java判断某个点是否在所画多边形/圆形内

java判断某个点是否在所画多边形判断某个点是否在所画多边形/圆形内圆形内

主要为大家详细介绍了java判断某个点是否在所画多边形或圆形内的方法，具有一定的参考价值，感兴趣的小伙

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本文实例为大家分享了java判断某个点是否在所画范围内的具体代码，供大家参考，具体内容如下

IsPtInPoly.java

package com.ardo.util.circle;

import java.util.ArrayList;

* @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

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

}

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

}

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