在索引处提升几何多边形插入点

Question

如何在多边形索引处添加点？以正确的索引插入点（2.5,7.5）。

输出：

(((0, 0), (0, 5), (5, 5), (5, 0), (0, 0), (2.5, 7.5)))

------------------- ▼

(((0, 0), (0, 5), (2.5, 7.5), (5, 5), (5, 0), (0, 0)))

#include <iostream>
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry/geometries/polygon.hpp>

int main()
{
    typedef boost::geometry::model::d2::point_xy<double> point;
    typedef boost::geometry::model::polygon<point> polygon;


    polygon poly;

    boost::geometry::append ( poly, point(0, 0) );
    boost::geometry::append ( poly, point(0, 5) );
    boost::geometry::append ( poly, point(5, 5) );
    boost::geometry::append ( poly, point(5, 0) );
    boost::geometry::append ( poly, point(0, 0) );

    poly.outer().push_back( point(2.5, 7.5) );

    std::cout << boost::geometry::dsv(poly) << std::endl;


    return 0;
}

Answer 1

根据我的理解，poly.outer只是一个std :: vector，所以你应该能够使用insert方法将值放在所需的索引处：

poly.outer().insert( poly.outer().begin()+2, point(2.5, 7.5) );

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