How to add multiple watermarks in PDF document using C# and VB.NET?

The Syncfusion Essential® PDF is a feature rich and high-performance .NET PDF library used to create, read, and edit PDF documents programmatically without Adobe dependencies. This library also offers functionality to merge, split, stamp, forms, compress, and secure PDF files.

You can add multiple watermarks in a PDF document using this library.

Steps to add multiple Watermark in PDF document using C# and VB.Net:

1. Create a new C# console application project.

2. Install the Syncfusion.Pdf.WinForms NuGet package as a reference to your .NET standard applications from NuGet.org.

3. Include the following namespaces in Form.cs file:

      C#:

using Syncfusion.Pdf;
       using Syncfusion.Pdf.Parsing;

             VB.Net:

Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Parsing

4. Include the following namespaces in the Program.cs file:

C#:

//Load the PDF document
PdfLoadedDocument loadedDocument = new PdfLoadedDocument("Barcode.pdf");
 
//Set the font
PdfFont font = new PdfStandardFont(PdfFontFamily.Helvetica, 20);
 
foreach (var page in loadedDocument.Pages)
{
//Get the loaded page
PdfLoadedPage loadedPage = page as PdfLoadedPage;
//Create graphics 
PdfGraphics graphics = loadedPage.Graphics;
 
//Draw watermark text
PdfGraphicsState state = graphics.Save();
graphics.SetTransparency(0.25f);
graphics.RotateTransform(-80);
int y = 100;
for (int i = 0; i < 4; i++)
{
graphics.DrawString("WaterMark", font, PdfPens.Red, PdfBrushes.Red, new PointF(-150, y));
graphics.DrawString("WaterMark", font, PdfPens.Red, PdfBrushes.Red, new PointF(-300, y));
y = y + 100;
}
graphics.Restore();
}
 
//Save and close the document
loadedDocument.Save("Watermark.pdf");
loadedDocument.Close(true);
 

             VB.Net:

Private Sub SurroundingSub()
  Dim loadedDocument As PdfLoadedDocument = New PdfLoadedDocument("Barcode.pdf")
        Dim font As PdfFont = New PdfStandardFont(PdfFontFamily.Helvetica, 20)
 
        For Each page In loadedDocument.Pages
            Dim loadedPage As PdfLoadedPage = TryCast(page, PdfLoadedPage)
            Dim graphics As PdfGraphics = loadedPage.Graphics
            Dim state As PdfGraphicsState = graphics.Save()
            graphics.SetTransparency(0.25F)
            graphics.RotateTransform(-80)
            Dim y As Integer = 100
 
            For i As Integer = 0 To 4 - 1
                graphics.DrawString("WaterMark", font, PdfPens.Red, PdfBrushes.Red, New PointF(-150, y))
                graphics.DrawString("WaterMark", font, PdfPens.Red, PdfBrushes.Red, New PointF(-300, y))
                y = y + 100
            Next
 
            graphics.Restore()
        Next
 
        loadedDocument.Save("Watermark.pdf")
        loadedDocument.Close(True)
End Sub

5. By executing the program, you will get the PDF document as follows:

A complete working sample can be downloaded from WatermarkSample.zip

Take a moment to peruse the documentation, where you can find the options like adding text and image watermark to the PDF document.

Refer here to explore the rich set of Syncfusion Essential® PDF features.

Note:

Starting with v16.2.0.x, if you reference Syncfusion® assemblies from the trial setup or the NuGet feed, include a license key in your projects. Refer to the link to learn about generating and registering the Syncfusion® license key in your application to use the components without a trial message.

Conclusion:

I hope you enjoyed learning about how to add multiple watermarks in PDF document using C# and VB.NET.

You can refer to our Flutter PDF feature tour page to learn about its other groundbreaking features and documentation, and how to quickly get started with configuration specifications. You can also explore our Flutter PDF Flutter PDF examples to understand how to create and manipulate data.

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