如何在ggplot中实现文本换行？大科技公司股价分面图优化

我参与了上周的TidyTuesday挑战，正在绘制大科技公司股价的分面图。部分公司名称过长（比如Cisco Systems, Inc.、Intel Corporation），希望对这些特定的公司名称文本进行换行处理。以下是我目前的代码：

library(tidyverse)
library(showtext)
library(patchwork)
library(janitor)
library(glue)
library(ggtext)
library(gghighlight)
library(lubridate)


font_add_google("Archivo", family = "title")
font_add_google("Nunito", family = "subtitle")
font_add_google("Martel", family = "axis")
font_add_google("Spartan", family = "caption")

font_add('fa-reg', 'fonts/Font Awesome 6 Free-Regular-400.otf')
font_add('fa-brands', 'fonts/Font Awesome 6 Brands-Regular-400.otf')
font_add('fa-solid', 'fonts/Font Awesome 6 Free-Solid-900.otf')

showtext_auto()
dat <- tidytuesdayR::tt_load(2023, week = 6)

big_tech_stock_prices <- dat$big_tech_stock_prices
big_tech_company_name <- dat$big_tech_companies


big_tech_stock_prices <- big_tech_stock_prices %>%
  left_join(big_tech_company_name, by = "stock_symbol") %>%
  mutate(company = case_when(company == "International Business Machines Corporation" ~ "IBM",
                             TRUE ~ company))


plot <- ggplot(big_tech_stock_prices, aes(x = date, y = close, group = company)) +
  geom_line() +
  gghighlight(company %in% c("Apple Inc.", "Adobe Inc.", "Amazon.com, Inc.", "Salesforce, Inc.", "Cisco Systems, Inc.",
                             "Alphabet Inc.", "IBM", "Intel Corporation", "Meta Platforms, Inc.", "Microsoft Corporation",
                             "Netflix, Inc.", "NVIDIA Corporation", "Oracle Corporation", "Tesla, Inc."),
              use_direct_label = FALSE,
              unhighlighted_params = list(linewidth = 0.1, colour = alpha("grey20", 0.3))) +
  geom_area(aes(date, close, colour = stock_symbol, fill = stock_symbol), big_tech_stock_prices, alpha = 0.2, size = 0.5) +
  geom_text(
            aes(x = lubridate::ymd("2014-01-01"), y = 500, label = company, color = company), size = 30) +
  facet_wrap(~company) +
  theme_minimal() +
  labs(title = "Stock Market Values for BigTech Companies (2010-2022)",
       subtitle = "The plot demonstrates the stock market value for 14 BigTech companies. Note that the values<br>displays the closed prices for each days",
       y = "US Dollar - $",
       x = "") +
  theme(legend.position = "none",
        strip.background = element_blank(),
        strip.text = element_blank(),
        axis.title.y = element_markdown(family = "axis", size = 55, linewidth = 0.2),
        axis.title.x = element_markdown(family = "axis", size = 55, linewidth = 0.2),
        axis.text.y = element_markdown(family = "axis", size = 35),
        axis.text.x = element_markdown(family = "axis", hjust = 0.43, size = 35),
        plot.title = element_markdown(family = "title", size = 95, hjust = 0.5, lineheight = 0.15, linewidth = 0.1),
        plot.subtitle = element_markdown(family = "subtitle", size = 75, hjust = 0.5, lineheight = 0.15, linewidth = 0.1),
        plot.caption = element_markdown(family = "title", size = 45, lineheight = 0.15, linewidth = 0.1, hjust = 0.5),
        plot.background = element_rect(fill = "white", color = "white"))


ggsave("deneme.png", height = 6,  width = 7.5, dpi = 720)

从图表可见，长名称的公司文本超出了分面区域，需要换行优化。

方法1：手动替换特定公司名称，添加换行符 #

在数据处理阶段，针对需要换行的公司名称插入\n换行符，同时调整文本对齐和行间距：

# 修改数据处理部分的mutate逻辑
big_tech_stock_prices <- big_tech_stock_prices %>%
  left_join(big_tech_company_name, by = "stock_symbol") %>%
  mutate(company = case_when(
    company == "International Business Machines Corporation" ~ "IBM",
    company == "Cisco Systems, Inc." ~ "Cisco Systems\nInc.",
    company == "Intel Corporation" ~ "Intel\nCorporation",
    company == "Microsoft Corporation" ~ "Microsoft\nCorporation",
    # 其他需要换行的公司可继续添加
    TRUE ~ company
  ))

# 修改geom_text的参数，优化换行后的显示
geom_text(
  aes(x = lubridate::ymd("2014-01-01"), y = 500, label = company, color = company),
  size = 30,
  hjust = 0.5,  # 居中对齐文本
  lineheight = 0.8  # 调整换行后的行间距
)

方法2：结合ggtext使用富文本换行（更灵活） #

利用已加载的ggtext包，用<br>标签实现换行，并替换geom_text为支持富文本的geom_richtext：

# 修改公司名称为带<br>的格式
big_tech_stock_prices <- big_tech_stock_prices %>%
  left_join(big_tech_company_name, by = "stock_symbol") %>%
  mutate(company = case_when(
    company == "International Business Machines Corporation" ~ "IBM",
    company == "Cisco Systems, Inc." ~ "Cisco Systems<br>Inc.",
    company == "Intel Corporation" ~ "Intel<br>Corporation",
    TRUE ~ company
  ))

# 替换geom_text为geom_richtext，去掉背景和边框保持原风格
geom_richtext(
  aes(x = lubridate::ymd("2014-01-01"), y = 500, label = company, color = company),
  size = 30,
  hjust = 0.5,
  fill = NA,  # 移除背景色
  label.color = NA,  # 移除边框
  lineheight = 0.8
)

方法3：自动批量处理长文本（可选） #

如果有大量长名称，可使用stringr的str_wrap函数自动按指定宽度换行：

library(stringr)

big_tech_stock_prices <- big_tech_stock_prices %>%
  left_join(big_tech_company_name, by = "stock_symbol") %>%
  mutate(company = case_when(
    company == "International Business Machines Corporation" ~ "IBM",
    str_length(company) > 15 ~ str_wrap(company, width = 12),  # 长度超过15的自动换行
    TRUE ~ company
  ))

内容的提问来源于stack exchange，提问作者mzkrc