PHP

PDF Signature with Background Image (Seal/Stamp/etc.)

See more PDF Signatures Examples

Demonstrates how to sign a PDF with an appearance that includes a background image, such as a seal, stamp, etc.

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

Chilkat2 PHP

<?php

use Chilkat2\BinData;
use Chilkat2\Cert;
use Chilkat2\JsonObject;
use Chilkat2\Pdf;

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

$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 (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

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

// 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 10.0
$json->UpdateString('appearance.fontScale', '10.0');

// In this example, the appearance of the digital signature will contain three lines:
// 1) The signing certificate's common name
// 2) The current date/time
// 3) Some arbitrary text.
// The keyword "cert_cn" is replaced with the Certificate's Subject Common Name.
// The keyword "current_dt" is replaced with the current date/time.
// Any number of appearance text lines can be added.
$json->UpdateString('appearance.text[0]', 'Digitally signed by: cert_cn');
$json->UpdateString('appearance.text[1]', 'current_dt');
$json->UpdateString('appearance.text[2]', 'The crazy brown fox jumps over the lazy dog.');

// Load a JPG image to be shown with 30% opacity in the background.
// (the image must be in the JPG format)
// The sample university.jpb is available at https://example-code.com/images/university.jpg

$jpgData = new BinData();
try {
    $jpgData->LoadFile('qa_data/jpg/university.jpg');
} catch (\Chilkat2\Exception $e) {
    echo "Failed to load the JPG image.\n";
    exit;
}

try {
    $pdf->SetSignatureJpeg($jpgData);

    // Specify that we want to display the JPG image in the center with 30% opacity.
    $json->UpdateString('appearance.image', 'custom-jpg');
    $json->UpdateString('appearance.imagePlacement', 'center');
    $json->UpdateString('appearance.imageOpacity', '30');

    // Load the signing certificate. (Use your own certificate.)
    $cert = new Cert();
    $cert->LoadPfxFile('qa_data/pfx/myPdfSigningCert.pfx', 'secret');

    // Tell the pdf object to use the certificate for signing.
    $pdf->SetSigningCert($cert);

    $pdf->SignPdf($json, 'qa_output/hello_signed.pdf');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo "The PDF has been successfully cryptographically signed.\n";

// The appearance of the signature appears in Adobe Acrobat as shown below.
// The JPG is automatically scaled to the size of the signature based on the signature's font scale
// and number of text lines.
//