java判断某个点是否在所画范围内(多边形/圆形)

如题：

IsPtInPoly.java

package com.ardo.util.circle;import java.util.ArrayList;import java.util.List;/**  * java判断某个点是否在所画范围内(多边形【isPtInPoly】/圆形【distencePC】)  * @param point 检测点  * @param pts   多边形的顶点  * @return      点在多边形内返回true,否则返回false  * @author ardo */ public class IsPtInPoly {/**  * 判断点是否在多边形内  * @param point 检测点  * @param pts   多边形的顶点  * @return      点在多边形内返回true,否则返回false  */  public static boolean isPtInPoly(Point2D point, List<Point2D> pts){            int N = pts.size();      boolean boundOrVertex = true; //如果点位于多边形的顶点或边上，也算做点在多边形内，直接返回true      int intersectCount = 0;//cross points count of x       double precision = 2e-10; //浮点类型计算时候与0比较时候的容差      Point2D p1, p2;//neighbour bound vertices      Point2D p = point; //当前点            p1 = pts.get(0);//left vertex              for(int i = 1; i <= N; ++i){//check all rays                      if(p.equals(p1)){              return boundOrVertex;//p is an vertex          }                    p2 = pts.get(i % N);//right vertex                      if(p.x < Math.min(p1.x, p2.x) || p.x > Math.max(p1.x, p2.x)){//ray is outside of our interests                              p1 = p2;               continue;//next ray left point          }                    if(p.x > Math.min(p1.x, p2.x) && p.x < Math.max(p1.x, p2.x)){//ray is crossing over by the algorithm (common part of)              if(p.y <= Math.max(p1.y, p2.y)){//x is before of ray                                      if(p1.x == p2.x && p.y >= Math.min(p1.y, p2.y)){//overlies on a horizontal ray                      return boundOrVertex;                  }                                    if(p1.y == p2.y){//ray is vertical                                              if(p1.y == p.y){//overlies on a vertical ray                          return boundOrVertex;                      }else{//before ray                          ++intersectCount;                      }                   }else{//cross point on the left side                                              double xinters = (p.x - p1.x) * (p2.y - p1.y) / (p2.x - p1.x) + p1.y;//cross point of y                                              if(Math.abs(p.y - xinters) < precision){//overlies on a ray                          return boundOrVertex;                      }                                            if(p.y < xinters){//before ray                          ++intersectCount;                      }                   }              }          }else{//special case when ray is crossing through the vertex                              if(p.x == p2.x && p.y <= p2.y){//p crossing over p2                                      Point2D p3 = pts.get((i+1) % N); //next vertex                                      if(p.x >= Math.min(p1.x, p3.x) && p.x <= Math.max(p1.x, p3.x)){//p.x lies between p1.x & p3.x                      ++intersectCount;                  }else{                      intersectCount += 2;                  }              }          }                      p1 = p2;//next ray left point      }            if(intersectCount % 2 == 0){//偶数在多边形外          return false;      } else { //奇数在多边形内          return true;      }        } /** * 判断是否在圆形内 * @param p * @param c * @return */public static String distencePC(Point2D p,Circle c){//判断点与圆心之间的距离和圆半径的关系        String s ;        double d2 = Math.hypot( (p.getX() - c.getCC().getX() ), (p.getY() - c.getCC().getY()) );        System.out.println("d2=="+d2);        double r = c.getR();        if(d2 > r){              s = "圆外";        }else if(d2 < r){             s = "圆内";        }else{              s = "圆上";        }        return s;}public static void main(String[] args) {            Point2D point = new Point2D(116.404072, 39.916605);            // 测试一个点是否在多边形内      List<Point2D> pts = new ArrayList<Point2D>();      pts.add(new Point2D(116.395, 39.910));      pts.add(new Point2D(116.394, 39.914));      pts.add(new Point2D(116.403, 39.920));      pts.add(new Point2D(116.402, 39.914));      pts.add(new Point2D(116.410, 39.913));            if(isPtInPoly(point, pts)){          System.out.println("点在多边形内");      }else{          System.out.println("点在多边形外");      }          // 测试一个点是否在圆形内      Point2D centerPoint = new Point2D(116.404172, 39.916605);      Circle c = new Circle();        c.setCC(centerPoint);        c.setR(0.0056);        String s = distencePC(point,c);        System.out.println("点是否在圆内："+s);} }

Circle.java

/** * 圆形类 * @author ardo * */public class Circle { private double r;     private Point2D cc;          public void setR(double a){           r = a;     }     public void setCC(Point2D centerOfCir){           cc = centerOfCir;     }     public double getR(){           return r;     }     public Point2D getCC(){           return cc;     }}

Point2D.java

public class Point2D {public double x;public double y;public Point2D(double x, double y) {super();this.x = x;this.y = y;}public double getX() {return x;}public void setX(double x) {this.x = x;}public double getY() {return y;}public void setY(double y) {this.y = y;}}