if (h == LengthConstraintType.NONE) {
                return arrangeNN(container, g2);  
            }
            else if (h == LengthConstraintType.FIXED) {
                
                throw new RuntimeException("Not yet implemented.");  
            }
            else if (h == LengthConstraintType.RANGE) {
                // find optimum height, then map to range
                throw new RuntimeException("Not yet implemented.");