Magento 1.9 add admin order comments to invoice.php

invoice.php

         <?php   
         
         /* add these lines to /app/code/core/Mage/Sales/Model/Order/Pdf/invoice.php */
         
         /* Add Comments */
            $statusHistory = $order->getStatusHistoryCollection()->getData();
            $order_comments = '';
            foreach($statusHistory as $status) {
              $new_comment = '';
              if ($status['comment']) {
                if ($new_comment) {
                  $new_comment .= ', ';
                }
                $new_comment .= $status['comment'];
              }
              if ($new_comment) {
                if (strlen($order_comments) > 0) { $order_comments .= '; '; }
                $order_comments .= $new_comment;
              }
            }

            if ($order_comments){
                $page->setFillColor(new Zend_Pdf_Color_RGB(0.93, 0.92, 0.92));
                $page->setLineColor(new Zend_Pdf_Color_GrayScale(0.5));
                $page->setLineWidth(0.5);
                if (strlen($order_comments) > 100) {
                    $line_count = (int)((strlen($order_comments) + 17) / 118); // Excepting first line with order comment label
                    $order_comments_1st = "Order Comments : " . substr($order_comments, 0, 100);
                    $page->drawRectangle(25, $this->y + 5, 570, $this->y - 15 - $line_count * 12);
                    $this->y -= 8;
                    $page->setFillColor(new Zend_Pdf_Color_RGB(0, 0, 0));
                    $page->drawText($order_comments_1st, 35, $this->y, 'UTF-8');

                    for ($i = 0; $i < $line_count; $i++) {
                        $begin_point = 100 + i * 118;
                        $order_comments_2nd = substr($order_comments, 100 + $i * 118, 118);
                        $this->y -= 13;
                        $page->drawText($order_comments_2nd, 35, $this->y, 'UTF-8');
                    }
                }
                else{
                    $page->drawRectangle(25, $this->y + 5, 570, $this->y - 15);
                    $this->y -= 8;
                    $orderComment = "Order Comments : " . $order_comments;
                    $page->setFillColor(new Zend_Pdf_Color_RGB(0, 0, 0));
                    $page->drawText($orderComment, 35, $this->y, 'UTF-8');
                }
                
             
                ?>