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r - ggplot geom_point 形状（和 pdf）中未显示 unicode 符号

问题描述

我正在尝试在 ggplot 中使用 unicode 符号作为 geom_point 形状。它主要按预期工作，但一个符号（▶，“\u25b6”）没有显示在 RStudio 图中，并且在 pdf 中没有任何符号显示。这是我的示例（数据显示听音乐期间的用户输入）：

library(tidyverse)
library(ggplot2)
library(Cairo)

event_levels <- c("open", "play", "q", "pause", "ff", "exit")
# 1st try: add the symbols directly
event_shapes1 <- c("⏏️", "▶&quot;, "❓&quot;, "⏸️", "⏩&quot;, "⏹️")
# 2nd try: add unicode
event_shapes2 <- c("\u23cf", "\u25b6", "\u2753", "\u23f8", "\u23e9", "\u23f9")
# 3rd try: add unicode with ucap letters
event_shapes3 <- c("\U23CF", "\U25B6", "\U2753", "\U23F8", "\U23E9", "\U23F9")
event_colours <- c("black", "green", "red", "orange", "blue", "black")

data <- tibble(event = factor(c("open", "play", "q", "play", "q", "play", "pause", "play", "ff", "exit"), levels = event_levels),
               time = seq(0, 100, length.out = length(event)),
               pos = c(0, 0, 50, 50, 100, 100, 150, 150, 200, 300))

p <- ggplot(data) +
  geom_line(mapping = aes(x = time, y = pos), alpha = 0.5) +
  geom_point(mapping = aes(x = time, y = pos, color = event, shape = event), size = 6) +
  scale_shape_manual(values = event_shapes2) + 
  # event_shapes1 doesn't work, no difference between event_shapes2 and event_shapes3
  scale_color_manual(values = event_colours)

ggsave("test.pdf", plot = p, device=cairo_pdf)

我可能做错了什么，或者可能是系统特定的故障（Win 10）。我尝试在-line （以及许多其他字体系列）中使用library(extrafont)and par(family = "Consolas")，但没有成功。symbolfamily="Consolas"ggsave

我还尝试使用以下符号打印符号geom_text并将符号添加到tibble如下所示：

data <- data %>%
  mutate(event_shape = case_when(
    event == "open" ~ "⏏️",
    event == "play"~ "▶&quot;,
    event == "q" ~ "❓&quot;,
    event == "pause" ~ "⏸️",
    event == "ff" ~ "⏩&quot;,
    event == "exit" ~ "⏹️",
  ), .after = event)

p <- ggplot(data) +
  geom_line(mapping = aes(x = time, y = pos), alpha = 0.5) +
  geom_text(mapping = aes(x = time, y = pos, label = event_shape), size = 6)

但仍然没有成功。我能做些什么？我不想每次都下载符号，也许我可以在本地将符号保存为 png 或 svg，然后将它们添加到图表中？或者可能是不那么复杂的东西？

标签： rggplot2cairo

解决方案

该emojifont软件包解决了这个问题。

这是一个例子：

library(emojifont)
library(ggplot2)
library(Cairo)

df <- data.frame(
  x=1,
  y=1,
  text="\u25b6"
)

p <- ggplot(df, aes(x=x,y=y, label=text)) +
  geom_text()
ggsave('test.pdf', p)

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