I'm working in R and Rstudio arranging a set of rather complicated plots using the usually magnificent ggarrange(), but this time I've run into a persistent issue which seems easy to reproduce and possibly is a bug?
library(ggplot2)
library(egg)
datar <- data.frame(cbind(xxx = c(1,4,6,7,9,7,6,5,4,3,2,4,5,6),
yyy = c(6,8,9,0,6,5,4,3,6,7,5,9,6,2)))
ggarrange(
ggplot(datar, aes(xxx, yyy))+geom_point(),
ggplot(datar, aes(xxx, yyy))+geom_point(),
ggplot(datar, aes(xxx, yyy))+geom_point(),
ggplot(datar, aes(xxx, yyy))+geom_point(),
ggplot(datar, aes(xxx, yyy))+geom_point(),
ggplot(datar, aes(xxx, yyy))+geom_point(),
ncol = 2,
widths = c(1,2)
)
Which produces the following error:
Error in unit.c(sum(left$widths), width, sum(right$widths)) : it is invalid to combine 'unit' objects with other types
This does not happen of you remove two of the plots (turning the plot into a 2x2 matrix). Furthermore, this pattern seems to scale up; if I run 9 plots in a 3x3 matrix (ncol = 3, widths = c(1,2,3)) it works, but if I add 3 more plots (as in a 3x4 matrix), I again get the same error message.
Is this a bug? Does it have a fix? Is there a work-around?
Definitely a bug. Try the following replacement which seems to work,
ggarrange <- function(..., plots = list(...), nrow = NULL, ncol = NULL, widths = NULL,
heights = NULL, byrow = TRUE, top = NULL, bottom = NULL, left = NULL, right = NULL,
padding = unit(0.5, "line"), clip = "on", draw = TRUE, newpage = TRUE, debug = FALSE,
labels = NULL, label.args = list(gp = grid::gpar(font = 4, cex = 1.2))) {
n <- length(plots)
grobs <- lapply(plots, ggplot2::ggplotGrob)
## logic for the layout if nrow/ncol supplied, honour this if not, use length of
## widths/heights, if supplied if nothing supplied, work out sensible defaults
## nothing to be done but check inconsistency
if (!is.null(ncol) && !is.null(widths)) {
stopifnot(length(widths) == ncol)
}
if (!is.null(nrow) && !is.null(heights)) {
stopifnot(length(heights) == nrow)
}
## use widths/heights if supplied
if (is.null(ncol) && !is.null(widths)) {
ncol <- length(widths)
}
if (is.null(nrow) && !is.null(heights)) {
nrow <- length(heights)
}
## work out the missing one
if (is.null(nrow) && !is.null(ncol)) {
nrow <- ceiling(n/ncol)
}
if (is.null(ncol) && !is.null(nrow)) {
ncol <- ceiling(n/nrow)
}
## it may happen that sufficient info was passed, but incompatible with number of grobs
## (fewer cells)
stopifnot(nrow * ncol >= n)
## last case: nothing exists
if (is.null(nrow) && is.null(ncol) && is.null(widths) && is.null(heights)) {
nm <- grDevices::n2mfrow(n)
nrow <- nm[1]
ncol <- nm[2]
}
if (n%/%nrow) {
# trouble, we need to add dummy grobs to fill the layout
grobs <- c(grobs, rep(list(.dummy_gtable), nrow * ncol - n))
# add dummy labels if needed
if ((!is.null(labels)) && (length(labels) != nrow * ncol)) {
labels <- c(labels, rep("", nrow * ncol - length(labels)))
}
}
## case numeric
if (is.numeric(widths) && !inherits(widths, "unit")) {
widths <- lapply(widths, unit, "null")
}
if (is.numeric(heights) && !inherits(heights, "unit")) {
heights <- lapply(heights, unit, "null")
}
## sizes
if (is.null(widths))
widths <- lapply(rep(1, n), unit, "null")
if (is.null(heights))
heights <- lapply(rep(1, n), unit, "null")
# user may naively have passed grid units, but only unit.list units work well with `[`
# so convert to this class
if (grid::is.unit(widths))
widths <- as.unit.list(widths)
if (grid::is.unit(heights))
widths <- as.unit.list(heights)
# indexing is problematic, wrap in list
if (grid::is.unit(widths) && length(widths) == 1) {
widths <- list(widths)
}
if (grid::is.unit(heights) && length(heights) == 1) {
heights <- list(heights)
}
## split the list into rows/cols
nrc <- if (byrow)
nrow else ncol
if (nrc == 1) {
splits <- rep(1, n)
} else {
seqgrobs <- seq_along(grobs)
splits <- cut(seqgrobs, nrc, labels = seq_len(nrc))
## widths and heights refer to the layout repeat for corresponding grobs
repw <- rep_len(seq_along(widths), length.out=n)
reph <- rep_len(seq_along(heights), length.out=n)
widths <- c(matrix(widths[repw], ncol = nrc, byrow = !byrow))
heights <- c(matrix(heights[reph], ncol = nrc, byrow = byrow))
}
fg <- mapply(gtable_frame, g = grobs, width = widths, height = heights, MoreArgs = list(debug = debug),
SIMPLIFY = FALSE)
if (!is.null(labels)) {
stopifnot(length(labels) == length(fg))
# make grobs
labels <- do.call(label_grid, c(list(labels), label.args))
# add each grob to the whole gtable
fg <- mapply(function(g, l) {
gtable::gtable_add_grob(g, l, t = 1, l = 1, b = nrow(g), r = ncol(g), z = Inf,
clip = "off", name = "label")
}, g = fg, l = labels, SIMPLIFY = FALSE)
}
spl <- split(fg, splits)
if (byrow) {
rows <- lapply(spl, function(.r) do.call(gridExtra::gtable_cbind, .r))
gt <- do.call(gridExtra::gtable_rbind, rows)
} else {
# fill colwise
cols <- lapply(spl, function(.c) do.call(gridExtra::gtable_rbind, .c))
gt <- do.call(gridExtra::gtable_cbind, cols)
}
## titles given as strings are converted to text grobs
if (is.character(top)) {
top <- textGrob(top)
}
if (is.grob(top)) {
h <- grobHeight(top) + padding
gt <- gtable_add_rows(gt, heights = h, 0)
gt <- gtable_add_grob(gt, top, t = 1, l = 1, r = ncol(gt), z = Inf, clip = clip)
}
if (is.character(bottom)) {
bottom <- textGrob(bottom)
}
if (is.grob(bottom)) {
h <- grobHeight(bottom) + padding
gt <- gtable_add_rows(gt, heights = h, -1)
gt <- gtable_add_grob(gt, bottom, t = nrow(gt), l = 1, r = ncol(gt), z = Inf, clip = clip)
}
if (is.character(left)) {
left <- textGrob(left, rot = 90)
}
if (is.grob(left)) {
w <- grobWidth(left) + padding
gt <- gtable_add_cols(gt, widths = w, 0)
gt <- gtable_add_grob(gt, left, t = 1, b = nrow(gt), l = 1, r = 1, z = Inf, clip = clip)
}
if (is.character(right)) {
right <- textGrob(right, rot = -90)
}
if (is.grob(right)) {
w <- grobWidth(right) + padding
gt <- gtable_add_cols(gt, widths = w, -1)
gt <- gtable_add_grob(gt, right, t = 1, b = nrow(gt), l = ncol(gt), r = ncol(gt),
z = Inf, clip = clip)
}
if (draw) {
if (newpage)
grid.newpage()
grid.draw(gt)
}
class(gt) <- c("egg", class(gt))
invisible(gt) # return the full gtable
}