C# WPF PDF导出水印添加

需要添加引用iTextSharp.dll，具体的添加方式可以通过nuget添加，不做赘述。

public static bool ExportRange2CSV(IEnumerable dataSource, DataGrid grid, string fileName)
        {
            try
            {
                PdfPTable table1 = new PdfPTable(16);
                table1.TotalWidth = 820;
                table1.LockedWidth = true;//锁定宽度

                //int[] a = { 0, 1, 1, 4, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };          //设置列宽比例
                float[] a = { 0, 33, 36, 130, 100, 100, 27, 50, 36, 50, 50, 50, 25, 50, 25, 50 };          //设置列宽比例
                table1.SetWidths(a);
                string str = Export2Text(dataSource, ",", grid.Columns.ToArray());
                //File.WriteAllText(fileName, str, encoding);
                string[] strArray = str.Split(',');
                foreach (string s in strArray)
                {
                   // table1.AddCell(s);     //添加单元格
                }

                //字体定义
                var bfchinese = BaseFont.CreateFont(@"c:\windows\fonts\simkai.ttf", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);//simkai.ttf
                var ChFont_12 = new Font(bfchinese, 12);
                var ChFont_10 = new Font(bfchinese, 10);
                var ChFont_8 = new Font(bfchinese, 8);
                var ChFont_12_red = new Font(bfchinese, 12, iTextSharp.text.Font.ITALIC, BaseColor.RED);

                int coordinate = 1;
                foreach (string str2 in strArray)
                {
                    PdfPCell cell = new PdfPCell(new Phrase(str2, ChFont_10));
                    cell.HorizontalAlignment = 1;       //居中输入 默认 0：居左 1：居中 
                    if(coordinate>17) cell.HorizontalAlignment = 0;
                    table1.AddCell(cell);     //添加单元格
                    coordinate++;
                }
                

                //定义一个Document，并设置页面大小为A4，竖向 
                Document doc = new Document(PageSize.A4.Rotate());
                try
                {
                    //写实例 
                    PdfWriter.GetInstance(doc, new FileStream("C:\\Windows\\cache.pdf", FileMode.Create));
                    #region 设置PDF的头信息，一些属性设置，在Document.Open 之前完成
                    doc.AddAuthor("Mr J");
                    doc.AddCreationDate();
                    doc.AddCreator("HYBIOME");
                    doc.AddSubject("本文件解释权在医院");
                    doc.AddTitle("结果导出文件");
                    doc.AddKeywords("HYBIOME");
                    //自定义头 
                    doc.AddHeader("Expires", "0");                      
                    #endregion //打开document
                    doc.Open();
                    //载入字体 
                    //BaseFont.AddToResourceSearch("iTextAsian.dll");
                    //BaseFont.AddToResourceSearch("iTextAsianCmaps.dll");
                    //"UniGB-UCS2-H" "UniGB-UCS2-V"是简体中文，分别表示横向字 和 // 纵向字 //" STSong-Light"是字体名称 
                    BaseFont baseFT = BaseFont.CreateFont(@"c:\windows\fonts\SIMHEI.TTF", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
                    Font font = new Font(baseFT); //写入一个段落, Paragraph 
                    doc.Add(table1);

                    //font.Size = 15;
                    //doc.Add(new Paragraph(str, font));
                    
                    //关闭document 
                    doc.Close();

                    SetWatermark("C:\\Windows\\cache.pdf", fileName, "HYBIOME", "", "", 123456);

                    //打开PDF，看效果 
                    Process.Start(fileName);
                }
                catch (DocumentException de) { Console.WriteLine(de.Message); Console.ReadKey(); }
                catch (IOException io) { Console.WriteLine(io.Message); Console.ReadKey(); }


            }
            catch (Exception)
            {
                return false;
            }
            return true;
        }

        /// <summary>
        /// 添加倾斜水印
        /// </summary>
        /// <param name="inputfilepath"></param>
        /// <param name="outputfilepath"></param>
        /// <param name="waterMarkName"></param>
        /// <param name="userPassWord"></param>
        /// <param name="ownerPassWord"></param>
        /// <param name="permission"></param>
        public static void SetWatermark(string inputfilepath, string outputfilepath, string waterMarkName, string userPassWord, string ownerPassWord, int permission)
        {
            PdfReader pdfReader = null;
            PdfStamper pdfStamper = null;
            try
            {
                pdfReader = new PdfReader(inputfilepath);
                pdfStamper = new PdfStamper(pdfReader, new FileStream(outputfilepath, FileMode.Create));
                // 设置密码  
                //pdfStamper.SetEncryption(false,userPassWord, ownerPassWord, permission);

                int total = pdfReader.NumberOfPages + 1;
                PdfContentByte content;
                BaseFont font = BaseFont.CreateFont(@"C:\WINDOWS\Fonts\SIMFANG.TTF", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
                PdfGState gs = new PdfGState();
                gs.FillOpacity = 0.2f;//透明度

                //waterMarkName = waterMarkName + DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
                int j = waterMarkName.Length;
                char c;
                int rise = 0;
                for (int i = 1; i < total; i++)
                {                    
                    rise = 500;
                    //content = pdfStamper.GetOverContent(i);//在内容上方加水印
                    content = pdfStamper.GetUnderContent(i);//在内容下方加水印

                    content.SetGState(gs);
                    content.BeginText();
                    content.SetColorFill(BaseColor.DARK_GRAY);
                    content.SetFontAndSize(font, 100);
                    // 设置水印文字字体倾斜 开始
                    if (j >= 15)
                    {
                        content.SetTextMatrix(200, 120);
                        for (int k = 0; k < j; k++)
                        {
                            content.SetTextRise(rise);
                            c = waterMarkName[k];
                            content.ShowText(c + "");
                            rise -= 20;
                        }
                    }
                    else
                    {
                        content.SetTextMatrix(220, -200);
                        for (int k = 0; k < j; k++)
                        {
                            content.SetTextRise(rise);
                            c = waterMarkName[k];
                            content.ShowText(c + "");
                            //rise -= 18;                            
                        }

                        content.SetFontAndSize(font, 20);
                        content.SetTextMatrix(250, -250);
                        string dateTimeStr= DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");
                        for (int k=0;k<dateTimeStr.Length;k++)
                        {
                            content.SetTextRise(rise);
                            c = dateTimeStr[k];
                            content.ShowText(c + "");
                        }
                    }
                    // 字体设置结束
                    content.EndText();
                    ////画一个圆
                    ////content.Ellipse(250, 450, 350, 550);
                    //content.Ellipse(260, 260, 480, 360);
                    //content.SetLineWidth(3f);
                    ////content.SetGState(gs);//试图使其透明 但无效 姜彦20181021 1702
                    //content.Stroke();
                }

            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {

                if (pdfStamper != null)
                    pdfStamper.Close();

                if (pdfReader != null)
                    pdfReader.Close();
            }
        }