Symfony\Bundle\FrameworkBundle\Controller\Controller::renderView PHP Method

    protected function renderView($view, array $parameters = array())
    {
        if ($this->container->has('templating')) {
            return $this->container->get('templating')->render($view, $parameters);
        }
        if (!$this->container->has('twig')) {
            throw new \LogicException('You can not use the "renderView" method if the Templating Component or the Twig Bundle are not available.');
        }
        return $this->container->get('twig')->render($view, $parameters);
    }

 /**
  * Returns a rendered structure.
  *
  * @param StructureInterface $structure The structure, which has been loaded for rendering
  * @param array $attributes Additional attributes, which will be passed to twig
  * @param bool $preview Defines if the site is rendered in preview mode
  * @param bool $partial Defines if only the content block of the template should be rendered
  *
  * @return Response
  */
 protected function renderStructure(StructureInterface $structure, $attributes = [], $preview = false, $partial = false)
 {
     // extract format twig file
     if (!$preview) {
         $request = $this->getRequest();
         $requestFormat = $request->getRequestFormat();
     } else {
         $requestFormat = 'html';
     }
     $viewTemplate = $structure->getView() . '.' . $requestFormat . '.twig';
     try {
         // get attributes to render template
         $data = $this->getAttributes($attributes, $structure, $preview);
         // if partial render only content block else full page
         if ($partial) {
             $content = $this->renderBlock($viewTemplate, 'content', $data);
         } else {
             $content = parent::renderView($viewTemplate, $data);
         }
         return new Response($content);
     } catch (InvalidArgumentException $e) {
         // template not found
         throw new HttpException(406, 'Error encountered when rendering content', $e);
     }
 }