r - 如何将标签放在饼图之外？

Question

如何将标签放在饼图之外，以便标签位于正确的位置？

Product <- c("Product1","Product2","Product3","Product4","Product5","Product6","Product7")
Value <- c(1000000,200002,599996,1399994,2199992,2999990,3799988)
df <- data.frame(Product,Value)
df$Label <- paste(Product, paste(round(((df$Value/sum(df$Value))*100),2),"%"), sep="-")

library(ggplot2)

p <-  ggplot(df, aes(x = 1, y = Value, fill = Product)) + geom_bar(stat = "identity")
p <- p + coord_polar(theta = 'y') + theme_void()
p <- p + geom_text(aes(label = Label), position = position_stack(vjust = 0.5))

Answer 1

使用:

library(dplyr)
df <- df %>% 
  mutate(end = 2 * pi * cumsum(Value)/sum(Value),
         start = lag(end, default = 0),
         middle = 0.5 * (start + end),
         hjust = ifelse(middle > pi, 1, 0),
         vjust = ifelse(middle < pi/2 | middle > 3 * pi/2, 0, 1))

library(ggforce) # for 'geom_arc_bar'
ggplot(df) + 
  geom_arc_bar(aes(x0 = 0, y0 = 0, r0 = 0, r = 1,
                   start = start, end = end, fill = Product)) +
  geom_text(aes(x = 1.05 * sin(middle), y = 1.05 * cos(middle), label = Label,
                hjust = hjust, vjust = vjust)) +
  coord_fixed() +
  scale_x_continuous(limits = c(-1.5, 1.5),  # Adjust so labels are not cut off
                     name = "", breaks = NULL, labels = NULL) +
  scale_y_continuous(limits = c(-1, 1.1),    # Adjust so labels are not cut off
                     name = "", breaks = NULL, labels = NULL)

给出: