$_params
$_params : array
Valid parameters:
Image effect for adding a drop shadow.
$_image : \Horde_Image
The bound Horde_Image object
setImageObject(\Horde_Image  $image) 
                Bind this effect to a Horde_Image object.
| \Horde_Image | $image | The Horde_Image object | 
factory(string $type, string $driver, array $params) : \Horde_Image_Effect
Effect factory.
| string | $type | An effect name. | 
| string | $driver | An image driver name. | 
| array | $params | Any effect parameters. | 
An effect instance.