framework/base/View.php
public function renderFile($viewFile, $params = [], $context = null)
    {
        $viewFile = $requestedFile = Yii::getAlias($viewFile);

        if ($this->theme !== null) {
            $viewFile = $this->theme->applyTo($viewFile);
        }
        if (is_file($viewFile)) {
            $viewFile = FileHelper::localize($viewFile);
        } else {
            throw new ViewNotFoundException("The view file does not exist: $viewFile");
        }

        $oldContext = $this->context;
        if ($context !== null) {
            $this->context = $context;
        }
        $output = '';
        $this->_viewFiles[] = [
            'resolved' => $viewFile,
            'requested' => $requestedFile
        ];

        if ($this->beforeRender($viewFile, $params)) {
            Yii::debug("Rendering view file: $viewFile", __METHOD__);
            $ext = pathinfo($viewFile, PATHINFO_EXTENSION);
            if (isset($this->renderers[$ext])) {
                if (is_array($this->renderers[$ext]) || is_string($this->renderers[$ext])) {
                    $this->renderers[$ext] = Yii::createObject($this->renderers[$ext]);
                }
                /* @var $renderer ViewRenderer */
                $renderer = $this->renderers[$ext];
                $output = $renderer->render($this, $viewFile, $params);
            } else {
                $output = $this->renderPhpFile($viewFile, $params);
            }
            $this->afterRender($viewFile, $params, $output);
        }

        array_pop($this->_viewFiles);
        $this->context = $oldContext;

        return $output;
    }
public function renderFile($viewFile, $params = [], $context = null)
    {
        $viewFile = $requestedFile = Yii::getAlias($viewFile);

        if ($this->theme !== null) {
            $viewFile = $this->theme->applyTo($viewFile);
        }
        if (is_file($viewFile)) {
            $viewFile = FileHelper::localize($viewFile);
        } else {
            throw new ViewNotFoundException("The view file does not exist: $viewFile");
        }

        $oldContext = $this->context;
        if ($context !== null) {
            $this->context = $context;
        }
        $output = '';
        $this->_viewFiles[] = [
            'resolved' => $viewFile,
            'requested' => $requestedFile
        ];

        if ($this->beforeRender($viewFile, $params)) {
            Yii::debug("Rendering view file: $viewFile", __METHOD__);
            $ext = pathinfo($viewFile, PATHINFO_EXTENSION);
            if (isset($this->renderers[$ext])) {
                if (is_array($this->renderers[$ext]) || is_string($this->renderers[$ext])) {
                    $this->renderers[$ext] = Yii::createObject($this->renderers[$ext]);
                }
                /* @var $renderer ViewRenderer */
                $renderer = $this->renderers[$ext];
                $output = $renderer->render($this, $viewFile, $params);
            } else {
                $output = $this->renderPhpFile($viewFile, $params);
            }
            $this->afterRender($viewFile, $params, $output);
        }

        array_pop($this->_viewFiles);
        $this->context = $oldContext;

        return $output;
    }
Renders a view file.

If [[theme]] is enabled (not null), it will try to render the themed version of the view file as long
as it is available.

The method will call [[FileHelper::localize()]] to localize the view file.

If [[renderers|renderer]] is enabled (not null), the method will use it to render the view file.
Otherwise, it will simply include the view file as a normal PHP file, capture its output and
return it as a string.

@param string $viewFile the view file. This can be either an absolute file path or an alias of it.
@param array $params the parameters (name-value pairs) that will be extracted and made available in the view file.
@param object $context the context that the view should use for rendering the view. If null,
existing [[context]] will be used.
@return string the rendering result
@throws ViewNotFoundException if the view file does not exist