合并tileplot与dendrogram时，如何对齐Y轴元素并调整树状图尺寸？

问题背景 #

需要将tile对象生成的tileplot与dendro对象生成的dendrogram合并，同时固定Y轴所有元素的位置，但使用ggarrange合并后，树状图的Y轴尺寸过长，导致标签无法对应层级，且默认heatmap()函数无法满足展示需求。

解决方案 #

核心思路是让两个图的Y轴范围完全匹配，同时通过对齐参数和布局调整确保标签层级对应。以下是具体实现步骤：

1. 确保Y轴因子顺序一致 #

先保证tile图的Y轴因子顺序与树状图的叶子节点顺序完全匹配（已完成的代码保留）：

library(tidyverse)
library(dendextend)
library(ggpubr)
library(ggdendro)

df <- tibble(
    Method=c("kbest_f","fpr_chi2","perc_f","kbest_chi2","fpr_chi2","perc_mutual","perc_f","perc_mutual","fpr_chi2","fpr_chi2"),
    Coincidence = c("AVV","ENH","MPN","WET","TKR","LEA","SPQ","PIY","VYL","AGL"), 
    n=rep(1,10))

scores <- with(df, table(Coincidence, Method))
dendro <- as.dendrogram(hclust(dist(scores, method="binary"), method="ward.D"))

tile <- df %>%
    mutate(Coincidence = factor(Coincidence,levels=partition_leaves(dendro)[[1]]))

2. 生成对齐后的Tile图和树状图 #

修改tile图和树状图的代码，确保Y轴范围一致并调整布局：

# 生成Tile图，调整主题去掉多余元素
tileplot <- tile %>%
    ggplot(aes(Method, Coincidence, fill= n)) + 
    geom_tile()+
    theme(
        axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1),
        axis.text.y = element_text(size=5),
        legend.position="none",
        axis.title.y = element_blank(), # 去掉Y轴标题避免重复
        plot.margin = margin(0, 0, 0, 0)
    )

# 手动提取树状图数据，映射叶子节点到Tile图的Y轴位置
dendro_data <- dendro_data(dendro, type = "rectangle")
# 将树状图叶子节点的Y坐标匹配到Tile图的因子顺序
leaf_y <- match(dendro_data$labels$label, levels(tile$Coincidence))
dendro_data$labels$y <- leaf_y

# 调整树状图线段数据，确保结构适配Tile图Y轴范围
dendro_data$segments <- dendro_data$segments %>%
    mutate(
        y = ifelse(y %in% dendro_data$labels$y, y, y),
        yend = ifelse(yend %in% dendro_data$labels$y, yend, yend)
    )

# 绘制对齐后的树状图
dendroplot <- ggplot() +
    geom_segment(data = dendro_data$segments, aes(x = x, y = y, xend = xend, yend = yend)) +
    geom_text(data = dendro_data$labels, aes(x = x, y = y, label = label), 
              size = 5/.pt, vjust = 0.5, hjust = 1.0) +
    coord_flip() +
    # 设置Y轴范围与Tile图完全一致
    scale_y_continuous(limits = c(0.5, length(levels(tile$Coincidence)) + 0.5)) +
    theme(
        axis.text.y = element_blank(), # 去掉树状图Y轴文本，复用Tile图的标签
        axis.title.y = element_blank(),
        axis.text.x = element_blank(),
        axis.title.x = element_blank(),
        axis.ticks = element_blank(),
        plot.margin = margin(0, 0, 0, 0)
    )

3. 合并并对齐两个图 #

使用ggarrange的垂直对齐参数，同时调整宽度比例让树状图更紧凑：

ggarrange(
    tileplot,
    dendroplot,
    labels=c("A","B"),
    ncol=2,
    nrow=1,
    align = "v", # 垂直对齐Y轴
    widths = c(4, 1) # 调整两个图的宽度比例
)

关键说明 #

• 手动映射树状图叶子节点的Y坐标，确保每个标签与Tile图的因子位置完全对应；
• 设置一致的Y轴范围，避免两个图的Y轴缩放差异；
• 调整widths参数控制树状图的宽度，避免其占用过多空间；
• 使用align="v"确保两个图的Y轴完全对齐，消除偏移。

内容的提问来源于stack exchange，提问作者Adonis Cedeño