protected internal RectangleF BaseGroupRotate(float angle, PointF center)
{
DataBk.State = ControlState.GroupRotate;
DataBk.Offset = Calculation.GetRotateAtOffset(DataBk, center, angle);
_rotateAngle = DataBk.RotateAngle + angle;
Calculation.LimitAngle(ref _rotateAngle);
return(CalculateOffset());
}