id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
6366	"Bug in ""boost::polygon::contains"" for polygon_90 type"	sebastien.mirabel@…	Andrii Sydorchuk	"For a polygon ((0,0) (10,0) (10,10) (0,10)) the function ""contains"" returns true for (15,5) whereas it should return true

{{{
#include <boost/polygon/polygon.hpp>

#include <cassert>
#include <iostream>

namespace gtl = boost::polygon;
using namespace boost::polygon::operators;

int main() {
    //lets construct a 10x10 rectangle shaped polygon
    typedef gtl::polygon_90_data<int> Polygon;
    typedef gtl::polygon_traits_90<Polygon>::point_type Point;
	Point pts[] = {
		gtl::construct<Point>(0, 0),
		gtl::construct<Point>(10, 0),
		gtl::construct<Point>(10, 10),
		gtl::construct<Point>(0, 10)};
    Polygon poly;
    gtl::set_points(poly, pts, pts+4);
	
    Point point = gtl::construct<Point>(15, 5);
	{
		// Wrong result here :
		bool result = gtl::contains(poly, point);
		std::cout << std::boolalpha << result << std::endl;
	}
    //assert(!gtl::contains(poly, point));
    //assert(!gtl::contains(poly, gtl::construct<Point>(15, 5)));
    return 0;
}

}}}

The bugs seems to come from line 1176 of ""boost\polygon\polygon_traits.hpp"" :
{{{
    //an odd number of edges to the left implies interior pt
    return counts[winding(polygon) == COUNTERCLOCKWISE ? 0 : 1] % 4 != 0; 
}}}

There is ""% 4"" whereas the previous comment indicate ""an odd number of edges"" (this logicaly should be ""% 2"")
"	Bugs	closed	Boost 1.57.0	polygon	Boost 1.51.0	Problem	fixed		sebastien.mirabel@…