Add missing axes to a lattice multi-panel plot when as.table=TRUE

add_axes.R

# See http://stackoverflow.com/a/34552387/489704 for motivation and an example
# Based on code provided by StackOverflow user @user20650
add_axes <- function() {
  library(grid)
  library(lattice)
  l <- trellis.currentLayout()
  pan <- which(l[nrow(l), ]==0)
  if(length(pan) > 0) {
    g <- grid.ls(print=FALSE)
    ticks <- grid.get(g$name[grep("ticks.bottom.panel", g$name)][[1]])
    labels <- grid.get(g$name[grep("ticklabels.bottom.panel", g$name)][[1]])
    ax <- grobTree(ticks, labels)
    invisible(sapply(pan, function(x) {
      trellis.focus("panel", x, nrow(l)-1, clip.off=TRUE)
      grid.draw(ax)
      trellis.unfocus()  
    }))
  }
}