Add watermark to PDF file

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Add watermark to PDF file

sahin kaya 20

Hello

I tried to adapt the codes below from the internet, but as a result I get a PDF printout without watermark. I wonder where the error is. source code > https://www.pdfsharp.net/wiki/Watermark-sample.ashx

 string watermark = "DENEME";             // Get an XGraphics object for drawing beneath the existing content.             PdfDocument destDocument = PdfSharp.Pdf.IO.PdfReader.Open(@"D:\test\cıktı.pdf", PdfSharp.Pdf.IO.PdfDocumentOpenMode.Modify);             var page = destDocument.Pages[0];             var gfx = XGraphics.FromPdfPage(page, XGraphicsPdfPageOptions.Append);              // Get the size (in points) of the text.             XFont xFontt = new Font(Font.FontFamily, 40, Font.Style, GraphicsUnit.World);             var size = gfx.MeasureString(watermark,xFontt);              // Define a rotation transformation at the center of the page.             gfx.TranslateTransform(page.Width / 2, page.Height / 2);             gfx.RotateTransform(-Math.Atan(page.Height / page.Width) * 180 / Math.PI);             gfx.TranslateTransform(-page.Width / 2, -page.Height / 2);              // Create a graphical path.             var path = new XGraphicsPath();              // Create a string format.             var format = new XStringFormat();             format.Alignment = XStringAlignment.Near;             format.LineAlignment = XLineAlignment.Near;              // Add the text to the path.             // AddString is not implemented in PDFsharp Core.             path.AddString(watermark, xFontt.FontFamily, XFontStyle.BoldItalic, 150,             new XPoint((page.Width - size.Width) / 2, (page.Height - size.Height) / 2),                 format);              // Create a dimmed red pen.             var pen = new XPen(XColor.FromArgb(128, 255, 0, 0), 2);              // Stroke the outline of the path.             gfx.DrawPath(pen, path);              //destDocument.AddPage(gfx.PdfPage);             destDocument.Save("d:/test/yeni1.pdf");

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Answer 1

P a u l 10,756

Two things I've noticed:

var gfx = XGraphics.FromPdfPage(page, XGraphicsPdfPageOptions.Append);

Here XGraphicsPdfPageOptions.Append will draw your watermark behind the original page, so if the original page is opaque then you won't see it.

Also I don't think you need this line:

destDocument.AddPage(gfx.PdfPage);

As the XGraphics context you're drawing to is already drawing to the original page, so once you .Save() the PdfDocument it will affect the original page. .AddPage() will just add a new page to the document that's a duplicate of the page you're drawing on.

sahin kaya 20

thanks. It saves the original page as it is, but does not add the watermark. What could be the mistake?

sahin kaya 20

I found the following codes on Github, but it does not add a watermark to the PDF file consisting of a scanned document, what should I do?

const string watermark = "test";             const int emSize = 150;             MessageBox.Show(watermark);             // Get a fresh copy of the sample PDF file             const string filename = "sss1.pdf";             File.Copy(Path.Combine("D:/test/", filename),               Path.Combine(Directory.GetCurrentDirectory(), filename), true);              // Create the font for drawing the watermark             XFont font = new XFont("Times New Roman", emSize, XFontStyle.BoldItalic);              // Open an existing document for editing and loop through its pages             PdfDocument document = PdfReader.Open(filename);              // Set version to PDF 1.4 (Acrobat 5) because we use transparency.             if (document.Version < 14)                 document.Version = 14;              for (int idx = 0; idx < document.Pages.Count; idx++)             {                 //if (idx == 1) break;                 PdfPage page = document.Pages[idx];                  switch (idx % 3)                 {                     case 0:                         {                             // Variation 1: Draw watermark as text string                              // Get an XGraphics object for drawing beneath the existing content                             XGraphics gfx = XGraphics.FromPdfPage(page, XGraphicsPdfPageOptions.Prepend);  #if true_             // Fill background with linear gradient color             XRect rect = page.MediaBox.ToXRect();             XLinearGradientBrush gbrush = new XLinearGradientBrush(rect,               XColors.LightSalmon, XColors.WhiteSmoke, XLinearGradientMode.Vertical);             gfx.DrawRectangle(gbrush, rect); #endif                              // Get the size (in point) of the text                             XSize size = gfx.MeasureString(watermark, font);                              // Define a rotation transformation at the center of the page                             gfx.TranslateTransform(page.Width / 2, page.Height / 2);                             gfx.RotateTransform(-Math.Atan(page.Height / page.Width) * 180 / Math.PI);                             gfx.TranslateTransform(-page.Width / 2, -page.Height / 2);                              // Create a string format                             XStringFormat format = new XStringFormat();                             format.Alignment = XStringAlignment.Near;                             format.LineAlignment = XLineAlignment.Near;                              // Create a dimmed red brush                             XBrush brush = new XSolidBrush(XColor.FromArgb(128, 255, 0, 0));                              // Draw the string                             gfx.DrawString(watermark, font, brush,                               new XPoint((page.Width - size.Width) / 2, (page.Height - size.Height) / 2),                               format);                         }                         break;                      case 1:                         {                             // Variation 2: Draw watermark as outlined graphical path                              // Get an XGraphics object for drawing beneath the existing content                             XGraphics gfx = XGraphics.FromPdfPage(page, XGraphicsPdfPageOptions.Prepend);                              // Get the size (in point) of the text                             XSize size = gfx.MeasureString(watermark, font);                              // Define a rotation transformation at the center of the page                             gfx.TranslateTransform(page.Width / 2, page.Height / 2);                             gfx.RotateTransform(-Math.Atan(page.Height / page.Width) * 180 / Math.PI);                             gfx.TranslateTransform(-page.Width / 2, -page.Height / 2);                              // Create a graphical path                             XGraphicsPath path = new XGraphicsPath();                              // Add the text to the path                             path.AddString(watermark, font.FontFamily, XFontStyle.BoldItalic, 150,                               new XPoint((page.Width - size.Width) / 2, (page.Height - size.Height) / 2),                               XStringFormats.Default);                              // Create a dimmed red pen                             XPen pen = new XPen(XColor.FromArgb(128, 255, 0, 0), 2);                              // Stroke the outline of the path                             gfx.DrawPath(pen, path);                         }                         break;                      case 2:                         {                             // Variation 3: Draw watermark as transparent graphical path above text                              // Get an XGraphics object for drawing above the existing content                             XGraphics gfx = XGraphics.FromPdfPage(page, XGraphicsPdfPageOptions.Append);                              // Get the size (in point) of the text                             XSize size = gfx.MeasureString(watermark, font);                              // Define a rotation transformation at the center of the page                             gfx.TranslateTransform(page.Width / 2, page.Height / 2);                             gfx.RotateTransform(-Math.Atan(page.Height / page.Width) * 180 / Math.PI);                             gfx.TranslateTransform(-page.Width / 2, -page.Height / 2);                              // Create a graphical path                             XGraphicsPath path = new XGraphicsPath();                              // Add the text to the path                             path.AddString(watermark, font.FontFamily, XFontStyle.BoldItalic, 150,                               new XPoint((page.Width - size.Width) / 2, (page.Height - size.Height) / 2),                               XStringFormats.Default);                              // Create a dimmed red pen and brush                             XPen pen = new XPen(XColor.FromArgb(50, 75, 0, 130), 3);                             XBrush brush = new XSolidBrush(XColor.FromArgb(50, 106, 90, 205));                              // Stroke the outline of the path                             gfx.DrawPath(pen, brush, path);                         }                         break;                 }             }             // Save the document...             document.Save(filename);             // ...and start a viewer             Process.Start(filename);

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sahin kaya 20 Reputation points

2023-10-08T10:43:01.4733333+00:00

thanks

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Add watermark to PDF file

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