问如何使用ggplot2封装X轴标签？

EN

library(dplyr)
library(ggplot2)

tibble::rownames_to_column(mtcars) %>%
  ggplot(aes(rowname, mpg)) + 
  geom_col() +
  theme(axis.text.x = element_text(angle = 90, hjust = 1)) +
  labs(x = "name")

grid::grid.rect(x = unit(32, "pt"), y = unit(5.5, "pt"), 
                height = unit(0.265, "npc"), width = unit(0.93, "npc"), 
                vjust = 0, hjust = 0, gp = grid::gpar(fill = NA))

library(dplyr)
library(ggplot2)

p <- tibble::rownames_to_column(mtcars) %>%
  ggplot(aes(rowname, mpg)) + 
  geom_col() +
  theme(axis.text.x = element_text(angle = 90, hjust = 1)) +
  labs(x = "name")

p2 <- ggplot_gtable(ggplot_build(p))

p2$grobs[[which(p3$layout$name == "axis-b")]]$children[[1]] <- 
  grid::rectGrob(gp = grid::gpar(fill = NA))

grid::grid.newpage()
grid::grid.draw(p2)