adjust width based on density

[bvernot]

Hi - thanks for this package, it's really super!

Is it possible to adjust the width of the point distribution based on the density - similar to how geom_violin() works? I see that you can adjust the width based on the number of points, but it's not quite the same. I've given an example below - ideally, it would be possible to have the points inside the violin in the third column as well. Something analogous to geom_violin(scale = 'area').

Thank you,
Benjamin

library(ggbeeswarm)
library(data.table)

dt.tmp <- data.table(x = c('a', 'b', 'c'), 
                     y = rnorm(300))
dt.tmp[x == 'c', y := runif(100, -4, 4)]

ggplot(dt.tmp, aes(x=x, y=y)) + 
  geom_violin() +
  geom_quasirandom(method='tukeyDense')

ggplot(dt.tmp, aes(x=x, y=y)) + 
  geom_violin() +
  geom_quasirandom(method='quasirandom')

[sherrillmix]

It does seem reasonable to match geom_violin's default (I think it changed since this package was made). I'll look into it. In the mean time, geom_quasirandom is doing the equivalent of geom_violin(scale='width') so:

ggplot(dt.tmp, aes(x=x, y=y))+ 
geom_violin(scale='width')+
geom_quasirandom(method='quasirandom')

produces matching violins and points.

[bvernot]

Yes - matching the default would be nice. Would it be possible to have geom_quasirandom() accept the scale parameter? That would be ideal, I think.

[malisas]

I would like to also request a similar feature for geom_beeswarm().
Perhaps the cex argument, which controls the spacing between the points, can be dependent on the density of the points of each group. This would be useful when using geom_violin(scale="width").

For instance, you can see below that cex = 1.5 looks good for the left violin, but cex = 2.5 looks better for the right violin.

Thanks for your work on this useful package!

library(ggbeeswarm)
#> Loading required package: ggplot2

dat <- structure(list(x = structure(c(1L, 1L, 2L, 1L, 1L, 2L, 1L, 1L, 
                                      1L, 1L, 1L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 
                                      2L, 1L, 1L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 1L, 1L, 1L, 2L, 1L, 
                                      2L, 1L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 2L, 1L), .Label = c("1", 
                                                                                              "2"), class = "factor"),
                      y = c(0.00743015064770599, 0.00402350008901549, 
                            0.0182015059430295, 0.0931013077022777, 0.0201296467502311, 0.00988912196583758, 
                            0.00890949491496453, 0.0040521814310705, 0.0748063422432635, 
                            0.0028265114618079, 0.0033580728734968, 0.0011570364882694, 0.00174334311680045, 
                            0.300698451786883, 0.00186244761866073, 0.0117684502764761, 0.00578161092355426, 
                            0.00651988531447871, 0.079985399989931, 0.00184351402134222, 
                            0.00871624623132749, 0.00274545650752541, 0.00481711124028504, 
                            0.00301568797492199, 0.00206841018634773, 0.00678981408558268, 
                            0.00222290514238885, 0.00984868656785107, 0.00162418058758061, 
                            0.00557005888481755, 0.121683319866249, 0.0030356653660198, 0.00210656116734316, 
                            0.00353151727636117, 0.000903423206896699, 0.0162988509558787, 
                            0.000853474507087549, 0.00220279909556151, 0.000414831444223472, 
                            0.00233948134370524, 0.019787161002403, 0.00318015236414923, 
                            0.00257190063774256, 0.0176909379302089, 0.00598338665216149, 
                            0.136596738744799, 0.00128003795128495, 0.0202978906365311, 0.00156548169986173, 
                            0.0168584387682024, 0.252985835349248)), row.names = c(NA, -51L
                            ), class = c("tbl_df", "tbl", "data.frame"))

ggplot(dat, aes(x, y)) +
  theme_bw(base_size = 22) +
  geom_violin(draw_quantiles = c(0.5),
              scale="width", width=0.6) +
  geom_beeswarm(size=0.5, cex=1.5, priority = "random") +
  ggtitle("cex = 1.5")
#> Warning in regularize.values(x, y, ties, missing(ties)): collapsing to unique
#> 'x' values

ggplot(dat, aes(x, y)) +
  theme_bw(base_size = 22) +
  geom_violin(draw_quantiles = c(0.5),
              scale="width", width=0.6) +
  geom_beeswarm(size=0.5, cex=2.5, priority = "random") +
  ggtitle("cex = 2.5")
#> Warning in regularize.values(x, y, ties, missing(ties)): collapsing to unique
#> 'x' values

^{Created on 2020-09-08 by the reprex package (v0.3.0)}