Pascal (Lazarus/Delphi)

PDF Signature Appearance Text Substitution Keywords

See more PDF Signatures Examples

This example demonstrates the text substitution keywords that can be used in the PDF signature's appearance text.

Note: This example requires Chilkat v9.5.0.85 or greater.

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.BinData,
  Chilkat.Pdf,
  Chilkat.Cert,
  Chilkat.JsonObject;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  pdf: TPdf;
  json: TJsonObject;
  jpgData: TBinData;
  cert: TCert;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  pdf := TPdf.Create;

  //  Load a PDF to be signed.
  success := pdf.LoadFile('qa_data/pdf/empty.pdf');
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  //  Options for signing are specified in JSON.
  json := TJsonObject.Create;

  //  In most cases, the signingCertificateV2 and signingTime attributes are required.
  json.UpdateInt('signingCertificateV2',1);
  json.UpdateInt('signingTime',1);

  //  Put the signature on page 1, top left
  json.UpdateInt('page',1);
  json.UpdateString('appearance.y','top');
  json.UpdateString('appearance.x','left');

  //  Use a font scale of 7.0
  json.UpdateString('appearance.fontScale','7.0');

  //  The appearance of the PDF signature can contain any number of text lines.
  //  Chilkat has defined a number of special keywords that can be used in any text line.
  //  Each keyword is replaced with the actual value.
  //  For example, "cert_cn" is replaced with the certificate subject's common name (CN).

  //  Here we are creating a signature with many lines of text, to demonstrate each
  //  keyword.
  json.UpdateString('appearance.text[0]','Date/time in PDF format: current_dt');
  json.UpdateString('appearance.text[1]','Current Local date/time: current_datetime');
  json.UpdateString('appearance.text[2]','GMT Timestamp: current_timestamp_gmt');
  json.UpdateString('appearance.text[3]','Local Timestamp: current_timestamp_local');
  json.UpdateString('appearance.text[4]','GMT RFC822 date/time: current_rfc822_dt_gmt');
  json.UpdateString('appearance.text[5]','Local RFC822 date/time: current_rfc822_dt_local');
  json.UpdateString('appearance.text[6]','Cert DN (Distinguished Name): cert_dn');
  json.UpdateString('appearance.text[7]','Cert Common Name: cert_cn');
  json.UpdateString('appearance.text[8]','Cert Organizational ID (2.5.4.97): cert_org_id');
  json.UpdateString('appearance.text[9]','Cert Email: cert_email');
  json.UpdateString('appearance.text[10]','Cert Organization: cert_organization');
  json.UpdateString('appearance.text[11]','Cert Organziational Unit: cert_ou');
  json.UpdateString('appearance.text[12]','Cert State: cert_state');
  json.UpdateString('appearance.text[13]','Cert Country: cert_country');
  json.UpdateString('appearance.text[14]','Cert Locality: cert_locality');
  json.UpdateString('appearance.text[15]','Cert Serial Number (hex): cert_serial_hex');
  json.UpdateString('appearance.text[16]','Cert Serial Number (decimal): cert_serial_dec');
  json.UpdateString('appearance.text[17]','Cert Thumbprint: cert_thumbprint');
  json.UpdateString('appearance.text[18]','Cert Issuer Common Name: cert_issuer_cn');

  jpgData := TBinData.Create;
  success := jpgData.LoadFile('qa_data/jpg/seal1.jpg');
  if (success = False) then
    begin
      WriteLn('Failed to load the JPG image.');
      Exit;
    end;
  success := pdf.SetSignatureJpeg(jpgData);
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  //  Specify that we want to display the JPG image in the center with 33% opacity.
  json.UpdateString('appearance.image','custom-jpg');
  json.UpdateString('appearance.imagePlacement','center');
  json.UpdateString('appearance.imageOpacity','33');

  //  Load the signing certificate. (Use your own certificate.)
  cert := TCert.Create;
  success := cert.LoadPfxFile('qa_data/pfx/myPdfSigningCert.pfx','pfx_password');
  if (success = False) then
    begin
      WriteLn(cert.LastErrorText);
      Exit;
    end;

  //  Tell the pdf object to use the certificate for signing.
  success := pdf.SetSigningCert(cert);
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  success := pdf.SignPdf(json,'qa_output/hello_signed.pdf');
  if (success = False) then
    begin
      WriteLn(pdf.LastErrorText);
      Exit;
    end;

  WriteLn('The PDF has been successfully cryptographically signed.');

  //  The appearance of the signature appears in Adobe Acrobat as shown here:

  //  (image:https://example-code.com/images/pdf_signature_text_replacements.jpg/endImage)


  pdf.Free;
  json.Free;
  jpgData.Free;
  cert.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.