package com.lf.server.helper;

import com.lf.server.entity.ctrl.CoordinateEntity;
import org.locationtech.jts.geom.*;
import org.locationtech.jts.triangulate.ConformingDelaunayTriangulationBuilder;

import java.util.List;

/**
 * JTS帮助类
 *
 * @author WWW
 * @date 2024-02-28
 */
public class JtsHelper {
    /**
     * 根据坐标点计算面积
     */
    public static double calcAreaByPoints(List<CoordinateEntity> ces) {
        Coordinate[] cs = new Coordinate[ces.size()];
        for (int i = 0, c = ces.size(); i < c; i++) {
            cs[i] = new Coordinate(ces.get(i).getX(), ces.get(i).getY());
        }

        GeometryFactory gf = new GeometryFactory();
        MultiPoint mp = gf.createMultiPointFromCoords(cs);

        ConformingDelaunayTriangulationBuilder builder = new ConformingDelaunayTriangulationBuilder();
        builder.setSites(mp);

        // 实际为GeometryCollection（组成的geometry紧密相连）
        Geometry ts = builder.getTriangles(gf);
        // 以0的距离进行缓冲（因为各多边形两两共边），此时则将点云构造成了多边形
        Geometry union = ts.buffer(0);

        // String text = union.toText()
        double area = union.getArea();

        return Math.round(area * 100.0) / 100.0;
    }
}