gradient_external.hh

// Copyright (C) 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_MORPHO_ELEMENTARY_GRADIENT_EXTERNAL_HH
# define MLN_MORPHO_ELEMENTARY_GRADIENT_EXTERNAL_HH


# include <mln/morpho/elementary/like_ero_fun.hh>
# include <mln/morpho/elementary/like_ero_set.hh>


namespace mln
{

  namespace morpho
  {

    namespace elementary
    {


      template <typename I, typename N>
      mln_concrete(I)
      gradient_external(const Image<I>& input, const Neighborhood<N>& nbh);


# ifndef MLN_INCLUDE_ONLY

      namespace internal
      {

        struct f_grad_ext
        {
          template <typename V, typename A>
          V operator()(const V& input_p, const A& a) const
          {
            return a.to_result() - input_p;
          }
        };

        // Dispatch.

        template <typename I, typename N>
        mln_concrete(I)
        gradient_external_dispatch(trait::image::kind::any,
                         const Image<I>& input, const Neighborhood<N>& nbh)
        {
          return like_ero_fun(accu::meta::stat::max(), f_grad_ext(), input, nbh);
        }

        template <typename I, typename N>
        mln_concrete(I)
        gradient_external_dispatch(trait::image::kind::logic,
                                   const Image<I>& input, const Neighborhood<N>& nbh)
        {
          bool val[] =
            {
              0, // ext_value
              0, // do_duplicate
              0, // on_input_p
              1, // on_input_n
              1, // output_p
            };
          return like_ero_set(val, input, nbh);
        }

        template <typename I, typename N>
        mln_concrete(I)
        gradient_external_dispatch(const Image<I>& input, const Neighborhood<N>& nbh)
        {
          return gradient_external_dispatch(mln_trait_image_kind(I)(),
                                            input, nbh);
        }

      } // end of namespace mln::morpho::elementary::internal


      // Facade.

      template <typename I, typename N>
      mln_concrete(I)
      gradient_external(const Image<I>& input, const Neighborhood<N>& nbh)
      {
        trace::entering("morpho::elementary::gradient_external");

        mln_precondition(exact(input).is_valid());
        mln_precondition(exact(nbh).is_valid());

        mln_concrete(I) output = internal::gradient_external_dispatch(input, nbh);

        trace::exiting("morpho::elementary::gradient_external");
        return output;
      }

# endif // ! MLN_INCLUDE_ONLY

    } // end of namespace mln::morpho::elementary

  } // end of namespace mln::morpho

} // end of namespace mln


#endif // ! MLN_MORPHO_ELEMENTARY_GRADIENT_EXTERNAL_HH