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r - R使用scale_linetype_manual在ggplot图例中旋转vline

问题描述

我有以下简单的 MWE。我希望我的图例中的绿线是一条垂直线。一旦我在 geom_vline 中启用 show.legend，它还会在图例中的每一行添加一条垂直线。有没有人暗示我如何做到这一点？

library(ggplot2)
ggplot(data = df) +
  geom_line(aes(x = a, y = b, colour = "one", linetype = "one"), size = 2) +
  geom_line(aes(x = a, y = c, colour = "two", linetype = "two"), size = 2) +
  geom_vline(aes(xintercept = 0.5, colour = "three", linetype = "three"), alpha = 1, show.legend = F) +
  scale_colour_manual("",
                      breaks = c("one", "two", "three"),
                      values = c("blue", "red", "green")) +
  scale_linetype_manual("",
                        breaks = c("one", "two", "three"),
                        values = c("dashed", "solid", "solid")) +
  theme_bw() +
  theme(legend.key.size = unit(2, "cm"),
        legend.position = c(0.05, 0.995), legend.justification = c(0.05, 0.995))

在此处输入图像描述

标签： rggplot2

解决方案

调整此答案以实现您想要的结果的一个选项是使用自定义键字形功能。这种方法的一个缺点是它会根据线的条件在color水平线或垂直线之间进行选择，也就是说，如果您更改颜色，您也必须调整条件。

编辑要在图例中获得正确的线条大小，有两个选项。一种是在自定义键字形函数中设置大小。第二种选择是通过using的override.aes参数设置大小guide_legendguides(linetype = guide_legend(override.aes = list(size = c(2, 2, .5))))

library(ggplot2)

# Custom Key Glyph. Vertical Line if color = "green". Horizontal Line otherwise
draw_key_cust <- function(data, params, size) {
  if (data$colour == "green") {
    data$size <- .5
    draw_key_vpath(data, params, size)
  } else {
    data$size <- 2
    draw_key_path(data, params, size)
  }
}

ggplot(data = df) +
  geom_line(aes(x = a, y = b, colour = "one", linetype = "one"), size = 2, key_glyph = "cust") +
  geom_line(aes(x = a, y = c, colour = "two", linetype = "two"), size = 2, key_glyph = "cust") +
  geom_vline(aes(xintercept = 0.5, colour = "three", linetype = "three"), alpha = 1, key_glyph = "cust") +
  scale_colour_manual(breaks = c("one", "two", "three"),
                      values = c("blue", "red", "green")) +
  scale_linetype_manual(breaks = c("one", "two", "three"),
                        values = c("dashed", "solid", "solid")) +
  labs(color = NULL, linetype = NULL) +
  theme_bw() +
  theme(legend.key.size = unit(2, "cm"),
        legend.position = c(0.05, 0.995), 
        legend.justification = c(0.05, 0.995))

数据

set.seed(42)
df <- data.frame(
  a = runif(100),
  b = runif(100),
  c = runif(100)
)

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