c++ - 用boost::geometry扩展多边形？

Question

我知道可以通过boost::geometry向彼此添加/减去不同的多边形，示例可以在网络的不同位置找到。现在我要做的是不同的事情:
我有一个2D多边形，我想按给定的大小扩展/缩小。因此，我不是在谈论简单的缩放操作，而是在讨论一个函数，该函数将从输入数据中计算出一个新的多边形:

在扩展功能的情况下

必须在输入多边形的角上添加新的坐标点，例如在这个位置的圆角或平角

，如果输入多边形的收缩函数 vector 太小而无法“存活”到收缩操作中，则必须完全删除

我的问题:boost::geometry这样的操作可能吗？如果是，该怎么办？
谢谢!

Answer 1

该功能在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(并且您可以轻松地通过转换完成其余部分)，并且仅在其他坐标系中指向。
Documentation
可用策略:

加入策略:join_round (cartesian)

加入策略:join_miter (cartesian)

EndStrategy:end_round (cartesian)

EndStrategy:end_flat (cartesian)

DistanceStrategy:distance_symmetric

DistanceStrategy:distance_asymmetric

PointStrategy:point_circle (cartesian)

PointStrategy:point_square (cartesian)

PointStrategy:geographic_point_circle (geographic)

SideStrategy:side_straight (cartesian)

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;
}

点可以像这样 “一起成长”
带有圆角的线串示例: