Preserve and restore x and y origin of editor viewport in Editor state.

Clean up Editor's update of various things by:
1. merging Editor's handlers of SuperRapidScreenUpdate.
2. separating out work to be done on this update and work to be done
   on a locate.
Hopefully easier to understand this way.


git-svn-id: svn://localhost/ardour2/branches/3.0@6648 d708f5d6-7413-0410-9779-e7cbd77b26cf

5 files changed, 148 insertions, 156 deletions

diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index 3bbd748277..ee205237bb 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -1416,7 +1416,6 @@ ARDOUR_UI::transport_goto_zero ()
 	if (_session) {
 		_session->request_locate (0);
 
-
 		/* force displayed area in editor to start no matter
 		   what "follow playhead" setting is.
 		*/
@@ -3147,7 +3146,6 @@ ARDOUR_UI::push_buffer_stats (uint32_t capture, uint32_t playback)
 void
 ARDOUR_UI::write_buffer_stats ()
 {
-
 	std::ofstream fout;
 	struct tm tm;
 	char buf[64];
diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index ca1a35cb4b..4dbd316d35 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -263,6 +263,7 @@ Editor::Editor ()
 	, nudge_clock (X_("nudge"), false, X_("NudgeClock"), true, false, true)
 	, meters_running(false)
 	, _pending_locate_request (false)
+	, _pending_initial_locate (false)
 
 {
 	constructed = false;
@@ -923,8 +924,6 @@ Editor::access_action (std::string action_group, std::string action_item)
 	if (act) {
 		act->activate();
 	}
-
-
 }
 
 void
@@ -935,20 +934,6 @@ Editor::on_realize ()
 }
 
 void
-Editor::start_scrolling ()
-{
-	scroll_connection = ARDOUR_UI::instance()->SuperRapidScreenUpdate.connect
-		(sigc::mem_fun(*this, &Editor::update_current_screen));
-
-}
-
-void
-Editor::stop_scrolling ()
-{
-	scroll_connection.disconnect ();
-}
-
-void
 Editor::map_position_change (nframes64_t frame)
 {
 	ENSURE_GUI_THREAD (*this, &Editor::map_position_change, frame)
@@ -1068,7 +1053,6 @@ Editor::set_session (Session *t)
 	compute_fixed_ruler_scale ();
 
 	/* there are never any selected regions at startup */
-
 	sensitize_the_right_region_actions (false);
 
 	XMLNode* node = ARDOUR_UI::instance()->editor_settings();
@@ -1077,6 +1061,7 @@ Editor::set_session (Session *t)
 	/* catch up with the playhead */
 
 	_session->request_locate (playhead_cursor->current_frame);
+	_pending_initial_locate = true;
 
 	update_title ();
 
@@ -1158,8 +1143,10 @@ Editor::set_session (Session *t)
 		(static_cast<TimeAxisView*>(*i))->set_samples_per_unit (frames_per_unit);
 	}
 
-	start_scrolling ();
-
+	super_rapid_screen_update_connection = ARDOUR_UI::instance()->SuperRapidScreenUpdate.connect (
+		sigc::mem_fun (*this, &Editor::super_rapid_screen_update)
+		);
+	
 	switch (_snap_type) {
 	case SnapToRegionStart:
 	case SnapToRegionEnd:
@@ -1175,7 +1162,7 @@ Editor::set_session (Session *t)
 	/* register for undo history */
 	_session->register_with_memento_command_factory(_id, this);
 
-	start_updating ();
+	start_updating_meters ();
 }
 
 void
@@ -2296,11 +2283,13 @@ Editor::set_state (const XMLNode& node, int /*version*/)
 		nframes64_t pos;
 		if (sscanf (prop->value().c_str(), "%" PRId64, &pos) == 1) {
 			reset_x_origin (pos);
-			/* this hack prevents the initial call to update_current_screen() from doing re-centering on the playhead */
-			last_update_frame = pos;
 		}
 	}
 
+	if ((prop = node.property ("y-origin")) != 0) {
+		reset_y_origin (atof (prop->value ()));
+	}
+
 	if ((prop = node.property ("internal-edit"))) {
 		bool yn = string_is_affirmative (prop->value());
 		RefPtr<Action> act = ActionManager::get_action (X_("MouseMode"), X_("toggle-internal-edit"));
@@ -2455,6 +2444,8 @@ Editor::get_state ()
 	node->add_property ("playhead", buf);
 	snprintf (buf, sizeof (buf), "%" PRIi64, leftmost_frame);
 	node->add_property ("left-frame", buf);
+	snprintf (buf, sizeof (buf), "%f", vertical_adjustment.get_value ());
+	node->add_property ("y-origin", buf);
 
 	node->add_property ("show-waveforms-recording", _show_waveforms_recording ? "yes" : "no");
 	node->add_property ("show-measures", _show_measures ? "yes" : "no");
@@ -3699,7 +3690,7 @@ Editor::set_follow_playhead (bool yn)
 	if (_follow_playhead != yn) {
 		if ((_follow_playhead = yn) == true) {
 			/* catch up */
-			update_current_screen ();
+			reset_x_origin_to_follow_playhead ();
 		}
 		instant_save ();
 	}
@@ -4066,10 +4057,12 @@ Editor::on_key_release_event (GdkEventKey* ev)
 	// return key_press_focus_accelerator_handler (*this, ev);
 }
 
+/** Queue up a change to the viewport x origin.
+ *  @param frame New x origin.
+ */
 void
 Editor::reset_x_origin (nframes64_t frame)
 {
-	//cerr << "resetting x origin" << endl;
 	queue_visual_change (frame);
 }
 
@@ -4731,7 +4724,13 @@ Editor::located ()
 {
 	ENSURE_GUI_THREAD (*this, &Editor::located);
 
+	playhead_cursor->set_position (_session->audible_frame ());
+	if (_follow_playhead && !_pending_initial_locate) {
+		reset_x_origin_to_follow_playhead ();
+	}
+
 	_pending_locate_request = false;
+	_pending_initial_locate = false;
 }
 
 void
@@ -5025,115 +5024,127 @@ Editor::horizontal_scroll_right ()
 	reset_x_origin (leftmost_position() + current_page_frames() / 5);
 }
 
+/** Queue a change for the Editor viewport x origin to follow the playhead */
 void
-Editor::update_current_screen ()
+Editor::reset_x_origin_to_follow_playhead ()
 {
-	if (_pending_locate_request) {
-		/* we don't update things when there's a pending locate request, otherwise
-		   when the editor requests a locate there is a chance that this method
-		   will move the playhead before the locate request is processed, causing
-		   a visual glitch. */
-		return;
-	}
-
-	if (_session && _session->engine().running()) {
+	nframes64_t const frame = playhead_cursor->current_frame;
 
-		nframes64_t const frame = _session->audible_frame();
+	if (frame < leftmost_frame || frame > leftmost_frame + current_page_frames()) {
 
-		if (_dragging_playhead) {
-			goto almost_done;
+		if (_session->transport_speed() < 0) {
+			
+			if (frame > (current_page_frames() / 2)) {
+				center_screen (frame-(current_page_frames()/2));
+			} else {
+				center_screen (current_page_frames()/2);
+			}
+			
+		} else {
+						
+			if (frame < leftmost_frame) {
+				/* moving left */
+				nframes64_t l = 0;
+				if (_session->transport_rolling()) {
+					/* rolling; end up with the playhead at the right of the page */
+					l = frame - current_page_frames ();
+				} else {
+					/* not rolling: end up with the playhead 3/4 of the way along the page */
+					l = frame - (3 * current_page_frames() / 4);
+				}
+				
+				if (l < 0) {
+					l = 0;
+				}
+				
+				center_screen_internal (l + (current_page_frames() / 2), current_page_frames ());
+			} else {
+				/* moving right */
+				if (_session->transport_rolling()) {
+					/* rolling: end up with the playhead on the left of the page */
+					center_screen_internal (frame + (current_page_frames() / 2), current_page_frames ());
+				} else {
+					/* not rolling: end up with the playhead 1/4 of the way along the page */
+					center_screen_internal (frame + (current_page_frames() / 4), current_page_frames ());
+				}
+			}
 		}
+	}
+}
 
-		/* only update if the playhead is on screen or we are following it */
-
-		if (_follow_playhead && _session->requested_return_frame() < 0) {
+void
+Editor::super_rapid_screen_update ()
+{
+	if (!_session || !_session->engine().running()) {
+		return;
+	}
 
-			//playhead_cursor->canvas_item.show();
+	/* METERING / MIXER STRIPS */
 
-			if (frame != last_update_frame) {
+	/* update track meters, if required */
+	if (is_mapped() && meters_running) {
+		RouteTimeAxisView* rtv;
+		for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
+			if ((rtv = dynamic_cast<RouteTimeAxisView*>(*i)) != 0) {
+				rtv->fast_update ();
+			}
+		}
+	}
 
+	/* and any current mixer strip */
+	if (current_mixer_strip) {
+		current_mixer_strip->fast_update ();
+	}
 
-#undef CONTINUOUS_SCROLL
-#ifndef  CONTINUOUS_SCROLL
-				if (frame < leftmost_frame || frame > leftmost_frame + current_page_frames()) {
-
-					if (_session->transport_speed() < 0) {
-						if (frame > (current_page_frames()/2)) {
-							center_screen (frame-(current_page_frames()/2));
-						} else {
-							center_screen (current_page_frames()/2);
-						}
-						
-					} else {
-
-						if (frame < leftmost_frame) {
-							/* moving left */
-							nframes64_t l = 0;
-							if (_session->transport_rolling()) {
-								/* rolling; end up with the playhead at the right of the page */
-								l = frame - current_page_frames ();
-							} else {
-								/* not rolling: end up with the playhead 3/4 of the way along the page */
-								l = frame - (3 * current_page_frames() / 4);
-							}
-							
-							if (l < 0) {
-								l = 0;
-							}
-							
-							center_screen_internal (l + (current_page_frames() / 2), current_page_frames ());
-						} else {
-							/* moving right */
-							if (_session->transport_rolling()) {
-								/* rolling: end up with the playhead on the left of the page */
-								center_screen_internal (frame + (current_page_frames() / 2), current_page_frames ());
-							} else {
-								/* not rolling: end up with the playhead 1/4 of the way along the page */
-								center_screen_internal (frame + (current_page_frames() / 4), current_page_frames ());
-							}
-						}
-					}
-				}
+	/* PLAYHEAD AND VIEWPORT */
 
-				playhead_cursor->set_position (frame);
+	nframes64_t const frame = _session->audible_frame();
 
-#else  // CONTINUOUS_SCROLL
+	/* There are a few reasons why we might not update the playhead / viewport stuff:
+	 *
+	 * 1.  we don't update things when there's a pending locate request, otherwise
+	 *     when the editor requests a locate there is a chance that this method
+	 *     will move the playhead before the locate request is processed, causing
+	 * 2.  if we're not rolling, there's nothing to do here (locates are handled elsewhere).
+	 * 3.  if we're still at the same frame that we were last time, there's nothing to do.
+	 */
 
-				/* don't do continuous scroll till the new position is in the rightmost quarter of the
-				   editor canvas
-				*/
-
-				if (_session->transport_speed()) {
-					double target = ((double)frame - (double)current_page_frames()/2.0) / frames_per_unit;
-					if (target <= 0.0) target = 0.0;
-					if ( fabs(target - current) < current_page_frames()/frames_per_unit ) {
-						target = (target * 0.15) + (current * 0.85);
-					} else {
-						/* relax */
-					}
-					//printf("frame: %d,  cpf: %d,  fpu: %6.6f, current: %6.6f, target : %6.6f\n", frame, current_page_frames(), frames_per_unit, current, target );
-					current = target;
-					horizontal_adjustment.set_value ( current );
-				}
+	if (!_pending_locate_request && _session->transport_speed() != 0 && frame != last_update_frame) {
 
-				playhead_cursor->set_position (frame);
+		last_update_frame = frame;
 
-#endif // CONTINUOUS_SCROLL
+		if (!_dragging_playhead) {
+			playhead_cursor->set_position (frame);
+		}
 
-			}
+#undef CONTINUOUS_SCROLL
+#ifndef CONTINUOUS_SCROLL		
 
-		} else {
-			if (frame != last_update_frame) {
-				playhead_cursor->set_position (frame);
-			}
+		if (!_dragging_playhead && _follow_playhead && _session->requested_return_frame() < 0) {
+			reset_x_origin_to_follow_playhead ();
 		}
 
-	  almost_done:
-		last_update_frame = frame;
-		if (current_mixer_strip) {
-			current_mixer_strip->fast_update ();
+#else  // CONTINUOUS_SCROLL
+				
+		/* don't do continuous scroll till the new position is in the rightmost quarter of the
+		   editor canvas
+		*/
+		
+		double target = ((double)frame - (double)current_page_frames()/2.0) / frames_per_unit;
+		if (target <= 0.0) {
+			target = 0.0;
+		}
+		if (fabs(target - current) < current_page_frames() / frames_per_unit) {
+			target = (target * 0.15) + (current * 0.85);
+		} else {
+			/* relax */
 		}
+		
+		current = target;
+		horizontal_adjustment.set_value (current);
 
+#endif // CONTINUOUS_SCROLL
+		
 	}
 }
 
@@ -5145,7 +5156,8 @@ Editor::session_going_away ()
 
 	_session_connections.drop_connections ();
 
-	stop_scrolling ();
+	super_rapid_screen_update_connection.disconnect ();
+	
 	selection->clear ();
 	cut_buffer->clear ();
 
diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 4568a80630..8f50883ea8 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -401,6 +401,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	void restore_editing_space();
 
 	void reset_x_origin (nframes64_t);
+	void reset_x_origin_to_follow_playhead ();
 	void reset_y_origin (double);
 	void reset_zoom (double);
 	void reposition_and_zoom (nframes64_t, double);
@@ -987,11 +988,11 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 
 	static void build_cursors ();
 
-	sigc::connection scroll_connection;
+	sigc::connection super_rapid_screen_update_connection;
 	nframes64_t last_update_frame;
 	void center_screen_internal (nframes64_t, float);
 
-	void update_current_screen ();
+	void super_rapid_screen_update ();
 
 	void session_going_away ();
 
@@ -1253,9 +1254,6 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	void reverse_selection ();
 	void edit_envelope ();
 
-	void start_scrolling ();
-	void stop_scrolling ();
-
 	double last_scrub_x;
 	int scrubbing_direction;
 	int scrub_reversals;
@@ -1966,10 +1964,8 @@ public:
 
 	void get_regions_for_action (RegionSelection&, bool allow_entered = false, bool allow_edit_position = true);
 
-	sigc::connection fast_screen_update_connection;
-	gint start_updating ();
-	gint stop_updating ();
-	void fast_update_strips ();
+	void start_updating_meters ();
+	void stop_updating_meters ();
 	bool meters_running;
 
 	void select_next_route ();
@@ -1999,7 +1995,15 @@ public:
 	void visible_order_range (int*, int*) const;
 
 	void located ();
+	
+	/** true if we've made a locate request that hasn't yet been processed */
 	bool _pending_locate_request;
+	
+	/** if true, there is a pending Session locate which is the initial one when loading a session;
+	    we need to know this so that we don't (necessarily) set the viewport to show the playhead
+	    initially.
+	*/
+	bool _pending_initial_locate;
 
 	Gtk::HBox _summary_hbox;
 	EditorSummary* _summary;
diff --git a/gtk2_ardour/editor_audiotrack.cc b/gtk2_ardour/editor_audiotrack.cc
index ea703c415c..143da8aa08 100644
--- a/gtk2_ardour/editor_audiotrack.cc
+++ b/gtk2_ardour/editor_audiotrack.cc
@@ -49,12 +49,11 @@ Editor::set_show_waveforms_recording (bool yn)
 	}
 }
 
-gint
-Editor::start_updating ()
+void
+Editor::start_updating_meters ()
 {
 	RouteTimeAxisView* rtv;
 
-	//cerr << "Editor::start_updating () called" << endl;//DEBUG
 	if (is_mapped() && _session) {
 		for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
 			if ((rtv = dynamic_cast<RouteTimeAxisView*>(*i)) != 0) {
@@ -63,21 +62,16 @@ Editor::start_updating ()
 		}
 	}
 
-	if (!meters_running) {
-		fast_screen_update_connection = ARDOUR_UI::SuperRapidScreenUpdate.connect (sigc::mem_fun(*this, &Editor::fast_update_strips));
-		meters_running = true;
-	}
-    return 0;
+	meters_running = true;
 }
 
-gint
-Editor::stop_updating ()
+void
+Editor::stop_updating_meters ()
 {
 	RouteTimeAxisView* rtv;
 
 	meters_running = false;
-	fast_screen_update_connection.disconnect();
-	//cerr << "Editor::stop_updating () called" << endl;//DEBUG
+
 	if (is_mapped() && _session) {
 		for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
 			if ((rtv = dynamic_cast<RouteTimeAxisView*>(*i)) != 0) {
@@ -85,32 +79,17 @@ Editor::stop_updating ()
 			}
 		}
 	}
-
-    return 0;
 }
 
 void
 Editor::toggle_meter_updating()
 {
 	if (Config->get_show_track_meters()) {
-		start_updating();
+		start_updating_meters ();
 	} else {
-		stop_updating ();
-	}
-	track_canvas_allocate(track_canvas->get_allocation());
-}
-
-void
-Editor::fast_update_strips ()
-{
-	RouteTimeAxisView* rtv;
-
-	if (is_mapped() && _session) {
-		for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
-			if ((rtv = dynamic_cast<RouteTimeAxisView*>(*i)) != 0) {
-				rtv->fast_update ();
-			}
-		}
+		stop_updating_meters ();
 	}
+	
+	track_canvas_allocate (track_canvas->get_allocation());
 }
 
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 69d20fa68d..1ca4c1d245 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -820,7 +820,6 @@ Editor::cursor_to_region_boundary (bool with_selection, int32_t dir)
 		return;
 	}
 
-
 	_session->request_locate (target);
 }