Retrieves the widget's requisition.
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
gtk_widget_queue_resize() instead of gtk_widget_queue_draw()).
Normally, gtk_widget_size_request() should be used.
Since 2.20
Retrieves the widget's requisition. 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 gtk_widget_queue_resize() instead of gtk_widget_queue_draw()). Normally, gtk_widget_size_request() should be used. Since 2.20