如何调整ggalluvial桑基图的标签位置与黑色层样式？

针对你提出的三个需求，我们可以通过调整原代码参数、修正小错误来实现：

需求对应修改点 #

1. 将流的标签置于图的下方：通过theme调整x轴标题的位置，让其更靠下；若不需要总标题也可直接隐藏。
2. 加宽黑色stratum（层）的宽度：修改geom_stratum的width参数，增大数值即可（原代码为1/12，可改为1/6或0.2这类更大的值）。
3. 将层的标签放置在黑色柱体的中间位置：给geom_label添加position = position_stack(vjust = 0.5)，让标签垂直居中在柱体内部；同时调整标签样式，避免遮挡黑色柱体。

修改后的完整代码 #

library(ggalluvial)
library(ggplot2)
library(dplyr)

df <- data.frame(status = c("open", "close", "close", "open/close", "close"), 
                 stock = c("google", "amazon", "amazon", "yahoo", "amazon"), 
                 newspaper = c("times", "newyork", "london", "times", "times"))

# 统计每个组合的出现次数，添加.groups避免dplyr警告
df <- df %>% 
  dplyr::group_by(stock, newspaper, status) %>% 
  summarise(n = n(), .groups = "drop") 

# 定义因子水平
df$status <- factor(df$status, levels = c("open", "open/close", "close"))
df$stock <- factor(df$stock, levels = c("google", "amazon", "yahoo"))
df$newspaper <- factor(df$newspaper, levels = c("times", "newyork", "london"))

# 绘制定制化桑基图
ggplot(df, aes(y = n, axis1 = stock, axis2 = newspaper)) +
  geom_alluvium(aes(fill = status), width = 1/12) +
  # 加宽黑色层的宽度
  geom_stratum(width = 1/6, fill = "black", color = "grey") +
  # 标签居中在黑色柱体，设置白色文字+透明填充更清晰
  geom_label(stat = "stratum", aes(label = after_stat(stratum)),
             position = position_stack(vjust = 0.5), fill = NA, color = "white") +
  scale_x_discrete(limits = c("stock", "newspaper"), expand = c(.05, .05)) +
  scale_fill_brewer(type = "qual", palette = "Set1") +
  # 将x轴标题移至图下方（若不需要可改为element_blank()隐藏）
  theme(axis.title.x = element_text(vjust = -2, size = 12))

补充说明 #

• 修正了原代码中ggplot(df.2, ...)的错误，改为ggplot(df, ...)；
• position_stack(vjust = 0.5)确保标签精准落在黑色柱体的垂直中心；
• 若不需要x轴总标题，可将theme中的axis.title.x设置为element_blank()。

内容的提问来源于stack exchange，提问作者Erik Brole