Connect LayoutManager to LayoutChild

If we want to inspect the type of layout properties exposed by a
GtkLayoutManager, we need a way to connect the layout manager type to
the GtkLayoutChild type it creates. In order to do so, we can set the
GtkLayoutChild type on a field of the GtkLayoutManagerClass structure.

Storing the GtkLayoutChild type on the class structure of the layout
manager also allows us to implement a default create_layout_child()
virtual function.

1 files changed, 3 insertions, 0 deletions

diff --git a/gtk/gtklayoutmanager.h b/gtk/gtklayoutmanager.h
index 53f4931c69..06659ee70e 100644
--- a/gtk/gtklayoutmanager.h
+++ b/gtk/gtklayoutmanager.h
@@ -39,6 +39,7 @@ G_DECLARE_DERIVABLE_TYPE (GtkLayoutManager, gtk_layout_manager, GTK, LAYOUT_MANA
  *   sizes of the widget using the layout manager for a given orientation
  * @allocate: a virtual function, used to allocate the size of the widget
  *   using the layout manager
+ * @layout_child_type: the type of #GtkLayoutChild used by this layout manager
  * @create_layout_child: a virtual function, used to create a #GtkLayoutChild
  *   meta object for the layout properties
  *
@@ -70,6 +71,8 @@ struct _GtkLayoutManagerClass
                                               int               height,
                                               int               baseline);
 
+  GType              layout_child_type;
+
   GtkLayoutChild *   (* create_layout_child) (GtkLayoutManager *manager,
                                               GtkWidget        *widget,
                                               GtkWidget        *for_child);