使用scale_y_cut后plot.margin设置失效问题求助

问题原因 #

scale_y_cut会将原始ggplot图形分割为多个子面板并重新拼接成新图形，普通theme()中的plot.margin仅作用于单个子面板，无法影响拼接后的整体图形边距。

解决方案 #

方法一：使用theme_break()设置整体边距 #

ggbreak包提供了theme_break()函数，专门用于处理断裂图形的主题设置，它能将plot.margin应用到拼接后的整体图形上：

set.seed(5)
library(tidyverse)
library(ggbreak)

data <- data.frame(
  id = c(1:100),
  age = sample(20:80, 100, replace = TRUE),
  sex = sample(c("M", "F"), 100, replace = TRUE, prob = c(0.7, 0.3)),
  type = sample(letters[1:5], 100, replace = TRUE),
  name = sample(c("longnamelongnamelongname1", "longnamelongname2longname", "longnamelongnamelongname3", "longnamelongnamelongname4"), 100, replace = TRUE, prob = c(0.25, 0.25, 0.25, 0.25)),
  direction = sample(c("Up", "Down"), 100, replace = TRUE, prob = c(0.7, 0.3)),
  bmi = sample(15:35, 100, replace = TRUE),
  sbp = sample(75:160, 100, replace = TRUE)
 )


ggplot(data, aes(name, age, color=sex, fill=sex, size=sex, shape = type)) + 
  geom_point() +
  theme_bw() +
  scale_y_cut(breaks=(c(40)), scale=0.15) +
  # 用theme_break替代theme，统一设置主题与整体边距
  theme_break(plot.margin = unit(c(0.5, 0.5, 0.5, 3), "cm"),
        panel.grid.minor = element_blank(),
        axis.text.x = element_markdown(angle = 45, vjust = 1, hjust = 1, size = 10.5), 
        legend.title = element_text(size=12), 
        legend.text = element_text(size=11),
        legend.key.size = unit(.8, "cm"), 
        legend.key.height = unit(.5, "cm"))

方法二：手动调整拼接后的图形对象 #

如果方法一效果不佳，可以将图形转为gtable对象，直接修改整体边距：

set.seed(5)
library(tidyverse)
library(ggbreak)
library(grid)

data <- data.frame(
  id = c(1:100),
  age = sample(20:80, 100, replace = TRUE),
  sex = sample(c("M", "F"), 100, replace = TRUE, prob = c(0.7, 0.3)),
  type = sample(letters[1:5], 100, replace = TRUE),
  name = sample(c("longnamelongnamelongname1", "longnamelongname2longname", "longnamelongnamelongname3", "longnamelongnamelongname4"), 100, replace = TRUE, prob = c(0.25, 0.25, 0.25, 0.25)),
  direction = sample(c("Up", "Down"), 100, replace = TRUE, prob = c(0.7, 0.3)),
  bmi = sample(15:35, 100, replace = TRUE),
  sbp = sample(75:160, 100, replace = TRUE)
 )

# 先绘制基础图形
p <- ggplot(data, aes(name, age, color=sex, fill=sex, size=sex, shape = type)) + 
  geom_point() +
  theme_bw() +
  scale_y_cut(breaks=(c(40)), scale=0.15) +
  theme(panel.grid.minor = element_blank(),
        axis.text.x = element_markdown(angle = 45, vjust = 1, hjust = 1, size = 10.5), 
        legend.title = element_text(size=12), 
        legend.text = element_text(size=11),
        legend.key.size = unit(.8, "cm"), 
        legend.key.height = unit(.5, "cm"))

# 转为gtable并调整整体边距
gt <- ggplotGrob(p)
gt$margins <- unit(c(0.5, 0.5, 0.5, 3), "cm")
grid.draw(gt)

内容的提问来源于stack exchange，提问作者celilati