Add GtkLayoutChild

Layout managers needs a way to store properties that control the layout
policy of a widget; typically, we used to store these in GtkContainer's
child properties, but since GtkLayoutManager is decoupled from the
actual container widget, we need a separate storage. Additionally, child
properties have their own downsides, like requiring a separate, global
GParamSpecPool storage, and additional lookup API.

GtkLayoutChild is a simple GObject class, which means you can introspect
and document it as you would any other type.

1 files changed, 27 insertions, 0 deletions

diff --git a/gtk/gtklayoutchild.h b/gtk/gtklayoutchild.h
new file mode 100644
index 0000000000..3be8fdaf6a
--- /dev/null
+++ b/gtk/gtklayoutchild.h
@@ -0,0 +1,27 @@
+#pragma once
+
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
+#include <gtk/gtktypes.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_LAYOUT_CHILD (gtk_layout_child_get_type())
+
+GDK_AVAILABLE_IN_ALL
+G_DECLARE_DERIVABLE_TYPE (GtkLayoutChild, gtk_layout_child, GTK, LAYOUT_CHILD, GObject)
+
+struct _GtkLayoutChildClass
+{
+  /*< private >*/
+  GObjectClass parent_class;
+};
+
+GDK_AVAILABLE_IN_ALL
+GtkLayoutManager *      gtk_layout_child_get_layout_manager     (GtkLayoutChild *layout_child);
+GDK_AVAILABLE_IN_ALL
+GtkWidget *             gtk_layout_child_get_child_widget       (GtkLayoutChild *layout_child);
+
+G_END_DECLS