itext 加上圖片浮水印

        string FileLocation = "D:\\pdftmp\\102\\09\\10209240001.pdf";  //PDF原始檔路徑
        string WatermarkLocation = "D:\\www\\aspx\\cute\\water-4.png"; //浮水印圖檔路徑

        Document document = new Document();
        PdfReader pdfReader = new PdfReader(FileLocation);
        PdfStamper stamp = new PdfStamper(pdfReader, new FileStream(FileLocation.Replace(".pdf", "[temp][file].pdf"), FileMode.Create));

        iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(WatermarkLocation);
        img.SetAbsolutePosition(560, 100); // 圖片位置 (560,0 = 距離 左方,下方 位置)
        img.ScalePercent(35f);  //縮放比例

        PdfContentByte waterMark;
        for (int page = 1; page <= pdfReader.NumberOfPages; page++)
        {
            waterMark = stamp.GetOverContent(page);
            waterMark.AddImage(img);
        }
        stamp.FormFlattening = true;
        stamp.Close();
        File.Delete(FileLocation);
        File.Move(FileLocation.Replace(".pdf", "[temp][file].pdf"), FileLocation);