1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
# function contributed by Bill Venables as a replacement for thigmophobe
thigmophobe <- function (x, y = NULL, names = seq_along(z),
xlog = par("xlog"), ylog = par("ylog"),
usr = par("usr"), pin = par("pin"),
eps = .Machine$double.eps, pi = base::pi) {
# convert separete x and y coordinates to a two element list
xy <- grDevices::xy.coords(x, y, recycle = TRUE)
z <- with(xy, {
x <- ((if(xlog) log(x) else x) - usr[1])/diff(usr[1:2])*pin[1]
y <- ((if(ylog) log(y) else y) - usr[3])/diff(usr[3:4])*pin[2]
complex(real = x, imaginary = y)
})
# calculate the matrix of distances
xydist <- outer(z, z, function(x, y) Mod(x - y))
# remove "self" distances
diag(xydist) <- Inf
# get the indicies of the smallest distances
nearby <- apply(xydist, 2, which.min)
zdiff <- z - z[nearby]
# get the offset away from the nearest point for each label
pos <- findInterval((-pi/4 - Arg(zdiff)) %% (2*pi),
seq(0, 2*pi, by = pi/2), all.inside = TRUE)
# stagger the offsets for points with essentially zero differences
if(any(k <- Mod(zdiff) <= eps)) {
for(k in which(k)) {
pos[sort(c(k, nearby[k]))] <- c(1,3)
}
}
names(pos)<-names
return(pos)
}
|
