private static void Draw_Text_With_OUTER_line(ref PdfPage dst_page, string text, XFont xfont, XPen x_pen, XBrush x_brush, XStringFormat x_sf, XRect xr)
    {
        XGraphics gfx = XGraphics.FromPdfPage(dst_page);
        XGraphicsPath path = new XGraphicsPath();
        path.AddString(text, xfont.FontFamily, xfont.Style, xfont.Size, xr, x_sf);
        gfx.DrawPath(x_pen, x_brush, path);
        gfx.DrawString(text, xfont, x_brush, xr, x_sf);
        gfx.Dispose();
    }

// Create a graphical path.
var path = new XGraphicsPath();
 
// Create a string format.
var format = new XStringFormat();
format.Alignment = XStringAlignment.Near;
format.LineAlignment = XLineAlignment.Near;
 
// Add the text to the path.
// AddString is not implemented in PDFsharp Core.
path.AddString(watermark, font.FontFamily, XFontStyle.BoldItalic, 150,
    new XPoint((page.Width - size.Width) / 2, (page.Height - size.Height) / 2),
    format);
 
// Create a dimmed red pen and brush.
var pen = new XPen(XColor.FromArgb(50, 75, 0, 130), 3);
XBrush brush = new XSolidBrush(XColor.FromArgb(50, 106, 90, 205));
 
// Stroke the outline of the path.
gfx.DrawPath(pen, brush, path);