Changing Plot Font with Cairo in R - r

Question

I have found R's default plots to be poorly aliased. As a solution, I set Cairo as the graphics device, and now the plots look much better.
Unfortunately, using Cairo has created another issue, which is that for some reason, I am not able to apply the font that I was using when the graph was displayed in the plot window (in the left-hand diagram above, Cambria is used, but the right-hand diagram fails to apply this font).
Here is my code:
library(readxl)
library(scales)
library(ggplot2)
library(dplyr)
library('Cairo')
windowsFonts(Cam = windowsFont("Cambria"))
dataset <- read_excel('CW Data.xlsx')
colnames(dataset)[4] <- "Broadband Subs (%)"
options(scipen = 1000)
# Scatter plot FDI~GDP with regression line
CairoWin()
ggplot(dataset, aes(x=`2019 GDP ($bn)`, y=`2019 FDI ($m)`)) +
geom_point(size=3, shape=1) +
geom_smooth(method='lm',formula=y~x, se=FALSE, color='black') +
scale_x_continuous(label = comma) + scale_y_continuous(label=comma) +
theme(panel.background = element_rect(fill="peachpuff"),
plot.background = element_rect(fill="peachpuff")) +
theme(panel.grid.major = element_line(colour = "gray72"),
panel.grid.minor = element_line(colour = "gray72")) +
theme(text = element_text(family = "Cam"))
ggsave("FDI~GDP.png", device="png", type = "cairo")
And here is a OneDrive link for the Excel data that I am using
https://1drv.ms/x/s!AvGKDeEV3LOs4gNr714Ie0KbOjhO?e=bkdPvk

Answer 1

I suggest you have a look at the packages ragg and systemfonts. They make working with fonts extremly easy and the results are better than the output of the base options.
First, I suggest you query all available fonts using View(systemfonts::system_fonts()). You can select every font present here and use it for plotting or saving a plot.
I recreated your plot using a built in dataset as the onedrive link you shared was broken. I used the Cambria font like this.
plot <- ggplot(dataset, aes(x = mpg, y = hp)) +
geom_point(size = 3, shape = 1) +
geom_smooth(
method = 'lm',
formula = y ~ x,
se = FALSE,
color = 'black'
) +
scale_x_continuous(label = comma) +
scale_y_continuous(label = comma) +
labs(x = "2019 GDP ($bn)", y = "2019 FDI ($m)") +
theme(
panel.background = element_rect(fill = "peachpuff"),
plot.background = element_rect(fill = "peachpuff")
) +
theme(
panel.grid.major = element_line(colour = "gray72"),
panel.grid.minor = element_line(colour = "gray72")
) +
theme(text = element_text(family = "Cambria")) # relevant line
I prefer saving the plot in an object and passing it explicitly to the save function.
ggsave(
"FDI~GDP.png",
plot = plot,
device = ragg::agg_png, # this is the relevant part
width = 1920,
height = 1080,
units = "px"
)
Here is the result:
I would say it worked flawlessly. You can also use ragg as your graphics device in RStudio to make this more consistent. Have a look here.
If you want to output the plot to a PDF, you can use showtext to register system fonts with all newly opening graphics devices. So what you need to do is:
library(showtext)
showtext_auto()
ggsave(
"FDI~GDP.pdf",
plot = plot,
width = 1920,
height = 1080,
units = "px"
)