Signature pad and dompdf

I am using Thomas J Bradley's plugin for drawing two signatures at the bottom of a html form, which is then converted to a pdf using dompdf and sent by email as an attachment using sendmail.

Everything works well except the fact that i can't seem to be able to redraw the signatures on to the pdf file without saving them to disk which i would like to avoid.

Mr. Bradley provided several methods for regenerating the signature but i need some advices on how to pass the signature data along with the form values to the pdf converter preferably 'on the fly' (without saving the data to disk or database).

I would appreciate any answer. If you need any sample code, please let me know.

Thank you in advance!

Solution

Brian, you rock ! I had to do the following to get it to work, since we were checking for this line included data:image/png;base64, .

But with your help and some digging around i obtained a pdf with the signature on it :) This is the code in case somebody needs it in the future.

the html part :

<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="jquery.signaturepad.css" media="screen">
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script>
<script type="text/javascript" src="jquery.signaturepad.min.js"></script>
</head>
<body>
<form method="post" action="pdf.php" class="sigPad">
  <label for="name">Print your name</label>
  <input type="text" name="name" id="name" class="name">
  <p class="drawItDesc">Draw your signature</p>
  <ul class="sigNav">

    <li class="drawIt"><a href="#draw-it">Draw It</a></li>
    <li class="clearButton"><a href="#clear">Clear</a></li>
  </ul>
  <div class="sig sigWrapper">
    <canvas class="pad" width="198" height="55"></canvas>
    
    <input type="hidden" name="imgOutput" class="imgOutput">
  </div>
  <button type="submit">I accept the terms of this agreement.</button>
</form>

<script>
    var sig;
  $(document).ready(function() {
    /*sig = $('.sigPad').signaturePad();*/
    sig = $('.sigPad').signaturePad({drawOnly:true});
  });
  $('.sigPad').submit(function(evt) {
    $('.imgOutput').val( sig.getSignatureImage() );
  });  
</script>

</body>
</html>

pdf.php :

<?php
if(isset($_POST['imgOutput'])){$img_output = $_POST['imgOutput'];}

$bse = preg_replace('#^data:image/[^;]+;base64,#', '', $img_output );

if ( base64_encode( base64_decode($bse) ) === $bse ) {

  require_once 'dompdf/dompdf_config.inc.php';
  $html = '<!DOCTYPE html><html><head></head><body><p>Your signature:</p>
  <br />
  <img src="'. $img_output .'"></body></html>';
  $dompdf = new DOMPDF;
  $dompdf->load_html($html);
  $dompdf->render();
  $dompdf->stream("test.pdf");
} 
else {
    echo ("ERROR !");
}
?>

Many thanks to @Thomas J Bradley, the dompdf team and @BrianS who saved the day.