[VB.Net] Add watermark to existing Pdf file using iTextSharp

[pessi]

Thank you. I am in the process of building 10 more nice applications that can be of use to lot of people.

[BigJRofC]

This is excellent code and this is what i needed. BTW, I have question if this is possible, can the watermark appear behind page?

Thanks

[stanav]

This is excellent code and this is what i needed. BTW, I have question if this is possible, can the watermark appear behind page?

Thanks

Yes, in the code I posted, the water mark is written to the over content of the page... This will ensure that the water mark will always be visible (even when the page contains an image, for example). If your page contains mostly text, it is recommended to put the water mark on the under content of the page instead. All you have to do is changing this line:

underContent = stamper.GetOverContent(i)

To this

underContent = stamper.GetUnderContent(i)

The rest of the code remains unchanged.

[BigJRofC]

Thanks, Stanav. This is great...

[gnoter]

For those of us who find this solution via a web search and want a C# (C-Sharp) version, here it is, tested and working.

Foremost: Major thx to stanav; excellent post.

You'll note there are 2 functions, with the first functions calling the second function. This mimics the "OPTIONAL" params in VB

public static void AddWatermarkTextC(string sourceFile, string outputFile, string[] watermarkText)
  {
    iTextSharp.text.pdf.BaseFont tWatermarkFont = null;
    float tWatermarkFontSize = 48F;
    iTextSharp.text.Color 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.Color.BLUE;
    AddWatermarkTextC(sourceFile, outputFile, watermarkText, tWatermarkFont, tWatermarkFontSize, tWatermarkFontColor, tWatermarkFontOpacity, tWatermarkRotation);
  }//void AddWatermarkTextC(string sourceFile, string outputFile, string[] watermarkText )
 
 
  public static void AddWatermarkTextC(string sourceFile, string outputFile, string[] watermarkText, iTextSharp.text.pdf.BaseFont watermarkFont, float watermarkFontSize, iTextSharp.text.Color 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);
      stamper = new iTextSharp.text.pdf.PdfStamper(reader, new System.IO.FileStream(outputFile, System.IO.FileMode.Create));
      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 (watermarkFont == null)
 
      if (watermarkFontColor == null)
      {
        watermarkFontColor = iTextSharp.text.Color.BLUE;
      }//if (watermarkFontColor == null)
 
      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);
        if (watermarkText.Length > 1)
        {
          currentY = (rect.Height / 2) + ((watermarkFontSize * watermarkText.Length) / 2);
        }//if (watermarkText.Length > 1)
        else
        {
          currentY = (rect.Height / 2);
        }//else if (watermarkText.Length > 1)
 
        for (int j = 0; j < watermarkText.Length; j++)
        {
          if (j > 0)
          {
            offset = (j * watermarkFontSize) + (watermarkFontSize / 4) * j;
          }//if (j > 0)
          else
          {
            offset = 0.0F;
          }//else if (j > 0)
 
          underContent.ShowTextAligned(iTextSharp.text.Element.ALIGN_CENTER, watermarkText[j], rect.Width / 2, currentY - offset, watermarkRotation);
        }//for (int j = 0; j < watermarkText.Length; j++)
 
        underContent.EndText();
        underContent.RestoreState();
      }//for (int i = 1; i <= pageCount; i++)
 
      stamper.Close();
      reader.Close();
    }
    catch (Exception ex)
    {
      throw ex;
    }
  }//void AddWatermarkTextC(string sourceFile, string outputFile, string[] watermarkText, iTextSharp.text.pdf.BaseFont watermarkFont, float watermarkFontSize, iTextSharp.text.Color watermarkFontColor, float watermarkFontOpacity, float watermarkRotation)

Signed,

MacSpudster / GNoter
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