/// <summary>
/// Calculates the centroid of the polygon by moving it according to each holes
/// weighted centroid.
/// </summary>
public C2DPoint GetCentroid()
{
C2DPoint HoleCen = new C2DPoint(0, 0);
if (_Holes.Count == 0)
{
return(Rim.GetCentroid());
}
C2DPoint PolyCen = Rim.GetCentroid();
double dPolyArea = Rim.GetArea();
double dHoleArea = 0;
for (int i = 0; i < _Holes.Count; i++)
{
dHoleArea += GetHole(i).GetArea();
}
if (dHoleArea == 0 || dHoleArea == dPolyArea)
{
return(Rim.GetCentroid());
}
else
{
for (int i = 0; i < _Holes.Count; i++)
{
C2DPoint pt = GetHole(i).GetCentroid();
pt.Multiply(GetHole(i).GetArea() / dHoleArea);
HoleCen += pt;
}
}
C2DVector Vec = new C2DVector(HoleCen, PolyCen);
Vec.Multiply(dHoleArea / (dPolyArea - dHoleArea));
PolyCen.Move(Vec);
return(PolyCen);
}