rgbhsv.hh

Go to the documentation of this file.

// Copyright (C) 2001, 2002, 2003, 2004  EPITA Research and Development Laboratory
//
// This file is part of the Olena Library.  This library is free
// software; you can redistribute it and/or modify it under the terms
// of the GNU General Public License version 2 as published by the
// Free Software Foundation.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this library; see the file COPYING.  If not, write to
// the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
// MA 02111-1307, USA.
//
// As a special exception, you may use this file as part of a free
// software library without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to
// produce an executable, this file does not by itself cause the
// resulting executable to be covered by the GNU General Public
// License.  This exception does not however invalidate any other
// reasons why the executable file might be covered by the GNU General
// Public License.


#ifndef OLENA_CONVERT_RGBHSV_HH
# define OLENA_CONVERT_RGBHSV_HH

# include <oln/basics.hh>
# include <oln/convert/abstract/colorconv.hh>

# include <ntg/basics.hh>
# include <ntg/color/rgb.hh>
# include <ntg/color/hsv.hh>

# include <mlc/contract.hh>

# include <sstream>

namespace oln {

  using namespace ntg;

  namespace convert {

    template<unsigned inbits, unsigned outbits>
    struct f_rgb_to_hsv
      : public abstract::color_conversion<3, inbits, rgb_traits,
                                          3, outbits, hsv_traits, f_rgb_to_hsv<inbits, outbits> >
    {
      color<3, outbits, hsv_traits>
      doit(const color<3, inbits, rgb_traits>& v) const
      {
        vec<3, float> in = v.to_float();
        vec<3, float> out;
        float max_in = std::max(in[rgb_R], std::max(in[rgb_B], in[rgb_G]));
        float min_in = std::min(in[rgb_R], std::min(in[rgb_B], in[rgb_G]));
        float delta = max_in - min_in;


        out[hsv_V] = max_in;

        if (max_in != 0)
          out[hsv_S] = delta / max_in;
        else
          out[hsv_S] = 0;

        if (out[hsv_S] == 0)
          out[hsv_H] = -1;   // undefined
        else {
          if (in[rgb_R] == max_in)
            out[hsv_H] = (in[rgb_G] - in[rgb_B]) / delta;
          else if (in[rgb_G] == max_in)
            out[hsv_H] = 2 + (in[rgb_B] - in[rgb_R]) / delta;
          else
            out[hsv_H] = 4 + (in[rgb_R] - in[rgb_G]) / delta;
          out[hsv_H] *= 60;
          if (out[hsv_H] < 0)
            out[hsv_H] += 360;
        }

        return out;
      }

      static std::string
      name()
      {
        std::ostringstream s;
        s << "f_rgb_to_hsv<" << inbits << ", " << outbits << '>';
        s.str();
      }
    };

    template <unsigned inbits, unsigned outbits>
    color<3, outbits, hsv_traits>
    rgb_to_hsv(const color<3, inbits, rgb_traits>& v)
    {
      f_rgb_to_hsv<inbits, outbits> f;
      return f(v);
    }

    template<unsigned inbits, unsigned outbits>
    struct f_hsv_to_rgb
      : public abstract::color_conversion<3, inbits, hsv_traits,
                                3, outbits, rgb_traits, f_hsv_to_rgb<inbits, outbits> >
    {
      color<3, outbits, rgb_traits>
      doit(const color<3, inbits, hsv_traits>& v) const
      {
        vec<3, float> in = v.to_float();
        vec<3, float> out;

        if(in[hsv_S] == 0)
          out[rgb_G] = out[rgb_B] = out[rgb_R] = in[hsv_V];
        else
          {
            in[hsv_H] /= 60;
            int i = (int)floor (in[hsv_H]);
            float f = in[hsv_H] - i;
            float p = in[hsv_V] * (1 - in[hsv_S]);
            float q = in[hsv_V] * (1 - in[hsv_S] * f);
            float t = in[hsv_V] * (1 - in[hsv_S] * (1 - f));

            switch (i){
            case 0:
            case 6:
              out[rgb_R] = in[hsv_V];
              out[rgb_G] = t;
              out[rgb_B] = p;
              break;
            case 1:
              out[rgb_R] = q;
              out[rgb_G] = in[hsv_V];
              out[rgb_B] = p;
              break;
            case 2:
              out[rgb_R] = p;
              out[rgb_G] = in[hsv_V];
              out[rgb_B] = t;
              break;
            case 3:
              out[rgb_R] = p;
              out[rgb_G] = q;
              out[rgb_B] = in[hsv_V];
              break;
            case 4:
              out[rgb_R] = t;
              out[rgb_G] = p;
              out[rgb_B] = in[hsv_V];
              break;
            default:
              out[rgb_R] = in[hsv_V];
              out[rgb_G] = p;
              out[rgb_B] = q;
              break;
            }
          }
        return out;
      }

      static std::string
      name()
      {
        std::ostringstream s;
        s << "f_hsv_to_rgb<" << inbits << ", " << outbits << '>';
        s.str();
      }
    };

    template <unsigned inbits, unsigned outbits>
    color<3, outbits, rgb_traits>
    hsv_to_rgb(const color<3, inbits, hsv_traits>& v)
    {
      f_hsv_to_rgb<inbits, outbits> f;
      return f(v);
    }

  } // convert
} // oln

#endif // OLENA_CONVERT_RGBHSV_HH

---