directlabels - utility.function - Positioning Method - draw.polygons

Draw polygons around label positions.

draw.polygons <- function(d,...){
  stopifnot(c("left.y", "left.x", "right.y", "right.x") %in% names(d))
  if(! "box.color" %in% names(d)){
    d$box.color <- "black"
  }
  for(i in 1:nrow(d)){
    with(d[i,], {
      L <-
        list(x=c(left.x, left, right, right.x, right, left),
             y=c(left.y, top, top, right.y, bottom, bottom))
      for(xy.name in names(L)){
        xy <- L[[xy.name]]
        L[[xy.name]] <- xy[!is.na(xy)]
      }
      grid.polygon(L$x, L$y,
                   default.units="cm", gp=gpar(col=box.color, fill=colour))
    })
  }
  d$colour <- "white"
  d
}