public Requisition get_requisition ()
Warning: get_requisition is deprecated since "3.0".
Retrieves the widget’s requisition.
The Requisition cache on the widget was removed, If you need to cache sizes across requests and allocations, add an explicit cache to the widget in question instead.
This function should only be used by widget implementations in order to figure whether the widget’s requisition has actually changed after some internal state change (so that they can call queue_resize instead of queue_draw).
Normally, size_request should be used.
a pointer to a Requisition to copy to