How to Export Diagram to PDF?

using Syncfusion.Pdf.Graphics;
using Syncfusion.Pdf;

function GeneratePDF() {
  var fileType = "png";
  var fileName = "diagram";
  var region = "content";
  var diagram = $("#Diagram1").data("ejDiagram");
   var image = diagram.exportDiagram({ mode: "data"});
  $.ajax({
     url: '/Diagram/createPDF',
     type: "POST",
     dataType: 'text',
     data: { base64data: image },
     success: function (data) {                 
     window.open("../Images/" + data);
     },
     error: function (xhr) {
      }
   })
  }

 [AcceptVerbs(HttpVerbs.Post)]
public ActionResult createPDF()
{
  string filename = "sample.pdf";
  string filepath = null;
  if (Request.Form["base64data"] != null)
  {
   string image = Request.Form["base64data"].ToString();
   image = image.Substring(image.IndexOf(',') + 1);
   byte[] data = Convert.FromBase64String(image);
   var path = Path.Combine(Server.MapPath("~/Images"), "snapshot.png");
   // An image is generated.
   System.IO.File.WriteAllBytes(path, data); 
   Thread t = new Thread(CreateDocument);
   t.SetApartmentState(ApartmentState.STA);
   t.Start();
   t.Join();
   filepath = Path.Combine(Server.MapPath("~/Images"), "sample.pdf");
   //Saves the PDF document.
   document.Save(filepath);
   document.Close(true);                
  }
  return Content(filename);
}
public void CreateDocument()
{          
 //Creates a PDF document.
 PdfPage page = document.Pages.Add();
 PdfGraphics graphics = page.Graphics;
 string imgPath = ResolveApplicationImagePath("snapshot.png");
 graphics.DrawImage(PdfImage.FromFile(imgPath), 100, 200, 300, 300);            
}
protected string ResolveApplicationImagePath(string fileName)
{
 string dataPath = new System.IO.DirectoryInfo(Request.PhysicalApplicationPath + "\\Images").FullName;
 return string.Format("{0}\\{1}", dataPath, fileName);
}