-void image_filter_response(IMAGE *im, int domain, double bw, int filt_type, double filt_param, int opt_trace);
+void image_filter_response(IMAGE *im, const DomainType domain, double bw, const FilterType filt_type, double filt_param, const int opt_trace);
+int image_display (const IMAGE *im);
+int image_display_scale (const IMAGE *im, const int scale, const double pmin, const double pmax);