我有以下代码：
class Program {
static void Main(string[] args) {
Polygon a = new Polygon();
a.Add(new IntPoint(0,0));
a.Add(new IntPoint(2,0));
a.Add(new IntPoint(2,1));
a.Add(new IntPoint(1,1));
a.Add(new IntPoint(1,2));
a.Add(new IntPoint(2,2));
a.Add(new IntPoint(2,3));
a.Add(new IntPoint(0,3));
Polygon b = new Polygon();
b.Add(new IntPoint(2,0));
b.Add(new IntPoint(3,0));
b.Add(new IntPoint(3,3));
b.Add(new IntPoint(2,3));
PolyTree solution = new PolyTree();
Clipper c = new Clipper();
c.AddPolygon(a,PolyType.ptSubject);
c.AddPolygon(b,PolyType.ptSubject);
c.Execute(ClipType.ctUnion,solution);
printPolygonTree(solution);
Console.ReadLine();
}
static void printPolygonTree(PolyNode tree) {
Console.WriteLine((tree.IsHole?"Hole":"Polygon")+":");
foreach(IntPoint point in tree.Contour) {
Console.WriteLine(point.X+"/"+point.Y);
}
foreach(PolyNode node in tree.Childs) {
printPolygonTree(node);
}
}
}
它应该统一多边形a和b，这应该会产生一个包含一个小正方形作为孔的大正方形。但是我得到了一个多边形，它有一个切口，可以将内部和外部多边形连接成一个多边形。
有没有办法按预期统一 2 个多边形？
形象的：
