Imports System.Drawing
Imports System.Security.Cryptography.X509Certificates
Imports Vintasoft.Imaging.Pdf
Imports Vintasoft.Imaging.Pdf.Drawing
Imports Vintasoft.Imaging.Pdf.Tree.Fonts

''' <summary>
''' Adds visible digital signature with custom appearance to a PDF page.
''' </summary>
Public Class PdfPageDigitalSignatureHelper_CustomAppearance
    ''' <summary>
    ''' Signs a PDF document using specified PFX file.
    ''' </summary>
    ''' <param name="inputFilename">The name of input PDF file.</param>
    ''' <param name="outputFilename">The name of output PDF file.</param>
    ''' <param name="pfxFileName">The name of PFX file.</param>
    ''' <param name="pfxFilePassword">The password for PDF file.</param>
    Public Shared Sub SignPdfDocument(inputFilename As String, outputFilename As String, pfxFileName As String, pfxFilePassword As String)
        ' get the X509 certificate from .pfx-file
        Using certificate As New X509Certificate2(pfxFileName, pfxFileName)
            ' create a helper that alows to add digital signature to a PDF document
            Dim digitalSignatureHelper As New MyDigitalSignatureHelper(certificate, New RectangleF(20, 20, 250, 100))

            ' set the background color for signature
            digitalSignatureHelper.SignatureBackgoundColor = Color.Green

            ' set the reason for signing
            digitalSignatureHelper.SigningReason = "Approve document"

            ' set text for signature appearance
            digitalSignatureHelper.SignatureText = String.Format("Digitally signed by" & vbLf & "{0}", digitalSignatureHelper.SignerName)

            ' add digital signature to the first PDF page, sign PDF document and save PDF document to the output file
            digitalSignatureHelper.SignDocument(inputFilename, outputFilename, 0)
        End Using
    End Sub

    Public Class MyDigitalSignatureHelper
        Inherits PdfPageDigitalSignatureHelper
        Public Sub New(certificate As X509Certificate2, signatureRect As RectangleF)
            MyBase.New(certificate, signatureRect)
        End Sub

        ''' <summary>
        ''' Draws the text on signature appearance.
        ''' </summary>
        ''' <param name="graphics">The PDF graphics.</param>
        ''' <param name="rect">The rectangle.</param>
        ''' <param name="font">The text font.</param>
        ''' <param name="text">The text do draw.</param>
        Protected Overrides Sub DrawSignatureAppearanceText(graphics As PdfGraphics, rect As RectangleF, font As PdfFont, text As String)
            ' create border pen
            Dim borderPen As New PdfPen(Color.Orange, 10)

            ' draw border
            graphics.DrawRectangle(borderPen, rect)

            ' padding
            rect.Inflate(-borderPen.Width * 2, -borderPen.Width * 2)

            ' measure font size
            Dim fontSize As Single = graphics.MeasureFontSize(text, font, rect.Width, rect.Height)

            ' draw the signature text
            graphics.DrawString(text, font, fontSize, New PdfBrush(SignatureTextColor), rect, SignatureTextAlignment, _
                False)
        End Sub
    End Class
End Class

using System.Drawing;
using System.Security.Cryptography.X509Certificates;
using Vintasoft.Imaging.Pdf;
using Vintasoft.Imaging.Pdf.Drawing;
using Vintasoft.Imaging.Pdf.Tree.Fonts;

/// <summary>
/// Adds visible digital signature with custom appearance to a PDF page.
/// </summary>
public class PdfPageDigitalSignatureHelper_CustomAppearance
{
    /// <summary>
    /// Signs a PDF document using specified PFX file.
    /// </summary>
    /// <param name="inputFilename">The name of input PDF file.</param>
    /// <param name="outputFilename">The name of output PDF file.</param>
    /// <param name="pfxFileName">The name of PFX file.</param>
    /// <param name="pfxFilePassword">The password for PDF file.</param>
    public static void SignPdfDocument(
        string inputFilename,
        string outputFilename,
        string pfxFileName,
        string pfxFilePassword)
    {
        // get the X509 certificate from .pfx-file
        using (X509Certificate2 certificate = new X509Certificate2(pfxFileName, pfxFileName))
        {
            // create a helper that alows to add digital signature to a PDF document
            MyDigitalSignatureHelper digitalSignatureHelper = new MyDigitalSignatureHelper(certificate, new RectangleF(20, 20, 250, 100));

            // set the background color for signature
            digitalSignatureHelper.SignatureBackgoundColor = Color.Green;

            // set the reason for signing
            digitalSignatureHelper.SigningReason = "Approve document";

            // set text for signature appearance
            digitalSignatureHelper.SignatureText = string.Format("Digitally signed by\n{0}", digitalSignatureHelper.SignerName);

            // add digital signature to the first PDF page, sign PDF document and save PDF document to the output file
            digitalSignatureHelper.SignDocument(inputFilename, outputFilename, 0);
        }
    }

    public class MyDigitalSignatureHelper : PdfPageDigitalSignatureHelper
    {
        public MyDigitalSignatureHelper(X509Certificate2 certificate, RectangleF signatureRect)
            : base(certificate, signatureRect)
        {
        }

        /// <summary>
        /// Draws the text on signature appearance.
        /// </summary>
        /// <param name="graphics">The PDF graphics.</param>
        /// <param name="rect">The rectangle.</param>
        /// <param name="font">The text font.</param>
        /// <param name="text">The text do draw.</param>
        protected override void DrawSignatureAppearanceText(PdfGraphics graphics, RectangleF rect, PdfFont font, string text)
        {
            // create border pen
            PdfPen borderPen = new PdfPen(Color.Orange, 10);

            // draw border
            graphics.DrawRectangle(borderPen, rect);

            // padding
            rect.Inflate(-borderPen.Width * 2, -borderPen.Width * 2);

            // measure font size
            float fontSize = graphics.MeasureFontSize(text, font, rect.Width, rect.Height);

            // draw the signature text
            graphics.DrawString(text, font, fontSize, new PdfBrush(SignatureTextColor), rect, SignatureTextAlignment, false);
        }
    }
}