Widget.queueResize
void queueResize()This function is only for use in widget implementations. Flags a widget to have its size renegotiated; should be called when a widget for some reason has a new size request. For example, when you change the text in a #GtkLabel, #GtkLabel queues a resize to ensure there’s enough space for the new text.
Note that you cannot call [gtk.widget.Widget.queueResize] on a widget from inside its implementation of the GtkWidgetClass::size_allocate virtual method. Calls to [gtk.widget.Widget.queueResize] from inside GtkWidgetClass::size_allocate will be silently ignored.