+static void
+incratio(const char *arg, double *ratio, double def) {
+ double delta;
+
+ if(lt->arrange != tile)
+ return;
+ if(!arg)
+ *ratio = def;
+ else {
+ if(1 == sscanf(arg, "%lf", &delta)) {
+ if(delta + (*ratio) < .1 || delta + (*ratio) > 1.9)
+ return;
+ *ratio += delta;
+ }
+ }
+ lt->arrange();
+}
+