public virtual void get_preferred_height (out int minimum_height, out int natural_height)
Retrieves a widget’s initial minimum and natural height.
This call is specific to width-for-height requests.
The returned request will be modified by the GtkWidgetClass:
GtkWidget:adjust_size_request virtual method and by any
SizeGroups that have been applied. That is, the returned request is the one that should
be used for layout, not necessarily the one returned by the widget itself.
a Widget instance
location to store the minimum height, or null
location to store the natural height, or null