R/axisChrono.R

In heibl/viper: VIsualitaion of Phylogenetics and Evolution with R

## This code is part of the ips package
## © C. Heibl 2014 (last update 2018-03-26)

#' @importFrom graphics axis mtext
#' @export

axisChrono <- function (side = 1, unit = "Ma", fact = 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 * fact), ...)
    line <- ifelse("line" %in% names(list(...)), 
                   list(...)$line + 1, 1)
    mtext(text = unit, side = side, at = 1.07 * maxi, line = line)
}