search for: ga_polyline

# polygon ignores requests to have its border transparent, look at par(bg="transparent") plot(c(0, 3), 0:1) polygon(c(0, 1, 1, 0), c(0, 0, 1, 1), border=NA, col = 0) polygon(c(1, 2, 2, 1), c(0, 0, 1, 1), border="transparent", col = 0) polygon(c(2, 3, 3, 2), c(0, 0, 1, 1), border=0, col = 0) # a quick fix for erase.screen() is the following erase.screen <- function (n =