ManaPHP\Image\Adapter\Gd::__construct PHP Метод

    public function __construct($file)
    {
        if (!extension_loaded('gd')) {
            throw new GdException('gd is not installed, or the extension is not loaded');
        }
        $this->_file = realpath($this->alias->resolve($file));
        if (!$this->_file) {
            throw new GdException('`:file` file is not exists', ['file' => $file]);
        }
        $imageInfo = getimagesize($this->_file);
        $this->_width = $imageInfo[0];
        /** @noinspection MultiAssignmentUsageInspection */
        $this->_height = $imageInfo[1];
        /** @noinspection MultiAssignmentUsageInspection */
        $type = $imageInfo[2];
        if ($type === IMAGETYPE_GIF) {
            $this->_image = imagecreatefromgif($this->_file);
        } elseif ($type === IMAGETYPE_JPEG) {
            $this->_image = imagecreatefromjpeg($this->_file);
        } elseif ($type === IMAGETYPE_PNG) {
            $this->_image = imagecreatefrompng($this->_file);
        } else {
            throw new GdException('Installed GD does not support such images');
        }
        imagesavealpha($this->_image, true);
    }