How to reduce plot margins of one column of plots of an arrange of plots using `plot_grid` in R?

Question

I need to make an arrange of plots in which each row of plots shares a common legend. All plots share the same units for y and x-axis. Below I show how my arrange of plots looks like:

I extract the common legend for each row as a plot and then I add it as an additional column in my arrange.

As you can see, the column with the legends "consume" a lot of space in the arrange, what could I do to reduce their margins in favour of the other two columns?

I used plot_grid because I saw in this link that you can create common x and y-axis titles using ggdraw .

Answer 1

You can use the rel_widths argument of plot_grid . Here's a reproducible example:

library(ggplot2)
library(cowplot)
library(ggpubr)
theme_set(theme_cowplot())

df <- data.frame(x = 1:12, y = (1:12)^2)
df$grp = c('Some', 'Things', 'In a legend')

p <- ggplot(df, aes(x, y, color=grp)) + geom_point()
leg <- get_legend(p)
leg <- as_ggplot(leg)
p = p + theme(legend.position = "none")

plot_grid(
  p, p, leg, 
  p, p, leg,
  ncol = 3, rel_widths=c(2,2,1)
)