public function __construct()
 {
     parent::__construct(0.0, 1.0, 0.0, 1.0, -4.0, 1.0, 0.0, 1.0, 0.0);
     // findEdges
 }
 public function __construct()
 {
     parent::__construct(1, 1, -1, 1, 1, -1, 1, -1, -1);
 }
 public function __construct()
 {
     parent::__construct(-1, -1, -1, -1, 16, -1, -1, -1, -1);
     // sharpen
 }
 public function __construct()
 {
     parent::__construct(0, 0, 1, 0, 0, 0, 1, 0, 0);
     // sharpen
 }