class ImageFactory

class ImageFactory {
    
    /**
     * The image toolkit plugin manager.
     *
     * @var \Drupal\Core\ImageToolkit\ImageToolkitManager
     */
    protected $toolkitManager;
    
    /**
     * The image toolkit ID to use for this factory.
     *
     * @var string
     */
    protected $toolkitId;
    
    /**
     * Constructs a new ImageFactory object.
     *
     * @param \Drupal\Core\ImageToolkit\ImageToolkitManager $toolkit_manager
     *   The image toolkit plugin manager.
     */
    public function __construct(ImageToolkitManager $toolkit_manager) {
        $this->toolkitManager = $toolkit_manager;
        $this->toolkitId = $this->toolkitManager
            ->getDefaultToolkitId();
    }
    
    /**
     * Sets the ID of the image toolkit.
     *
     * @param string $toolkit_id
     *   The ID of the image toolkit to use for this image factory.
     *
     * @return $this
     */
    public function setToolkitId($toolkit_id) {
        $this->toolkitId = $toolkit_id;
        return $this;
    }
    
    /**
     * Gets the ID of the image toolkit currently in use.
     *
     * @return string
     *   The ID of the image toolkit in use by the image factory.
     */
    public function getToolkitId() {
        return $this->toolkitId;
    }
    
    /**
     * Constructs a new Image object.
     *
     * Normally, the toolkit set as default in the admin UI is used by the
     * factory to create new Image objects. This can be overridden through
     * \Drupal\Core\Image\ImageInterface::setToolkitId() so that any new Image
     * object created will use the new toolkit specified. Finally, a single
     * Image object can be created using a specific toolkit, regardless of the
     * current factory settings, by passing its plugin ID in the $toolkit_id
     * argument.
     *
     * @param string|null $source
     *   (optional) The path to an image file, or NULL to construct the object
     *   with no image source.
     * @param string|null $toolkit_id
     *   (optional) The ID of the image toolkit to use for this image, or NULL
     *   to use the current toolkit.
     *
     * @return \Drupal\Core\Image\ImageInterface
     *   An Image object.
     *
     * @see ImageFactory::setToolkitId()
     */
    public function get($source = NULL, $toolkit_id = NULL) {
        $toolkit_id = $toolkit_id ?: $this->toolkitId;
        return new Image($this->toolkitManager
            ->createInstance($toolkit_id), $source);
    }
    
    /**
     * Returns the image file extensions supported by the toolkit.
     *
     * @param string|null $toolkit_id
     *   (optional) The ID of the image toolkit to use for checking, or NULL
     *   to use the current toolkit.
     *
     * @return array
     *   An array of supported image file extensions (e.g. png/jpeg/gif).
     *
     * @see \Drupal\Core\ImageToolkit\ImageToolkitInterface::getSupportedExtensions()
     */
    public function getSupportedExtensions($toolkit_id = NULL) {
        $toolkit_id = $toolkit_id ?: $this->toolkitId;
        $definition = $this->toolkitManager
            ->getDefinition($toolkit_id);
        return call_user_func($definition['class'] . '::getSupportedExtensions');
    }

}