如何在Quarto RevealJS演示文稿中移除ggplot2图表边框？

问题描述 #

使用Quarto制作RevealJS演示文稿时，ggplot2生成的图表（第2页）周围出现黑色边框，需移除该边框。可复现代码如下：

Quarto演示文稿代码 #

---
title: "Test Presentation"
format: 
  revealjs:
    theme: [default, custom.scss]
---

## Some plot

```{r}
library(ggplot2)

ggplot(mtcars) +
  geom_boxplot(aes(as.factor(cyl), disp, fill = cyl)) +
  theme_minimal() +
  theme(
      legend.position = "none",
      panel.grid = element_blank(),
      axis.title = element_text(size = 20, color = "#fefefe"),
      axis.text = element_text(size = 15, color = "#fefefe"),
      plot.title = element_text(size = 20, color = "#fefefe"),
      plot.background = element_rect(fill = "#505050"),
      panel.background = element_rect(fill = "#505050"),
      axis.line.x.top = element_line(color = "#fefefe"),
      axis.line.x.bottom = element_line(color = "#fefefe"),
      axis.line.y.left = element_line(color = "#fefefe"),
      axis.line.y.right = element_line(color = "#fefefe")
    ) +
    guides(x.sec = "axis", y.sec = "axis")

### 自定义SCSS代码
```scss
/*-- scss:defaults --*/

// fonts
$font-family-sans-serif: "Palatino Linotype", "Book Antiqua", Palatino,
  FreeSerif, serif !default;

// colors
$body-bg: #505050;
$body-color: #ffffff;
$link-color: #51483d !default;
$selection-bg: #26351c !default;

// headings
$presentation-heading-font: "Palatino Linotype", "Book Antiqua", Palatino,
  FreeSerif, serif !default;
$presentation-heading-color: #ffffff !default;

/*-- scss:rules --*/

.reveal a {
  line-height: 1.3em;
}

解决方案 #

黑色边框通常来自两个地方：ggplot图表自身的边框，或是RevealJS为图片容器添加的默认边框。以下两种方法可解决问题：

方法1：修改ggplot2主题设置 #

在theme()函数中添加plot.border = element_blank()，直接移除图表自身的边框：

ggplot(mtcars) +
  geom_boxplot(aes(as.factor(cyl), disp, fill = cyl)) +
  theme_minimal() +
  theme(
      legend.position = "none",
      panel.grid = element_blank(),
      axis.title = element_text(size = 20, color = "#fefefe"),
      axis.text = element_text(size = 15, color = "#fefefe"),
      plot.title = element_text(size = 20, color = "#fefefe"),
      plot.background = element_rect(fill = "#505050"),
      panel.background = element_rect(fill = "#505050"),
      axis.line.x.top = element_line(color = "#fefefe"),
      axis.line.x.bottom = element_line(color = "#fefefe"),
      axis.line.y.left = element_line(color = "#fefefe"),
      axis.line.y.right = element_line(color = "#fefefe"),
      plot.border = element_blank()  # 新增该行移除图表边框
    ) +
    guides(x.sec = "axis", y.sec = "axis")

方法2：修改自定义SCSS样式 #

如果边框来自RevealJS的图片容器，在custom.scss的scss:rules区块中添加样式，移除图片的边框和阴影：

/*-- scss:rules --*/

.reveal a {
  line-height: 1.3em;
}

// 移除所有演示文稿图片的边框与阴影
.reveal section img {
  border: none !important;
  box-shadow: none !important;
}

若仅需针对ggplot生成的图表修改，可给代码块添加自定义类名后设置针对性样式，但全局移除的方式更简洁高效。

内容的提问来源于stack exchange，提问作者Shubham