EVO HTML to PDF Converter allows you add elements over the PDF pages main content in HtmlToPdfConverterAfterRenderPdfPageEvent event handler which is called right after the main content of the PDF page was rendered by converter.
Code Sample - Add Elements Over PDF Page Main Content
protected void convertToPdfButton_Click(object sender, EventArgs e) { // Create a HTML to PDF converter object with default settings HtmlToPdfConverter htmlToPdfConverter = new HtmlToPdfConverter(); // Set license key received after purchase to use the converter in licensed mode // Leave it not set to use the converter in demo mode htmlToPdfConverter.LicenseKey = "4W9+bn19bn5ue2B+bn1/YH98YHd3d3c="; // Set an adddional delay in seconds to wait for JavaScript or AJAX calls after page load completed // Set this property to 0 if you don't need to wait for such asynchcronous operations to finish htmlToPdfConverter.ConversionDelay = 2; // Set a handler for AfterRenderPdfPageEvent where to add the stamp in each PDF page over the main content htmlToPdfConverter.AfterRenderPdfPageEvent += new AfterRenderPdfPageDelegate(htmlToPdfConverter_AfterRenderPdfPageEvent); try { // The buffer to receive the generated PDF document byte[] outPdfBuffer = null; if (convertUrlRadioButton.Checked) { string url = urlTextBox.Text; // Convert the HTML page given by an URL to a PDF document in a memory buffer outPdfBuffer = htmlToPdfConverter.ConvertUrl(url); } else { string htmlString = htmlStringTextBox.Text; string baseUrl = baseUrlTextBox.Text; // Convert a HTML string with a base URL to a PDF document in a memory buffer outPdfBuffer = htmlToPdfConverter.ConvertHtml(htmlString, baseUrl); } // Send the PDF as response to browser // Set response content type Response.AddHeader("Content-Type", "application/pdf"); // Instruct the browser to open the PDF file as an attachment or inline Response.AddHeader("Content-Disposition", String.Format("attachment; filename=Add_Elements_Over_Main_Content.pdf; size={0}", outPdfBuffer.Length.ToString())); // Write the PDF document buffer to HTTP response Response.BinaryWrite(outPdfBuffer); // End the HTTP response and stop the current page processing Response.End(); } finally { // Uninstall the handler htmlToPdfConverter.AfterRenderPdfPageEvent -= new AfterRenderPdfPageDelegate(htmlToPdfConverter_AfterRenderPdfPageEvent); } } void htmlToPdfConverter_AfterRenderPdfPageEvent(AfterRenderPdfPageParams eventParams) { if (!addStampCheckBox.Checked) return; // Get the rendered PDF page PdfPage pdfPage = eventParams.Page; int pageNumber = eventParams.PageNumber; int pageCount = eventParams.PageCount; bool isOddPage = pageNumber % 2 != 0; // Get the PDF document Document pdfDocument = pdfPage.Document; // Get the PDF page drawable area width and height float pdfPageWidth = pdfPage.ClientRectangle.Width; float pdfPageHeight = pdfPage.ClientRectangle.Height; // Create a .NET font Font timesNewRomanFont = new Font("Times New Roman", 50, GraphicsUnit.Point); // Create a PDF font PdfFont pdfFont = pdfDocument.AddFont(timesNewRomanFont, true); // The stamp text string text = String.Format("Stamp on Page {0} of {1}", pageNumber, pageCount); // Measure the text float textWidth = pdfFont.GetTextWidth(text); // Calculate the PDF page diagonal float pdfPageDiagonal = (float)Math.Sqrt(pdfPageWidth * pdfPageWidth + pdfPageHeight * pdfPageHeight); // The text location on PDF page diagonal float xLocation = (pdfPageDiagonal - textWidth) / 2; // Create the stamp as a rotated text element TextElement stampTextElement = new TextElement(xLocation, 0, text, pdfFont); stampTextElement.ForeColor = isOddPage ? Color.Blue : Color.Green; stampTextElement.Rotate((float)(Math.Atan(pdfPageHeight / pdfPageWidth) * (180 / Math.PI))); stampTextElement.Opacity = 75; // Add the stamp to PDF page pdfPage.AddElement(stampTextElement); }