quantize speed changes in semitone mode to whole semitones, range is 2 octaves

git-svn-id: svn://localhost/ardour2/branches/2.0-ongoing@4882 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 27 insertions, 7 deletions

diff --git a/gtk2_ardour/ardour_ui2.cc b/gtk2_ardour/ardour_ui2.cc
index 1dabb25c4b..6ff37bce2e 100644
--- a/gtk2_ardour/ardour_ui2.cc
+++ b/gtk2_ardour/ardour_ui2.cc
@@ -370,6 +370,7 @@ ARDOUR_UI::setup_transport ()
 
 	speed_display_box.add (speed_display_label);
 	speed_display_box.set_name (X_("ShuttleDisplay"));
+	set_size_request_to_display_given_text (speed_display_label, X_("> 24.0"), 2, 2);
 
 	shuttle_units_button.set_name (X_("ShuttleButton"));
 	shuttle_units_button.signal_clicked().connect (mem_fun(*this, &ARDOUR_UI::shuttle_unit_clicked));
@@ -772,15 +773,33 @@ ARDOUR_UI::use_shuttle_fract (bool force)
 	
 	last_shuttle_request = now;
 
-	bool neg = (shuttle_fract < 0.0);
+	if (Config->get_shuttle_units() == Semitones) {
 
-	double fract = 1 - sqrt (1 - (shuttle_fract * shuttle_fract)); // Formula A1
+		const double step = 1.0 / 24.0; // range is 24 semitones up & down
+		double semitones;
+		double speed;
 
-	if (neg) {
-		fract = -fract;
+		semitones = round (shuttle_fract / step);
+		speed = pow (2.0, (semitones / 12.0));
+
+		session->request_transport_speed (speed);
+
+	} else {
+
+		bool neg;
+		double fract;
+		
+		neg = (shuttle_fract < 0.0);
+
+		fract = 1 - sqrt (1 - (shuttle_fract * shuttle_fract)); // Formula A1
+
+		if (neg) {
+			fract = -fract;
+		}
+
+		session->request_transport_speed (shuttle_max_speed * fract);
 	}
 
-	session->request_transport_speed (shuttle_max_speed * fract); // Formula A2
 	shuttle_box.queue_draw ();
 }
 
@@ -851,10 +870,11 @@ ARDOUR_UI::update_speed_display ()
 			if (Config->get_shuttle_units() == Percentage) {
 				snprintf (buf, sizeof (buf), "%.2f", x);
 			} else {
+
 				if (x < 0) {
-					snprintf (buf, sizeof (buf), "< %.1f", 12.0 * fast_log2 (-x));
+					snprintf (buf, sizeof (buf), "< %d", (int) round (12.0 * fast_log2 (-x)));
 				} else {
-					snprintf (buf, sizeof (buf), "> %.1f", 12.0 * fast_log2 (x));
+					snprintf (buf, sizeof (buf), "> %d", (int) round (12.0 * fast_log2 (x)));
 				}
 			}
 			speed_display_label.set_text (buf);