如何独立更改图例中的颜色线大小和形状大小？

我有一个线图，将颜色和形状组合到同一个图例中。我希望图例中的点尺寸更大，图例中的线条保持不变，以便形状更清晰。

From 如何增加ggplot2图例中点的大小？ https://stackoverflow.com/questions/20415963/how-to-increase-the-size-of-points-in-legend-of-ggplot2据我所知，点的大小可以改变+ guides(colour = guide_legend(override.aes = list(size=10)))，但这也会改变线的大小。如果我添加guides(shape = guide_legend(override.aes = list(size=4)),color = guide_legend(override.aes = list(size=1)))它说“重复的 override.aes 被忽略，仅使用第二个大小。

如何独立更改图例中的颜色线大小和形状大小？

示例代码：

example <- data.frame(a=c(1,2,3,1,2,3), b=c(0.1,0.2,0.3,0.4,0.5,0.6), c=c('a','a','a','b','b','b'))

ggplot(example, aes(x=a, y=b, color=c, shape=c))+
  geom_line()+
  geom_point()+
  scale_colour_manual(name="title", breaks=c("a","b"),
                      labels=c("label1","label2"),
                      values=c("#e41a1c", "#377eb8"))+
  scale_shape_manual(name="title", breaks=c("a","b"),
                     labels=c("label1","label2"),
                     values=c(15, 16))+
  guides(shape = guide_legend(override.aes = list(size=4)),
         color = guide_legend(override.aes = list(size=1)))

示例图 https://i.stack.imgur.com/1TJPn.jpg

The layer()ggplot 在底层使用的函数有一个key_glyph您可以为其提供自定义函数的参数。您可以使用它来使点变大，但不能使线变大。如果需要自定义线路调整，可以写一个类似的函数包装draw_key_path().

library(ggplot2)

example <- data.frame(a=c(1,2,3,1,2,3), b=c(0.1,0.2,0.3,0.4,0.5,0.6), c=c('a','a','a','b','b','b'))

large_points <- function(data, params, size) {
  # Multiply by some number
  data$size <- data$size * 2
  draw_key_point(data = data, params = params, size = size)
}

ggplot(example, aes(x=a, y=b, color=c, shape=c))+
  geom_line()+
  geom_point(key_glyph = large_points)+
  scale_colour_manual(name="title", breaks=c("a","b"),
                      labels=c("label1","label2"),
                      values=c("#e41a1c", "#377eb8"))+
  scale_shape_manual(name="title", breaks=c("a","b"),
                     labels=c("label1","label2"),
                     values=c(15, 16))

^{Created on 2020-04-08 by the reprex package https://reprex.tidyverse.org (v0.3.0)}