+#define SPAN_PREFIX "<span font_family='monospace'>"
+#define SPAN_POST "</span>"
+#define LABEL_FMT(s) SPAN_PREFIX s SPAN_POST
+#define CHANGE_LABEL(w,fmt,val) change_label_text(w, SPAN_PREFIX fmt SPAN_POST, val)
+#define CHANGE_LABEL2(w,fmt,val1, val2) change_label_text(w, SPAN_PREFIX fmt SPAN_POST, val1, val2)
+
+static void change_label_text(GtkWidget *l, gchar *format, ...)
+{
+ va_list args;
+ gchar buf[512];
+ va_start(args, format);
+ g_vsnprintf(buf, sizeof(buf), format, args);
+ va_end(args);
+ gtk_label_set_markup(GTK_LABEL(l), buf);
+}
+
+static void on_gps_device_changed (LocationGPSDevice *device, gpointer data)