/// <summary>
        /// 将PDF文档转换为图片的方法
        /// </summary>
        /// <param name="pdfInputPath"></param>
        /// <param name="desPath">输出相对路径</param>
        /// <param name="definition">设置图片的清晰度，数字越大越清晰</param>
        /// <returns></returns>
        public static List<string> ConvertPDF2Image(string pdfInputPath, string desPath, Definition definition, string title)
        {
            List<string> imgList = new List<string>();
            PDFFile pdfFile = PDFFile.Open(pdfInputPath);
            int startPageNum = 1, endPageNum = pdfFile.PageCount;
            int number = 1;
            for (int i = startPageNum; i <= endPageNum; i++)
            {
                Bitmap pageImage = pdfFile.GetPageImage(i - 1, 56 * (int)definition);
                string filePath = desPath + title + "-" + number + ".jpg";
                imgList.Add(filePath);
                pageImage.Save(System.Web.HttpContext.Current.Server.MapPath(filePath));
                number++;
            }
            pdfFile.Dispose();
            return imgList;
        }

        
        public enum Definition
        {
            One = 1, Two = 2, Three = 3, Four = 4, Five = 5, Six = 6, Seven = 7, Eight = 8, Nine = 9, Ten = 10
        }

        /// <summary>
        /// 合并PDF
        /// </summary>
        /// <param name="fileList">绝对路径集合</param>
        /// <param name="outMergeFile">合并后的文件存在地址绝对路径</param>
        public static void mergePdfFiles(List<string> fileList, string outMergeFile)
        {
            PdfReader reader;
            //此处将内容从文本提取至文件流中的目的是避免文件被占用,无法删除
            FileStream fs1 = new FileStream(fileList[0], FileMode.Open);
            byte[] bytes1 = new byte[(int)fs1.Length];
            fs1.Read(bytes1, 0, bytes1.Length);
            fs1.Close();
            reader = new PdfReader(bytes1);
            reader.GetPageSize(1);
            // iTextSharp.text.Rectangle rec = new iTextSharp.text.Rectangle(1000,800);//设置样式
            iTextSharp.text.Rectangle rec = reader.GetPageSize(1);
            float width = rec.Width;
            float height = rec.Height;
            //创建一个文档变量
            iTextSharp.text.Document document = new iTextSharp.text.Document(rec, 50, 50, 50, 50);
            //创建该文档
            PdfWriter pdfWrite = PdfWriter.GetInstance(document, new FileStream(outMergeFile, FileMode.Create));
            //打开文档
            document.Open();
            //添加内容
            PdfContentByte contentByte = pdfWrite.DirectContent;
            PdfImportedPage newPage;
            for (int i = 0; i < fileList.Count; i++)
            {

                FileStream fs = new FileStream(fileList[i], FileMode.Open);
                byte[] bytes = new byte[(int)fs.Length];
                fs.Read(bytes, 0, bytes.Length);
                fs.Close();
                reader = new PdfReader(bytes);
                int pageNum = reader.NumberOfPages;//获取文档页数
                for (int j = 1; j <= pageNum; j++)
                {
                    document.NewPage();
                    newPage = pdfWrite.GetImportedPage(reader, j);
                    contentByte.AddTemplate(newPage, 0, 0);
                }

            }
            document.Close();
        }

        /// <summary>
        /// 图片转PDF
        /// </summary>
        /// <param name="imagepath">图片位置（绝地路径）</param>
        /// <param name="pdfpath">存放PDF地址（绝地路径）</param>
        public static void iTextSharpCreatPDF(string imagepath, string pdfpath)
        {
            iTextSharp.text.Image image = iTextSharp.text.Image.GetInstance(imagepath);
            float percentage = 1;
            //这里都是图片最原始的宽度与高度
            float resizedWidht = image.Width;
            float resizedHeight = image.Height;
            Document doc = new Document(new iTextSharp.text.Rectangle(resizedWidht, resizedHeight), 0, 0, 0, 0); //new Rectangle(1000,1000)

            //指定文件预设开档时的缩放为100%
            //PdfDestination pdfDest = new PdfDestination(PdfDestination.XYZ, 0, doc.PageSize.Height, 1f);
            try
            {
                PdfWriter.GetInstance(doc, new FileStream(pdfpath, FileMode.Create));
                doc.Open();
                #region 下面对图片进行操作
                ////这时判断图片宽度是否大于页面宽度减去也边距，如果是，那么缩小，如果还大，继续缩小，
                ////这样这个缩小的百分比percentage会越来越小
                while (resizedWidht > (doc.PageSize.Width - doc.LeftMargin - doc.RightMargin))
                {
                    percentage = percentage * 0.9f;
                    resizedHeight = image.Height * percentage;
                    resizedWidht = image.Width * percentage;
                }
                #region 注释
                ////There is a 0.8 here. If the height of the image is too close to the page size height,
                ////the image will seem so big
                //while (resizedHeight > (doc.PageSize.Height - doc.TopMargin - doc.BottomMargin) * 0.8)
                //{
                //    percentage = percentage * 0.9f;
                //    resizedHeight = image.Height * percentage;
                //    resizedWidht = image.Width * percentage;
                //}
                #endregion
                ////这里用计算出来的百分比来缩小图片
                image.ScalePercent(percentage * 100);
                //让图片的中心点与页面的中心点进行重合
                image.SetAbsolutePosition(doc.PageSize.Width / 2 - resizedWidht / 2, doc.PageSize.Height / 2 - resizedHeight / 2);
                doc.Add(image);
                #endregion
            }
            catch (DocumentException dex)
            {
                System.Web.HttpContext.Current.Response.Write(dex.Message);
            }
            catch (IOException ioex)
            {
                System.Web.HttpContext.Current.Response.Write(ioex.Message);
            }

            catch (Exception ex)
            {
                System.Web.HttpContext.Current.Response.Write(ex.Message);
            }
            finally
            {
                doc.Close();
            }
        }