Add Watermark to PDF with QuestPDF for .NET

add-watermark-to-pdf-with-questpdf-api.cs

using QuestPDF.Fluent;
using QuestPDF.Helpers;
using QuestPDF.Infrastructure;

class Program
{
    static void Main(string[] args)
    {
        // Create a PDF document
        Document.Create(document =>
        {
            // Define document structure
            document.Page(page =>
            {
                // Set page size and margin
                page.Size(PageSizes.A4);
                page.Margin(2, Unit.Centimetre);

                // Define page content
                page.Content().Layer(layer =>
                {
                    // Main content (e.g., text)
                    layer.Element()
                        .PaddingBottom(5, Unit.Centimetre)
                        .Text("This is the main content of the PDF")
                        .FontSize(16)
                        .AlignCenter();

                    // Watermark overlay
                    layer.Element()
                        .AlignCenter()
                        .AlignMiddle()
                        .Text("CONFIDENTIAL")
                        .FontSize(60)
                        .Color(Colors.Grey.Medium)
                        .Opacity(0.2f)
                        .Rotate(45);
                });
            });
        })
        .GeneratePdf("WatermarkedDocument.pdf"); // Save the PDF to a file
    }
}