ggstance::geom_barh not flipping axes? - r

Question

Posting this for a more general audience
Consider the following:
ggplot2::ggplot(ggplot2::mpg, ggplot2::aes(class)) + ggplot2::geom_bar()
This yields
However
ggplot2::ggplot(ggplot2::mpg, ggplot2::aes(class)) + ggstance::geom_barh()
produces the (broken!?)
Where am I getting this wrong?

Answer 1

Use the following stat:
stat_counth <- function(mapping = NULL, data = NULL,
geom = "fillbar", position = "stack",
...,
width = NULL,
na.rm = FALSE,
show.legend = NA,
inherit.aes = TRUE) {
params <- list(
na.rm = na.rm,
width = width,
...
)
if (!is.null(params$y)) {
stop("stat_count() must not be used with a y aesthetic.", call. = FALSE)
}
layer(
data = data,
mapping = mapping,
stat = StatCounth,
geom = geom,
position = position,
show.legend = show.legend,
inherit.aes = inherit.aes,
params = params
)
}
#' #rdname ggplot2-ggproto
#' #format NULL
#' #usage NULL
#' #export
#' #include stat-.r
StatCounth <- ggproto("StatCounth", Stat,
required_aes = "y",
default_aes = aes(x = calc(count), weight = 1),
setup_params = function(data, params) {
if (!is.null(data$y)) {
stop("stat_counth() must not be used with a x aesthetic.", call. = FALSE)
}
params
},
compute_group = function(self, data, scales, width = NULL) {
y <- data$y
weight <- data$weight %||% rep(1, length(y))
width <- width %||% (resolution(y) * 0.9)
count <- as.numeric(tapply(weight, y, sum, na.rm = TRUE))
count[is.na(count)] <- 0
data.frame(
count = count,
prop = count / sum(abs(count)),
x = sort(unique(y)),
width = width
)
}
)
Then plot as follows:
ggplot2::ggplot(ggplot2::mpg, ggplot2::aes(y = class)) + ggstance::geom_barh(stat = "counth")
Edit: Actually this stat is also implemented in ggstance, seems to just have been forgotten to make it default.
This works too:
ggplot2::ggplot(ggplot2::mpg, ggplot2::aes(y = class)) + ggstance::geom_barh(stat = ggstance::StatCounth)

Answer 2

If you are just trying to flip the axes you can use the following:
ggplot(mpg, aes(class)) + geom_bar() + coord_flip()

Answer 3

I think this is a problem with ggstance::geom_barh.
Remember, with ggstance, you must supply aesthetics in their natural order. geom_barh will flip the geom only; it will not flip the axes like coord_flip(). For your example to work, you would have to do this:
ggplot(mpg, (aes(y = class) +
geom_barh()
However, this produces an error:
Error: stat_count() must not be used with a y aesthetic.