when tabbing between track/bus name entries, attempt to scroll appropriately (#4223)

git-svn-id: svn://localhost/ardour2/branches/3.0@9924 d708f5d6-7413-0410-9779-e7cbd77b26cf

gtk2_ardour/editor.h

@@ -375,6 +375,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 
 	void show_window ();
 
+	void ensure_time_axis_view_is_visible (const TimeAxisView& tav);
 	void scroll_tracks_down_line ();
 	void scroll_tracks_up_line ();
 

gtk2_ardour/editor_canvas.cc

@@ -697,6 +697,22 @@ Editor::entered_track_canvas (GdkEventCrossing */*ev*/)
 	return FALSE;
 }
 
+void
+Editor::ensure_time_axis_view_is_visible (const TimeAxisView& tav)
+{
+	double begin = tav.y_position();
+
+	double v = vertical_adjustment.get_value ();
+
+	if (begin < v || begin > v + _canvas_height) {
+		/* try to put the TimeAxisView roughly central */
+		if (begin >= _canvas_height/2.0) {
+			begin -= _canvas_height/2.0;
+		}
+		vertical_adjustment.set_value (begin);
+	}
+}
+
 void
 Editor::tie_vertical_scrolling ()
 {

gtk2_ardour/public_editor.h

@@ -260,6 +260,7 @@ class PublicEditor : public Gtk::Window, public PBD::StatefulDestructible {
 	virtual framecnt_t current_page_frames() const = 0;
 	virtual double canvas_height () const = 0;
 	virtual void temporal_zoom_step (bool coarser) = 0;
+	virtual void ensure_time_axis_view_is_visible (const TimeAxisView& tav) = 0;
 	virtual void scroll_tracks_down_line () = 0;
 	virtual void scroll_tracks_up_line () = 0;
 	virtual void prepare_for_cleanup () = 0;

gtk2_ardour/time_axis_view.cc

@@ -581,8 +581,9 @@ TimeAxisView::name_entry_key_release (GdkEventKey* ev)
 				} while ((*i)->hidden());
 			}
 		}
-
+		
 		(*i)->name_entry.grab_focus();
+		_editor.ensure_time_axis_view_is_visible (**i);
 	}
 	return true;