ggplot2：降低色相，以可视化因子变量

问题描述

我正在尝试可视化某些东西，目前看起来与此类似：

library(ggplot2)
library(ggpubr)
head(ToothGrowth)
ToothGrowth$dose <- as.factor(ToothGrowth$dose)

# what I got:
p <- ggpaired(ToothGrowth,x="supp",y="len",fill="dose",line.color = "gray",line.size = 0.4)+
  scale_fill_manual(name="Dosis",labels=c("0.5","1","2"),values = c("darkorange2","olivedrab","cadetblue4"))+ # <= these colours are fixed as used in all other graphs already
  facet_grid(~dose)+
  stat_compare_means(method = "t.test",paired = TRUE)
p

现在，我希望根据状态（变量'supp'），相同颜色的两个盒子的色调有所不同；例如与VC相比，OJ总是显得褪色。我知道调色板等等有很多选择，但是不幸的是，配色方案是固定的，因为它是在所有其他图中设置的，并与合著者共享以进行一致的设计。

# what I tried so far:
p1 <- p +
  scale_alpha(name="supp",labels=c("OJ","VC"),range = c(0.5,1))
p1  # doesn't change anything

p2 <- p +
  scale_fill_hue(name="supp",h.start = c(0.5))
p2  # overwrites existing scale_fill (and does not do a hue)

p3 <- ggpaired(ToothGrowth,hue="supp","cadetblue4"))+
  facet_grid(~dose)+
  stat_compare_means(method = "t.test",paired = TRUE)
p3  # 'hue =' doesn't change anything

p4 <- ggpaired(ToothGrowth,alpha="supp",paired = TRUE)
p4  # 'alpha =' doesn't change anything

此外，通常我会在普通的“ ggplot”命令中执行所有操作，但是由于需要这种成对比较，因此我认为我会陷入“ ggpaired”状态；还是我不？

有人对此有什么好主意吗？预先感谢！

解决方法

您可以在ggplot中本地完成全部操作，只需要很多代码。您可以这样做：

ggplot(ToothGrowth,aes(supp,len,fill = dose,alpha = supp)) +
  geom_boxplot() +
  scale_fill_manual(name   = "Dosis",labels = c("0.5","1","2"),values = c("darkorange2","olivedrab","cadetblue4")) +
  scale_alpha_discrete(range = c(0.5,1),guide = guide_none()) +
  geom_line(inherit.aes = FALSE,group = 0:59 %% 30),color = "gray75") +
  geom_text(data = data.frame(
              x    = 1.5,y    = 40,dose = c("0.5",pval = sapply(c("0.5",function(x) {
                       round(t.test(len ~ supp,data = ToothGrowth[ToothGrowth$dose == x,],paired = TRUE)$p.val,4)})),inherit.aes = FALSE,aes(x = 1.5,y = 40,label = paste("T test: p value =",pval)),check_overlap = TRUE) +
  facet_grid(~dose) +
  theme_classic() +
  theme(legend.position = "top",strip.background = element_rect(fill = "gray95",size = 0.25))

ggplot2 r r