C#使用iTextSharp给PDF添加水印

代码：

/// <summary>
/// 添加普通偏转角度文字水印
</summary>
public static void SetWatermark(string filePath,string text)
{
    PdfReader pdfReader = null;
    pdfstamper pdfstamper = ;
    string tempPath = Path.GetDirectoryName(filePath) + Path.GetFileNameWithoutExtension(filePath) + "_temp.pdf";

    try
    {
        pdfReader = new PdfReader(filePath);
        pdfstamper = new pdfstamper(pdfReader,1)"> FileStream(tempPath,FileMode.Create));
        int total = pdfReader.NumberOfPages + 1;
        iTextSharp.text.Rectangle psize = pdfReader.GetPageSize();
        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 =  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.GRAY);
            content.SetFontAndSize(font,30);
            content.SetTextMatrix(0,0);
            content.showtextAligned(Element.ALIGN_CENTER,text,width - 120,height - 45);
            content.SetColorFill(BaseColor.BLACK);
            content.SetFontAndSize(font,8);
            content.showtextAligned(Element.ALIGN_CENTER,waterMarkName,0);
            content.EndText();
        }
    }
    catch (Exception ex)
    {
        throw ex;
    }
    finally
    {
        if (pdfstamper != )
            pdfstamper.Close();

        if (pdfReader != )
            pdfReader.Close();
        System.IO.File.copy(tempPath,filePath,true);
        System.IO.File.Delete(tempPath);
    }
}

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