Convert to Tiff to pdf using itextsharp c#

            // creation of the document with a certain size and certain margins

            iTextSharp.text.Document document = new iTextSharp.text.Document(iTextSharp.text.PageSize.A4, 0, 0, 0, 0);

            // creation of the different writers

            iTextSharp.text.pdf.PdfWriter writer = iTextSharp.text.pdf.PdfWriter.GetInstance(document, new System.IO.FileStream(Server.MapPath("~/App_Data/result.pdf"), System.IO.FileMode.Create));

            // load the tiff image and count the total pages

            System.Drawing.Bitmap bm = new System.Drawing.Bitmap(Server.MapPath("~/App_Data/source.tif"));

            int total = bm.GetFrameCount(System.Drawing.Imaging.FrameDimension.Page);

            document.Open();

            iTextSharp.text.pdf.PdfContentByte cb = writer.DirectContent;

            for (int k = 0; k < total; ++k)

            {

                bm.SelectActiveFrame(System.Drawing.Imaging.FrameDimension.Page, k);

               

                iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(bm, ImageFormat.Tiff);

                img.SetAbsolutePosition(0, 0);

                img.ScaleAbsoluteHeight(document.PageSize.Height);

                img.ScaleAbsoluteWidth(document.PageSize.Width);

                cb.AddImage(img);

                document.NewPage();               

            }

            document.Close();