(gobject:define-genum "GtkIconSize" icon-size
  (:export t
   :type-initializer "gtk_icon_size_get_type")
  (:inherit 0)
  (:normal 1)
  (:large 2))  

:inherit

Keep the size of the parent element.

:normal

Size similar to text size.

:large

Large size, for example in an icon view.

Built-in icon sizes. Icon sizes default to being inherited. Where they cannot be inherited, text size is the default.

All widgets which use the gtk:icon-size enumeration set the .normal-icons or .large-icons style classes correspondingly, and let themes determine the actual size to be used with the -gtk:icon-size CSS property.