+ auto i = find_if(parts, [&name](const Part &p){ return p.get_name()==name; });
+ return (i!=parts.end() ? &*i : nullptr);
+}
+
+bool Style::compare_states(State s1, State s2) const
+{
+ if(s1>=N_STATES_ || s2>=N_STATES_)
+ throw invalid_argument("Style::compare_states");
+
+ const GL::Color &c1 = font_color[s1];
+ const GL::Color &c2 = font_color[s2];
+ if(c1.r!=c2.r || c1.g!=c2.g || c1.b!=c2.b)
+ return true;