/**
* This function will read an image with a Code 39 Barcode and will decode it.
*
* @access public
* @static
* @param IO\File $file the image's URI
* @return string the decode value
*/
public static function decode(IO\File $file)
{
$image = NULL;
$ext = $file->getFileExtension();
switch ($ext) {
case 'png':
$image = imagecreatefrompng($file);
break;
case 'jpg':
$image = imagecreatefromjpeg($file);
break;
default:
throw new Throwable\InvalidArgument\Exception('Unrecognized file format. File name must have either a png or jpg extension.', array('file' => $file));
}
$width = imagesx($image);
$height = imagesy($image);
$y = floor($height / 2);
// finds middle
$pixels = array();
for ($x = 0; $x < $width; $x++) {
$rgb = imagecolorat($image, $x, $y);
$r = $rgb >> 16 & 0xff;
$g = $rgb >> 8 & 0xff;
$b = $rgb & 0xff;
$pixels[$x] = ($r + $g + $b) / 3 < 128.0 ? 1 : 0;
}
$code = array();
$bw = array();
$i = 0;
$code[0] = 1;
$bw[0] = 'b';
for ($x = 1; $x < $width; $x++) {
if ($pixels[$x] == $pixels[$x - 1]) {
$code[$i]++;
} else {
$code[++$i] = 1;
$bw[$i] = $pixels[$x] == 1 ? 'b' : 'w';
}
}
$max = 0;
for ($x = 1; $x < count($code) - 1; $x++) {
if ($code[$x] > $max) {
$max = $code[$x];
}
}
$code_string = '';
for ($x = 1; $x < count($code) - 1; $x++) {
$code_string .= $code[$x] > $max / 2 * 1.5 ? strtoupper($bw[$x]) : $bw[$x];
}
// parse code string
$msg = '';
for ($x = 0; $x < strlen($code_string); $x += 10) {
$msg .= self::$patterns[substr($code_string, $x, 9)];
}
return $msg;
}
