R IRange Class plotRanges Function

plotRanges <- function(x, xlim=x, main=deparse(substitute(x)), col="red", sep=0.5, ...) {
height <- 1
if (is(xlim, "IRanges")) {
xlim <- c(min(start(xlim)), max(end(xlim)))
}
bins <- disjointBins(IRanges(start(x), end(x) + 1))
plot.new()
plot.window(xlim, c(0, max(bins)*(height + sep)))
ybottom <- bins * (sep + height) - height
rect(start(x)-0.5, ybottom, end(x)+0.5, ybottom + height, col=col, ...)
title(main)
axis(1)
}