Add an error function for polyline simplification

Triangulation_2/include/CGAL/Polyline_simplification_2/Squared_distance_cost.h

@@ -0,0 +1,86 @@
+// Copyright (c) 2012  INRIA Sophia-Antipolis (France).
+// All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org).
+// You can redistribute it and/or modify it under the terms of the GNU
+// General Public License as published by the Free Software Foundation,
+// either version 3 of the License, or (at your option) any later version.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+//
+// Author(s)     : Fernando Cacciola <fernando.cacciola@geometryfactory.com>
+//
+#ifndef CGAL_POLYLINE_SIMPLIFICATION_2_SQUARED_DISTANCE_COST_H
+#define CGAL_POLYLINE_SIMPLIFICATION_2_SQUARED_DISTANCE_COST_H
+
+#include <CGAL/squared_distance_2.h>
+
+namespace CGAL {
+
+namespace Polyline_simplification_2
+{
+
+/// This class is a cost function which calculates the cost as the square of the distance between the original and simplified polylines.
+///
+/// @heading Is Model for the Concepts: 'PolylineSimplificationCostFunction'.
+template<class FT>
+class Squared_distance_cost
+{
+ 
+public:
+
+  /// Initializes the cost function
+  Squared_distance_cost() {}
+  
+
+
+    template<class PolylineConstraintTriangulation, class CVI>  
+  boost::optional<FT> operator()( PolylineConstraintTriangulation const& pct
+                                  , CVI p
+                                  , CVI q
+                                  , CVI r) const
+  {
+
+    typedef typename PolylineConstraintTriangulation::Geom_traits Geom_traits ;
+
+    typedef typename Geom_traits::Compute_squared_distance_2 Compute_squared_distance ;
+    typedef typename Geom_traits::Construct_segment_2        Construct_segment ;
+    typedef typename Geom_traits::Segment_2                  Segment ;
+    typedef typename Geom_traits::Point_2                    Point ;                   
+
+    Compute_squared_distance compute_squared_distance = pct.geom_traits().compute_squared_distance_2_object() ;
+    Construct_segment        construct_segment        = pct.geom_traits().construct_segment_2_object() ;
+    
+    Point const& lP = p->point;
+    Point const& lR = r->point;
+     
+    Segment lP_R = construct_segment(lP, lR) ;
+
+    FT d1 = 0.0;
+    ++p;
+
+    for ( ;p != r; ++p )
+      d1 = (std::max)(d1, compute_squared_distance( lP_R, p->point ) ) ;
+
+    return d1 ;
+  }
+
+
+};
+
+
+} // namespace Polyline_simplification_2
+
+
+} //namespace CGAL
+
+#endif // CGAL_POLYLINE_SIMPLIFICATION_2_SQUARED_DISTANCE_COST_H
+// EOF //
+