ggplot2带分位数小提琴图美学定制：线条样式与颜色设置问询

原始代码与需求 #

用户提供的小提琴图绘制代码如下：

library(ggplot2)
#Make data frame
Label <- c("Blue", "Blue", "Blue", "Blue","Red", "Red","Red","Red","Blue", "Blue","Blue","Blue")
n <- c(10, 223, 890, 34, 78, 902, 34, 211, 1007,209, 330, 446)
data <- data.frame(Label, n)

# make violin plot with quantiles
ggplot(data, aes(Label, n)) +
  geom_violin(legend = FALSE, trim = FALSE, adjust = 0.6, draw_quantiles = c(0.25, 0.5, 0.75)) 

当前所有分位数线条均为黑色，需求：

• 将中位数（0.5分位数）线条加粗醒目，0.25/0.75分位数设为细虚线（或通过透明度区分）
• 左侧小提琴填充色设为#42E894，右侧使用该颜色的浅色调，无需手动查找色值

1. 分位数线条样式调整 #

geom_violin的draw_quantiles无法直接为不同分位数设置差异化样式，可通过**两次调用geom_violin**实现：

• 第一次绘制小提琴主体与0.25/0.75分位数，设置为细虚线
• 第二次仅绘制中位数线条，设置为加粗实线（通过fill=NA避免覆盖原有小提琴）

示例代码：

library(ggplot2)
# 构建数据框
Label <- c("Blue", "Blue", "Blue", "Blue","Red", "Red","Red","Red","Blue", "Blue","Blue","Blue")
n <- c(10, 223, 890, 34, 78, 902, 34, 211, 1007,209, 330, 446)
data <- data.frame(Label, n)

ggplot(data, aes(Label, n)) +
  # 绘制小提琴主体+0.25/0.75分位数（细虚线）
  geom_violin(trim = FALSE, adjust = 0.6, 
              draw_quantiles = c(0.25, 0.75),
              linetype = "dashed", size = 0.5) +
  # 单独绘制中位数（加粗实线）
  geom_violin(trim = FALSE, adjust = 0.6, 
              draw_quantiles = 0.5,
              fill = NA, size = 1.2)

如果偏好透明度方案，可给0.25/0.75分位数添加alpha=0.5，中位数保持alpha=1，同样能突出中位数。

2. 小提琴颜色深浅调整 #

无需手动查找浅色调十六进制值，可使用scales包的lighten()函数直接调亮原颜色：

完整代码（结合样式调整） #

library(ggplot2)
library(scales) # 加载颜色调整包

# 构建数据框
Label <- c("Blue", "Blue", "Blue", "Blue","Red", "Red","Red","Red","Blue", "Blue","Blue","Blue")
n <- c(10, 223, 890, 34, 78, 902, 34, 211, 1007,209, 330, 446)
data <- data.frame(Label, n)

ggplot(data, aes(Label, n, fill = Label)) +
  # 0.25/0.75分位数：细虚线
  geom_violin(trim = FALSE, adjust = 0.6, 
              draw_quantiles = c(0.25, 0.75),
              linetype = "dashed", size = 0.5) +
  # 中位数：加粗实线
  geom_violin(trim = FALSE, adjust = 0.6, 
              draw_quantiles = 0.5,
              fill = NA, size = 1.2) +
  # 设置填充色：左侧为#42E894，右侧调亮30%
  scale_fill_manual(values = c("Blue" = "#42E894", 
                               "Red" = lighten("#42E894", amount = 0.3))) +
  guides(fill = FALSE) # 隐藏填充色图例

• lighten()的amount参数取值0-1，值越大颜色越浅；如需调暗可使用darken()函数
• 若未安装scales包，先运行install.packages("scales")安装

内容的提问来源于stack exchange，提问作者MM1