从带有图像和水印的pdf创建pdf

时间:2019-02-01 07:11:00

标签: c# itext

我要创建一个新的pdf文件,添加一个水印,然后使每个页面成为一个图像页面。

itext可以吗?

1 个答案:

答案 0 :(得分:0)

我不知道如何将其转换为图像,但是对于水印,正如Usama Kiyani在评论中所说,您应该考虑使用可以通过块软件包管理器安装的itextsharp。我已经使用它在现有的pdf文件中添加水印。

这是我使用的代码,它在现有pdf文件(sourceFile)的每页中央添加一个对角红色水印(文本为自变量watermarkText),然后将此修改后的版本保存在给定位置(outputFile):

public static void AddWatermarkTextC(string sourceFile, string outputFile, string watermarkText)
    {
        BaseFont tWatermarkFont = null;
        float tWatermarkFontSize = 48F;
        iTextSharp.text.BaseColor tWatermarkFontColor = null;
        float tWatermarkFontOpacity = 0.3F;
        float tWatermarkRotation = 45.0F;

        tWatermarkFont = iTextSharp.text.pdf.BaseFont.CreateFont(iTextSharp.text.pdf.BaseFont.HELVETICA, iTextSharp.text.pdf.BaseFont.CP1252, iTextSharp.text.pdf.BaseFont.NOT_EMBEDDED);
        tWatermarkFontColor = iTextSharp.text.BaseColor.RED;
        AddWatermarkTextC(sourceFile, outputFile, watermarkText, tWatermarkFont, tWatermarkFontSize, tWatermarkFontColor, tWatermarkFontOpacity, tWatermarkRotation);
    }

public static void AddWatermarkTextC(string sourceFile, string outputFile, string watermarkText, iTextSharp.text.pdf.BaseFont watermarkFont, float watermarkFontSize, iTextSharp.text.BaseColor watermarkFontColor, float watermarkFontOpacity, float watermarkRotation)
    {

        iTextSharp.text.pdf.PdfReader reader = null;
        iTextSharp.text.pdf.PdfStamper stamper = null;
        iTextSharp.text.pdf.PdfGState gstate = null;
        iTextSharp.text.pdf.PdfContentByte underContent = null;
        iTextSharp.text.Rectangle rect = null;
        float currentY = 0.0F;
        float offset = 0.0F;
        int pageCount = 0;

        try
        {
            reader = new iTextSharp.text.pdf.PdfReader(sourceFile);
            rect = reader.GetPageSizeWithRotation(1);
            FileStream stream = new System.IO.FileStream(outputFile, System.IO.FileMode.Create);
            stamper = new iTextSharp.text.pdf.PdfStamper(reader, stream);

            if (watermarkFont == null)
            {
                watermarkFont = iTextSharp.text.pdf.BaseFont.CreateFont(iTextSharp.text.pdf.BaseFont.HELVETICA, iTextSharp.text.pdf.BaseFont.CP1252, iTextSharp.text.pdf.BaseFont.NOT_EMBEDDED);
            }

            if (watermarkFontColor == null)
            {
                watermarkFontColor = iTextSharp.text.BaseColor.RED;
            }

            gstate = new iTextSharp.text.pdf.PdfGState();
            gstate.FillOpacity = watermarkFontOpacity;
            gstate.StrokeOpacity = watermarkFontOpacity;
            pageCount = reader.NumberOfPages;

            for (int i = 1; i <= pageCount; i++)
            {
                underContent = stamper.GetOverContent(i);
                underContent.SaveState();
                underContent.SetGState(gstate);
                underContent.SetColorFill(watermarkFontColor);
                underContent.BeginText();
                underContent.SetFontAndSize(watermarkFont, watermarkFontSize);
                underContent.SetTextMatrix(30, 30);

                currentY = (rect.Height / 2);

                underContent.ShowTextAligned(iTextSharp.text.Element.ALIGN_CENTER, watermarkText, rect.Width / 2, currentY - offset, watermarkRotation);

                underContent.EndText();
                underContent.RestoreState();
            }

            stamper.Close();
            reader.Close();
            stream.Close();
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }  

我想根据您的需要对其进行更改并不是很困难,但是如果有任何需要我解释的内容,请提出要求。