/// <summary> /// Converts the angle of the line to Arithmetic Rotation. /// </summary> /// <param name="source">The source.</param> /// <returns>Returns a <see cref="double" /> representing the angle.</returns> public static double GetArithmeticAngle(this IPolyline source) { if (source == null) { return(0); } ILine line = new LineClass(); line.PutCoords(source.FromPoint, source.ToPoint); return(line.GetArithmeticAngle()); }