try to rationalize zoom/scroll ops for the canvas

git-svn-id: svn://localhost/ardour2/trunk@1305 d708f5d6-7413-0410-9779-e7cbd77b26cf

7 files changed, 195 insertions, 132 deletions

diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index b6142bbd59..8b1bc78e68 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -956,7 +956,7 @@ ARDOUR_UI::transport_goto_start ()
 		*/
 		
 		if (editor) {
-			editor->reposition_x_origin (session->current_start_frame());
+			editor->reset_x_origin (session->current_start_frame());
 		}
 	}
 }
@@ -973,7 +973,7 @@ ARDOUR_UI::transport_goto_zero ()
 		*/
 		
 		if (editor) {
-			editor->reposition_x_origin (0);
+			editor->reset_x_origin (0);
 		}
 	}
 }
@@ -990,7 +990,7 @@ ARDOUR_UI::transport_goto_end ()
 		*/
 		
 		if (editor) {
-			editor->reposition_x_origin (frame);
+			editor->reset_x_origin (frame);
 		}
 	}
 }
diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index 2e50a778df..2fdbb5c7fb 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -291,7 +291,6 @@ Editor::Editor (AudioEngine& eng)
 	new_transport_marker_menu = 0;
 	editor_mixer_strip_width = Wide;
 	show_editor_mixer_when_tracks_arrive = false;
-	repos_zoom_queued = false;
 	region_edit_menu_split_item = 0;
 	temp_location = 0;
 	region_edit_menu_split_multichannel_item = 0;
@@ -322,7 +321,7 @@ Editor::Editor (AudioEngine& eng)
 	
 	set_mouse_mode (MouseObject, true);
 
-	frames_per_unit = 2048; /* too early to use set_frames_per_unit */
+	frames_per_unit = 2048; /* too early to use reset_zoom () */
 	reset_hscrollbar_stepping ();
 	
 	zoom_focus = ZoomFocusLeft;
@@ -825,65 +824,6 @@ Editor::tie_vertical_scrolling ()
 }
 
 void
-Editor::set_frames_per_unit (double fpu)
-{
-	nframes_t frames;
-
-	if (fpu == frames_per_unit) {
-		return;
-	}
-
-	if (fpu < 2.0) {
-		fpu = 2.0;
-	}
-
-	// convert fpu to frame count
-
-	frames = (nframes_t) floor (fpu * canvas_width);
-	
-	/* don't allow zooms that fit more than the maximum number
-	   of frames into an 800 pixel wide space.
-	*/
-
-	if (max_frames / fpu < 800.0) {
-		return;
-	}
-
-	if (fpu == frames_per_unit) {
-		return;
-	}
-
-	frames_per_unit = fpu;
-
-	if (frames != zoom_range_clock.current_duration()) {
-		zoom_range_clock.set (frames);
-	}
-
-	if (mouse_mode == MouseRange && selection->time.start () != selection->time.end_frame ()) {
-		if (!selection->tracks.empty()) {
-			for (TrackSelection::iterator i = selection->tracks.begin(); i != selection->tracks.end(); ++i) {
-				(*i)->reshow_selection (selection->time);
-			}
-		} else {
-			for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
-				(*i)->reshow_selection (selection->time);
-			}
-		}
-	}
-
-	ZoomChanged (); /* EMIT_SIGNAL */
-
-	reset_hscrollbar_stepping ();
-	reset_scrolling_region ();
-	
-	if (edit_cursor) edit_cursor->set_position (edit_cursor->current_frame);
-	if (playhead_cursor) playhead_cursor->set_position (playhead_cursor->current_frame);
-
-	instant_save ();
-
-}
-
-void
 Editor::instant_save ()
 {
 	if (!constructed || !ARDOUR_UI::instance()->session_loaded) {
@@ -898,28 +838,6 @@ Editor::instant_save ()
 }
 
 void
-Editor::reposition_x_origin (nframes_t frame)
-{
-	cerr << "repsosition to " << frame << endl;
-
-	if (frame != leftmost_frame) {
-		leftmost_frame = frame;
-		
-		nframes_t rightmost_frame = leftmost_frame + current_page_frames ();
-
-		if (rightmost_frame > last_canvas_frame) {
-			last_canvas_frame = rightmost_frame;
-			reset_scrolling_region ();
-		}
-
-		horizontal_adjustment.set_value (frame/frames_per_unit);
-	} else {
-		update_fixed_rulers();
-		tempo_map_changed (Change (0));
-	}
-}
-
-void
 Editor::edit_cursor_clock_changed()
 {
 	if (edit_cursor->current_frame != edit_cursor_clock.current_time()) {
@@ -974,9 +892,9 @@ Editor::control_scroll (float fraction)
 
 	if (target > (current_page_frames() / 2)) {
 		/* try to center PH in window */
-		reposition_x_origin (target - (current_page_frames()/2));
+		reset_x_origin (target - (current_page_frames()/2));
 	} else {
-		reposition_x_origin (0);
+		reset_x_origin (0);
 	}
 
 	/* cancel the existing */
@@ -995,36 +913,6 @@ Editor::deferred_control_scroll (nframes_t target)
 	return false;
 }
 
-void 
-Editor::canvas_horizontally_scrolled ()
-{
-
-  	leftmost_frame = (nframes_t) floor (horizontal_adjustment.get_value() * frames_per_unit);
-	update_fixed_rulers ();
-	tempo_map_changed (Change (0));
-
-}
-
-void
-Editor::reposition_and_zoom (nframes_t frame, double nfpu)
-{
-	if (!repos_zoom_queued) {
-		repos_zoom_queued = true;
-		Glib::signal_idle().connect (bind (mem_fun(*this, &Editor::deferred_reposition_and_zoom), frame, nfpu));
-	}
-}
-
-gint
-Editor::deferred_reposition_and_zoom (nframes_t frame, double nfpu)
-{
-
-	set_frames_per_unit (nfpu);
-	reposition_x_origin  (frame);
-	repos_zoom_queued = false;
-	
-	return FALSE;
-}
-
 void
 Editor::on_realize ()
 {
@@ -1082,7 +970,7 @@ Editor::center_screen_internal (nframes_t frame, float page)
 		frame = 0;
 	}
 
-    reposition_x_origin (frame);
+	reset_x_origin (frame);
 }
 
 void
@@ -2114,7 +2002,7 @@ Editor::set_state (const XMLNode& node)
 	} else {
 		playhead_cursor->set_position (0);
 
-		/* ::reposition_x_origin() doesn't work right here, since the old
+		/* reset_x_origin() doesn't work right here, since the old
 		   position may be zero already, and it does nothing in such
 		   circumstances.
 		*/
@@ -2135,7 +2023,7 @@ Editor::set_state (const XMLNode& node)
 	}
 
 	if ((prop = node.property ("zoom"))) {
-		set_frames_per_unit (PBD::atof (prop->value()));
+		reset_zoom (PBD::atof (prop->value()));
 	}
 
 	if ((prop = node.property ("snap-to"))) {
@@ -4250,3 +4138,156 @@ Editor::on_key_press_event (GdkEventKey* ev)
 	return key_press_focus_accelerator_handler (*this, ev);
 }
 
+void
+Editor::reset_x_origin (nframes_t frame)
+{
+	queue_visual_change (frame);
+}
+
+void
+Editor::reset_zoom (double fpu)
+{
+	queue_visual_change (fpu);
+}
+
+void
+Editor::reposition_and_zoom (nframes_t frame, double fpu)
+{
+	reset_x_origin (frame);
+	reset_zoom (fpu);
+}
+
+void
+Editor::set_frames_per_unit (double fpu)
+{
+	nframes_t frames;
+
+	/* this is the core function that controls the zoom level of the canvas. it is called
+	   whenever one or more calls are made to reset_zoom(). it executes in an idle handler.
+	*/
+
+	if (fpu == frames_per_unit) {
+		return;
+	}
+
+	if (fpu < 2.0) {
+		fpu = 2.0;
+	}
+
+	// convert fpu to frame count
+
+	frames = (nframes_t) floor (fpu * canvas_width);
+	
+	/* don't allow zooms that fit more than the maximum number
+	   of frames into an 800 pixel wide space.
+	*/
+
+	if (max_frames / fpu < 800.0) {
+		return;
+	}
+
+	if (fpu == frames_per_unit) {
+		return;
+	}
+
+	frames_per_unit = fpu;
+
+	if (frames != zoom_range_clock.current_duration()) {
+		zoom_range_clock.set (frames);
+	}
+
+	if (mouse_mode == MouseRange && selection->time.start () != selection->time.end_frame ()) {
+		if (!selection->tracks.empty()) {
+			for (TrackSelection::iterator i = selection->tracks.begin(); i != selection->tracks.end(); ++i) {
+				(*i)->reshow_selection (selection->time);
+			}
+		} else {
+			for (TrackViewList::iterator i = track_views.begin(); i != track_views.end(); ++i) {
+				(*i)->reshow_selection (selection->time);
+			}
+		}
+	}
+
+	ZoomChanged (); /* EMIT_SIGNAL */
+
+	reset_hscrollbar_stepping ();
+	reset_scrolling_region ();
+	
+	if (edit_cursor) edit_cursor->set_position (edit_cursor->current_frame);
+	if (playhead_cursor) playhead_cursor->set_position (playhead_cursor->current_frame);
+
+	instant_save ();
+}
+
+void 
+Editor::canvas_horizontally_scrolled ()
+{
+	/* this is the core function that controls horizontal scrolling of the canvas. it is called
+	   whenever the horizontal_adjustment emits its "value_changed" signal. it executes in an
+	   idle handler.
+	*/
+
+  	leftmost_frame = (nframes_t) floor (horizontal_adjustment.get_value() * frames_per_unit);
+	nframes_t rightmost_frame = leftmost_frame + current_page_frames ();
+	
+	if (rightmost_frame > last_canvas_frame) {
+		last_canvas_frame = rightmost_frame;
+		reset_scrolling_region ();
+	}
+	
+	update_fixed_rulers ();
+	tempo_map_changed (Change (0));
+}
+
+void
+Editor::queue_visual_change (nframes_t where)
+{
+	pending_visual_change.pending = VisualChange::Type (pending_visual_change.pending | VisualChange::TimeOrigin);
+	pending_visual_change.time_origin = where;
+
+	if (pending_visual_change.idle_handler_id < 0) {
+		pending_visual_change.idle_handler_id = g_idle_add (_idle_visual_changer, this);
+	}
+}
+
+void
+Editor::queue_visual_change (double fpu)
+{
+	pending_visual_change.pending = VisualChange::Type (pending_visual_change.pending | VisualChange::ZoomLevel);
+	pending_visual_change.frames_per_unit = fpu;
+
+	if (pending_visual_change.idle_handler_id < 0) {
+		pending_visual_change.idle_handler_id = g_idle_add_full (G_PRIORITY_HIGH_IDLE, _idle_visual_changer, this, 0);
+	}
+}
+
+int
+Editor::_idle_visual_changer (void* arg)
+{
+	return static_cast<Editor*>(arg)->idle_visual_changer ();
+}
+
+int
+Editor::idle_visual_changer ()
+{
+	VisualChange::Type p = pending_visual_change.pending;
+
+	pending_visual_change.pending = (VisualChange::Type) 0;
+	pending_visual_change.idle_handler_id = -1;
+	
+	if (p & VisualChange::ZoomLevel) {
+		set_frames_per_unit (pending_visual_change.frames_per_unit);
+	}
+
+	if (p & VisualChange::TimeOrigin) {
+		if (pending_visual_change.time_origin != leftmost_frame) {
+			horizontal_adjustment.set_value (pending_visual_change.time_origin/frames_per_unit);
+			/* the signal handler will do the rest */
+		} else {
+			update_fixed_rulers();
+			tempo_map_changed (Change (0));
+		}
+	}
+
+	return 0;
+}
diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 8ee9c45ed1..82f60e8d3d 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -332,11 +332,13 @@ class Editor : public PublicEditor
 	bool new_regionviews_display_gain () { return _new_regionviews_show_envelope; }
 	void prepare_for_cleanup ();
 
-	void reposition_x_origin (nframes_t sample);
-
 	void maximise_editing_space();
 	void restore_editing_space();
 
+	void reset_x_origin (nframes_t);
+	void reset_zoom (double);
+	void reposition_and_zoom (nframes_t, double);
+
   protected:
 	void map_transport_state ();
 	void map_position_change (nframes_t);
@@ -678,10 +680,31 @@ class Editor : public PublicEditor
 	void tie_vertical_scrolling ();
 	void canvas_horizontally_scrolled ();
 
-	void reposition_and_zoom (nframes_t sample, double fpu);
-	gint deferred_reposition_and_zoom (nframes_t sample, double fpu);
+	struct VisualChange {
+	    enum Type { 
+		    TimeOrigin = 0x1,
+		    ZoomLevel = 0x2
+	    };
+
+	    Type pending;
+	    nframes_t time_origin;
+	    double frames_per_unit;
+
+	    int idle_handler_id;
+
+	    VisualChange() : pending ((VisualChange::Type) 0), time_origin (0), frames_per_unit (0), idle_handler_id (-1) {}
+	};
+
+
+	VisualChange pending_visual_change;
+
+	static int _idle_visual_changer (void *arg);
+	int idle_visual_changer ();
+
+	void queue_visual_change (nframes_t);
+	void queue_visual_change (double);
+
 	void end_location_changed (ARDOUR::Location*);
-	bool repos_zoom_queued;
 
 	struct RegionListDisplayModelColumns : public Gtk::TreeModel::ColumnRecord {
 	    RegionListDisplayModelColumns() {
@@ -1798,7 +1821,6 @@ class Editor : public PublicEditor
 	Glib::RefPtr<Gtk::Action>              redo_action;
 
 	void history_changed ();
-
 };
 
 #endif /* __ardour_editor_h__ */
diff --git a/gtk2_ardour/editor_canvas.cc b/gtk2_ardour/editor_canvas.cc
index 5415ffa9cf..3f70322573 100644
--- a/gtk2_ardour/editor_canvas.cc
+++ b/gtk2_ardour/editor_canvas.cc
@@ -638,7 +638,7 @@ Editor::autoscroll_canvas ()
 	} 
 
 	if (new_frame != leftmost_frame) {
-		reposition_x_origin (new_frame);
+		reset_x_origin (new_frame);
 	}
 
 	if (autoscroll_cnt == 50) { /* 0.5 seconds */
diff --git a/gtk2_ardour/editor_imageframe.cc b/gtk2_ardour/editor_imageframe.cc
index 0e5131bb97..b65ce93178 100644
--- a/gtk2_ardour/editor_imageframe.cc
+++ b/gtk2_ardour/editor_imageframe.cc
@@ -107,7 +107,7 @@ Editor::scroll_timeaxis_to_imageframe_item(const TimeAxisViewItem* item)
 		x_pos = item->get_position() - offset + (item->get_duration() / 2);
 	}
 	
-	reposition_x_origin (x_pos);
+	reset_x_origin (x_pos);
 }
 
 void
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 2e78f63ee2..2e271d7671 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -926,7 +926,7 @@ Editor::scroll_backward (float pages)
 		frame = leftmost_frame - cnt;
 	}
 
-	reposition_x_origin (frame);
+	reset_x_origin (frame);
 }
 
 void
@@ -954,7 +954,7 @@ Editor::scroll_forward (float pages)
 		frame = leftmost_frame + cnt;
 	}
 
-	reposition_x_origin (frame);
+	reset_x_origin (frame);
 }
 
 void
diff --git a/gtk2_ardour/public_editor.h b/gtk2_ardour/public_editor.h
index 1e93e17735..f672ea180d 100644
--- a/gtk2_ardour/public_editor.h
+++ b/gtk2_ardour/public_editor.h
@@ -129,7 +129,7 @@ class PublicEditor : public Gtk::Window, public PBD::StatefulThingWithGoingAway
 	virtual void scroll_tracks_up_line () = 0;
 	virtual bool new_regionviews_display_gain () = 0;
 	virtual void prepare_for_cleanup () = 0;
-	virtual void reposition_x_origin (nframes_t frame) = 0;
+	virtual void reset_x_origin (nframes_t frame) = 0;
 	virtual void remove_last_capture () = 0;
 	virtual void maximise_editing_space() = 0;
 	virtual void restore_editing_space() = 0;