(PureBasic) PDF Signature Appearance Width and Height

See more PDF Signatures Examples

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

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkCert.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkPdf.pb"

Procedure ChilkatExample()

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

    pdf.i = CkPdf::ckCreate()
    If pdf.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Load a PDF to be signed.
    ; The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
    success.i = CkPdf::ckLoadFile(pdf,"qa_data/pdf/hello.pdf")
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        ProcedureReturn
    EndIf

    ; Options for signing are specified in JSON.
    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; In most cases, the signingCertificateV2 and signingTime attributes are required.
    CkJsonObject::ckUpdateInt(json,"signingCertificateV2",1)
    CkJsonObject::ckUpdateInt(json,"signingTime",1)

    ; Put the signature on page 1, top left
    CkJsonObject::ckUpdateInt(json,"page",1)
    CkJsonObject::ckUpdateString(json,"appearance.y","top")
    CkJsonObject::ckUpdateString(json,"appearance.x","left")

    ; Add some text.
    CkJsonObject::ckUpdateString(json,"appearance.text[0]","Digitally signed by: cert_cn")
    CkJsonObject::ckUpdateString(json,"appearance.text[1]","current_dt")

    ; Add a built-in SVG graphic to the right.
    CkJsonObject::ckUpdateString(json,"appearance.image","blue-check-mark")
    CkJsonObject::ckUpdateString(json,"appearance.imagePlacement","right")
    CkJsonObject::ckUpdateString(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::ckUpdateInt(json,"appearance.width",72 * 3)
    CkJsonObject::ckUpdateInt(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::ckUpdateInt(json,"appearance.width",72 * 4)
    CkJsonObject::ckUpdateString(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::ckUpdateString(json,"appearance.width","auto")
    CkJsonObject::ckUpdateInt(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.i = CkJsonObject::ckObjectOf(json,"appearance")
    CkJsonObject::ckDelete(jAppearance,"width")
    CkJsonObject::ckDelete(jAppearance,"height")
    CkJsonObject::ckDispose(jAppearance)

    CkJsonObject::ckUpdateString(json,"appearance.fontScale","10.0")

    ; With fontScale = "10.0"
    

    ; Load the signing certificate. (Use your own certificate.)
    cert.i = CkCert::ckCreate()
    If cert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkCert::ckLoadPfxFile(cert,"qa_data/pfx/myPdfSigningCert.pfx","pfx_password")
    If success = 0
        Debug CkCert::ckLastErrorText(cert)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    ; Tell the pdf object to use the certificate for signing.
    success = CkPdf::ckSetSigningCert(pdf,cert)
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    success = CkPdf::ckSignPdf(pdf,json,"qa_output/hello_signed.pdf")
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkCert::ckDispose(cert)
        ProcedureReturn
    EndIf

    Debug "The PDF has been successfully cryptographically signed."


    CkPdf::ckDispose(pdf)
    CkJsonObject::ckDispose(json)
    CkCert::ckDispose(cert)


    ProcedureReturn
EndProcedure