如何根据R中ggplot2中的离散y轴标签更改面板的背景 colored颜色

这是一个使用geom_tile()的解决方案，

1. 我们为背景 colored颜色 创建了一个数据框
2. 当我们使用geom_tile()时，我们将设置x美学，以便覆盖整个地块的宽度，并相应地调整每个平铺的宽度.
3. geom_tile()使用x = sum(x_limits) / 2将切片定位在地块中心，使用width = diff(x_limits)将切片定位在地块的整个宽度上

library(ggplot2)
library(dplyr)

set.seed(123)
plot_df <- data.frame(
  gene = rep(paste0("ENSG", 1:10, ".17"), each = 2),
  mean = rnorm(20, 0.5, 0.1),
  sd = rnorm(20, 0.02, 0.01),
  group = rep(c("group_a", "group_b"), 10)
)

# df for background colors
bg_df <- plot_df %>%
  distinct(gene) %>%
  arrange(gene) %>% 
  mutate(color = ifelse(row_number() %% 2 == 1, "gold", "lightgrey"))

# x axis limts based on data 
x_limits <- range(plot_df$mean - plot_df$sd, plot_df$mean + plot_df$sd, na.rm = TRUE)

# the plot
ggplot(plot_df, aes(y = gene, x = mean)) +
  geom_tile(data = bg_df, aes(y = gene, x = sum(x_limits) / 2, width = diff(x_limits), fill = color), 
            alpha = 0.3, inherit.aes = FALSE) +
  geom_point(aes(color = group), position = position_dodge(width = 0.9)) +
  geom_errorbar(aes(xmin = mean - sd, xmax = mean + sd, color = group), 
                width = 0.2, position = position_dodge(.9)) +
  scale_color_manual(values = c("steelblue3", "red3"))+
  geom_vline(xintercept = 0.5, linetype = 2, color = 'gray80') +
  theme_bw() +
  theme(panel.background = element_blank(),
        panel.grid.major = element_blank(), 
        panel.grid.minor = element_blank(),
        legend.position = "right") +
  scale_fill_identity()