利用iTextSharp组件给PDF文档添加图片水印，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);