C#给PDF文件添加水印的代码方法分享

这篇文章主要为大家详细介绍了c#给pdf文件添加水印的相关代码，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

本文实例为大家分享了C#添加PDF文件水印的具体代码，供大家参考，具体内容如下

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();
    }