在ggplot2中将批注添加到图例颜色栏

library(ggplot2)

# 创建示例数据
data <- data.frame(
  x = rnorm(100),
  y = rnorm(100),
  group = sample(c("A", "B", "C"), 100, replace = TRUE)
)

# 创建基本图表
p <- ggplot(data, aes(x = x, y = y, color = group)) +
  geom_point(size = 3) +
  scale_color_manual(values = c("red", "blue", "green")) +
  labs(title = "Example Plot with Annotations in Legend")

# 添加批注到图例颜色栏
p + theme(legend.position = "bottom") +
  guides(color = guide_legend(
    override.aes = list(shape = 19, size = 5),
    title = "Groups",
    label.theme = element_text(size = 12),
    byrow = TRUE
  )) +
  annotate("text", x = -Inf, y = Inf, hjust = -0.2, vjust = 1.2,
           label = "Important Note:\nGroup A represents high values,\nGroup B represents medium values,\nGroup C represents low values.",
           size = 4)