ggplot如何根据变量类型为geom_text设置不同位置对齐方式

实现方法 #

你可以通过将对齐参数映射到类别变量的方式，为不同类别的标签单独设置对齐规则，无需拆分图层，修改逻辑如下：

• 你绘制的是水平堆叠条形图，文本水平方向对齐使用hjust参数（垂直对齐才用vjust，注意不要混淆）
• 在geom_text的美学映射里新增hjust = variable，将对齐规则和变量类别绑定
• 新增scale_hjust_manual()指定每个类别对应的对齐值即可

修改后的完整代码：

(empilhado<-ggplot(dfm, aes(y = Year, x = abs(value), fill = variable)) + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~.*1, name="Trab."), expand=expansion(mult=c(0,0.05)))+
  geom_col(data = rotulo, aes(y = Year, x=abs(trabalho), fill=NULL), width = .7, colour="black", lwd=0.1, position = "fill", orientation = "y") +
  geom_label(data = rotulo, aes(y= Year, x = abs(trabalho), fill=NULL, label=paste(format(round(trabalho, digits=0), nsmall=0, decimal.mark=",", big.mark="."), format(round(aprovado, digits=0), nsmall=0, decimal.mark=",", big.mark="."))), color="black", size=4, position = position_fill(vjust=1.06)) +
  geom_col(width = .7, colour="black", lwd=0.1, position = "fill", orientation = "y") +
  # 新增hjust映射到variable变量
  geom_text(aes(label=format(round(value, digits=0), nsmall=0, decimal.mark=",", big.mark="."), hjust = variable), size=4, color="white", position = position_fill(vjust=0.5)) +
  theme(panel.grid.major = element_line(colour = "gray90",size=0.75), panel.grid.minor = element_line(colour = "gray90",size=0.75), legend.position="top", axis.text.x = element_blank(), axis.ticks.x = element_blank(), axis.title.x = element_blank(), panel.background = element_blank())+
  scale_fill_manual(values = c("#000000","tomato","blue")) +
  # 按类别指定对齐值，注意键名要和数据中variable的实际取值完全一致
  scale_hjust_manual(values = c("Marionete" = 0, "Pedido" = 0.5, "Fatura" = 1))
)

如果最终效果里标签太贴近条形块边缘，可以微调对应数值，比如把Marionete的hjust改成0.1，Fatura的改成0.9，避免文字超出块的显示范围。

内容的提问来源于stack exchange，提问作者Diogo Tasquin Reducino