Feature request for transparency

[MxNl]

I think it would be nice to have an argument in geom_pointdensity that allows to set the alpha value depending on the point density. Could you implement that? Thanks a lot for this package!

[LKremer]

Hi @MxNl ,

sorry for the late reply, I did not see this issue. This is already possible by using ggplot2's after_stat function. Maybe I should add a short example to the docs. For now, here is a minimal example:

library(ggplot2)
library(dplyr)
library(viridis)
library(ggpointdensity)

dat <- bind_rows(
  tibble(x = rnorm(7000, sd = 1),
         y = rnorm(7000, sd = 10),
         group = "foo"),
  tibble(x = rnorm(3000, mean = 1, sd = .5),
         y = rnorm(3000, mean = 7, sd = 5),
         group = "bar"))

ggplot(data = dat, mapping = aes(x = x, y = y, alpha = after_stat(density))) +
  geom_pointdensity() +
  scale_color_viridis()

after_stat() allows you to use the density calculated by the geom_pointdensity (or rather stat_pointdensity internally). If you want to learn more, check out this part of the ggplot2 docs: aes_eval