ggpairs labels on bar plots

Question

I am wondering if there is a way to add labels on top of bar plots and grouped bar plots in ggpairs,

library(GGally)
data(diamonds, package="ggplot2")
diamonds.samp <- diamonds[sample(1:dim(diamonds)[1], 1000), ]

    pm <- ggpairs(
      diamonds.samp[, 1:5],
      mapping = ggplot2::aes(color = cut),
      upper = list(continuous = wrap("density", alpha = 0.5), combo = "box_no_facet"),
      lower = list(continuous = wrap("points", alpha = 0.3), combo = wrap("dot_no_facet", alpha = 0.4)),
      title = "Diamonds"
    )
    pm

Answer 1

Sure is this possible. One option would be to extend the default plotting function by adding a geom_text layer to add the labels:

library(GGally)

set.seed(123)

data(diamonds, package = "ggplot2")

diamonds.samp <- diamonds[sample(nrow(diamonds), 1000), ]

bar_label <- function(data,
                         mapping,
                         ...) {
  ggally_barDiag(
    data,
    mapping
  ) +
    geom_text(
      aes(
        label = after_stat(count)
      ),
      stat = "count",
      position = position_stack(vjust = 1),
      vjust = 1
    )
}

pm <- ggpairs(
  diamonds.samp[, 1:5],
  mapping = ggplot2::aes(color = cut),
  upper = list(continuous = wrap("density", alpha = 0.5), combo = "box_no_facet"),
  lower = list(continuous = wrap("points", alpha = 0.3), combo = wrap("dot_no_facet", alpha = 0.4)),
  diag = list(discrete = wrap(bar_label)), title = "Diamonds"
)
pm