消除一个轴上的strip.background(ggplot2)

Question

ggplot2中的许多主题元素只有.x或.y扩展名,只能在一个轴上删除/修改某些内容. strip.background没有strip.background.x相同的,如下所示.

如何strip.background仅从一个轴上删除文本和构面标签？

a <- ggplot(mtcars, aes(mpg, hp)) +
    geom_point() +
    facet_grid(cyl~gear) 

a + theme(strip.text.y = element_blank(), 
    strip.background.x = element_blank())

##     > a + theme(strip.text.y = element_blank(), strip.background.x = element_blank())
##     Error in (function (el, elname)  : 
##       "strip.background.x" is not a valid theme element name.

Answer 1

library(ggplot2)
a <- ggplot(mtcars, aes(mpg, hp)) +
  geom_point() +
  facet_grid(cyl~gear) 

strip.remover <- function(ggp, what="x") {
  require(gridExtra)

  zeroGrob <- function() {
    g0 <- grob(name="NULL")
    class(g0) <- c("zeroGrob",class(g0))
    g0
  }

  g <- ggplotGrob(ggp)

  g$grobs <- lapply(g$grob, function(gr) {
    if (any(grepl(paste0("strip.text.", what),names(gr$children)))) {
      gr$children[[grep("strip.background",names(gr$children))]] <- zeroGrob()
      gr$children[[grep("strip.text",names(gr$children))]] <- zeroGrob()
    }
    return(gr)
  }
  )

  class(g) = c("arrange", "ggplot",class(g)) 
  g
}

strip.remover(a, "y")

Answer 2

这是一种删除相关条带的方法,

library(grid)  # for the grid functions
g <- ggplotGrob(a)
keep <- !grepl("strip-right", g$layout$name)
g$grobs <- g$grobs[keep]
g$layout <- g$layout[keep, ]
grid.newpage()
grid.draw(g)

Answer 3

至少对于ggplot2版本2.0.0.如果设置strip.text.x=或strip.text.y=以element_blank()它消除文字和特定轴的背景.

a + theme(strip.text. = element_blank())