freHueToRGBPixelAccessor.cxx

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

  Program:   F.R.E.E. - flexible registration evaluation engine
  Version:   v.1.0.0
  Date:      $Date: 2006/09/01 12:00:00 $
  Module:    $RCSfile: freHueToRGBPixelAccessor.cxx,v $
  Language:  C++



  Copyright (c) 2007 Ralf o Floca (Department of Medical Informatics,
  Institute for Medical Biometry and Informatics, University of Heidelberg,
  Germany). All rights reserved.
  See FREECopyright.txt or http://www.mi.med.uni-hd.de/free/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 _freHueToRGBPixelAccessor_cxx
#define _freHueToRGBPixelAccessor_cxx

#include "freHueToRGBPixelAccessor.h"

namespace FREE
{
namespace Accessor
{

  template <class T>
  typename HueToRGBPixelAccessor<T>::ExternalType
  HueToRGBPixelAccessor<T>::
  Get( const InternalType & input ) const
  {
    InternalType inputMod = input%360;
    unsigned int iColorCircleSeg = floor(input/60);
    
    float rgbProp = inputMod-360;

    if (inputMod<60) rgbProp = inputMod;
    else if (inputMod<60) rgbProp = inputMod-120;
    else if (inputMod<180) rgbProp = inputMod-240;
    else if (inputMod<300) rgbProp = inputMod-360;
    
    rgbProp = abs(rgbProp/60)*255;

    ExternalType rgbPixel;

    switch (iColorCircleSeg)
    {
    case 0:
      {
        rgbPixel[0] = 255;
        rgbPixel[1] = rgbProp;
        rgbPixel[2] = 0;
        break;
      }
    case 1:
      {
        rgbPixel[0] = rgbProp;
        rgbPixel[1] = 255;
        rgbPixel[2] = 0;
        break;
      }
    case 2:
      {
        rgbPixel[0] = 0;
        rgbPixel[1] = 255;
        rgbPixel[2] = rgbProp;
        break;
      }
    case 3:
      {
        rgbPixel[0] = 0;
        rgbPixel[1] = rgbProp;
        rgbPixel[2] = 255;
        break;
      }
    case 4:
      {
        rgbPixel[0] = rgbProp;
        rgbPixel[1] = 0;
        rgbPixel[2] = 255;
        break;
      }
    case 5:
      {
        rgbPixel[0] = 255;
        rgbPixel[1] = 0;
        rgbPixel[2] = rgbProp;
        break;
      }
    }

    return rgbPixel;
  }

  template <class T>
  void
  HueToRGBPixelAccessor<T>::
  Set( InternalType & output, const ExternalType & input ) const
        {
   double minRGB = min(min(input[0],input[1]),input[2]);
   double maxRGB = max(max(input[0],input[1]),input[2]);
   
   double delta = maxRGB - minRGB;

   double s = 0.0;
   double h = 0.0;

   if (maxRGB != 0.0) s = 255.0 * delta / maxRGB;

   if (s != 0.0)
   {
     if (input[0] == maxRGB)
     {
       h = (input[1] - input[2]) / delta;
     }
     else if (input[1] == maxRGB)
     {
       h = 2.0 + ((input[2] - input[0]) / delta);
     }
     else
     {
       h = 4.0 + (input[0] - input[1]) / delta;
     }
   }
   else
   {
     h = -1.0;
   }

   h *= 60 ;

   if (h < 0.0) h = h + 360.0;

   output = h;
        };

} // namespace Accessor
} // namespace free

#endif

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