c++ - 我们如何获得存储在boost多边形中的所有点

Question

我正在尝试迭代 boost 多边形中的所有点。有没有 API 可以处理这个问题？

Answer 1

以下是设置和检索 BOOST 多边形顶点坐标的简单示例:

#include <boost/geometry.hpp>
namespace bg = boost::geometry;
typedef bg::model::d2::point_xy<double> boost_point;
typedef bg::model::polygon<boost_point> boost_polygon;

[...]

//setting vertices
boost_polygon poly;
bg::append(poly.outer(), boost_point(-1, -1));
bg::append(poly.outer(), boost_point(-1,  1));
bg::append(poly.outer(), boost_point( 1,  1));
bg::append(poly.outer(), boost_point( 1, -1));
bg::append(poly.outer(), boost_point(-1, -1));

//getting the vertices back
for(auto it = boost::begin(boost::geometry::exterior_ring(poly)); it != boost::end(boost::geometry::exterior_ring(poly)); ++it)
{
    double x = bg::get<0>(*it);
    double y = bg::get<1>(*it);
    //use the coordinates...
}