add API to select TAV height mode.

preparation for further Summary and Number of visible
track count fixes.

* “Only Self”: don’t resize child-views (old default)
* “Total Height”: distribute height equally among 
   all visible child [automation] lanes
* “Height per Lane”: given height should be applied
   to all sub-views.

gtk2_ardour/automation_time_axis.cc

@@ -454,13 +454,13 @@ AutomationTimeAxisView::clear_clicked ()
 }
 
 void
-AutomationTimeAxisView::set_height (uint32_t h)
+AutomationTimeAxisView::set_height (uint32_t h, TrackHeightMode m)
 {
 	bool const changed = (height != (uint32_t) h) || first_call_to_set_height;
 	uint32_t const normal = preset_height (HeightNormal);
 	bool const changed_between_small_and_normal = ( (height < normal && h >= normal) || (height >= normal || h < normal) );
 
-	TimeAxisView::set_height (h);
+	TimeAxisView::set_height (h, m);
 
 	_base_rect->set_y1 (h);
 

gtk2_ardour/automation_time_axis.h

@@ -69,7 +69,7 @@ class AutomationTimeAxisView : public TimeAxisView {
 
 	~AutomationTimeAxisView();
 
-	virtual void set_height (uint32_t);
+	virtual void set_height (uint32_t, TrackHeightMode m = OnlySelf);
 	void set_samples_per_pixel (double);
 	std::string name() const { return _name; }
 

gtk2_ardour/midi_time_axis.cc

@@ -467,7 +467,7 @@ MidiTimeAxisView::midi_view()
 }
 
 void
-MidiTimeAxisView::set_height (uint32_t h)
+MidiTimeAxisView::set_height (uint32_t h, TrackHeightMode m)
 {
 	if (h >= MIDI_CONTROLS_BOX_MIN_HEIGHT) {
 		_midi_controls_box.show ();
@@ -496,7 +496,7 @@ MidiTimeAxisView::set_height (uint32_t h)
 	   which needs to know if we have just shown or hidden a scroomer /
 	   piano roll.
 	*/
-	RouteTimeAxisView::set_height (h);
+	RouteTimeAxisView::set_height (h, m);
 }
 
 void

gtk2_ardour/midi_time_axis.h

@@ -78,7 +78,7 @@ public:
 
 	MidiStreamView* midi_view();
 
-	void set_height (uint32_t);
+	void set_height (uint32_t, TrackHeightMode m = OnlySelf);
 
 	boost::shared_ptr<ARDOUR::MidiRegion> add_region (ARDOUR::framepos_t, ARDOUR::framecnt_t, bool);
 

gtk2_ardour/route_time_axis.cc

@@ -961,7 +961,7 @@ RouteTimeAxisView::show_selection (TimeSelection& ts)
 }
 
 void
-RouteTimeAxisView::set_height (uint32_t h)
+RouteTimeAxisView::set_height (uint32_t h, TrackHeightMode m)
 {
 	int gmlen = h - 9;
 	bool height_changed = (height == 0) || (h != height);
@@ -972,7 +972,7 @@ RouteTimeAxisView::set_height (uint32_t h)
 	}
 	gm.get_level_meter().setup_meters (gmlen, meter_width);
 
-	TimeAxisView::set_height (h);
+	TimeAxisView::set_height (h, m);
 
 	if (_view) {
 		_view->set_height ((double) current_height());

gtk2_ardour/route_time_axis.h

@@ -84,7 +84,7 @@ public:
 	void set_button_names ();
 
 	void set_samples_per_pixel (double);
- 	void set_height (uint32_t h);
+ 	void set_height (uint32_t h, TrackHeightMode m = OnlySelf);
 	void show_timestretch (framepos_t start, framepos_t end, int layers, int layer);
 	void hide_timestretch ();
 	void selection_click (GdkEventButton*);

gtk2_ardour/time_axis_view.cc

@@ -568,8 +568,16 @@ TimeAxisView::set_height_enum (Height h, bool apply_to_selection)
 }
 
 void
-TimeAxisView::set_height (uint32_t h)
+TimeAxisView::set_height (uint32_t h, TrackHeightMode m)
 {
+	uint32_t lanes = 0;
+	if (m == TotalHeight) {
+		for (Children::iterator i = children.begin(); i != children.end(); ++i) {
+			if ( !(*i)->hidden()) ++lanes;
+		}
+	}
+	h /= (lanes + 1);
+
 	if (h < preset_height (HeightSmall)) {
 		h = preset_height (HeightSmall);
 	}
@@ -590,6 +598,12 @@ TimeAxisView::set_height (uint32_t h)
 		show_selection (_editor.get_selection().time);
 	}
 
+	if (m != OnlySelf) {
+		for (Children::iterator i = children.begin(); i != children.end(); ++i) {
+			(*i)->set_height(h, OnlySelf);
+		}
+	}
+
 	_editor.override_visible_track_count ();
 }
 

gtk2_ardour/time_axis_view.h

@@ -142,7 +142,13 @@ class TimeAxisView : public virtual AxisView
 	virtual void entered () {}
 	virtual void exited () {}
 
-	virtual void set_height (uint32_t h);
+	enum TrackHeightMode {
+		OnlySelf,
+		TotalHeight,
+		HeightPerLane
+	};
+
+	virtual void set_height (uint32_t h, TrackHeightMode m = OnlySelf);
 	void set_height_enum (Height, bool apply_to_selection = false);
 	void reset_height();