Add merge::components routine.

scribo/scribo/primitive/merge/components.hh

+// Copyright (C) 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.
+
+/// \file
+///
+///
+
+#ifndef SCRIBO_PRIMITIVE_MERGE_COMPONENTS_HH
+# define SCRIBO_PRIMITIVE_MERGE_COMPONENTS_HH
+
+# include <mln/core/image/vmorph/fun_image.hh>
+
+
+namespace scribo
+{
+
+  namespace primitive
+  {
+
+    namespace merge
+    {
+
+      using namespace mln;
+
+
+# ifndef MLN_INCLUDE_ONLY
+
+      namespace internal
+      {
+
+	template <typename V>
+	struct rebase_label : mln::Function_v2v<rebase_label<V> >
+	{
+	  typedef V result;
+
+	  rebase_label()
+	    : base_label_(0)
+	  {}
+
+	  rebase_label(const V& base_label)
+	    : base_label_(base_label)
+	  {}
+
+	  V operator()(const V& v) const
+	  {
+	    if (v)
+	      return unsigned(base_label_) + unsigned(v);
+	    return literal::zero;
+	  }
+
+
+	  V base_label_;
+	};
+
+
+      } // end of namespace scribo::primitive::merge
+
+
+      template <typename L>
+      component_set<L>
+      components(const component_set<L>& lhs, const component_set<L>& rhs)
+      {
+	trace::entering("scribo::primitive::merge::components");
+
+	const L& lhs_lbl = lhs.labeled_image();
+	const L& rhs_lbl = rhs.labeled_image();
+
+	typedef mln_value(L) V;
+
+
+	V nlabels = unsigned(lhs.nelements()) + unsigned(rhs.nelements());
+
+	// Merge labeled images.
+	//
+	// Rebase labeling in the second image, according to the
+	// number of labels in the first one.
+	//
+	L lbl_merge = duplicate(lhs_lbl);
+
+	internal::rebase_label<V> f(lhs.nelements());
+	fun_image<internal::rebase_label<V>, L> fima(f, rhs_lbl);
+	data::fill((lbl_merge | (pw::value(lbl_merge) == pw::cst(0))).rw(), fima);
+
+ 	component_set<L> output(lbl_merge, nlabels);
+
+	trace::exiting("scribo::primitive::merge::components");
+	return output;
+      }
+
+# endif // ! MLN_INCLUDE_ONLY
+
+    } // end of namespace scribo::primitive::merge
+
+  } // end of namespace scribo::primitive
+
+} // end of namespace scribo
+
+
+#endif // ! SCRIBO_PRIMITIVE_MERGE_COMPONENTS_HH