cgal/Kernel_23/examples/Kernel_23/intersections.cpp

77 lines
2.4 KiB
C++

#include <CGAL/Simple_cartesian.h>
#include <CGAL/intersections.h>
#include <CGAL/iterator.h>
#include <CGAL/point_generators_2.h>
#include <boost/bind.hpp>
using namespace CGAL;
typedef CGAL::Simple_cartesian<double> K;
typedef K::Point_2 Point;
typedef K::Segment_2 Segment;
typedef CGAL::Creator_uniform_2<double,Point> Pt_creator;
typedef Random_points_on_segment_2<Point,Pt_creator> P1;
typedef Random_points_on_circle_2<Point,Pt_creator> P2;
typedef Creator_uniform_2< Point, Segment> Seg_creator;
typedef Join_input_iterator_2< P1, P2, Seg_creator> Seg_iterator;
using boost::result_of;
int main()
{
std::vector<Segment> input;
// Prepare point generator for the horizontal segment, length 200.
P1 p1( Point(-100,0), Point(100,0));
// Prepare point generator for random points on circle, radius 250.
P2 p2( 250);
// Create segments.
Seg_iterator g( p1, p2);
std::copy_n( g, 200, std::back_inserter(input));
// intersection of two objects
#if !defined(CGAL_CFG_NO_CPP0X_AUTO)
// with C++11
auto v = intersection(input.back(), input.front());
#else
// without C++11
result_of<K::Intersect_2(Segment, Segment)>::type v
= intersection(input.back(), input.front());
#endif
// splitting results with Dispatch_output_iterator
std::vector<Point> points;
std::vector<Segment> segments;
typedef Dispatch_output_iterator<
cpp0x::tuple<Point,Segment>, cpp0x::tuple< std::back_insert_iterator<std::vector<Point> >,
std::back_insert_iterator<std::vector<Segment> > > >
Dispatcher;
Dispatcher disp = dispatch_output<Point,Segment>( std::back_inserter(points),
std::back_inserter(segments) );
// intersections of many objects, directly dispatched
#if !defined(CGAL_CFG_NO_CPP0X_LAMBDA)
// with C++11 lambdas
auto& s1 = input.front();
std::transform(input.begin(), input.end(), disp,
[&s1] (const Segment& s) { return intersection(s1, s); });
#else
// without
K::Intersect_2 intersector = K().intersect_2_object();
std::transform(input.begin(), input.end(), disp,
boost::bind(intersector, input.front(), _1));
#endif
std::cout << "Point intersections: " << points.size() << std::endl;
std::cout << "Segment intersections: " << segments.size() << std::endl;
return 0;
}