我正试图在ggplot中使用unicode符号作为geom_point形状。它基本上按预期工作，但有一个符号(▶, "\u25b6"(没有显示在RStudio图中，在pdf中也没有显示任何符号。下面是我的例子(数据显示用户在听音乐时的输入(：
library(tidyverse)
library(ggplot2)
library(Cairo)
event_levels <- c("open", "play", "q", "pause", "ff", "exit")
# 1st try: add the symbols directly
event_shapes1 <- c("⏏️", "▶", "❓", "⏸️", "⏩", "⏹️")
# 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，也可能是系统特定的故障(Win 10(。我尝试在ggsave行(以及许多其他字体系列(中使用library(extrafont)、par(family = "Consolas")和symbolfamily="Consolas"，但没有成功。
我还尝试用geom_text打印符号，并将符号添加到tibble中，如下所示：
data <- data %>%
mutate(event_shape = case_when(
event == "open" ~ "⏏️",
event == "play"~ "▶",
event == "q" ~ "❓",
event == "pause" ~ "⏸️",
event == "ff" ~ "⏩",
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形中？或者是不那么复杂的东西？
emojifont包修复了此问题。
这里有一个例子：
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)