Useful php function: Crop String

    public function cropString($str, $len) {

        if ( mb_strlen($str) <= $len ) {
            return $str;
        }

        // find the longest possible match
        $pos = 0;
        foreach ( array('. ', '? ', '! ') as $punct ) {
            $npos = mb_strrpos($str, $punct);
            if ( $npos > $pos && $npos < $len ) {
                $pos = $npos;
            }
        }

        if ( !$pos ) {
            // substr $len-3, because the ellipsis adds 3 chars
            return mb_substr($str, 0, $len-3, 'UTF-8') . '...';
        }
        else {
            // $pos+1 to grab punctuation mark
            return mb_substr($str, 0, $pos+1, 'UTF-8');
        }
    }