+void map_scroll (struct Map * map, char dir) {
+// Scroll map into direction dir if possible by changing the offset.
+ if ('n' == dir && map->offset_y > 0)
+ map->offset_y--;
+ else if ('s' == dir)
+ map->offset_y++;
+ else if ('w' == dir && map->offset_x > 0)
+ map->offset_x--;
+ else if ('e' == dir)
+ map->offset_x++; }
+