+#include <assert.h>
+#include "libpspp/cast.h"
+
+extern const struct chart_item_class scree_class;
+
+/* Returns true if SUPER is a scree, otherwise false. */
+static inline bool
+is_scree (const struct chart_item *super)
+{
+ return super->class == &scree_class;
+}
+
+/* Returns SUPER converted to scree. SUPER must be a scree, as
+ reported by is_scree. */
+static inline struct scree *
+to_scree (const struct chart_item *super)
+{
+ assert (is_scree (super));
+ return UP_CAST (super, struct scree, chart_item);
+}
+
+/* Returns INSTANCE converted to chart_item. */
+static inline struct chart_item *
+scree_super (const struct scree *instance)
+{
+ return CONST_CAST (struct chart_item *, &instance->chart_item);
+}
+
+/* Increments INSTANCE's reference count and returns INSTANCE. */
+static inline struct scree *
+scree_ref (const struct scree *instance)
+{
+ return to_scree (chart_item_ref (&instance->chart_item));
+}
+
+/* Decrements INSTANCE's reference count, then destroys INSTANCE if
+ the reference count is now zero. */
+static inline void
+scree_unref (struct scree *instance)
+{
+ chart_item_unref (&instance->chart_item);
+}
+
+/* Returns true if INSTANCE's reference count is greater than 1,
+ false otherwise. */
+static inline bool
+scree_is_shared (const struct scree *instance)
+{
+ return chart_item_is_shared (&instance->chart_item);
+}
+
+static inline void
+scree_submit (struct scree *instance)
+{
+ chart_item_submit (&instance->chart_item);
+}
+\f
+#endif /* output/charts/scree.h */