public static function filter( $region )
    {
        $r = array(
            'x'      => intval( $region['x'] ),
            'y'      => intval( $region['y'] ),
            'width'  => intval( $region['w'] ),
            'height' => intval( $region['h'] ) 
        );
        return array( new ezcImageFilter( 'crop', $r ) );
    }