使用的是iTextSharp添加PDF水印，由于是接口动态生成PDF，所以采用的是全部是内存流的形式，而且水印是平铺是。iTextSharp版本是5.5。
/// <summary>
/// 添加倾斜水印
/// </summary>
/// <param name="pdfStream">pdf文件流</param>
/// <param name="waterMarkName">水印字符串</param>
/// <param name="width">页面宽度</param>
/// <param name="height">页面高度</param>
public MemoryStream SetWaterMark(MemoryStream pdfStream, string waterMarkName, float width, float height)
{
try
{
int fontSize = 50; //设置字体大小
int span = 40; //设置垂直位移
MemoryStream outStream = new MemoryStream();
PdfReader pdfReader = new PdfReader(pdfStream);
PdfStamper pdfStamper = new PdfStamper(pdfReader, outStream);
pdfStamper.Writer.CloseStream = false ;
int total = pdfReader.NumberOfPages + 1;
PdfContentByte content;
BaseFont font = BaseFont.CreateFont( @"C:\WINDOWS\Fonts\STCAIYUN.TTF" , BaseFont.IDENTITY_H, BaseFont.EMBEDDED); //华文云彩字体
PdfGState gs = new PdfGState();
gs.FillOpacity = 0.15f; //透明度
int waterMarkNameLenth = waterMarkName.Length;
char c;
int rise = 0;
string spanString = " " ; //水平位移
for ( int i = 1; i < total; i++)
{
rise = waterMarkNameLenth * span;
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.SetGState(gs);
content.BeginText();
content.SetColorFill(BaseColor.GREEN);
content.SetFontAndSize(font, fontSize);
int heightNumbert = ( int )Math.Ceiling(( decimal )height / ( decimal )rise); //垂直重复的次数，进一发
int panleWith = (fontSize + span) * waterMarkNameLenth;
int widthNumber = ( int )Math.Ceiling(( decimal )width / ( decimal )panleWith); //水平重复次数
// 设置水印文字字体倾斜 开始
for ( int w = 0; w < widthNumber; w++)
{
for ( int h = 1; h <= heightNumbert; h++)
{
int yleng = rise * h;
content.SetTextMatrix(w * panleWith, yleng); //x,y设置水印开始的绝对左边，以左下角为x，y轴的起点
for ( int k = 0; k < waterMarkNameLenth; k++)
{
content.SetTextRise(yleng); //指定的y轴值处添加
c = waterMarkName[k];
content.ShowText(c + spanString);
yleng -= span;
}
}
}
content.EndText();
}
if (pdfStamper != null )
pdfStamper.Close();
if (pdfReader != null )
pdfReader.Close();
return outStream;
}
catch (Exception ex)
{
throw ex;
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
dy("nrwz");
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