ZF3: How to get view of an action from another action in the controller?

In my controller action, I want to grap a rendered full page of another action:

class MycontrollerController extends AbstractActionController
{
    public function firstactionAction()
    {
         $html = some_function_to_get_the_rendered_page_of_secondaction();
    }

    public function secondactionAction()
    {
         return new ViewModel();
    }
}

Be careful to use setTemplate()

MycontrollerControllerFactory.php

<?php

namespace Application\Controller\Service;

use Application\Controller\MycontrollerController;
use Interop\Container\ContainerInterface;
use Zend\ServiceManager\Factory\FactoryInterface;

class MycontrollerControllerFactory implements FactoryInterface
{
    public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
    {
        $controller = new MycontrollerController();
        $controller->setRenderer($container->get('Zend\View\Renderer\PhpRenderer'));
        return $controller;
    }
}

MycontrollerController.php

<?php

namespace Application\Controller;

use Zend\Mvc\Controller\AbstractActionController;
use Zend\View\Model\ViewModel;

class MycontrollerController extends AbstractActionController
{
    /**
     * @var \Zend\View\Renderer\PhpRenderer
     */
    protected $renderer;

    /**
     * @return \Zend\View\Renderer\PhpRenderer
     */
    public function getRenderer()
    {
        return $this->renderer;
    }

    /**
     * @param  \Zend\View\Renderer\PhpRenderer $renderer
     * @return self
     */
    public function setRenderer($renderer)
    {
        $this->renderer = $renderer;
        return $this;
    }

    public function firstAction()
    {
        if ($this->yourMethod()) {
            $secondView = $this->secondAction();
            $html = $this->getRenderer()->render($secondView);
        }

        $view = new ViewModel();
        $view->setTemplate('namespace/my-controller/first');
        return $view;
    }

    public function secondAction()
    {
        $view = new ViewModel();
        $view->setTemplate('namespace/my-controller/second');
        return $view;
    }
}