使用iTextSharp在C#中旋转PDF

虽然它是分割的pdf,内容正在颠倒.如何将其旋转180度.

请帮忙.下面是代码相同

private static void ExtractPages(string inputFile,string outputFile,int start,int end)
     {
         // get input document
         PdfReader inputPdf = new PdfReader(inputFile);

         // retrieve the total number of pages
         int pageCount = inputPdf.NumberOfPages;

         if (end < start || end > pageCount)
         {
             end = pageCount;
         }

         // load the input document
         Document inputDoc =
             new Document(inputPdf.GetPageSizeWithRotation(1));

         // create the filestream
         using (FileStream fs = new FileStream(outputFile,FileMode.Create))
         {
             // create the output writer
             PdfWriter outputWriter = PdfWriter.GetInstance(inputDoc,fs);
             inputDoc.Open();

             PdfContentByte cb1 = outputWriter.DirectContent;

             // copy pages from input to output document
             for (int i = start; i <= end; i++)
             {
                 inputDoc.SetPageSize(inputPdf.GetPageSizeWithRotation(1));
                 inputDoc.NewPage();

                 PdfImportedPage page =
                     outputWriter.GetImportedPage(inputPdf,i);
                 int rotation = inputPdf.GetPageRotation(i);


                 if (rotation == 90 || rotation == 270)
                 {
                     cb1.AddTemplate(page,-1f,1f,inputPdf.GetPageSizeWithRotation(i).Height);

                 }
                 else
                 {
                     cb1.AddTemplate(page,0);
                 }

             }

             inputDoc.Close();
         }
     }