r - 如何在绘图标题或标签中的文本下划线？

Question

我似乎不知道如何在情节标题的任何部分下划线。

我能找到的最好的是 annotate("segment") done by hand ，并且我创建了一个玩具图来说明其方法。

df <- data.frame(x = 1:10, y = 1:10)

rngx <- 0.5 * range(df$x)[2]  # store mid-point of plot based on x-axis value
rngy <- 0.5 * range(df$y)[2]  # stores mid-point of y-axis for use in ggplot

ggplot(df, aes(x = x, y = y)) + 
  geom_point() +
  ggtitle("Oh how I wish for ..." ) +
  ggplot2::annotate("text", x = rngx, y = max(df$y) + 1, label = "underlining!", color = "red") +
  # create underline:
  ggplot2::annotate("segment", x = rngx-0.8, xend = rngx + 0.8, y= 10.1, yend=10.1)

uses bquote(underline() with base R

pertains to lines over and under nodes on a graph

uses plotmath and offers a workaround, but it didn't help

Answer 1

试试这个:

ggplot(df, aes(x = x, y = y)) + geom_point() +
  ggtitle(expression(paste("Oh how I wish for ", underline(underlining))))

或者，正如 BondedDust 在评论中指出的那样，您可以完全避免 paste() 调用，但要注意 for:

ggplot(df, aes(x = x, y = y)) + geom_point() +
  ggtitle(expression(Oh~how~I~wish~'for'~underline(underlining)))

或者巴蒂斯特建议的另一种更短的方法，不使用表达式、paste()或许多波浪号:

ggplot(df, aes(x = x, y = y)) + geom_point() +
  ggtitle(~"Oh how I wish for "*underline(underlining))