* This allows a widget to tell it's parent container whether
* it preferrs to be allocated in %GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH
* or %GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT mode.
- *
* %GTK_SIZE_REQUEST_HEIGHT_FOR_WIDTH means the widget preferrs to
* have #GtkWidgetClass.get_preferred_width() called and then
* #GtkWidgetClass.get_preferred_height_for_width() and is the
* default return for unimplemented cases.
- *
* However it's important to note (as described below) that any
* widget which trades height-for-width must respond properly to
* both #GtkSizeRequestModes since it might be queried in either
* a width less than it's minimum and will only ever be allocated
* a width greater than the natural width once all of the said
* widget's siblings have received their natural widths.
- *
* Furthermore a widget will only ever be allocated a width greater
* than it's natural width if it was configured to receive extra
* expand space from it's parent container.
* <listitem>
* This is called by containers to obtain the minimum and
* natural height of a widget.
- *
* A widget that does not actually trade any height for width
* or width for height only has to implement these two virtual
* methods (#GtkWidgetClass.get_preferred_width() and