Controlling the Overall Appearance of Graphs - R Graphics - page 270

Chapter9.Controlling the Overall
Appearance of Graphs
In this chapter I'll discuss how to control the overall appearance of graphics made by ggplot2.
The grammar of graphics that underlies ggplot2 is concerned with how data is processed and dis-
played—it's not concerned with things like fonts, background colors, and so on. When it comes
to presenting your data, there's a good chance that you'll want to tune the appearance of these
things. ggplot2's theming system provides control over the appearance of non-data elements. I
touched on the theme system in the previous chapter, and here I'll explain a bit more about how
it works.
Setting the Title of a Graph
Problem
You want to set the title of a graph.
Solution
Set title with ggtitle() , as shown in Figure 9-1 :
library(gcookbook) # For the data set
p <- ggplot(heightweight, aes(x = ageYear, y = heightIn)) + geom_point()
p + ggtitle( "Age and Height of Schoolchildren" )
# Use \n for a newline
p + ggtitle( "Age and Height\nof Schoolchildren" )