在水平图例标题后添加换行符

Question

When theme(legend.position = "top") , the legend is horizontal and can be a bit too wide.

Here is an example:

library(ggplot2)
ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, color=Species)) + 
  geom_point() + 
  xlim(5,6) + 
  coord_fixed() +
  theme(legend.position = "top")

^{Created on 2021-01-14 by the reprex package (v0.3.0)}

In order to reduce the width of the legend, I'd like to add a line break after the "Species" title.

I'm aware of guides(guide_legend(ncol=2,nrow=2,byrow=TRUE)) , it is very nice but it yeilds a different output.

Answer 1

We can use the title.position argument inguide_legend in scale_colour_discrete :

ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, color=Species)) + 
  geom_point() + 
  xlim(5,6) + 
  coord_fixed() +
  theme(legend.position = "top")+
  scale_colour_discrete(guide = guide_legend(title.position = "top"))