当我在ggplot中将字体更改为LM Roman 10时，它会使破折号与字母发生冲突。如何在仍使用此字体的情况下解决此问题？

---
title: "Untitled"
output: pdf_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(
  echo = FALSE, 
  message=FALSE, 
  warning=FALSE
)
library(ggplot2)
library(extrafont)

df <- data.frame(
   x = c(1, 1, 2, 2, 1.5),
   y = c(1, 2, 1, 2, 1.5),
   text = c("bottom-left", "top-left", "bottom-right", "top-right", "label-with-dash")
)

ggplot(df, aes(x, y)) +
geom_text(aes(label = text))

ggplot(df, aes(x, y)) +
geom_text(aes(label = text), family="LM Roman 10") 

下面是上面代码的结果：

![](https://i.stack.imgur.com/Jbad1.png)