mirror of https://github.com/CGAL/cgal
139 lines
3.9 KiB
C++
139 lines
3.9 KiB
C++
// ============================================================================
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//
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// Copyright (c) 1998 The CGAL Consortium
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//
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// This software and related documentation is part of an INTERNAL release
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// of the Computational Geometry Algorithms Library (CGAL). It is not
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// intended for general use.
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//
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// ----------------------------------------------------------------------------
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//
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// release : $CGAL_Revision $
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// release_date : $CGAL_Date $
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//
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// file : include/CGAL/random_convex_set_2.h
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// package : $CGAL_Package: Generator 2.12 (28 Jul 1999) $
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// source : src/rcs/rcs.aw
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// revision : $Revision$
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// revision_date : $Date$
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// author(s) : Michael Hoffmann <hoffmann@inf.ethz.ch>
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//
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// coordinator : ETH Zurich (Bernd Gaertner <gaertner@inf.ethz.ch>)
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//
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// Random Convex Point Sets
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// ============================================================================
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#if ! (CGAL_RANDOM_CONVEX_SET_2_H)
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#define CGAL_RANDOM_CONVEX_SET_2_H 1
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#include <CGAL/basic.h>
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#include <CGAL/copy_n.h>
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#include <vector>
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#include <algorithm>
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#include <numeric>
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#ifdef CGAL_REP_CLASS_DEFINED
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#include <CGAL/Random_convex_set_traits_2.h>
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#endif
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CGAL_BEGIN_NAMESPACE
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template < class OutputIterator, class Point_generator, class Traits >
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OutputIterator
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random_convex_set_2( int n,
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OutputIterator o,
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const Point_generator& pg,
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Traits t)
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{
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CGAL_precondition( n >= 3);
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#ifndef CGAL_CFG_NO_NAMESPACE
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using std::vector;
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using std::back_inserter;
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using std::accumulate;
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using std::transform;
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using std::bind2nd;
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using std::sort;
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using std::partial_sum;
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using std::less;
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using std::max_element;
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using CGAL::copy_n;
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#endif
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typedef typename Traits::Point_2 Point_2;
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typedef typename Traits::FT FT;
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typedef vector< Point_2 > Container;
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typedef typename Traits::Sum Sum;
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typedef typename Traits::Scale Scale;
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typedef typename Traits::Angle_less Angle_less;
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typedef typename Traits::Max_coordinate Max_coordinate;
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// GCC 2.8 and egcs-1.0.1 require these:
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// (does not accept s.l. Scale()( p, 1))
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Scale scale;
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Max_coordinate max_coordinate;
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Sum sum;
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// build random point set:
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Container points;
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points.reserve( n);
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CGAL::copy_n( pg, n, back_inserter( points));
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// compute centroid of points:
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Point_2 centroid(
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scale(
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accumulate( points.begin(), points.end(), t.origin(), Sum()),
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FT( 1) / FT( n)));
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// translate s.t. centroid == origin:
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transform(
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points.begin(),
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points.end(),
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points.begin(),
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bind2nd( Sum(), scale( centroid, FT( -1))));
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// sort them according to their direction's angle
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// w.r.t. the positive x-axis:
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sort( points.begin(), points.end(), Angle_less());
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// construct polygon:
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partial_sum(
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points.begin(), points.end(), points.begin(), Sum());
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// and compute its centroid:
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Point_2 new_centroid(
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scale(
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accumulate( points.begin(), points.end(), t.origin(), Sum()),
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FT( 1) / FT( n)));
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// translate s.t. centroids match:
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transform(
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points.begin(),
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points.end(),
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points.begin(),
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bind2nd( Sum(), sum( centroid,
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scale( new_centroid, FT( -1)))));
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// compute maximal coordinate:
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FT maxcoord( max_coordinate(
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*max_element( points.begin(),
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points.end(),
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compose2_2( less< FT >(),
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Max_coordinate(),
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Max_coordinate()))));
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// and finally scale to fit into original grid:
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return transform(
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points.begin(),
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points.end(),
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o,
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bind2nd( Scale(), FT( pg.range()) / maxcoord));
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} // random_convex_set_2( n, o, pg, t)
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CGAL_END_NAMESPACE
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#endif // ! (CGAL_RANDOM_CONVEX_SET_2_H)
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// ----------------------------------------------------------------------------
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// ** EOF
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// ----------------------------------------------------------------------------
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