let mouse_area = |
#on_press: fn(button: MouseButton) -> Any = |_| null,
#on_release: fn(button: MouseButton) -> Any = |_| null,
#on_enter: fn(e: null) -> Any = |_| null,
#on_exit: fn(e: null) -> Any = |_| null,
#on_move: fn(pos: {x: f64, y: f64}) -> Any = |_| null,
child: &Widget
| -> Widget `MouseArea({ child, on_press: &on_press, on_release: &on_release, on_enter: &on_enter, on_exit: &on_exit, on_move: &on_move })