geom_rect和圖例，顯示矩形的寬度

Question

這是一個非常簡單的腳本

library(ggplot2)

df <- data.frame(xmin = c(1, 2.5, 3), xmax = c(2, 3.5, 5), ymin=c(1,1.5, 3), ymax = c(2,2.5,4), size = c(1,1,2), fill = c("red", "orange", "blue"))

p <- ggplot()
p <- p + geom_rect(data = df, aes(xmin = xmin, xmax = xmax, ymin = ymin, ymax = ymax, size = factor(size), fill = fill))
p <- p + scale_size_manual(values = c(1,2), guide = guide_legend(keywidth = 4, override.aes = list(colour = "black")))

p

該腳本創建以下圖表...

我要實現的目標是添加一個可反映矩形寬度的圖例（指南）！ 僅2條簡單的行作為“ legend key”，而鍵的寬度為1或2。

我被卡住了，所以任何提示都值得贊賞

Answer 1

由於您指定的是xmin / xmax和ymin / ymax，因此我不認為size參數在這里有任何作用

my_dat <- data.frame(xmin = c(1, 2.5, 3), xmax = c(2, 3.5, 5), 
                     ymin=c(1,1.5, 3), ymax = c(2,2.5,4), 
                     size = c(1,1,2), fill = c("red", "orange", "blue"))

# size doesn't do anything for geom_rect. compare this...
ggplot(my_dat) +
  geom_rect(aes(xmin = xmin, xmax = xmax, ymin = ymin, ymax = ymax, 
                size = factor(size), fill = fill))

# ...and this. same!
ggplot(my_dat) +
  geom_rect(aes(xmin = xmin, xmax = xmax, ymin = ymin, ymax = ymax, 
                fill = fill))

# try geom_linerange

ggplot(my_dat) +
  geom_linerange(aes(x=(xmin+xmax)/2, ymin=ymin, ymax=ymax, color=fill, 
                     size=factor(size))) +
  scale_size_manual(values=c(20, 50)) +
  xlim(1, 5)

經過編輯，使結果更接近原始圖，盡管這有點古怪。

並且如果添加+ theme(legend.direction = 'horizontal') ：