function displayError($msg)
 {
     //ttf from jpgraph
     $ttf = new TTF();
     $ttf->SetUserFont('dejavu-lgc/DejaVuLGCSans.ttf', 'dejavu-lgc/DejaVuLGCSans-Bold.ttf', 'dejavu-lgc/DejaVuLGCSans-Oblique.ttf', 'dejavu-lgc/DejaVuLGCSans-BoldOblique.ttf');
     //Calculate the baseline
     // @see http://www.php.net/manual/fr/function.imagettfbbox.php#75333
     //this should be above baseline
     $test2 = "H";
     //some of these additional letters should go below it
     $test3 = "Hjgqp";
     //get the dimension for these two:
     $box2 = imageTTFBbox(10, 0, $ttf->File(FF_USERFONT), $test2);
     $box3 = imageTTFBbox(10, 0, $ttf->File(FF_USERFONT), $test3);
     $baseline = abs(abs($box2[5]) + abs($box2[1]) - (abs($box3[5]) + abs($box3[1])));
     $bbox = imageTTFBbox(10, 0, $ttf->File(FF_USERFONT), $msg);
     if ($im = @imagecreate($bbox[2] - $bbox[6], $bbox[3] - $bbox[5])) {
         $background_color = imagecolorallocate($im, 255, 255, 255);
         $text_color = imagecolorallocate($im, 64, 64, 64);
         imagettftext($im, 10, 0, 0, $bbox[3] - $bbox[5] - $baseline, $text_color, $ttf->File(FF_USERFONT), $msg);
         header("Content-type: image/png");
         imagepng($im);
         imagedestroy($im);
     }
 }