is_simple_point.hh

// Copyright (C) 2009, 2011 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_TOPO_SKELETON_IS_SIMPLE_POINT_HH
# define MLN_TOPO_SKELETON_IS_SIMPLE_POINT_HH


# include <mln/core/concept/image.hh>
# include <mln/core/alias/point2d.hh>
# include <mln/core/alias/neighb2d.hh>

namespace mln
{

  namespace topo
  {

    namespace skeleton
    {

      template <typename N>
      struct is_simple_point
      {

        is_simple_point(const Neighborhood<N>& nbh);

        template <typename I>
        bool check(const I& ima, const mln_psite(I)& p) const;
        template <typename I>
        bool check__(const I& ima, unsigned p) const;

      protected:
        const N& nbh_;
        bool is_c8_;

        template <typename I, typename N2>
        unsigned nb_connexity2d(const I&, const N2 nbh,
                                const mln_psite(I)& p, bool object) const;
        template <typename I, typename N2>
        unsigned nb_connexity2d__(const I&, const N2 nbh,
                                  unsigned p, bool object) const;

      };

# ifndef MLN_INCLUDE_ONLY


      namespace internal
      {
        static const unsigned char nb_connexity_c8[256] =
        {
          0,  1,  1,  1,   1,  2,  1,  1,   1,  1,  1,  1,   2,  2,  1,  1,
          1,  2,  1,  1,   1,  2,  1,  1,   2,  2,  1,  1,   2,  2,  1,  1,
          1,  2,  2,  2,   2,  3,  2,  2,   1,  1,  1,  1,   2,  2,  1,  1,
          2,  3,  2,  2,   2,  3,  2,  2,   2,  2,  1,  1,   2,  2,  1,  1,

          1,  2,  2,  2,   2,  3,  2,  2,   1,  1,  1,  1,   2,  2,  1,  1,
          1,  2,  1,  1,   1,  2,  1,  1,   1,  1,  1,  1,   1,  1,  1,  1,
          1,  2,  2,  2,   2,  3,  2,  2,   1,  1,  1,  1,   2,  2,  1,  1,
          1,  2,  1,  1,   1,  2,  1,  1,   1,  1,  1,  1,   1,  1,  1,  1,

          1,  2,  2,  2,   2,  3,  2,  2,   2,  2,  2,  2,   3,  3,  2,  2,
          1,  2,  1,  1,   1,  2,  1,  1,   2,  2,  1,  1,   2,  2,  1,  1,
          2,  3,  3,  3,   3,  4,  3,  3,   2,  2,  2,  2,   3,  3,  2,  2,
          2,  3,  2,  2,   2,  3,  2,  2,   2,  2,  1,  1,   2,  2,  1,  1,

          1,  2,  2,  2,   2,  3,  2,  2,   1,  1,  1,  1,   2,  2,  1,  1,
          1,  2,  1,  1,   1,  2,  1,  1,   1,  1,  1,  1,   1,  1,  1,  1,
          1,  2,  2,  2,   2,  3,  2,  2,   1,  1,  1,  1,   2,  2,  1,  1,
          1,  2,  1,  1,   1,  2,  1,  1,   1,  1,  1,  1,   1,  1,  1,  1
        };

        static const unsigned char nb_connexity_c4[256] =
        {
          0,  0,  1,  1,   0,  0,  1,  1,   1,  1,  2,  1,   1,  1,  2,  1,
          1,  1,  2,  2,   1,  1,  1,  1,   2,  2,  3,  2,   2,  2,  2,  1,
          0,  0,  1,  1,   0,  0,  1,  1,   1,  1,  2,  1,   1,  1,  2,  1,
          1,  1,  2,  2,   1,  1,  1,  1,   2,  2,  3,  2,   2,  2,  2,  1,

          1,  1,  2,  2,   1,  1,  2,  2,   2,  2,  3,  2,   2,  2,  3,  2,
          2,  2,  3,  3,   2,  2,  2,  2,   3,  3,  4,  3,   3,  3,  3,  2,
          1,  1,  2,  2,   1,  1,  2,  2,   1,  1,  2,  1,   1,  1,  2,  1,
          2,  2,  3,  3,   2,  2,  2,  2,   2,  2,  3,  2,   2,  2,  2,  1,

          0,  0,  1,  1,   0,  0,  1,  1,   1,  1,  2,  1,   1,  1,  2,  1,
          1,  1,  2,  2,   1,  1,  1,  1,   2,  2,  3,  2,   2,  2,  2,  1,
          0,  0,  1,  1,   0,  0,  1,  1,   1,  1,  2,  1,   1,  1,  2,  1,
          1,  1,  2,  2,   1,  1,  1,  1,   2,  2,  3,  2,   2,  2,  2,  1,

          1,  1,  2,  2,   1,  1,  2,  2,   2,  2,  3,  2,   2,  2,  3,  2,
          1,  1,  2,  2,   1,  1,  1,  1,   2,  2,  3,  2,   2,  2,  2,  1,
          1,  1,  2,  2,   1,  1,  2,  2,   1,  1,  2,  1,   1,  1,  2,  1,
          1,  1,  2,  2,   1,  1,  1,  1,   1,  1,  2,  1,   1,  1,  1,  1
        };

      } // end of namespace internal

      template <typename N>
      is_simple_point<N>::is_simple_point(const Neighborhood<N>& nbh)
        : nbh_(exact(nbh))
      {
        mln_precondition(nbh_.is_valid());
      }


      template <typename N>
      template <typename I, typename N2>
      unsigned
      is_simple_point<N>::nb_connexity2d(const I& ima,
                                         const N2 nbh,
                                         const mln_psite(I)& p,
                                         bool object) const
      {
        unsigned res = 0;

        // Note: bkd here but fwd in is_simple_2d.hh...
        mln_bkd_niter(N2) n(c8(), p);
        for_all(n)
        {
          res = (res << 1);
          if (ima.domain().has(n) && ima(n) == object)
            res = res | 1;
        }

        switch (nbh.size())
        {
          case 4: // C4
            return internal::nb_connexity_c4[res];
          case 8: // C8
            return internal::nb_connexity_c8[res];
          default:
            mln_assertion(0);

        }
      }


      template <typename N>
      template <typename I, typename N2>
      unsigned
      is_simple_point<N>::nb_connexity2d__(const I& ima,
                                           const N2 nbh,
                                           unsigned p,
                                           bool object) const
      {
        unsigned res = 0;

        static util::array<int>
          noffset = mln::offsets_wrt(ima, c8());

        for (int i = noffset.nelements() - 1; i >= 0; --i)
        {
          res = (res << 1);
          if (ima.element(p + noffset[i]) == object)
            res = res | 1;
        }

        switch (nbh.size())
        {
          case 4: // C4
            return internal::nb_connexity_c4[res];
          case 8: // C8
            return internal::nb_connexity_c8[res];
          default:
            mln_assertion(0);

        }
        return 0;
      }


      template <typename N>
      template <typename I>
      inline
      bool
      is_simple_point<N>::check(const I& ima,
                                const mln_psite(I)& p) const
      {
        mln_precondition(ima.is_valid());
        return (nb_connexity2d(ima, nbh_.foreground(), p, true) == 1)  // Consider neighbor.
          && (nb_connexity2d(ima, nbh_.background(), p, false) == 1); // Consider complement neighbor.
      }




      template <typename N>
      template <typename I>
      inline
      bool
      is_simple_point<N>::check__(const I& ima,
                                  unsigned p) const
      {
        mln_precondition(ima.is_valid());
        return (nb_connexity2d__(ima, nbh_.foreground(), p, true) == 1)  // Consider neighbor
          && (nb_connexity2d__(ima, nbh_.background(), p, false) == 1); // Consider complement neighbor.
      }


# endif // MLN_TOPO_SKELETON_INCLUDE_ONLY

    } // end of namespace mln::topo::skeleton

  } // end of namespace mln::topo

} // end of namespace mln

#endif // ! MLN_TOPO_SKELETON_IS_SIMPLE_POINT_HH