facet_tags.R

library(ggplot2)
library(tagger)

d <- data.frame(x=rep(1:10, 5*4*2), y=rnorm(10*5*4*2), f1=gl(4,10*5*2,labels=letters[1:4]), f2=gl(5,10*4*2,labels = LETTERS[1:5]), f3=gl(2,10*4*5))

p <- ggplot(d, aes(x,y)) +
  facet_wrap(f1~f2+f3)

data <- ggplot_build(p)
str(data$layout$layout)
tag_pool <- glue::glue_data(data$layout$layout,"{f1}|{f2}, {f3}")
p2 <- p  + 
  tagger::tag_facets(tag_pool = tag_pool, tag_suffix = '') +  
  theme(strip.background = element_blank(),
        strip.text = element_blank(),
        tagger.panel.tag.background = element_rect(fill='gold'))

egg::ggarrange(p +ggtitle("original"), p2+ggtitle("strips stripped"),ncol=2)