Experiment
#' @rdname Stat
#' @format NULL
#' @usage NULL
#' @export
StatManual <- ggproto(
"StatManual", Stat,
setup_params = function(data, params) {
params[["fun"]] <- allow_lambda(params[["fun"]])
check_function(params[["fun"]], arg = "fun")
params
},
compute_group = function(data, scales, fun = identity, args = list()) {
as_gg_data_frame(inject(fun(data, !!!args)))
}
)
p <- ggplot(mtcars, aes(disp, mpg, colour = factor(cyl))) +
geom_point()
# The default just displays points as-is
p + stat_manual()
# Using a custom function
make_hull <- function(data) {
hull <- chull(x = data$x, y = data$y)
data.frame(x = data$x[hull], y = data$y[hull])
data.frame(x = mean(data$x),
y = mean(data$y))
}
p + stat_manual(
geom = "point",
fun = make_hull,
fill = NA,
size = 4
)
# Using the `with` function with quoting
p + stat_manual(
fun = with,
args = list(expr = quote({
hull <- chull(x, y)
list(x = x[hull], y = y[hull])
})),
geom = "polygon", fill = NA
)
# Using the `transform` function with quoting
p + stat_manual(
geom = "segment",
fun = transform,
args = list(
xend = quote(mean(x)),
yend = quote(mean(y))
)
)
# Using dplyr verbs with `vars()`
if (requireNamespace("dplyr", quietly = TRUE)) {
# Get centroids with `summarise()`
p + stat_manual(
size = 10, shape = 21,
fun = dplyr::summarise,
args = vars(x = mean(x), y = mean(y))
)
# Connect to centroid with `mutate`
p + stat_manual(
geom = "segment",
fun = dplyr::mutate,
args = vars(xend = mean(x), yend = mean(y))
)
# Computing hull with `reframe()`
p + stat_manual(
geom = "polygon", fill = NA,
fun = dplyr::reframe,
args = vars(hull = chull(x, y), x = x[hull], y = y[hull])
)
}
stat_manual <- make_constructor(StatManual, geom = "point")