如何在ComplexHeatmap顶部注释色块中央添加分组标签

不用column_km的话，可通过**自定义注释（custom annotation）**实现手动指定列顺序下的分组标签添加，核心思路是先定位每个分组的列区间，再在对应色块中央绘制标签。以下提供两种可行方案：

方案一：整合色块与标签的自定义注释 #

直接替换原有简单注释，在自定义函数中同时绘制分组色块和标签：

# 1. 先获取每个分组对应的列索引及中心位置
group_cols <- split(seq_along(order.ffpe$V1), order.ffpe$V1)
group_centers <- sapply(group_cols, function(x) mean(x))
group_names <- names(group_cols)
group_colors <- c("Group1" = "#c2a5cf", "Group2" = "#a6dba0", "Group3" = "#fdae61")

# 2. 定义自定义注释函数
custom_group_anno <- function(index) {
  pushViewport(viewport(xscale = c(0, length(index)), yscale = c(0, 1)))
  # 遍历每个分组，绘制色块+标签
  for(g in group_names) {
    cols <- group_cols[[g]]
    # 绘制分组色块
    grid.rect(x = (min(cols)-0.5 + max(cols)+0.5)/2, 
              width = max(cols)-min(cols)+1, 
              y = 0.5, height = 1, 
              gp = gpar(fill = group_colors[g], col = NA))
    # 在色块中央绘制标签
    grid.text(g, x = group_centers[g], y = 0.5, gp = gpar(fontsize = 10))
  }
  popViewport()
}

# 3. 创建顶部注释
top.ann.ffpe <- HeatmapAnnotation(
  Group = anno_custom(custom_group_anno),
  show_legend = FALSE,
  show_annotation_name = FALSE,
  simple_anno_size = unit(0.2, "cm")
)

方案二：保留原有色块注释，叠加文本注释 #

如果想保留原有简单注释的逻辑，可新增一层仅绘制文本的自定义注释：

# 1. 计算每个分组的中心位置
group_centers <- sapply(split(seq_along(order.ffpe$V1), order.ffpe$V1), mean)
group_names <- names(group_centers)

# 2. 定义文本注释函数
text_anno <- function(index) {
  pushViewport(viewport(xscale = c(0, length(index)), yscale = c(0, 1)))
  for(i in seq_along(group_names)) {
    grid.text(group_names[i], x = group_centers[i], y = 0.5, gp = gpar(fontsize = 10))
  }
  popViewport()
}

# 3. 创建叠加式顶部注释
top.ann.ffpe <- HeatmapAnnotation(
  Group = order.ffpe$V1,
  Text = anno_custom(text_anno, height = unit(0.2, "cm")), # 高度与色块注释一致
  show_legend = FALSE,
  show_annotation_name = FALSE,
  simple_anno_size = unit(0.2, "cm"),
  col = list(Group = c("Group1" = "#c2a5cf", "Group2" = "#a6dba0", "Group3" = "#fdae61"))
)

说明 #

• 两种方案均基于grid包的绘图函数实现，无需依赖聚类逻辑
• 可通过调整gpar(fontsize)参数修改标签大小，simple_anno_size调整注释高度

内容的提问来源于stack exchange，提问作者user2300940