The [replace_map] tag
The [replace_map] tag allows a complete change of the map in a scenario. Unlike terrain_mask, changing the map size is possible, although requires special attention. Since the map is changed completely, there is no equivalent of terrain_mask "alpha channel" feature.
- map: a Wesnoth map; see BuildingMaps.
- expand: (default=no) allow the map size to increase (in either dimension)
- shrink: (default=no) allow the map size to decrease (in either direction)
Expanding maps are generally more predictable than shrinking maps. When shrinking, units left off the new map area will be added to a recall list if there is one, and removed otherwise (and an error message is issued).
The expansion direction is currently always bottom-right.