Geom_sina vs geom_jitter on vertical (geom_sina with distribution of ints)

(hope this is a reasonable place for ggforce questions)

I'm intrigued by geom_sina but it doesn't seem to work for my data. The data is a distribution of ints between 1 and 5 (no in between values). Looking at the distribution using geom_jitter works fine:

library(tidyverse)
library(ggforce)

# create int version of area
midwest$area_ints <- (midwest$area * 100) %>% floor()

ggplot(midwest, aes(state, area_ints)) + 
  geom_jitter() 

That works in the sense that it jitters the points both horizontally and vertically, so one can see the distribution. geom_sina spreads the values horizontally as expected not vertically. geom_violin works as well (and actually shows the issue the best when combined with geom_sina)

library(tidyverse)
library(ggforce)

# create int version of area
midwest$area_ints <- (midwest$area * 100) %>% floor()

ggplot(midwest, aes(state, area_ints)) + 
  geom_violin() + geom_sina() 

I just get lines at each point, as though the jittering was only happening horizontally and not vertically as well. The expected behavior is that geom_sina() should also spread the values vertically, if I understand correctly essentially matching the shape of a violin plot but using the jitter with transparency approach.

The same thing happens with sinaplot directly, so I'm now wondering if this doesn't belong with the sinaplot devs?

Thanks,
James

Hmmm. Seems like intended behavior, ggforce visual guide says:

geom_sina is inspired by the strip chart and the violin plot and operates by letting the normalized density of points restrict the jitter along the x-axis.

I'll post this as an issue/enhancement at the ggforce repo.