rggplot2legend

How to change line height in legend?

How to change line height in legend ? In geom_line(size=2) ,change size can change line height both in plot and legend , how to change only legend line size ?

library(tidyverse)
plot_data <- data.frame(my_date= seq.Date(as.Date('2023-1-1'),
                                          as.Date('2023-12-31'),'1 day'),
                        my_value=rnorm(365)) %>% 
  mutate(my_month = lubridate::month(my_date))


plot_data %>% ggplot(aes(x = my_date,y=my_value,
                         color= factor(my_month))) +
  geom_line(size=2)+
  guides(color = guide_legend(nrow=1,title='color'))+
  theme(legend.position = 'top')

enter image description here

Solution

  • To change the linewidth (or other aesthetics) in the legend only you can use the override.aes= argument of guide_legend:

    Note: I switched to linewidth instead of size.

    library(ggplot2)

ggplot(plot_data, aes(
  x = my_date, y = my_value,
  color = factor(my_month)
)) +
  geom_line(linewidth = 2) +
  guides(
    color = guide_legend(
      nrow = 1, title = "color",
      override.aes = list(linewidth = 4)
    )
  ) +
  theme(legend.position = "top")