yii2-bootstrap/docs/view_renderers.md

Yii2 view renderers

By default Yii uses PHP as template language but you can change it in your application. The component responsible for rendering a view is called view. You can configure a custom template engine as follows:

array(
	'components' => array(
		'view' => array(
			'class' => 'yii\base\View',
			'renderer' => array(
				'class' => 'yii\renderers\TwigViewRenderer',
				// or 'class' => 'yii\renderers\SmartyViewRenderer',
			),
		),
	),
)

Twig

In order to use Twig you need to put you templates in files with extension .twig. Also you need to specify this extension explicitly when calling $this->render() or $this->renderPartial() from your controller.

Smarty

In order to use Smarty you need to put you templates in files with extension .tpl. Also you need to specify this extension explicitly when calling $this->render() or $this->renderPartial() from your controller.

Using multiple view renderers in a single application

If you need multiple view renderers at the same time in a single application you can use CompositeViewRenderer as follows:

'components' => array(
	'view' => array(
		'class' => 'yii\base\View',
		'renderer' => array(
			'class' => 'yii\renderers\CompositeViewRenderer',
			'renderers' => array(
				'tpl' => array(
					'class' => 'yii\renderers\SmartyViewRenderer',
				),
				'twig' => array(
					'class' => 'yii\renderers\TwigViewRenderer',
				),
			),
			//'class' => 'yii\renderers\TwigViewRenderer',
		),
	),
),