C# PDF添加水印

需要iTextSharp.dll, 下载地址http://sourceforge.net/projects/itextsharp/

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

using iTextSharp.text.html.simpleparser;
using iTextSharp.text.pdf;
using iTextSharp.text;
using System.IO;

namespace pdf_test
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
string source = @"D:\Sample\18.pdf"; //模板路径
string output = @"D:\Sample\Chap1018.pdf"; //导出水印背景后的PDF
string watermark = @"D:\Sample\03.gif"; // 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; //h////////////
}

//image.SetAbsolutePosition(left, (height - image.Height) - top); //h////////////
image.SetAbsolutePosition(136, 36);

//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();
}
}

//
}
}