Clears the surface with a uniform colour, or makes the surface entirely
transparent if no colour is provided.
Draws the core map layers: hex backgrounds, tiles, empty hex borders, and
track barriers.
Draws the core map layers for a subset of map hexes: hex backgrounds,
tiles, empty hex borders, and track barriers.
Draw an arbitrary tile and tokens at the specified map hex, rather than
the tile and tokens that are currently placed at the map hex (if any).
Draw an arbitrary tile at the specified map hex, rather than the tile that
is currently placed at the map hex (if any).
Highlights the active map hex by covering all other hexes with a
partially-transparent layer.
Highlights map hexes that satisfy a predicate by covering all other hexes
with a partially-transparent layer.
Highlights a single route, using the current source.
Highlights routes, using a different colour for each route.
Highlights a token space by drawing a border around it.
Highlights tokens that satisfy a predicate by drawing borders around them
and optionally filling the token space with, e.g., a semi-transparent
colour.
Returns the width and height of the image drawn by draw_fn
.