1 files changed, 44 insertions, 0 deletions
diff --git a/libs/pbd/pbd/controllable.h b/libs/pbd/pbd/controllable.h
new file mode 100644
index 0000000000..4948e4e4a0
--- /dev/null
+++ b/libs/pbd/pbd/controllable.h
@@ -0,0 +1,44 @@
+#ifndef __pbd_controllable_h__
+#define __pbd_controllable_h__
+
+#include <sigc++/trackable.h>
+#include <sigc++/signal.h>
+
+#include <pbd/stateful.h>
+#include <pbd/id.h>
+
+class XMLNode;
+
+namespace PBD {
+
+class Controllable : public virtual sigc::trackable, public Stateful {
+  public:
+	Controllable ();
+	virtual ~Controllable() { GoingAway (this); }
+
+	virtual void set_value (float) = 0;
+	virtual float get_value (void) const = 0;
+
+	virtual bool can_send_feedback() const { return true; }
+
+	static sigc::signal<void,Controllable*> Created;
+	static sigc::signal<void,Controllable*> GoingAway;
+
+
+	static sigc::signal<bool,PBD::Controllable*> StartLearning;
+	static sigc::signal<void,PBD::Controllable*> StopLearning;
+
+	sigc::signal<void> Changed;
+
+	const PBD::ID& id() const { return _id; }
+
+	int set_state (const XMLNode&) { return 0; }
+	XMLNode& get_state ();
+
+  private:
+	PBD::ID _id;
+};
+
+}
+
+#endif /* __pbd_controllable_h__ */