Add Elements in PDF Pages Background

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 BeforeRenderPdfPageEvent where to set the background image in each PDF page before main content is rendered
    htmlToPdfConverter.BeforeRenderPdfPageEvent += new BeforeRenderPdfPageDelegate(htmlToPdfConverter_BeforeRenderPdfPageEvent);

    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_in_Background.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.BeforeRenderPdfPageEvent -= new BeforeRenderPdfPageDelegate(htmlToPdfConverter_BeforeRenderPdfPageEvent);
    }
}

/// <summary>
/// The BeforeRenderPdfPageEvent event handler where a background image is set in each PDF page
/// before the main content is rendered
/// </summary>
/// <param name="eventParams">The event parameter containing the PDF page being rendered</param>
void htmlToPdfConverter_BeforeRenderPdfPageEvent(BeforeRenderPdfPageParams eventParams)
{
    if (!addBackgroundImageCheckBox.Checked)
        return;

    // Get the PDF page being rendered
    PdfPage pdfPage = eventParams.Page;

    // Get the PDF page drawable area width and height
    float pdfPageWidth = pdfPage.ClientRectangle.Width;
    float pdfPageHeight = pdfPage.ClientRectangle.Height;

    // The image to be added as background
    string backgroundImagePath = Server.MapPath("~/DemoAppFiles/Input/Images/background.jpg");

    // The image element to add in background
    ImageElement backgroundImageElement = new ImageElement(0, 0, pdfPageWidth, pdfPageHeight, backgroundImagePath);
    backgroundImageElement.KeepAspectRatio = true;
    backgroundImageElement.EnlargeEnabled = true;

    // Add the background image element to PDF page before the main content is rendered
    pdfPage.AddElement(backgroundImageElement);
}

Protected Sub convertToPdfButton_Click(ByVal sender As Object, ByVal e As EventArgs)
    ' Create a HTML to PDF converter object with default settings
    Dim htmlToPdfConverter As 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 BeforeRenderPdfPageEvent where to set the background image in each PDF page before main content is rendered
    AddHandler htmlToPdfConverter.BeforeRenderPdfPageEvent, AddressOf htmlToPdfConverter_BeforeRenderPdfPageEvent

    Try
        ' The buffer to receive the generated PDF document
        Dim outPdfBuffer() As Byte = Nothing

        If convertUrlRadioButton.Checked Then
            Dim url As String = urlTextBox.Text

            ' Convert the HTML page given by an URL to a PDF document in a memory buffer
            outPdfBuffer = htmlToPdfConverter.ConvertUrl(url)
        Else
            Dim htmlString As String = htmlStringTextBox.Text
            Dim baseUrl As String = baseUrlTextBox.Text

            ' Convert a HTML string with a base URL to a PDF document in a memory buffer
            outPdfBuffer = htmlToPdfConverter.ConvertHtml(htmlString, baseUrl)
        End If

        ' 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_in_Background.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
        RemoveHandler htmlToPdfConverter.BeforeRenderPdfPageEvent, AddressOf htmlToPdfConverter_BeforeRenderPdfPageEvent
    End Try
End Sub

''' <summary>
''' The BeforeRenderPdfPageEvent event handler where a background image is set in each PDF page
''' before the main content is rendered
''' </summary>
''' <param name="eventParams">The event parameter containing the PDF page being rendered</param>
Private Sub htmlToPdfConverter_BeforeRenderPdfPageEvent(ByVal eventParams As BeforeRenderPdfPageParams)
    If Not addBackgroundImageCheckBox.Checked Then
        Return
    End If

    ' Get the PDF page being rendered
    Dim pdfPage As PdfPage = eventParams.Page

    ' Get the PDF page drawable area width and height
    Dim pdfPageWidth As Single = pdfPage.ClientRectangle.Width
    Dim pdfPageHeight As Single = pdfPage.ClientRectangle.Height

    ' The image to be added as background
    Dim backgroundImagePath As String = Server.MapPath("~/DemoAppFiles/Input/Images/background.jpg")

    ' The image element to add in background
    Dim backgroundImageElement As New ImageElement(0, 0, pdfPageWidth, pdfPageHeight, backgroundImagePath)
    backgroundImageElement.KeepAspectRatio = True
    backgroundImageElement.EnlargeEnabled = True

    ' Add the background image element to PDF page before the main content is rendered
    pdfPage.AddElement(backgroundImageElement)
End Sub