r - Increasing whitespace between legend items in ggplot2

Question

My question is an extension of this question. Note that I'm using version 2.3.0 which is available on github, not yet on CRAN.

library(ggplot2)

df <- data.frame("Categories" = rep(c("A", "B", "C"), 3),  
                 "values" = c(rep(0.39, 3), rep(0.37, 3), rep(0.24, 3)),
                 "X" = 1:9)

ggplot(df, aes(x = X, y = values, colour = Categories)) +
  geom_line() +
  theme(
        legend.position = "top",
        legend.spacing.x = unit(2, unit = "cm"),
        legend.title = element_blank()
        ) 

The code above creates this plot.

I would like to move the legend labels (A, B, C) closer to their corresponding icons, as shown by the red arrows below, which would create more whitespace between the legend categories. How would I do that?

Answer 1

One possible workaround is to add extra whitespace on the right of Categories using stringr::str_pad

library(ggplot2)

df <- data.frame("Categories" = rep(c("A", "B", "C"), 3),  
                 "values" = c(rep(0.39, 3), rep(0.37, 3), rep(0.24, 3)),
                 "X" = 1:9)

# define a custom function
str_pad_custom <- function(labels){
  new_labels <- stringr::str_pad(labels, 10, "right")
  return(new_labels)
}

ggplot(df, aes(x = X, y = values, colour = Categories)) +
  geom_line() +
  scale_color_brewer(labels  = str_pad_custom,
                     palette = "Dark2") +
  theme(
    legend.position = "top",
    legend.key.width = unit(1.0,  unit = "cm"),
    legend.spacing.x = unit(0.25, unit = "cm"),
    legend.title = element_blank()
  ) 

^{Created on 2018-06-15 by the reprex package (v0.2.0).}