Is there a way to increase the height of the strip.text bar in a facet?

Question

I would like the grey bar at the top to be wider, as in, have the edges of it a little further from the top and bottom of the letters (the strip.text - A, B, C etc). I would

Answer 1

With ggplot2 2.2.0, you can apply Ricardo's trick without modifying the dataframe, by using labeller:

P <- ggplot(diamonds, aes(carat, price, fill = ..density..)) +
  xlim(0, 2) + stat_binhex(na.rm = TRUE)+
  facet_wrap(~ color, labeller = labeller(color=setNames(paste0("\n", levels(diamonds$color), "\n"), levels(diamonds$color))))

P +  theme(strip.text = element_text(size=9, lineheight=0.5))

Answer 2

First, modify the levels so that they include a linebreak:

levels(diamonds$color) <- paste0(" \n", levels(diamonds$color) , "\n ")

Then adjust as necessary. eg:

P <- ggplot(diamonds, aes(carat, price, fill = ..density..)) +
      xlim(0, 2) + stat_binhex(na.rm = TRUE)+
      facet_wrap(~ color)

P +  theme(strip.text = element_text(size=9, lineheight=0.5))

P +  theme(strip.text = element_text(size=9, lineheight=3.0))