(Delphi ActiveX) PDF Signature Appearance Width and Height

See more PDF Signatures Examples

This example explains how the width and height of the signature appearance rectangle box is determined.

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

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
pdf: TChilkatPdf;
success: Integer;
json: TChilkatJsonObject;
jAppearance: IChilkatJsonObject;
cert: TChilkatCert;

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

pdf := TChilkatPdf.Create(Self);

// Load a PDF to be signed.
// The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
success := pdf.LoadFile('qa_data/pdf/hello.pdf');
if (success = 0) then
  begin
    Memo1.Lines.Add(pdf.LastErrorText);
    Exit;
  end;

// Options for signing are specified in JSON.
json := TChilkatJsonObject.Create(Self);

// 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');

// Add some text.
json.UpdateString('appearance.text[0]','Digitally signed by: cert_cn');
json.UpdateString('appearance.text[1]','current_dt');

// Add a built-in SVG graphic to the right.
json.UpdateString('appearance.image','blue-check-mark');
json.UpdateString('appearance.imagePlacement','right');
json.UpdateString('appearance.imageOpacity','100');

// There are 4 ways the width and height of the signature rectangle can be specified.
// 1) The width and height (in points) are both explicitly specified.
//    User space coordinates use "points" where 72 points equals 1 inch.
//    For example (3 inches wide and 1 inch high)
//    The fontScale is automatically chose to fit.  In addition, if a graphic (JPG or built-in SVG) is included,
//    it is automatically scaled such that the text + graphic fit together in the specified rectangle.
//    Note: When both height and width are explicitly specified, the resultant signature appearance rectangle
//    will match one of the dimensions, but the other dimension will be equal or smaller.  This is because the text
//    must be proportionally scaled.
json.UpdateInt('appearance.width',72 * 3);
json.UpdateInt('appearance.height',72);

// The signature would have this appearance. In this case, the height is actually less than 1 inch because
// if Chilkat chose a fontScale to fill the height, the resulting text's width would be too long for the desired width. 


// 2) The width is explicitly specified, but we use the keyword "auto" for height.
//    In this case, the fontScale is chosen to achieve the desired width,
//    and the height will be whatever the result of the chosen font scale.
//    In this example, the width is 4 inches, and the height is "auto".
json.UpdateInt('appearance.width',72 * 4);
json.UpdateString('appearance.height','auto');

// The signature would have this appearance: 


// 3) The height is explicitly specified, but we use the keyword "auto" for width.
//    In this case, the fontScale is chosen to achieve the desired height,
//    and the width will be whatever the result of the chosen font scale.
//    In this example, the height is 1 inch (72 points) and the width is "auto".
json.UpdateString('appearance.width','auto');
json.UpdateInt('appearance.height',72);

// The signature would have this appearance.


// 4) Finally, we don't need to specify width/height at all.  Instead, we can choose a fontScale
//    and the dimensions of the PDF signature appearance's rectangle will be the result of using the
//    specified fontScale.

jAppearance := json.ObjectOf('appearance');
jAppearance.Delete('width');
jAppearance.Delete('height');

json.UpdateString('appearance.fontScale','10.0');

// With fontScale = "10.0"


// Load the signing certificate. (Use your own certificate.)
cert := TChilkatCert.Create(Self);
success := cert.LoadPfxFile('qa_data/pfx/myPdfSigningCert.pfx','pfx_password');
if (success = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

// Tell the pdf object to use the certificate for signing.
success := pdf.SetSigningCert(cert.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(pdf.LastErrorText);
    Exit;
  end;

success := pdf.SignPdf(json.ControlInterface,'qa_output/hello_signed.pdf');
if (success = 0) then
  begin
    Memo1.Lines.Add(pdf.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('The PDF has been successfully cryptographically signed.');
end;