2 files changed, 16 insertions, 21 deletions

diff --git a/gtk2_ardour/shuttle_control.cc b/gtk2_ardour/shuttle_control.cc
index b4095f7c0c..7096cd31bb 100644
--- a/gtk2_ardour/shuttle_control.cc
+++ b/gtk2_ardour/shuttle_control.cc
@@ -427,10 +427,10 @@ ShuttleControl::mouse_shuttle (double x, bool force)
 }
 
 void
-ShuttleControl::set_shuttle_fract (double f)
+ShuttleControl::set_shuttle_fract (double f, bool zero_ok)
 {
 	shuttle_fract = f;
-	use_shuttle_fract (false);
+	use_shuttle_fract (false, zero_ok);
 }
 
 int
@@ -472,7 +472,7 @@ ShuttleControl::fract_as_semitones (float fract, bool& reverse)
 }
 
 void
-ShuttleControl::use_shuttle_fract (bool force)
+ShuttleControl::use_shuttle_fract (bool force, bool zero_ok)
 {
 	microseconds_t now = get_microseconds();
 
@@ -503,7 +503,11 @@ ShuttleControl::use_shuttle_fract (bool force)
 		speed = shuttle_max_speed * shuttle_fract;
 	}
 
-	_session->request_transport_speed_nonzero (speed, Config->get_shuttle_behaviour() == Wheel);
+	if (zero_ok) {
+		_session->request_transport_speed (speed, Config->get_shuttle_behaviour() == Wheel);
+	} else {
+		_session->request_transport_speed_nonzero (speed, Config->get_shuttle_behaviour() == Wheel);
+	}
 }
 
 void
@@ -657,25 +661,13 @@ ShuttleControl::ShuttleControllable::ShuttleControllable (ShuttleControl& s)
 void
 ShuttleControl::ShuttleControllable::set_value (double val)
 {
-	double fract;
-
-	if (val == 0.5) {
-		fract = 0.0;
-	} else {
-		if (val < 0.5) {
-			fract = -((0.5 - val)/0.5);
-		} else {
-			fract = ((val - 0.5)/0.5);
-		}
-	}
-
-	sc.set_shuttle_fract (fract);
+	sc.set_shuttle_fract ((val - lower()) / (upper() - lower()), true);
 }
 
 double
 ShuttleControl::ShuttleControllable::get_value () const
 {
-	return sc.get_shuttle_fract ();
+	return lower() + (sc.get_shuttle_fract () * (upper() - lower()));
 }
 
 void
diff --git a/gtk2_ardour/shuttle_control.h b/gtk2_ardour/shuttle_control.h
index c16328e384..a8c2e71d59 100644
--- a/gtk2_ardour/shuttle_control.h
+++ b/gtk2_ardour/shuttle_control.h
@@ -40,7 +40,7 @@ class ShuttleControl : public CairoWidget, public ARDOUR::SessionHandlePtr
 
 	void map_transport_state ();
 	void update_speed_display ();
-	void set_shuttle_fract (double);
+        void set_shuttle_fract (double, bool zero_ok = false);
 	double get_shuttle_fract () const { return shuttle_fract; }
 	void set_session (ARDOUR::Session*);
 
@@ -49,6 +49,9 @@ class ShuttleControl : public CairoWidget, public ARDOUR::SessionHandlePtr
 		void set_value (double);
 		double get_value (void) const;
 
+                double lower() const { return -1.0; }
+                double upper() const { return  1.0; }
+
 		ShuttleControl& sc;
 	};
 
@@ -89,8 +92,8 @@ class ShuttleControl : public CairoWidget, public ARDOUR::SessionHandlePtr
 	void on_size_allocate (Gtk::Allocation&);
 	bool on_query_tooltip (int, int, bool, const Glib::RefPtr<Gtk::Tooltip>&);
 
-	gint mouse_shuttle (double x, bool force);
-	void use_shuttle_fract (bool force);
+        gint mouse_shuttle (double x, bool force);
+        void use_shuttle_fract (bool force, bool zero_ok = false);
 	void parameter_changed (std::string);
 
 	void set_shuttle_units (ARDOUR::ShuttleUnits);