add ArdourCanvas::Flag::width()

libs/canvas/canvas/flag.h

@@ -45,6 +45,8 @@ public:
 
         bool covers (Duple const &) const;
 
+	double width() const;
+
 private:
 	void setup (Distance height, Duple position);
 

libs/canvas/flag.cc

@@ -119,3 +119,12 @@ Flag::covers (Duple const & point) const
 
 	return false;
 }
+
+double
+Flag::width () const
+{
+	boost::optional<Rect> bbox = _text->bounding_box ();
+	assert (bbox);
+
+	return bbox.get().width() + 10;
+}