Replace/Mask Images of PDF file using Itextsharp

Article is about masking or replacing the images from PDF documents using iTextSharp. 

iTextSharp  is a free .NET component, you can download the DLL from http://sourceforge.net/projects/itextsharp/. 

After downloading the DLL, add reference of DLL in project by clicking on Add Reference from solution explorer.


Namespace :

using iTextSharp.text;
using iTextSharp.text.pdf;



Code:

   PdfReader pdf = new PdfReader("Test.pdf");
            PdfStamper stp = new PdfStamper(pdf, new FileStream("output.pdf",
FileMode.Create));
            

PdfWriter writer = stp.Writer;
             for (int pageNumber = 1; pageNumber <= pdf.NumberOfPages; pageNumber++)
            {
               
                Image img = Image.GetInstance("Img.jpg");
            PdfDictionary pg = pdf.GetPageN(pageNumber);
            PdfDictionary res =
              (PdfDictionary)PdfReader.GetPdfObject(pg.Get(PdfName.RESOURCES));
            PdfDictionary xobj =
              (PdfDictionary)PdfReader.GetPdfObject(res.Get(PdfName.XOBJECT));
            if (xobj != null)
            {
                foreach (PdfName name in xobj.Keys)
                {
                    PdfObject obj = xobj.Get(name);
                    if (obj.IsIndirect())
                    {
                        PdfDictionary tg = (PdfDictionary)PdfReader.GetPdfObject(obj);
                        PdfName type =
                          (PdfName)PdfReader.GetPdfObject(tg.Get(PdfName.SUBTYPE));
                        if (PdfName.IMAGE.Equals(type))
                        {
                            PdfReader.KillIndirect(obj);
                            Image maskImage = img.ImageMask;
                            if (maskImage != null)
                                writer.AddDirectImageSimple(maskImage);
                            writer.AddDirectImageSimple(img, (PRIndirectReference)obj);
                            break;
                        }
                    }
                }
            }
        }
            stp.Close();