Fix some workflow problems wrt automation.

- clearing automation points sets control to "off" rather than touch.
	- multiple touches on the same pass acts consistently (no more
	  fader jumps on mouse button press
	- use actual value for initial point rather than some arbitrary
	  default. clarify new semantics of add () (with_default->with_initial).
	- clean some whitespace
	- add guard points as needed in stop.
	- catch grab broken signal (i can't trigger it, but the docs seem
	  to think it is essential).

gtk2_ardour/automation_time_axis.cc

@@ -449,7 +449,7 @@ AutomationTimeAxisView::clear_clicked ()
 	} else if (_view) {
 		_view->clear ();
 	}
-
+	set_automation_state ((AutoState) ARDOUR::Off);
 	_editor.commit_reversible_command ();
 	_session->set_dirty ();
 }

libs/ardour/automation_control.cc

@@ -116,6 +116,8 @@ AutomationControl::start_touch(double when)
 	if (!_list) return;
 	if (!touching()) {
 		if (alist()->automation_state() == Touch) {
+			/* subtle. aligns the user value with the playback */
+			set_value (get_value ());
 			alist()->start_touch (when);
 			if (!_desc.toggled) {
 				AutomationWatch::instance().add_automation_watch (shared_from_this());

libs/evoral/evoral/ControlList.hpp

@@ -124,7 +124,7 @@ public:
 	void slide (iterator before, double distance);
 	void shift (double before, double distance);
 
-	virtual void add (double when, double value, bool with_guards=true, bool with_default=true);
+	virtual void add (double when, double value, bool with_guards=true, bool with_initial=true);
 	virtual void editor_add (double when, double value);
 	
 	void fast_simple_add (double when, double value);

libs/evoral/src/ControlList.cpp

@@ -399,7 +399,7 @@ ControlList::add_guard_point (double when)
 	most_recent_insert_iterator = lower_bound (_events.begin(), _events.end(), &cp, time_comparator);
 
 	double eval_value = unlocked_eval (insert_position);
-	
+
 	if (most_recent_insert_iterator == _events.end()) {
 		
 		DEBUG_TRACE (DEBUG::ControlList, string_compose ("@%1 insert iterator at end, adding eval-value there %2\n", this, eval_value));
@@ -407,7 +407,7 @@ ControlList::add_guard_point (double when)
 		/* leave insert iterator at the end */
 		
 	} else if ((*most_recent_insert_iterator)->when == when) {
-		
+
 		DEBUG_TRACE (DEBUG::ControlList, string_compose ("@%1 insert iterator at existing point, setting eval-value there %2\n", this, eval_value));
 		
 		/* most_recent_insert_iterator points to a control event
@@ -415,15 +415,15 @@ ControlList::add_guard_point (double when)
 		   nothing to do.
 		   
 		   ... except ... 
-		   
+
 		   advance most_recent_insert_iterator so that the "real"
 		   insert occurs in the right place, since it 
 		   points to the control event just inserted.
 		*/
-		
+
 		++most_recent_insert_iterator;
 	} else {
-		
+
 		/* insert a new control event at the right spot
 		 */
 		
@@ -431,7 +431,7 @@ ControlList::add_guard_point (double when)
 								 this, eval_value, (*most_recent_insert_iterator)->when));
 		
 		most_recent_insert_iterator = _events.insert (most_recent_insert_iterator, new ControlEvent (when, eval_value));
-		
+
 		/* advance most_recent_insert_iterator so that the "real"
 		 * insert occurs in the right place, since it 
 		 * points to the control event just inserted.
@@ -546,7 +546,7 @@ ControlList::erase_from_iterator_to (iterator iter, double when)
 }
 
 void
-ControlList::add (double when, double value, bool with_guards, bool with_default)
+ControlList::add (double when, double value, bool with_guards, bool with_initial)
 {
 	/* this is for making changes from some kind of user interface or
 	   control surface (GUI, MIDI, OSC etc)
@@ -561,12 +561,12 @@ ControlList::add (double when, double value, bool with_guards, bool with_default
 		ControlEvent cp (when, 0.0f);
 		iterator insertion_point;
 
-		if (_events.empty() && with_default) {
+		if (_events.empty() && with_initial) {
 			
 			/* empty: add an "anchor" point if the point we're adding past time 0 */
 
 			if (when >= 1) {
-				_events.insert (_events.end(), new ControlEvent (0, _default_value));
+				_events.insert (_events.end(), new ControlEvent (0, value));
 				DEBUG_TRACE (DEBUG::ControlList, string_compose ("@%1 added default value %2 at zero\n", this, _default_value));
 			}
 		}
@@ -628,10 +628,19 @@ ControlList::add (double when, double value, bool with_guards, bool with_default
 			if ((*most_recent_insert_iterator)->value != value) {
 				DEBUG_TRACE (DEBUG::ControlList, string_compose ("@%1 reset existing point to new value %2\n", this, value));
 
-				/* only one point allowed per time point, so just
-				 * reset the value here.
+				/* only one point allowed per time point, so add a guard point
+				 * before it if needed then reset the value of the point.
 				 */
-				
+
+				if ((when > 0) && most_recent_insert_iterator != _events.begin ()) {
+					--most_recent_insert_iterator;
+					double last_when =  (*most_recent_insert_iterator)->when;
+					++most_recent_insert_iterator;
+					if (when - last_when > 64) {
+						add_guard_point (when - 64);
+					}
+				}
+
 				(*most_recent_insert_iterator)->value = value;
 
 				/* if we modified the final value, then its as

libs/gtkmm2ext/gtkmm2ext/pixfader.h

@@ -58,6 +58,7 @@ class LIBGTKMM2EXT_API PixFader : public CairoWidget
 	void on_size_allocate (Gtk::Allocation& alloc);
 
 	void render (cairo_t *, cairo_rectangle_t*);
+	bool on_grab_broken_event (GdkEventGrabBroken*);
 	bool on_button_press_event (GdkEventButton*);
 	bool on_button_release_event (GdkEventButton*);
 	bool on_motion_notify_event (GdkEventMotion*);

libs/gtkmm2ext/pixfader.cc

@@ -71,7 +71,7 @@ PixFader::PixFader (Gtk::Adjustment& adj, int orientation, int fader_length, int
 
 	_adjustment.signal_value_changed().connect (mem_fun (*this, &PixFader::adjustment_changed));
 	_adjustment.signal_changed().connect (mem_fun (*this, &PixFader::adjustment_changed));
-
+	signal_grab_broken_event ().connect (mem_fun (*this, &PixFader::on_grab_broken_event));
 	if (_orien == VERT) {
 		CairoWidget::set_size_request(_girth, _span);
 	} else {
@@ -365,6 +365,18 @@ PixFader::on_size_allocate (Gtk::Allocation& alloc)
 	update_unity_position ();
 }
 
+bool
+PixFader::on_grab_broken_event (GdkEventGrabBroken* ev)
+{
+	if (_dragging) {
+		remove_modal_grab();
+		_dragging = false;
+		gdk_pointer_ungrab (GDK_CURRENT_TIME);
+		StopGesture ();
+	}
+	return (_tweaks & NoButtonForward) ? true : false;
+}
+
 bool
 PixFader::on_button_press_event (GdkEventButton* ev)
 {