private function collectChars($chars)
{
if (($unicodeEncodingTable = TTF::getEncodingTable($this->cmap, 3, 1)) === null) {
throw new Exception('No unicode (3,1) encoding table found');
}
for ($i = 0; $i < strlen($chars); $i += 2) {
$charCode = self::ORD(substr($chars, $i, 2));
$orgIndex = TTF::characterToIndex($unicodeEncodingTable, $charCode);
$description = $orgIndex > -1 ? $this->glyf[$orgIndex] : null;
if (!$this->orgIndexAlreadyExists($orgIndex)) {
$this->TTFchars[] = new TTFchar($charCode, $orgIndex, 0, $description);
}
}
}
