Rotate legend in ggplot2

Question

I wish to rotate a ggplot2 legend 90°

From

qplot(mpg, wt, data=mtcars, colour=cyl)

to produce

Answer 1

Something like:

p <- qplot(mpg, wt, data=mtcars, colour=cyl)
p + scale_colour_continuous(guide = guide_legend(direction = "horizontal", title.position = "top",
                             label.position="bottom", label.hjust = 0.5, label.vjust = 0.5,
                             label.theme = element_text(angle = 90))) + 
      theme(legend.position = c(0.5, 0.9))

Ref: ggplot docs

Answer 2

you can try this

library(ggplot2)
qplot(mpg, wt, data=mtcars, colour=cyl) + theme(legend.position = "top")