public static boolean onBoundary(ArrayList<Point> pol, Point p) {
int n = pol.size();
for (int i = 0; i < n; i++) {
int j = (i + 1) % n;
if (Points.onSegment(pol.get(i), pol.get(j), p)) return true;
}
return false;
}
public static boolean onBoundary(Point[] pol, Point p) {
int n = pol.length;
for (int i = 0; i < n; i++) {
int j = (i + 1) % n;
if (Points.onSegment(pol[i], pol[j], p)) return true;
}
return false;
}
public static ArrayList<Point> cut(ArrayList<Point> pol, Point p, Point q, Point x) {
ArrayList<Point> res = new ArrayList<>();
int orient = Points.orient(p, q, x);
Line L = new Line(p, q);
for (int i = 0; i < pol.size(); i++) {
int j = (i + 1) % pol.size();
if (Points.orient(p, q, pol.get(i)) == orient) {
res.add(pol.get(i));
}
Point inter = L.intersection(new Line(pol.get(i), pol.get(j)));
if (inter != null && Points.onSegment(pol.get(i), pol.get(j), inter)) {
res.add(inter);
}
}
return res;
}
/*
* Cut a polygon by the line pq
*/
@SuppressWarnings("rawtypes")
public static ArrayList[] cut(ArrayList<Point> pol, Point p, Point q) {
ArrayList<Point> polWithInter = new ArrayList<>();
Line L = new Line(p, q);
for (int i = 0; i < pol.size(); i++) {
polWithInter.add(pol.get(i));
int j = (i + 1) % pol.size();
Point inter = L.intersection(new Line(pol.get(i), pol.get(j)));
if (inter != null
&& Points.onSegment(pol.get(i), pol.get(j), inter)
&& !Points.eq(pol.get(i), inter)
&& !Points.eq(pol.get(j), inter)) {
polWithInter.add(inter);
}
}
ArrayList<Point> pol1 = new ArrayList<Point>();
ArrayList<Point> pol2 = new ArrayList<Point>();
for (Point x : polWithInter) {
int orient = Points.orient(x, p, q);
if (orient <= 0) pol1.add(x);
if (orient >= 0) pol2.add(x);
}
return new ArrayList[] {pol1, pol2};
}
