/*This is a Java Program to check whether a polygon contains another polygon or not. The class returns true if one polygon contains another, false otherwise.*/ //This is a java program to test whether a polygon is inside another polygon class Point { int x, y; Point() { } Point(int p, int q) { x = p; y = q; } } public class Position_Point_WRT_Polygon { public static boolean onSegment(Point p, Point q, Point r) { if (q.x <= Math.max(p.x, r.x) && q.x >= Math.min(p.x, r.x) && q.y <= Math.max(p.y, r.y) && q.y >= Math.min(p.y, r.y)) return true; return false; } public static int orientation(Point p, Point q, Point r) { int val = (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y); if (val == 0) return 0; return (val > 0) ? 1 : 2; } public static boolean doIntersect(Point p1, Point q1, Point p2, Point q2) { int o1 = orientation(p1, q1, p2); int o2 = orientation(p1, q1, q2); int o3 = orientation(p2, q2, p1); int o4 = orientation(p2, q2, q1); if (o1 != o2 && o3 != o4) return true; if (o1 == 0 && onSegment(p1, p2, q1)) return true; if (o2 == 0 && onSegment(p1, q2, q1)) return true; if (o3 == 0 && onSegment(p2, p1, q2)) return true; if (o4 == 0 && onSegment(p2, q1, q2)) return true; return false; } public static boolean isInside(Point polygon[], int n, Point p) { int INF = 10000; if (n < 3) return false; Point extreme = new Point(INF, p.y); int count = 0, i = 0; do { int next = (i + 1) % n; if (doIntersect(polygon[i], polygon[next], p, extreme)) { if (orientation(polygon[i], p, polygon[next]) == 0) return onSegment(polygon[i], p, polygon[next]); count++; } i = next; } while (i != 0); return (count & 1) == 1 ? true : false; } public static Boolean DoesPolygonContainPolygon(Point[] p1, Point[] p2) { Point p; for (int i = 0; i < p2.length; i++) { p = new Point(p2[i].x, p2[i].y); if (!isInside(p1, p1.length, p)) return false; } return true; } public static void main(String args[]) { Point polygon1[] = { new Point(0, 0), new Point(10, 0), new Point(10, 10), new Point(0, 10) }; Point polygon2[] = { new Point(0, 0), new Point(15, 5), new Point(5, 0) }; Point polygon3[] = { new Point(0, 0), new Point(10, 0), new Point(10, 10), new Point(0, 10), new Point(5, 5) }; System.out.println("Polygon 1 contains Polygon 2 :" + DoesPolygonContainPolygon(polygon1, polygon2)); System.out.println("Polygon 3 contains Polygon 1 :" + DoesPolygonContainPolygon(polygon3, polygon1)); } } /* Polygon 1 contains Polygon 2 :false Polygon 3 contains Polygon 1 :true