proc rect(self: VisibilityNotifier2D): Rect2 {.
gcsafe, locks: 0, raises: [], tags: []
.}

proc rect=(self: VisibilityNotifier2D; val: Rect2) {.
gcsafe, locks: 0, raises: [],
    tags: []
.}

proc isOnScreen(self: VisibilityNotifier2D): bool {.
gcsafe, locks: 0, raises: [],
    tags: []
.}