void compute_dimensions ();
void render (cairo_t *);
void render_group_pair (cairo_t *, boost::shared_ptr<const PortGroup>, boost::shared_ptr<const PortGroup>, uint32_t, uint32_t);
void compute_dimensions ();
void render (cairo_t *);
void render_group_pair (cairo_t *, boost::shared_ptr<const PortGroup>, boost::shared_ptr<const PortGroup>, uint32_t, uint32_t);