为 geom_segment 添加图例条目

Question

在下面的图表中，我想在图例中为蓝色参考线添加一个项目，在本示例中，我们可以将其称为“任意线”。任何人都可以为我提供一个解决方案来将其纳入传说吗？请注意，最终的情节必须以情节形式呈现。

library(tidyverse)
library(plotly)

dat <- data.frame(peeps= c("Bill", "Bob", "Becky"),
                  vals = c(10, 15, 12),
                  label = c("8% Fake", "12% Pizza", "45% Becky"),
                  grp = c("Bears", "Bears", "Mongoose") %>% as.factor)
p1 <- dat %>% 
  ggplot(aes(x = peeps, y = vals, fill = grp)) +
  geom_bar(stat = "identity") +
  geom_segment(aes(x = 0.55, xend = 3.45, y = 5, yend = 5), color = "blue") +
  scale_y_continuous(expand = c(0, 0)) +
  coord_flip()

ggplotly(p1) %>% 
  layout(legend = list(orientation = "h",
                       xanchor = "center",
                       y = -0.15,
                       x = 0.5))

Answer 1

尝试添加：

scale_fill_manual(name = "", values="blue", label="Arbitrary Line")