octagon2d.hh

// Copyright (C) 2007, 2008, 2009 EPITA Research and Development Laboratory (LRDE)
//
// This file is part of Olena.
//
// Olena is free software: you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation, version 2 of the License.
//
// Olena 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 Olena.  If not, see <http://www.gnu.org/licenses/>.
//
// As a special exception, you may use this file as part of a free
// software project 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 MLN_WIN_OCTAGON2D_HH
# define MLN_WIN_OCTAGON2D_HH


# include <mln/core/internal/classical_window_base.hh>
# include <mln/core/alias/dpoint2d.hh>


namespace mln
{

  mln_internal_add_classical_window_trait(octagon2d);


  namespace win
  {

    struct octagon2d : public internal::classical_window_base< dpoint2d, octagon2d >
    {
      octagon2d(unsigned length);

      unsigned length() const;

      unsigned delta_() const;

      unsigned area() const;

      void print_(std::ostream& ostr) const;

    protected:
      unsigned length_;
    };



# ifndef MLN_INCLUDE_ONLY

    inline
    octagon2d::octagon2d(unsigned length)
      : length_(length)
    {
      mln_precondition(length % 6 == 1);
      const def::coord
        y = static_cast<def::coord>(length / 6),
        x = static_cast<def::coord>(y * 2),
        z = static_cast<def::coord>(y + x);
      insert(dpoint2d(0, 0));
      for (def::coord a = 1; a <= x; ++a)
        for (def::coord b = 0; b <= x; ++b)
        {
          def::coord 
            _a = static_cast<def::coord>(-a),
            _b = static_cast<def::coord>(-b);
          insert(dpoint2d(a, b));
          insert(dpoint2d(_b, a));
          insert(dpoint2d(b, _a));
          insert(dpoint2d(_a, _b));
        }
      const def::coord a_min = static_cast<def::coord>(x + 1);
      for (def::coord a = a_min; a <= z; ++a)
        {
          const def::coord
            b_min = static_cast<def::coord>(-2 * x + a),
            b_max = static_cast<def::coord>(2 * x - a);
          for (def::coord b = b_min; b <= b_max; ++b)
            {
              def::coord 
                _a = static_cast<def::coord>(-a),
                _b = static_cast<def::coord>(-b);
              insert(dpoint2d(a, b));
              insert(dpoint2d(a, _b));
              insert(dpoint2d(_a, b));
              insert(dpoint2d(_a, _b));
              insert(dpoint2d(b, a));
              insert(dpoint2d(b, _a));
              insert(dpoint2d(_b, a));
              insert(dpoint2d(_b, _a));
            }
        }
    }

    inline
    unsigned octagon2d::length() const
    {
      return length_;
    }

    inline
    unsigned octagon2d::delta_() const
    {
      return length_ / 2;
    }

    inline
    unsigned octagon2d::area() const
    {
      unsigned l = (length_ - 1) / 6;
      return l * (28 * l + 8) + 4;
    }

    inline
    void octagon2d::print_(std::ostream& ostr) const
    {
      ostr << "[octagon2d: length=" << length_ << ']';
    }

# endif // ! MLN_INCLUDE_ONLY

  } // end of namespace mln::win

} // end of namespace mln



// When rectangle2d is involved, one surely also wants:
# include <mln/win/hline2d.hh>
# include <mln/win/vline2d.hh>
# include <mln/win/diag2d.hh>
# include <mln/win/backdiag2d.hh>

#endif // ! MLN_WIN_OCTAGON2D_HH