How can I add a subtitle and change the font size of ggplot plots in R?

Question

I tried adding a subtitle using +opts(subtitle=\"text\") but nothing showed up. The main title does work (+opts(title=\"text\")).

I would also

Answer 1

theme_get() will show you the "hidden" options that you can use in opts(), post 0.91 it's theme()

Current:

theme(axis.text.x=element_text(size=X))
theme(axis.text.y=element_text(size=X))

Pre 0.91:

opts(axis.text.x=theme_text(size=X))
opts(axis.text.y=theme_text(size=X))

Change size, to your desired size.

wrt the title, you can use "\n" to move the remaining text to a new line:

Current:

labs(title="text \n more text")

Pre 0.91:

opts(title="text \n more text") 

ggplot2 doesn't have "subtitle" functionality. But you can use the \n term in any of the labels to drop down a line.

Answer 2

Update: ggplot version 2.2.0 can do subtitles, as demonstrated e.g. in this blog post.

Example:

library(ggplot2)
packageVersion("ggplot2")  ## 2.2.0
d <- data.frame(x=1:5,y=1:5)
ggplot(d,aes(x,y))+
    labs(title="abc",subtitle="def")+
    ## default left-aligned: moved them to center alignment
    theme(plot.title=element_text(hjust=0.5),
          plot.subtitle=element_text(hjust=0.5))