Window.getUpdateArea

Transfers ownership of the update area from window to the caller of the function. That is, after calling this function, window will no longer have an invalid/dirty region; the update area is removed from window and handed to you. If a window has no update area, [gdk.window.Window.getUpdateArea] returns null. You are responsible for calling [cairo.region.Region.destroy] on the returned region if it’s non-null.