

};

} // end namespace functor

} // end namespace itk

#endif