## scales.R (2009-12-16)
## Add a Scale Bar or Axis to a Phylogeny Plot
## add.scale.bar: add a scale bar to a phylogeny plot
## axisPhylo: add a scale axis on the side of a phylogeny plot
## Copyright 2002-2009 Emmanuel Paradis
## This file is part of the R-package `ape'.
## See the file ../COPYING for licensing issues.
add.scale.bar <- function(x, y, length = NULL, ask = FALSE, ...)
{
lastPP <- get("last_plot.phylo", envir = .PlotPhyloEnv)
direc <- lastPP$direction
if (is.null(length)) {
nb.digit <-
if (direc %in% c("rightwards", "leftwards")) diff(range(lastPP$xx))
else diff(range(lastPP$yy))
nb.digit <- ceiling(log10(nb.digit)) - 2
length <- eval(parse(text = paste("1e", nb.digit, sep = "")))
}
if (ask) {
cat("\nClick where you want to draw the bar\n")
x <- unlist(locator(1))
y <- x[2]
x <- x[1]
} else if (missing(x) || missing(y)) {
if (lastPP$type %in% c("phylogram", "cladogram")) {
switch(direc,
"rightwards" = {
x <- 0
y <- 1
},
"leftwards" = {
x <- max(lastPP$xx)
y <- 1
},
"upwards" = {
x <- max(lastPP$xx)
y <- 0
},
"downwards" = {
x <- 1
y <- max(lastPP$yy)
})
} else {
direc <- "rightwards" # just to be sure for below
x <- lastPP$x.lim[1]
y <- lastPP$y.lim[1]
}
}
switch(direc,
"rightwards" = {
segments(x, y, x + length, y)
text(x + length * 1.1, y, as.character(length), adj = c(0, 0.5), ...)
},
"leftwards" = {
segments(x - length, y, x, y)
text(x - length * 1.1, y, as.character(length), adj = c(1, 0.5), ...)
},
"upwards" = {
segments(x, y, x, y + length)
text(x, y + length * 1.1, as.character(length), adj = c(0, 0.5), srt = 90, ...)
},
"downwards" = {
segments(x, y - length, x, y)
text(x, y - length * 1.1, as.character(length), adj = c(0, 0.5), srt = 270, ...)
})
}
axisPhylo <- function(side = 1, ...)
{
lastPP <- get("last_plot.phylo", envir = .PlotPhyloEnv)
if (lastPP$type %in% c("phylogram", "cladogram")) {
if (lastPP$direction %in% c("rightwards", "leftwards")) {
x <- pretty(lastPP$xx)
if (lastPP$direction == "rightwards") maxi <- max(lastPP$xx)
else {
maxi <- min(lastPP$xx)
x <- -x
}
} else {
x <- pretty(lastPP$yy)
if (lastPP$direction == "upwards") maxi <- max(lastPP$yy)
else {
maxi <- min(lastPP$yy)
x <- -x
}
}
}
axis(side = side, at = c(maxi - x), labels = abs(x), ...)
}
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