110 lines
3.3 KiB
Java
110 lines
3.3 KiB
Java
/*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.*/
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//This is a java program to test whether a polygon is inside another polygon
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class Point
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{
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int x, y;
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Point()
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{
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}
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Point(int p, int q)
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{
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x = p;
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y = q;
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}
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}
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public class Position_Point_WRT_Polygon
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{
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public static boolean onSegment(Point p, Point q, Point r)
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{
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if (q.x <= Math.max(p.x, r.x) && q.x >= Math.min(p.x, r.x)
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&& q.y <= Math.max(p.y, r.y) && q.y >= Math.min(p.y, r.y))
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return true;
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return false;
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}
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public static int orientation(Point p, Point q, Point r)
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{
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int val = (q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y);
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if (val == 0)
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return 0;
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return (val > 0) ? 1 : 2;
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}
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public static boolean doIntersect(Point p1, Point q1, Point p2, Point q2)
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{
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int o1 = orientation(p1, q1, p2);
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int o2 = orientation(p1, q1, q2);
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int o3 = orientation(p2, q2, p1);
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int o4 = orientation(p2, q2, q1);
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if (o1 != o2 && o3 != o4)
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return true;
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if (o1 == 0 && onSegment(p1, p2, q1))
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return true;
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if (o2 == 0 && onSegment(p1, q2, q1))
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return true;
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if (o3 == 0 && onSegment(p2, p1, q2))
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return true;
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if (o4 == 0 && onSegment(p2, q1, q2))
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return true;
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return false;
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}
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public static boolean isInside(Point polygon[], int n, Point p)
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{
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int INF = 10000;
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if (n < 3)
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return false;
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Point extreme = new Point(INF, p.y);
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int count = 0, i = 0;
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do
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{
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int next = (i + 1) % n;
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if (doIntersect(polygon[i], polygon[next], p, extreme))
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{
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if (orientation(polygon[i], p, polygon[next]) == 0)
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return onSegment(polygon[i], p, polygon[next]);
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count++;
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}
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i = next;
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}
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while (i != 0);
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return (count & 1) == 1 ? true : false;
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}
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public static Boolean DoesPolygonContainPolygon(Point[] p1, Point[] p2)
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{
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Point p;
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for (int i = 0; i < p2.length; i++)
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{
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p = new Point(p2[i].x, p2[i].y);
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if (!isInside(p1, p1.length, p))
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return false;
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}
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return true;
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}
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public static void main(String args[])
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{
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Point polygon1[] = { new Point(0, 0), new Point(10, 0),
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new Point(10, 10), new Point(0, 10)
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};
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Point polygon2[] = { new Point(0, 0), new Point(15, 5), new Point(5, 0) };
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Point polygon3[] = { new Point(0, 0), new Point(10, 0),
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new Point(10, 10), new Point(0, 10), new Point(5, 5)
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};
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System.out.println("Polygon 1 contains Polygon 2 :"
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+ DoesPolygonContainPolygon(polygon1, polygon2));
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System.out.println("Polygon 3 contains Polygon 1 :"
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+ DoesPolygonContainPolygon(polygon3, polygon1));
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}
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}
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/*
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Polygon 1 contains Polygon 2 :false
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Polygon 3 contains Polygon 1 :true |