Center Plot title in ggplot2

Question

Hi this simple code (and all my scripts from this morning) has started giving me a off center title in ggplot2

Ubuntu version: 16.04

R studio version: Versi         


        

Answer 1

As stated in the answer by Henrik, titles are left-aligned by default starting with ggplot 2.2.0. Titles can be centered by adding this to the plot:

theme(plot.title = element_text(hjust = 0.5))

However, if you create many plots, it may be tedious to add this line everywhere. One could then also change the default behaviour of ggplot with

theme_update(plot.title = element_text(hjust = 0.5))

Once you have run this line, all plots created afterwards will use the theme setting plot.title = element_text(hjust = 0.5) as their default:

theme_update(plot.title = element_text(hjust = 0.5))
ggplot() + ggtitle("Default is now set to centered")

To get back to the original ggplot2 default settings you can either restart the R session or choose the default theme with

theme_set(theme_gray())