breadth_first_thinning.hh

// Copyright (C) 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_TOPO_SKELETON_BREADTH_FIRST_THINNING_HH
# define MLN_TOPO_SKELETON_BREADTH_FIRST_THINNING_HH


# include <algorithm>

# include <mln/core/routine/duplicate.hh>

# include <mln/core/concept/image.hh>
# include <mln/core/concept/neighborhood.hh>

# include <mln/core/site_set/p_set.hh>

# include <mln/fun/p2b/tautology.hh>

namespace mln
{

  namespace topo
  {

    namespace skeleton
    {

      template <typename I, typename N, typename F, typename G, typename H>
      mln_concrete(I)
      breadth_first_thinning(const Image<I>& input,
                             const Neighborhood<N>& nbh,
                             Function_v2b<F>& is_simple,
                             G detach,
                             const Function_v2b<H>& constraint =
                               fun::p2b::tautology());


# ifndef MLN_INCLUDE_ONLY

      template <typename I, typename N, typename F, typename G, typename H>
      inline
      mln_concrete(I)
      breadth_first_thinning(const Image<I>& input_,
                             const Neighborhood<N>& nbh_,
                             Function_v2b<F>& is_simple_,
                             G detach,
                             const Function_v2b<H>& constraint_)
      {
        const I& input = exact(input_);
        const N& nbh = exact(nbh_);
        F& is_simple = exact(is_simple_);
        const H& constraint = exact(constraint_);

        I output = duplicate(input);
        // Attach the work image to IS_SIMPLE.
        is_simple.set_image(output);

        typedef mln_psite(I) psite;
        typedef p_set<psite> set_t;
        set_t set;
        // Populate SET with candidate simple points.
        mln_piter(I) p_(output.domain());
        for_all(p_)
        {
          /* CONSTRAINTS and IS_SIMPLE are site-to-boolean (p2b)
             predicate functors; passing an iterator as argument might
             not be possible (C++ cannot resolve template routines if
             an implicit conversion of the argument is needed).  Help
             the compiler and pass an actual, explicit psite.  */
          psite p = p_;
          if (output(p) && constraint(p) && is_simple(p))
            set.insert(p);
        }

        while (!set.is_empty())
          {
            set_t next_set;

            /* FIXME: Using the following code does not work (it does
               compiles, but does not behave like the code using a
               hand-made loop).  There must be a bug somewhere in
               p_set or p_indexed_psite. */
# if 0
            mln_piter(set_t) ps(set);
            for_all(ps);
            {
              // Same remark as above.
              psite p = p_;
# endif
            for (unsigned i = 0; i < set.nsites(); ++i)
              {
                psite p = set[i];

                /* FIXME: We compute the cell and attachment of P twice:
                   during the call to is_simple() and within detach().
                   How could we reuse this elegantly, without breaking
                   the genericity of the skeleton algorithm?  */
                if (constraint(p) && is_simple(p))
                  {
                    detach(p, output);
                    mln_niter(N) n(nbh, p);
                    for_all(n)
                      if (output.domain().has(n)
                          && output(n) && constraint(p) && is_simple(n))
                        next_set.insert(n);
                  }
              }
            set.clear();
            std::swap(set, next_set);
          }
        return output;
      }

# endif // MLN_INCLUDE_ONLY

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

  } // end of namespace mln::topo

} // end of namespace mln

#endif // ! MLN_TOPO_SKELETON_BREADTH_FIRST_THINNING_HH