itext 文字浮水印

        string sFileIn = "D:\\pdftmp\\102\\09\\10209240001.pdf";
        PdfReader reader = new PdfReader(sFileIn);
        MemoryStream ms = new MemoryStream();

        PdfStamper stamper = new PdfStamper(reader, ms);

        for (int i = 1; i <= reader.NumberOfPages; i++)
        {
            iTextSharp.text.Rectangle pageSize = reader.GetPageSizeWithRotation(i);
            PdfContentByte pdfPageContents = stamper.GetUnderContent(i);
            pdfPageContents.BeginText();
            BaseFont bfChinese = BaseFont.CreateFont(@"C:\WINDOWS\Fonts\kaiu.ttf", BaseFont.IDENTITY_V, BaseFont.NOT_EMBEDDED); //字體 標楷體直書
            //BaseFont bfChinese = BaseFont.createFont("C:\\windows\\fonts\\KAIU.TTF", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED); //字體 標楷體橫書

            pdfPageContents.SetFontAndSize(bfChinese, 14);//14 字型大小
            pdfPageContents.SetRGBColorFill(0, 0, 0); //文字顏色
            float textAngle = 0.0f; //旋轉角度
            float left = 570; //PageSize.Width / 2;
            float bottom = 700; // PapeSize.A4.Hight / 2 + 120f;
            pdfPageContents.ShowTextAligned(PdfContentByte.ALIGN_LEFT, "版權所有翻印必究。", left, bottom, textAngle);
            //pdfPageContents.ShowTextAligned(PdfContentByte.ALIGN_LEFT, "本內容之版權由相關機構擁有", left + 15, bottom, textAngle);
                    
            stamper.FormFlattening = true;
            stamper.Close();
            reader.Close();
            pdfPageContents.EndText();
        }
        //stamper.FormFlattening = true;
        //stamper.Close();
        FileStream fs = new FileStream("D:\\pdftmp\\102\\09\\watermarked-output.pdf", FileMode.Create, FileAccess.ReadWrite);
        BinaryWriter bw = new BinaryWriter(fs);
        bw.Write(ms.ToArray());
        fs.Close();
        bw.Close();

用此方式如產生
『此頁上有錯誤。Acrobat可能無法正確顯示頁面。請聯繫PDF文件的建立者來更正問題。』

請移除舊版檢視軟體(Adobe Reader)，移除後請至「ADOBE READER」網站，下載並安裝Adobe Reader（須10.1.4以上版本）。