public function forward($length) {
        $theta = $this->rotation / 180.0 * M_PI;
        $x     = $this->x + $length * cos($theta);
        $y     = $this->y + $length * sin($theta);

        $this->move($x, $y);
    }
public function forward($length) {
        $theta = $this->rotation / 180.0 * M_PI;
        $x     = $this->x + $length * cos($theta);
        $y     = $this->y + $length * sin($theta);

        $this->move($x, $y);
    }
public function forward ( $ length ) { $ theta = $ this -> rotation / 180.0 * M_PI ; $ x = $ this -> x + $ length * cos ( $ theta ) ; $ y = $ this -> y + $ length * sin ( $ theta ) ; $ this -> move ( $ x , $ y ) ; }
Move the pen forward

@param integer $length distance to move forward
Move the pen forward