用 boost::geometry 扩展多边形?

Expand polygons with boost::geometry?

我知道可以 add/subtract 不同的多边形 to/from 通过 boost::geometry 相互连接,示例可以在 web 的不同位置找到。现在我想做的是不同的事情:

我有一个 2D 多边形,我想按给定大小 expand/shrink。所以我不是在谈论一个简单的缩放操作,而是一个函数,它从输入数据中计算出一个新的多边形:

我的问题:boost::geometry 可以进行这样的操作吗?如果是,如何做到这一点?

谢谢!

此功能在 OGC 简单功能规范中称为“缓冲”。

Boost Geometry 支持大多数 2D 笛卡尔几何(您可以通过转换轻松完成其余部分),并且仅在其他坐标系中指向。

Documentation

可用策略:

这是示例代码

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


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

    // Declare strategies
    const double buffer_distance = 1.0;
    const int points_per_circle = 36;
    boost::geometry::strategy::buffer::distance_symmetric<coordinate_type> distance_strategy(buffer_distance);
    boost::geometry::strategy::buffer::join_round join_strategy(points_per_circle);
    boost::geometry::strategy::buffer::end_round end_strategy(points_per_circle);
    boost::geometry::strategy::buffer::point_circle circle_strategy(points_per_circle);
    boost::geometry::strategy::buffer::side_straight side_strategy;

    // Declare output
    boost::geometry::model::multi_polygon<polygon> result;

    // Declare/fill a linestring
    boost::geometry::model::linestring<point> ls;
    boost::geometry::read_wkt("LINESTRING(0 0,4 5,7 4,10 6)", ls);

    // Create the buffer of a linestring
    boost::geometry::buffer(ls, result,
                distance_strategy, side_strategy,
                join_strategy, end_strategy, circle_strategy);


    // Declare/fill a multi point
    boost::geometry::model::multi_point<point> mp;
    boost::geometry::read_wkt("MULTIPOINT((3 3),(4 4),(6 2))", mp);

    // Create the buffer of a multi point
    boost::geometry::buffer(mp, result,
                distance_strategy, side_strategy,
                join_strategy, end_strategy, circle_strategy);


    // Declare/fill a multi_polygon
    boost::geometry::model::multi_polygon<polygon> mpol;
    boost::geometry::read_wkt("MULTIPOLYGON(((0 1,2 5,5 3,0 1)),((1 1,5 2,5 0,1 1)))", mpol);

    // Create the buffer of a multi polygon
    boost::geometry::buffer(mpol, result,
                distance_strategy, side_strategy,
                join_strategy, end_strategy, circle_strategy);


    return 0;
}

积分可以这样“一起成长”

带圆角的线串示例: