C#利用iTextSharp组件给PDF文档添加图片/文字水印

最近在做关于PDF文档添加水印的功能，折腾了好久，终于好了。以下做个记录：

首先会用到iTextSharp组件，大家可以去官网下载，同时我也会在本文中附加进来。

代码中添加引用为：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using iTextSharp.text.pdf;
using System.IO;
using iTextSharp.text;

创建一个显示指定图片的pdf

/// <summary>
 /// 创建一个显示指定图片的pdf
 /// </summary>
 /// <param name="picPdfPath"></param>
 /// <param name="picPath"></param>
 /// <returns></returns>
 public static bool CreatePDFByPic(string picPdfPath,string picPath)
 {
  //新建一个文档
  Document doc = new Document();
  try
  {
  //建立一个书写器(Writer)与document对象关联
  PdfWriter.GetInstance(doc, new FileStream(picPdfPath, FileMode.Create, FileAccess.ReadWrite));
  //打开一个文档
  doc.Open();
  //向文档中添加内容
  Image img = Image.GetInstance(picPath);
  //img.SetAbsolutePosition();
  doc.Add(img);
  return true;
  }
  catch (Exception ex)
  {
  return false;
  throw ex;
  }
  finally
  {
  if (doc != null)
  {
   doc.Close();
  }
  }
 
 }

为PDF文档添加图片水印

/// <summary>
 /// 加图片水印
 /// </summary>
 /// <param name="inputfilepath"></param>
 /// <param name="outputfilepath"></param>
 /// <param name="ModelPicName"></param>
 /// <param name="top"></param>
 /// <param name="left"></param>
 /// <returns></returns>
 public static 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/2 - image.Width + left;
  }
 
  //image.SetAbsolutePosition(left, (height - image.Height) - top);
  image.SetAbsolutePosition(left, (height/2 - 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);//内容下层加水印
   waterMarkContent = pdfStamper.GetOverContent(i);//内容上层加水印
 
   waterMarkContent.AddImage(image);
  }
  //strMsg = "success";
  return true;
  }
  catch (Exception ex)
  {
  throw ex;
   
  }
  finally
  {
 
  if (pdfStamper != null)
   pdfStamper.Close();
 
  if (pdfReader != null)
   pdfReader.Close();
  }
 }

添加普通偏转角度文字水印

/// <summary>
 /// 添加普通偏转角度文字水印
 /// </summary>
 /// <param name="inputfilepath"></param>
 /// <param name="outputfilepath"></param>
 /// <param name="waterMarkName"></param>
 /// <param name="permission"></param>
 public static void setWatermark(string inputfilepath, string outputfilepath,string waterMarkName)
 {
  PdfReader pdfReader = null;
  PdfStamper pdfStamper = null;
  try
  {
  pdfReader = new PdfReader(inputfilepath);
  pdfStamper = new PdfStamper(pdfReader, new FileStream(outputfilepath, FileMode.Create));
  int total = pdfReader.NumberOfPages + 1;
  iTextSharp.text.Rectangle psize = pdfReader.GetPageSize(1);
  float width = psize.Width;
  float height = psize.Height;
  PdfContentByte content;
  BaseFont font = BaseFont.CreateFont(@"C:\WINDOWS\Fonts\SIMFANG.TTF", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
  PdfGState gs = new PdfGState();
  for (int i = 1; i < total; i++)
  {
   content = pdfStamper.GetOverContent(i);//在内容上方加水印
   //content = pdfStamper.GetUnderContent(i);//在内容下方加水印
   //透明度
   gs.FillOpacity = 0.3f;
   content.SetGState(gs);
   //content.SetGrayFill(0.3f);
   //开始写入文本
   content.BeginText();
   content.SetColorFill(BaseColor.LIGHT_GRAY);
   content.SetFontAndSize(font, 100);
   content.SetTextMatrix(0, 0);
   content.ShowTextAligned(Element.ALIGN_CENTER, waterMarkName, width / 2 - 50,height / 2 - 50, 55);
   //content.SetColorFill(BaseColor.BLACK);
   //content.SetFontAndSize(font, 8);
   //content.ShowTextAligned(Element.ALIGN_CENTER, waterMarkName, 0, 0, 0);
   content.EndText();
  }
  }catch (Exception ex)
  {
  throw ex;
  }
  finally
  {
 
  if (pdfStamper != null)
   pdfStamper.Close();
 
  if (pdfReader != null)
   pdfReader.Close();
  }
 }

添加倾斜水印

/// <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
 
  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.BeginText();
   content.SetColorFill(BaseColor.DARK_GRAY);
   content.SetFontAndSize(font, 50);
   // 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(180, 100);
   for (int k = 0; k < j; k++)
   {
    content.SetTextRise(rise);
    c = waterMarkName[k];
    content.ShowText(c + "");
    rise -= 18;
   }
   }
   // 字体设置结束
   content.EndText();
   // 画一个圆
   //content.Ellipse(250, 450, 350, 550);
   //content.SetLineWidth(1f);
   //content.Stroke();
  }
 
  }
  catch (Exception ex)
  {
  throw ex;
  }
  finally
  {
 
  if (pdfStamper != null)
   pdfStamper.Close();
 
  if (pdfReader != null)
   pdfReader.Close();
  }
 }

调用方法的例子：

string path = "D://my.pdf";
  HtmlToPDFUtil.HtmlToPdf(Request.Url.AbsoluteUri, path);
  //HtmlToPDFUtil.HtmlToPdf(sbUrlList.ToString(), path);
  PDFSetWaterMark.PDFWatermark(path, "D://my.pdf", Server.MapPath("/HtmlToPdf/Tools/sy.bmp"), 0, 0);
  PDFSetWaterMark.setWatermark("D://my.pdf", "D://my2.pdf", "TEST");
  //PDFSetWaterMark.setWatermark("D://my.pdf", "D://my2.pdf", "TEST", "", "", 1);

附件：iTextSharp

总结

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