Widget.sizeRequest

This function is typically used when implementing a #GtkContainer subclass. Obtains the preferred size of a widget. The container uses this information to arrange its child widgets and decide what size allocations to give them with [gtk.widget.Widget.sizeAllocate].

You can also call this function from an application, with some caveats. Most notably, getting a size request requires the widget to be associated with a screen, because font information may be needed. Multihead-aware applications should keep this in mind.

Also remember that the size request is not necessarily the size a widget will actually be allocated.