小块饼图上的标签（ggplot）

我想用ggplot制作饼图

My data:

lab <- c("a", "b", "c", "d", "e", "f", "g", "h")
percentage <- c(50, 20, 10, 10, 2, 2,2,2)
df.prison <- data.frame(lab, percentage)
df.prison$crime <- factor(df.prison$lab, levels=rev(levels(df.prison$lab)))
labels.prison <- paste(lab, "-", percentage, "%", sep="")

Plot:

plot <- ggplot(data=df.prison, aes(x=factor(1), y=percentage, fill=factor(lab))) +
   geom_bar(width=1, stat="identity") +
   coord_polar(theta="y") +
   ylab("") +
   xlab("") +
   labs(fill="") +
   theme(axis.ticks = element_blank(), panel.grid  = element_blank(), axis.text = element_blank()) +
   geom_text(aes(y = percentage/2 + c(0, cumsum(percentage)[-length(percentage)]), label=labels.prison))
plot

我对这个情节有两个问题： 1.我不想有图例（因为标签很短（一个字母），我想把它们放在饼图上 2. 是否可以在图旁边放置小块（小于几个百分比）的标签，因为标签太大而无法放置在这个小块内。例如这里：

http://www.conceptdraw.com/How-To-Guide/picture/Pie-chart-Sector-weightings.png http://www.conceptdraw.com/How-To-Guide/picture/Pie-chart-Sector-weightings.png

感谢您的任何建议:)

legend.position = 'none'将删除图例。您可以通过调整标签来调整x值与映射geom_text.

library(ggplot2)

lab <- c("a", "b", "c", "d", "e", "f", "g", "h")
percentage <- c(50, 20, 10, 10, 2, 2, 2, 2)
df.prison <- data.frame(lab, percentage)
df.prison$crime <- factor(df.prison$lab, levels=rev(levels(df.prison$lab)))
labels.prison <- paste(lab, "-", percentage, "%", sep="")

ggplot(data=df.prison, aes(x=factor(1), y=percentage, fill=factor(lab))) +
   geom_bar(width=1, stat="identity") +
   coord_polar(theta="y") +
   ylab("") +
   xlab("") +
   labs(fill="") +
   theme(legend.position = "none",   ### Solution to part 1, no legend
         axis.ticks = element_blank(), 
         panel.grid = element_blank(), 
         axis.text  = element_blank()) +
   geom_text(aes(x = c(1, 1, 1, 1, 1.2, 1.3, 1.4, 1.5), # Solution for part 2,
                 y = percentage / 2 + c(0, cumsum(percentage)[-length(percentage)]), 
                 label=labels.prison))