ggplot2中柱形图标签字体未生效，轴标签正常的解决方法

问题分析 #

你通过theme_bw(base_family = "LM Roman 10")设置了全局主题字体，但柱形上方的geom_text标签仍使用默认字体，核心原因是geom_text作为独立的几何图层，默认不会自动继承主题的base_family参数，需要单独指定或全局配置默认值。

另外要确保extrafont的字体加载流程正确，否则即使指定字体也可能不生效：

• 首次使用extrafont时需运行font_import()（仅需执行一次，耗时较长）
• 每次R会话启动时运行loadfonts()加载字体

解决方案 #

方法1：直接在geom_text中指定字体 #

修改geom_text代码，添加family = "LM Roman 10"参数，与主题字体保持一致：

ggplot(data, aes(x = Year, y = Value)) +
  geom_col(fill = "#7f7f7f", width = 0.5) +
  geom_text(aes(label = format(Value, big.mark = '.', scientific = FALSE)),
            position = position_dodge(width = 0.9), size = 3.5, 
            colour = 'black', vjust = -0.5, family = "LM Roman 10") +
  scale_y_continuous(limits = c(0, 10000), labels = scales::comma_format(big.mark = '.')) +
  scale_x_continuous(name = "Year", limits = c(2009.5, 2021.5), breaks = seq(2010, 2021, by = 1)) +
  labs(x = NULL, y = "Number of Units", title = NULL) +
  theme_bw(base_size = 14, base_family = "LM Roman 10") +
  theme(legend.position = "none", panel.grid = element_blank())

方法2：全局设置geom_text默认字体 #

如果需要多个图表统一geom_text的字体，可在代码开头用update_geom_defaults()设置全局默认值，后续所有geom_text都会自动使用该字体：

# 全局配置geom_text的默认字体
update_geom_defaults("text", list(family = "LM Roman 10"))

# 正常绘制图表，无需再给geom_text单独指定family参数
ggplot(data, aes(x = Year, y = Value)) +
  geom_col(fill = "#7f7f7f", width = 0.5) +
  geom_text(aes(label = format(Value, big.mark = '.', scientific = FALSE)),
            position = position_dodge(width = 0.9), size = 3.5, 
            colour = 'black', vjust = -0.5) +
  scale_y_continuous(limits = c(0, 10000), labels = scales::comma_format(big.mark = '.')) +
  scale_x_continuous(name = "Year", limits = c(2009.5, 2021.5), breaks = seq(2010, 2021, by = 1)) +
  labs(x = NULL, y = "Number of Units", title = NULL) +
  theme_bw(base_size = 14, base_family = "LM Roman 10") +
  theme(legend.position = "none", panel.grid = element_blank())

验证注意事项 #

• 若使用RStudio，有时需重启R会话或重新加载字体才能看到效果
• 可通过fonts()命令查看extrafont已加载的字体列表，确认"LM Roman 10"在列表中

内容的提问来源于stack exchange，提问作者pbraeutigm