C#给PDF文件添加水印的代码方法分享

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using iTextSharp.text.html.simpleparser;

using iTextSharp.text.pdf;

using iTextSharp.text;

using System.IO;

using System.Web.UI.HtmlControls;

using System.Drawing;

//itextsharp.dll version:5.1.10

protected void Button1_Click(object sender, EventArgs e)

   {

    string source =@"D:\My.Sample\C#NET\Exoport2PDF\Web2\Chap1011.pdf"; //模板路径

    string output = @"D:\My.Sample\C#NET\Exoport2PDF\Web2\Chap1012.pdf"; //导出水印背景后的PDF

    string watermark = @"D:\My.Sample\C#NET\Exoport2PDF\Web2\gp0.jpg";  // 水印图片

    bool isSurrcess = PDFWatermark(source, output, watermark, 10, 10);

   }

  public bool PDFWatermark(string inputfilepath, string outputfilepath, string ModelPicName, float top, float left)

  {

    //throw new NotImplementedException();

    PdfReader pdfReader = null;

    PdfStamper pdfStamper = null;

    try

    {

      pdfReader = new PdfReader(inputfilepath);

      int numberOfPages = pdfReader.NumberOfPages;

      iTextSharp.text.Rectangle psize = pdfReader.GetPageSize(1);

      float width = psize.Width;

      float height = psize.Height;

      pdfStamper = new PdfStamper(pdfReader, new FileStream(outputfilepath, FileMode.Create));

      PdfContentByte waterMarkContent;

      iTextSharp.text.Image image = iTextSharp.text.Image.GetInstance(ModelPicName);

      image.GrayFill = 20;//透明度，灰色填充

      //image.Rotation//旋转

      //image.RotationDegrees//旋转角度

      //水印的位置

      if (left < 0)

      {

        left = width - image.Width + left;

      }

      image.SetAbsolutePosition(left, (height - image.Height) - top);

      //每一页加水印,也可以设置某一页加水印

      for (int i = 1; i <= numberOfPages; i++)

      {

        waterMarkContent = pdfStamper.GetUnderContent(i);

        waterMarkContent.AddImage(image);

      }

      //strMsg = "success";

      return true;

    }

    catch (Exception ex)

    {

       ex.Message.Trim();

      return false;

    }

    finally

    {

      if (pdfStamper != null)

        pdfStamper.Close();

      if (pdfReader != null)

        pdfReader.Close();

    }