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

i grey bar @ top wider, in, have edges of little further top , bottom of letters (the strip.text - a, b, c etc). have thought lineheight have acted padding doesn't.

ggplot(diamonds, aes(carat, price, fill = ..density..)) +   xlim(0, 2) + stat_binhex(na.rm = true)+   facet_wrap(~ color) +   theme(strip.text = element_text(lineheight=20))  

first, modify levels include linebreak:

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

then adjust 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))