breadth_first_thinning.hh

// Copyright (C) 2009, 2010 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);


      template <typename I, typename N, typename F, typename G>
      mln_concrete(I)
      breadth_first_thinning(const Image<I>& input,
                             const Neighborhood<N>& nbh,
                             Function_v2b<F>& is_simple,
                             G detach);


# 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_);

        mln_concrete(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;

            mln_piter(set_t) ps(set);
            for_all(ps)
            {
              // Same remark as above.
              psite p = ps;

              /* 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?
                 Also, keep in mind that functors can maintain an
                 internal state and make side effects, meaning that
                 e.g. constraint(p) might not be constant for a
                 given p during the thinning.  */
              if (constraint(p) && is_simple(p))
                {
                  detach(p, output);
                  mln_niter(N) n_(nbh, p);
                  for_all(n_)
                  {
                    // Same remark as above regarding P and P_.
                    psite n = n_;
                    if (output.domain().has(n)
                        && output(n) && constraint(n) && is_simple(n))
                      next_set.insert(n);
                  }
                }
            }
            set.clear();
            std::swap(set, next_set);
          }
        return output;
      }


      template <typename I, typename N, typename F, typename G>
      inline
      mln_concrete(I)
      breadth_first_thinning(const Image<I>& input,
                             const Neighborhood<N>& nbh,
                             Function_v2b<F>& is_simple,
                             G detach)
      {
        return breadth_first_thinning(input, nbh, is_simple, detach,
                                      fun::p2b::tautology());
      }

# 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

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