public void AddRect(double width, double height, double x, double y, double rx = 0, double ry = 0)
 {
     x      = _calcx(x);
     y      = _calcy(y);
     width  = _scale(width);
     height = _scale(height);
     rx     = _scale(rx);
     ry     = _scale(ry);
     _svgWriter.AddRect(width.ToString("0.##"), height.ToString("0.##"), x.ToString("0.##"), y.ToString("0.##"), rx.ToString("0.##"), ry.ToString("0.##"));
 }