gtk-widget-get-preferred-height-for-width (widget width)
minimum-height -- the minimum height, or nil
natural-height -- the natural height, or nil
Retrieves a widget's minimum and natural height if it would be given the specified width.
The returned request will be modified by the GtkWidgetClass::adjust_size_request virtual method and by any gtk-size-group's 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.