Java

PDF Signature Page Location

See more PDF Signatures Examples

This example demonstrates how to specify the location of a PDF signature on a page.

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

Chilkat2 Java

import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.JsonObject;
import com.chilkatsoft.chilkat2.Pdf;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Pdf pdf = new Pdf();

        // Load a PDF to be signed.
        // The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
        try {
            pdf.loadFile("qa_data/pdf/hello.pdf");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Options for signing are specified in JSON.
        JsonObject json = new JsonObject();

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

        // When cryptographically signing a PDF, the signature's appearance can be placed on a specific
        // page in the PDF document, and at a specified location on the page.
        // The 1st page of the PDF document is page number 1 (we don't use 0-based numbering for PDF page numbers).
        // The PDF object has a NumPages property, so we can use it to sign on the last page of the PDF.
        json.updateInt("page", pdf.getNumPages());

        // appearance.y and appearance.x JSON properties control the x,y location of the signature.
        // The "appearance.y" can be "top" or "bottom".
        // The "appearance.x" can be "left", "middle", or "right".
        // It is also possible to specify exact PDF location in user space coordinates, which is discussed below.
        json.updateString("appearance.y", "bottom");
        json.updateString("appearance.x", "middle");

        // In this example, the fontScale (in combination with the number of appearance text lines and the length of the longest text line),
        // automatically determine the width/height of the signature text box. Any included graphic (JPG image or built-in SVG) is automatically
        // scaled to fit. It is alternatively possible to specify the desired width/height of the signature rectangle.  In that case
        // you would NOT specify a fontScale because Chilkat would automatically chose a font scale to fit the text to the desired rectangle.
        // This example demonstrates how to specify the exact width/height of the PDF signature text box.
        json.updateString("appearance.fontScale", "9.0");

        json.updateString("appearance.text[0]", "Digitally signed by: cert_cn");
        json.updateString("appearance.text[1]", "current_dt");
        json.updateString("appearance.image", "document-accepted");
        json.updateString("appearance.imagePlacement", "left");
        json.updateString("appearance.imageOpacity", "100");

        // Load the signing certificate. (Use your own certificate.)
        Cert cert = new Cert();
        try {
            cert.loadPfxFile("qa_data/pfx/myPdfSigningCert.pfx", "pfx_password");

            // Tell the pdf object to use the certificate for signing.
            pdf.setSigningCert(cert);

            pdf.signPdf(json, "qa_output/hello_signed.pdf");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("The PDF has been successfully cryptographically signed.");

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

        // ----------------------------------------------------------------------------------------------------
        // *** Scroll down for information about specifying the PDF signature x,y location in user space coordinates.
        // ----------------------------------------------------------------------------------------------------

        // 

        // The x,y coordinates of a PDF page are in "user space", called "points", and there are 72 pointes per inch.
        // A PDF page (8.5" x 11") is 612 points wide and 792 points high.
        // The bottom left is at 0,0.    The top right is at 612,792.
        //
        // To specify the location of a signature rectangle, the "appearance.y" is the y coordinate of the top of the signature rectangle,
        // and the "appearance.x" is the x coordinate of the left of the signature rectangle.
        // Therefore, to position the signature rectangle at the exact top/left of the page, we do this:

        json.updateString("appearance.y", "792");
        json.updateString("appearance.x", "0");

        json.updateString("appearance.text[0]", "Digitally signed again by: cert_cn");
        json.updateString("appearance.text[1]", "current_dt");
        json.updateString("appearance.image", "document-accepted");
        json.updateString("appearance.imagePlacement", "right");

        Pdf pdf2 = new Pdf();
        pdf2.loadFile("qa_output/hello_signed.pdf");
        pdf2.setSigningCert(cert);

        try {
            pdf2.signPdf(json, "qa_output/hello_signed2.pdf");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("The PDF has been successfully cryptographically signed again.");

        // Here we have the PDF with the signature just added at the exact top/left.
        // 
    }
}