| find_maze_refpoint {mazing} | R Documentation |
Get coordinates for a point in a maze
Description
A function that takes a description of a point in a maze and finds the matrix indices corresponding to that point.
Usage
find_maze_refpoint(point, maze)
Arguments
point |
A description of a relative position in the maze, such as
|
maze |
A |
Details
For standard values of point, this function will identify a "target"
(such as the top left corner of the matrix) and select the point in the maze
that is closest to that target, by Euclidean distance. The standard choices
for point are: "topleft", "top", "topright",
"righttop", "right", "rightbottom",
"bottomright", "bottom", "bottomleft",
"leftbottom", "left", "lefttop", and "center".
For convenience, there are several redundancies built in; for example,
"topleft" is identical to "lefttop".
In addition to the standard values, there is a complementary set of "matrix"
or "manhattan-like" values, each of which is prepended with an "m"
(for example, "mtopleft"). These options select the most extreme value
along one dimension (ie. the highest possible row), fix that value, and then
select the local extreme in the other dimension (column). For example, the
value "mtopleft" will select the highest possible row in the maze
before selecting the left-most point in that row. Note that this means values
such as "mtopleft" and "mlefttop" are not synonymous.
For convenience, if point is a 2-column matrix or numeric
vector that can be coerced into a 2-column matrix, it will be returned as
such, with minor formatting changes to match the usual output. This is so
that functions which rely on find_maze_refpoint can use either
relative descriptions or exact coordinates.
Value
A matrix of integers with 2 columns, giving the coordinates of the desired point(s). Note that the x-coordinate (column index) comes first, so for the corresponding index in the original matrix, these coordinates will need to be reversed.
Examples
m <- maze(15,15)
r <- find_maze_refpoint('topright', m)
plot(m, walls = TRUE)
points(r[1], r[2], col = 2, pch = 16)