+ static bool indicates_constraint (guint state);
+
+ static void set_constraint_modifier (guint);
+ /** @return Modifier mask to constrain drags in a particular direction; */
+ static ModifierMask constraint_modifier () { return ModifierMask (constraint_mod); }
+
+ static void set_trim_contents_modifier (guint);
+ /** @return Modifier mask to move contents rather than region bounds during trim; */