How to color a specific label on the y-axis in ggplot2, while at the same time avoid overlapping lab-CodePudding

I am trying to color a specific label on the y-axis by using: theme(axis.text.y = element_markdown(color = ...)) and it works perfectly fine. However, when I also want to prevent myself from potential label overlapping on this very same axis by using : scale_y_discrete(guide = guide_axis(check.overlap = T)) , then, the coulored label is changed. Here is a small example showing this issue.

As anyone already faced this issue? Do you have a solution for it ? Or another way of doing it?

library(ggplot2)
library(ggtext)

N              = 10
df             = data.frame(parameters = paste("paramters", seq(N), sep = "_"),
                            color      = rep("black", N))
df$parameters  = factor(df$parameters, levels = df$parameters, ordered = T)
best           = 5
df$color[best] = "red"
df
#>      parameters color
#> 1   paramters_1 black
#> 2   paramters_2 black
#> 3   paramters_3 black
#> 4   paramters_4 black
#> 5   paramters_5   red
#> 6   paramters_6 black
#> 7   paramters_7 black
#> 8   paramters_8 black
#> 9   paramters_9 black
#> 10 paramters_10 black

p = ggplot(df, aes(y = parameters))   theme(axis.text.y = element_markdown(color = df$color))
q = p   scale_y_discrete(guide = guide_axis(check.overlap = T))

^{Created on 2021-09-21 by the reprex package (v2.0.0)}

CodePudding user response：

I don't think the aim of ggtext is to allow vectorised colour assignments through the theme elements. It instead offers to interpret (a limited set of) markdown/html tags in the labels, so if you want one specific label to be red, you should construct the html tag for red text for it.

library(ggplot2)
library(ggtext)
#> Warning: package 'ggtext' was built under R version 4.1.1

N              = 10
df             = data.frame(parameters = paste("paramters", seq(N), sep = "_"))
df$parameters  = factor(df$parameters, levels = df$parameters, ordered = T)
best           = 5

levels(df$parameters) = ifelse(
  levels(df$parameters) == paste("paramters", best, sep = "_"),
  paste0("<span style='color:red'>",   levels(df$parameters), "</span>"),
  paste0("<span style='color:black'>", levels(df$parameters), "</span>")
)


(p = ggplot(df, aes(y = parameters))   
  theme(axis.text.y = element_markdown()))

(q = p   
  scale_y_discrete(guide = guide_axis(check.overlap = T)))

^{Created on 2021-09-21 by the reprex package (v2.0.1)}