Function enclosedTiles
Find an area of tiles enclosed by 'walls'.
Prototype
auto enclosedTiles(alias isWall, T)( T grid, RowCol origin, Diagonals diags = Diagonals.no ) if (is(typeof(isWall(grid.tileAt(RowCol(0, 0)))) : bool));
Parameters
| Name | Description |
|---|---|
| isWall | predicate which returns true if a tile should be considered a 'wall' |
| grid | grid of tiles to find enclosed area in |
| origin | tile that may be part of an enclosed region |
| diags | if yes, an area is not considered enclosed if there is a diagonal opening. |
Returns
a range of tiles in the enclosure (empty if origin is not part of an enclosed region)
Example
import std.array;
import std.algorithm : equal;
// let the 'X's represent 'walls', and the other letters 'open' areas we'd link to identify
auto tiles = rectGrid([
// 0 1 2 3 4 5 <-col| row
[ 'X', 'X', 'X', 'X', 'X', 'X' ], // 0
[ 'X', 'a', 'a', 'X', 'b', 'X' ], // 1
[ 'X', 'a', 'a', 'X', 'b', 'X' ], // 2
[ 'X', 'X', 'X', 'X', 'X', 'X' ], // 3
[ 'd', 'd', 'd', 'X', 'c', 'X' ], // 4
[ 'd', 'd', 'd', 'X', 'X', 'c' ], // 5
]);
static bool isWall(char c) { return c == 'X'; }
// starting on a wall should return an empty result
assert(tiles.enclosedTiles!isWall(RowCol(0, 0)).empty);
// all tiles in the [1,1] -> [2,2] area should find the 'a' room
assert(tiles.enclosedTiles!isWall(RowCol(1, 1)).equal(['a', 'a', 'a', 'a']));
assert(tiles.enclosedTiles!isWall(RowCol(1, 2)).equal(['a', 'a', 'a', 'a']));
assert(tiles.enclosedTiles!isWall(RowCol(2, 1)).equal(['a', 'a', 'a', 'a']));
assert(tiles.enclosedTiles!isWall(RowCol(2, 2)).equal(['a', 'a', 'a', 'a']));
// get the two-tile 'b' room at [1,4] -> [2,4]
assert(tiles.enclosedTiles!isWall(RowCol(1, 4)).equal(['b', 'b']));
assert(tiles.enclosedTiles!isWall(RowCol(2, 4)).equal(['b', 'b']));
// get the single tile 'c' room at 4,4
assert(tiles.enclosedTiles!isWall(RowCol(4, 4)).equal(['c']));
// if we require that diagonals be blocked too, 'c' is not an enclosure
assert(tiles.enclosedTiles!isWall(RowCol(4, 4), Diagonals.yes).empty);
// the 'd' region is not an enclosure (touches map edge)
assert(tiles.enclosedTiles!isWall(RowCol(4, 1)).empty);
assert(tiles.enclosedTiles!isWall(RowCol(5, 0)).empty);