ggplot2 - 在堆叠条形图中更改`geom_rect`颜色

Question

我想使用ggplot2::geom_bar绘制堆叠柱状图，并根据一个分类变量设置背景阴影（使用ggplot2::geom_rect()），方法如下：

shading <- data.frame(min = seq(from = 0.5, to = max(as.numeric(as.factor(diamonds$clarity))), by = 1),
                      max = seq(from = 1.5, to = max(as.numeric(as.factor(diamonds$clarity))) + 0.5, by = 1),
                      col = c(0,1))

ggplot() + 
  theme(panel.background = element_rect(fill = "transparent")) +
  geom_bar(data = diamonds, mapping = aes(clarity, fill=cut)) +
  geom_rect(data = shading,
            aes(xmin = min, xmax = max, ymin = -Inf, ymax = Inf,
                fill = factor(col), alpha = 0.1)) +
  geom_bar(data = diamonds, mapping = aes(clarity, fill=cut)) +
  guides(alpha = FALSE)

如何更改阴影颜色？我尝试了 scale_fill_manual(values = c("white", "gray53"))，但似乎ggplot2中不允许多个比例美学 (https://github.com/hadley/ggplot2/issues/578)。是否有其他方法可以获得所需的结果？

- Crops

Answer 1

是的，与其将颜色放在aes()中，不如将它们放在外面（以原样使用）。由于它在aes()调用之外，因此您将不得不使用显式的fill=shading$col而不是fill=col，并且shading$col应该具有您想要的颜色名称（而不是解释为因子的变量）。

shading$col <- ifelse(shading$col, 'white', 'gray53')
ggplot() + 
  theme(panel.background = element_rect(fill = "transparent")) +
  geom_bar(data = diamonds, mapping = aes(clarity, fill=cut)) +
  geom_rect(data = shading,
            aes(xmin = min, xmax = max, ymin = -Inf, ymax = Inf, alpha = 0.1),
                fill=shading$col) + # <-- here
  geom_bar(data = diamonds, mapping = aes(clarity, fill=cut)) +
  guides(alpha = FALSE)

- mathematical.coffee