(Delphi DLL) PDF Signature Appearance Width and Height

See more PDF Signatures Examples

Note: This example requires Chilkat v11.0.0 or greater.

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
pdf: HCkPdf;
json: HCkJsonObject;
jAppearance: HCkJsonObject;
cert: HCkCert;

begin
success := False;

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

pdf := CkPdf_Create();

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

// Options for signing are specified in JSON.
json := CkJsonObject_Create();

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

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

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

// Add a built-in SVG graphic to the right.
CkJsonObject_UpdateString(json,'appearance.image','blue-check-mark');
CkJsonObject_UpdateString(json,'appearance.imagePlacement','right');
CkJsonObject_UpdateString(json,'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.
CkJsonObject_UpdateInt(json,'appearance.width',72 * 3);
CkJsonObject_UpdateInt(json,'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".
CkJsonObject_UpdateInt(json,'appearance.width',72 * 4);
CkJsonObject_UpdateString(json,'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".
CkJsonObject_UpdateString(json,'appearance.width','auto');
CkJsonObject_UpdateInt(json,'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 := CkJsonObject_Create();
CkJsonObject_ObjectOf2(json,'appearance',jAppearance);

CkJsonObject_Delete(jAppearance,'width');
CkJsonObject_Delete(jAppearance,'height');
CkJsonObject_UpdateString(json,'appearance.fontScale','10.0');

// With fontScale = "10.0"


// Load the signing certificate. (Use your own certificate.)
cert := CkCert_Create();
success := CkCert_LoadPfxFile(cert,'qa_data/pfx/myPdfSigningCert.pfx','pfx_password');
if (success = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

// Tell the pdf object to use the certificate for signing.
success := CkPdf_SetSigningCert(pdf,cert);
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;

success := CkPdf_SignPdf(pdf,json,'qa_output/hello_signed.pdf');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPdf__lastErrorText(pdf));
    Exit;
  end;

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

CkPdf_Dispose(pdf);
CkJsonObject_Dispose(json);
CkJsonObject_Dispose(jAppearance);
CkCert_Dispose(cert);

end;