甜甜圈图的ggplot标签放置

Question

我决定违背一般规则，制作一个甜甜圈图。情节本身很好（相当均匀），但我似乎无法将标签放在正确的位置。我敢打赌这是微不足道的，但我就是看不到它。

代码如下：

mdat <- data.frame(
      category = c("C", "E", "I", "L", "Mi", "Mo", 
      "O", "Q", "S", "V"), 
      ct = c(147, 275, 431, 967, 121, 105, 17, 186, 620, 42))

mdat$category <- factor(mdat$category, levels = mdat$category)

# Fractions
mdat$fraction <- mdat$ct / sum(mdat$ct)

# Cumulative fractions; this forms the top of each rectangle
mdat$ymax <- cumsum(mdat$fraction)

# This will the the bottom of the rectangle
mdat$ymin <- c(0, head(mdat$ymax, n = -1))

# Label position - this isn't right
mdat$labelPosition <- ((mdat$ymax + mdat$ymin) / 2) 

# Labels
mdat$label <- paste0(mdat$category, " Fraction: \n", 
      round(mdat$ct/sum(mdat$ct), 4) * 100, "%")

# Plot
g <- ggplot(mdat, aes(ymax = ymax, ymin = ymin, xmax = 11, xmin = 10, 
      fill = category))
g <- g + geom_rect()
g <- g + geom_label(x = 2, aes(y = labelPosition, label = label), size = 3)
g <- g + scale_fill_brewer(palette = "Set3")
g <- g + scale_color_brewer(palette = "Set3")
g <- g + coord_polar(theta = "y")
g <- g + xlim(c(7, 12))
g <- g + theme_void()
g <- g + theme(legend.position = "none")
g

这是代码生成的图：

它们可能会因部分轮换而关闭？我就是没看到。

谢谢。

Answer 1

圆环图只是极坐标中的堆积条形图。因此，如果您在 xlim() 的下边界下方的 geom_label() 内选择 x，则标签会漂移到绘图的另一侧。

   g <- ggplot(mdat, aes(ymax = ymax, ymin = ymin, xmax = 11, xmin = 10, 
                          fill = category))
    g <- g + geom_rect()
    g <- g + geom_label(x = 12.1, aes(y = labelPosition, label = label), size = 3)
    g <- g + scale_fill_brewer(palette = "Set3")
    g <- g + scale_color_brewer(palette = "Set3")
    g <- g + coord_polar(theta = "y")
    g <- g + xlim(c(7, 12))
    g <- g + theme_void()
    g <- g + theme(legend.position = "none")
    g

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