public virtual void Offset(float x, float y)
        {
            PolygonF offsetPly = PolygonF.Offset(this, x, y);

            this.Clear();
            this._pnts.AddRange(offsetPly._pnts.ToArray());
            if (this._preCalcBBox)
            {
                this.UpdateMinMax(this._pnts);
            }
            offsetPly.Clear();
        }
 public static Polygon Offset(Polygon ply, int x, int y)
 {
     return(Polygon.Truncate(PolygonF.Offset(ply._ply, (float)x, (float)y)));
 }