使用可选箭头创建最佳饼图布局

Question

我只是想知道为饼图创建适当布局的一种想法。看看下面的代码：

library(ggplot2)


pie_chart=function(vec){
  if (class(vec)=='numeric'){vec<-as.character(vec)
  vec<-print(paste('var',vec))
  }
  #creating data frame : variables and number of their occurrences
  df<-data.frame(table(vec))
  colnames(df)[1]<-'group'
  #creating bar plot first
  bp<- ggplot(df, aes(x="", y=Freq, fill=group))+
    geom_bar(width = 1, stat = "identity")
  blank_theme <- theme_minimal()+
    theme(
      axis.title.x = element_blank(),
      axis.title.y = element_blank(),
      panel.border = element_blank(),
      panel.grid=element_blank(),
      axis.ticks = element_blank(),
      plot.title=element_text(size=14, face="bold")
    )
  #adding polar coordinates to make a circle
  pie <- bp + coord_polar("y", start=0)
  pie + scale_fill_brewer("Characteristic") + blank_theme +
    theme(axis.text.x=element_blank())+
    geom_text(aes(y = rev(Freq)/2 + c(0, cumsum(rev(Freq))[-length(Freq)]),
                  label = print(paste0(rev(Freq),'(',percent(rev(Freq)/(sum(Freq))),')'))), size=5)
  
}



pie_chart(c(rep(1,40),rep(2,30),rep(3,90),rep(8,2)))

如您所见，上面的数字“2(1.2%)”被其他数字所支配，这对我们的饼图有明显的不良影响。我想改变我的功能，如果某个值小于所有饼图的 5%，则该值应该在饼图之外，箭头指向饼图的适当部分，其他值不变（在饼图内）。

所以在我们的例子中，'2(1.2%)' 不应该在馅饼中，而是在馅饼之外，箭头指向馅饼的上侧。你知道怎么做吗？

提前致谢！

Answer 1

这是一种解决方案，通过使用 scales::oob_keep() 并关闭坐标裁剪，将文本标签置于 x-axis 限制之外。您可以使用 arrow() 函数控制箭头的外观。

library(ggplot2)
library(scales)

pie_chart=function(vec){
  if (class(vec)=='numeric'){vec<-as.character(vec)
  vec<-print(paste('var',vec))
  }
  #creating data frame : variables and number of their occurrences
  df<-data.frame(table(vec))
  colnames(df)[1]<-'group'
  #creating bar plot first
  bp<- ggplot(df, aes(x=1, y=Freq, fill=group))+
    geom_bar(width = 1, stat = "identity")
  blank_theme <- theme_minimal()+
    theme(
      axis.title.x = element_blank(),
      axis.title.y = element_blank(),
      panel.border = element_blank(),
      panel.grid=element_blank(),
      axis.ticks = element_blank(),
      axis.text = element_blank(),
      plot.title=element_text(size=14, face="bold")
    )
  #adding polar coordinates to make a circle
  pie <- bp + coord_polar("y", start=0, clip = "off")
  pie + scale_fill_brewer("Characteristic") + blank_theme +
    theme(axis.text.x=element_blank())+
    geom_text(aes(y = rev(Freq)/2 + c(0, cumsum(rev(Freq))[-length(Freq)]),
                  label = print(paste0(rev(Freq),'(',percent(rev(Freq)/(sum(Freq))),')')),
                  x = ifelse(rev(Freq) / sum(Freq) < 0.05, 1.7, 1)), 
              size=5) +
    geom_segment(aes(x = 1.6, xend = 1.5, 
                     y = rev(Freq)/2 + c(0, cumsum(rev(Freq))[-length(Freq)]),
                     yend = after_stat(y),
                     colour = I(ifelse(rev(Freq) / sum(Freq) < 0.05, "black", "transparent"))),
                 arrow = arrow(length = unit(1, "mm"))) +
    scale_x_continuous(limits = c(0.5, 1.5), oob = scales::oob_keep)
  
}

pie_chart(c(rep(1,40),rep(2,30),rep(3,90),rep(8,2)))

^{由 reprex package (v0.3.0)}

于 2020-08-11 创建

使用可选箭头创建最佳饼图布局

Creating best pie chart layout using optional arrows

visualization

r

ggplot2

pie-chart