启用showtext后ggplot2表情符号渲染失效的解决办法咨询

在ggplot中直接使用geom_text渲染表情符号（如✅、❌）可正常显示，但启用showtext::showtext_auto()后，表情符号的原生渲染会被破坏，无法正常显示。以下是几种可行的解决思路：

• 针对表情符号单独指定系统原生字体
  showtext会覆盖默认字体渲染逻辑，我们可以为表情符号单独指定支持emoji的系统字体（Windows用"Segoe UI Emoji"，macOS用"Apple Color Emoji"，Linux用"Noto Color Emoji"）。修改代码示例：

  library(ggplot2)
  library(dplyr)
  library(showtext)
  
  # 添加自定义字体（替换为你的字体路径）
  font_add(family = "fa", regular = "path/to/your/font.ttf")
  showtext_auto(enable = TRUE)
  
  df <- cars |>
    mutate(
      glyph = case_when(speed > 16 ~ "✅",
                        .default = "❌"),
      color = case_when(speed > 16 ~ "red",
                        .default = "green")
    )
  
  ggplot() +
    geom_text(
      data = df,
      aes(x = speed, y = dist, label = glyph, colour = color),
      size = 5,
      # 根据系统自动选择emoji支持字体
      family = case_when(
        Sys.info()[["sysname"]] == "Windows" ~ "Segoe UI Emoji",
        Sys.info()[["sysname"]] == "Darwin" ~ "Apple Color Emoji",
        TRUE ~ "Noto Color Emoji"
      )
    )
  

• 分开渲染文本与表情符号
  用两个geom_text层，一层处理自定义字体的文本，另一层专门渲染表情符号（临时关闭showtext避免干扰）：

  library(ggplot2)
  library(dplyr)
  library(showtext)
  
  font_add(family = "fa", regular = "path/to/your/font.ttf")
  showtext_auto(enable = TRUE)
  
  df <- cars |>
    mutate(
      glyph = case_when(speed > 16 ~ "✅",
                        .default = "❌"),
      label = case_when(speed > 16 ~ "Fast",
                        .default = "Slow"),
      color = case_when(speed > 16 ~ "red",
                        .default = "green")
    )
  
  ggplot() +
    # 渲染自定义字体的文本
    geom_text(
      data = df,
      aes(x = speed, y = dist + 5, label = label, colour = color),
      size = 3, family = "fa"
    ) +
    # 临时关闭showtext渲染表情符号
    {
      showtext_auto(FALSE)
      geom_text(
        data = df,
        aes(x = speed, y = dist, label = glyph, colour = color),
        size = 5
      )
    } +
    # 重新启用showtext
    {showtext_auto(TRUE)}
  

• 使用emojifont包替代原生表情符号
  emojifont包专门支持R环境中的表情符号渲染，配合showtext可避免字体冲突：

  library(emojifont)
  library(ggplot2)
  library(dplyr)
  library(showtext)
  
  font_add(family = "fa", regular = "path/to/your/font.ttf")
  # 添加emoji字体（需提前下载对应字体文件）
  font_add("EmojiOne", "EmojiOneColor-SVGinOT-2.2.7.ttf")
  showtext_auto(enable = TRUE)
  
  df <- cars |>
    mutate(
      # 使用emojifont提供的表情符号
      glyph = case_when(speed > 16 ~ emoji("check"),
                        .default = emoji("x")),
      color = case_when(speed > 16 ~ "red",
                        .default = "green")
    )
  
  ggplot() +
    geom_text(
      data = df,
      aes(x = speed, y = dist, label = glyph, colour = color),
      size = 5, family = "EmojiOne"
    )
  

内容的提问来源于stack exchange，提问作者rsh52