+ virtual double component_to_parent_x (double x) const = 0;
+ virtual double parent_to_component_x (double x) const = 0;
+ virtual double component_to_parent_y (double y) const = 0;
+ virtual double parent_to_component_y (double y) const = 0;
+ virtual void mouseover_changed (std::list<PortMatrixNode> const &) = 0;
+ virtual void draw_extra (cairo_t *) = 0;
+ virtual void button_press (double, double, GdkEventButton *) {}
+ virtual void button_release (double, double, GdkEventButton *) {}
+ virtual void motion (double, double) {}
+
+ void set_show_ports (bool);