PDF: How to add digital signature with text appearance to a PDF document?

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Here is C#/VB.NET code that demonstrates how to add digital signature with text appearance to a PDF document using PdfPageDigitalSignatureHelper class:

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

/// <summary>
/// Adds digital signature with text appearance to a PDF page.
/// </summary>
public class PdfPageDigitalSignatureHelper_TextAppearance
{
    public static void Run()
    {
        // get the X509 certificate from .pfx-file
        using (X509Certificate2 certificate = new X509Certificate2("TestCertificate.pfx", "test"))
        {
            // create a helper that alows to add digital signature to a PDF document
            PdfPageDigitalSignatureHelper digitalSignatureHelper =
                new PdfPageDigitalSignatureHelper(certificate, new RectangleF(20, 20, 250, 100));

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

            // set the signature appearance text
            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("TestDocumentToSign.pdf", "TestDocumentToSign-signed.pdf", 0);
        }
    }
}

VB.NET

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

''' <summary>
''' Adds digital signature with text appearance to a PDF page.
''' </summary>
Public Class PdfPageDigitalSignatureHelper_TextAppearance
    Public Shared Sub Run()
        ' get the X509 certificate from .pfx-file
        Using certificate As New X509Certificate2("TestCertificate.pfx", "test")
            ' create a helper that alows to add digital signature to a PDF document
            Dim digitalSignatureHelper As New PdfPageDigitalSignatureHelper(certificate, New RectangleF(20, 20, 250, 100))

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

            ' set the signature appearance text
            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("TestDocumentToSign.pdf", "TestDocumentToSign-signed.pdf", 0)
        End Using
    End Sub
End Class

Here is C#/VB.NET code that demonstrates how to add digital signature with text appearance to a PDF document using PdfPage.AddVisibleDigitalSignatureWithTextAppearance method:

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

/// <summary>
/// Adds visible digital signature with text appearance to a PDF page.
/// </summary>
public class AddVisibleDigitalSignatureWithTextAppearanceExample
{
    public static void Run()
    {
        // get the X509 certificate from .pfx-file
        using (X509Certificate2 certificate = new X509Certificate2("TestCertificate.pfx", "test"))
        {
            // get the signer name from X509 certificate
            string signerName = certificate.GetNameInfo(X509NameType.SimpleName, false);

            // open PDF document
            using (PdfDocument pdfDocument = new PdfDocument("TestDocumentToSign.pdf"))
            {
                // get the first PDF page
                PdfPage pdfPage = pdfDocument.Pages[0];

                // add visible digital signature with text appearance to the PDF page
                pdfPage.AddVisibleDigitalSignatureWithTextAppearance(
                    certificate, "Signature", "Approve document", string.Format("Digitally signed by\n{0}", signerName),
                    new RectangleF(20, 20, 250, 100), false);

                // sign PDF document and save PDF document to the output file
                pdfDocument.SaveChanges("TestDocumentToSign-signed-text.pdf");
            }
        }
    }
}

VB.NET

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

''' <summary>
''' Adds visible digital signature with text appearance to a PDF page.
''' </summary>
Public Class AddVisibleDigitalSignatureWithTextAppearanceExample
    Public Shared Sub Run()
        ' get the X509 certificate from .pfx-file
        Using certificate As New X509Certificate2("TestCertificate.pfx", "test")
            ' get the signer name from X509 certificate
            Dim signerName As String = certificate.GetNameInfo(X509NameType.SimpleName, False)

            ' open PDF document
            Using pdfDocument As New PdfDocument("TestDocumentToSign.pdf")
                ' get the first PDF page
                Dim pdfPage As PdfPage = pdfDocument.Pages(0)

                ' add visible digital signature with text appearance to the PDF page
                pdfPage.AddVisibleDigitalSignatureWithTextAppearance(certificate, "Signature", _
                    "Approve document", String.Format("Digitally signed by" & vbLf & "{0}", signerName), _
                    New RectangleF(20, 20, 250, 100), False)

                ' sign PDF document and save PDF document to the output file
                pdfDocument.SaveChanges("TestDocumentToSign-signed-text.pdf")
            End Using
        End Using
    End Sub
End Class

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