private void EnsurePointPairListLength(PointPairList ppl, int length) { int delta = length-ppl.Count; if(delta > 0) { // Add additional points. for(int i=0; i<delta; i++) { ppl.Add(0.0, 0.0); } } else if(delta < 0) { // Remove excess points. ppl.RemoveRange(length, -delta); } }