ggplot2：如何动态包装/调整大小/重新缩放 x 轴标签，使其不会重叠

我正在尝试实现一种包装 x 轴标签的解决方案，以便它们不会重叠。我知道这个问题已经被问过好几次了，并且有一些好的答案。但是，我见过的解决方案都没有回答如何随着情节的发展重新包装标签resized.

SO 的三个不同答案让我相信这是可以实现的。

1. 这个解决方案写了一份定制的geom用于安装bar的标签size当您调整绘图大小时，动态地适应条形的宽度。

2. 这个解决方案依赖于一个扩大包用于ggplot2 called ggtext。该解决方案允许对情节进行动态换行title，当您调整绘图大小时，基于创建element_textbox().

3. 这个解决方案依赖于另一个名为ggfittext。它显示了如何size当您调整绘图大小时，条形图内标签的大小可以动态变化以适应条形图的尺寸。本质上，它解决了与上述解决方案 (1) 相同的问题，但功能更强大。事实上，这是让我充满希望的功能，它依赖于通用解决方案geom_fit_text()使文本适合矩形内，而不仅仅是geom_bar()s.

一些可以使用的演示数据

1.只是为了显示x轴标签重叠时的典型输出

  library(tidyverse)
  
  my_mtcars <-
    mtcars[15:20,] %>% 
    rownames_to_column("cars")
  
  my_mtcars %>%
    ggplot(aes(x = cars, y = mpg, fill = cars)) + 
    geom_bar(stat = "identity")

^{Created on 2021-01-29 by the reprex package (v0.3.0)}

2.当我们使用ggfittext我们可以看到条形内的标签如何缩小尺寸以适应条形

  library(tidyverse)
  library(ggfittext)
#> Warning: package 'ggfittext' was built under R version 4.0.3
  
  my_mtcars <-
    mtcars[15:20,] %>% 
    rownames_to_column("cars")
  
  my_mtcars %>%
    ggplot(aes(x = cars, y = mpg, fill = cars)) + 
    geom_bar(stat = "identity") +
    geom_bar_text(aes(label = cars), 
      color = "blue", 
      vjust = 1, 
      size = 7 * ggplot2::.pt, 
      min.size = 0,
      padding.x = grid::unit(0, "pt"),
      padding.y = grid::unit(0, "pt"))
#> Warning: Ignoring unknown aesthetics: label

^{Created on 2021-01-29 by the reprex package (v0.3.0)}

3. ggfittext有reflow促进文本换行的论点

  library(tidyverse)
  library(ggfittext)
#> Warning: package 'ggfittext' was built under R version 4.0.3
  
  my_mtcars <-
    mtcars[15:20,] %>% 
    rownames_to_column("cars")
  
  my_mtcars %>%
    ggplot(aes(x = cars, y = mpg, fill = cars)) + 
    geom_bar(stat = "identity") +
    geom_bar_text(aes(label = cars), 
      color = "blue", 
      vjust = 1, 
      size = 7 * ggplot2::.pt, 
      min.size = 0,
      padding.x = grid::unit(0, "pt"),
      padding.y = grid::unit(0, "pt"),
      reflow = TRUE ## <--------------- added this
      )
#> Warning: Ignoring unknown aesthetics: label

^{Created on 2021-01-29 by the reprex package (v0.3.0)}

我的问题

我不知道该怎么做，但是我们可以通过某种方式让 x 轴标签动态包装/调整大小/重新缩放吗ggfittext为我们做艰苦的工作吗？在我看来，条形内的文本已经以正确的方式呈现，我们可以以某种方式将此渲染“复制”到轴标签吗？

我们只需将ggfittexty 轴下方的文本？我们关闭剪辑并设置oob and limits以适应我们的数据。可能应该调整axis.text.x大小以更好地与 x 轴标题对齐。

library(tidyverse)
#> Warning: package 'tidyr' was built under R version 4.0.3
#> Warning: package 'readr' was built under R version 4.0.3
#> Warning: package 'dplyr' was built under R version 4.0.3
library(ggfittext)
#> Warning: package 'ggfittext' was built under R version 4.0.3

my_mtcars <-
  mtcars[15:20,] %>% 
  rownames_to_column("cars")

my_mtcars %>%
  ggplot(aes(x = cars, y = mpg, fill = cars)) + 
  geom_bar(stat = "identity") +
  geom_fit_text(aes(label = cars, y = -4),
                reflow = TRUE, height = 50,
                show.legend = FALSE) +
  scale_y_continuous(oob = scales::oob_keep,
                     limits = c(0, NA)) +
  coord_cartesian(clip = "off") +
  theme(axis.text.x = element_text(colour = "transparent", size = 18))

^{Created on 2021-01-29 by the reprex package (v0.3.0)}

编辑：从 grob 中取出标签

library(tidyverse)
library(ggfittext)

my_mtcars <-
  mtcars[15:20,] %>% 
  rownames_to_column("cars")

p <- my_mtcars %>%
  ggplot(aes(x = cars, y = mpg, fill = cars)) + 
  geom_bar(stat = "identity") +
  geom_fit_text(aes(label = cars, y = -1),
                reflow = TRUE, height = 50,
                show.legend = FALSE) +
  scale_y_continuous(oob = scales::oob_keep,
                     limits = c(0, NA)) +
  coord_cartesian(clip = "off") +
  theme(axis.text.x = element_text(colour = "transparent", size = 18))

grob <- grid::makeContent(layer_grob(p, 2)[[1]])$children

sizes <- vapply(grob, function(x){x$gp$fontsize}, numeric(1))
labels <- unname(vapply(grob, function(x){x$label}, character(1)))
print(labels)
#> [1] "Cadillac\nFleetwood"  "Lincoln\nContinental" "Chrysler\nImperial"  
#> [4] "Fiat 128"             "Honda Civic"          "Toyota\nCorolla"

^{Created on 2021-01-29 by the reprex package (v0.3.0)}