Introduction

Fonts are one of the most important aspects of a good visualization. Choosing the right font can make a huge difference in the readability and overall quality of a chart. showtext and ragg are two R packages that help to work with custom fonts in R and ggplot2.

• showtext provides a set of functions that make it easy to use various types of fonts in R plots
• ragg provides graphic devices based on the AGG library, which gives direct access to all system fonts, making the usage of custom fonts painless and easy.

The following two fonts are going to be used in along this post:

• Hydrophilia Iced from Floodfonts. Here you can download a zipped folder that contains the font as both .otf and .ttf types.
• Special Elite from Google Fonts here.

Custom fonts with showtext

The easiest way to add a custom font is to use font_add_google(). This function will search the Google Fonts repository for a specified family name, download the proper font files, and then add them to sysfonts (an auxiliar package that makes showtext work). See how simple it is in practice:

library(showtext)
font_add_google("Special Elite", family = "special")

The second argument, family, is optional. It gives the family name of the font that will be used in R. In other words, it means that the name used to refer to the font in R does not need to be the same than the original name of the font. In this case, the font Special Elite is going to be the special family.

note: if the font wanted is not available on Google Fonts, one can use font_add(). The first argument is like the family above, and the second argument is a path to the font file for the font face (both .ttf and .otf work). Not that you have to download the font locally and update the path below

font_add("hydrophilia", "~/Downloads/Hydrophilia/HydrophiliaIced-Regular.ttf")

And last but not least, showtext_auto() must be called to indicate that showtext is going to be automatically invoked to draw text whenever a plot is created.

showtext_auto()

Now it’s a good time to make a plot to showcase the fonts just imported and see how they look like.

library(ggplot2)

data <- data.frame(x = 1:4, y = 1:4)

ggplot(data) +
  geom_point(aes(x, y), size = 10, color = "cadetblue4") +
  geom_label(
    aes(x, y), 
    data = data.frame(x = 3, y = 2), 
    label = "This is Hydrophilia Iced!",
    family = "hydrophilia", # Use Hydrophilia Iced for the label,
    size = 7
  ) + 
  labs(
    x = "Horizontal Label",
    y = "Vertical label too!",
    title = "Do you like titles with nice-looking fonts?"
  ) +
  theme(
    # Special Elite for both axis title and plot title
    axis.title = element_text(family = "special"),
    title = element_text(family = "special")
  )

Cool! That worked pretty well!

However, it’s good to note some caveats with showtext before jumping to the next section:

• If you are using showtext in a common R script, set dpi according to the device you use to export your figure via showtext_opts(dpi = dpi). For example if you use ggsave(), then you need to set up a dpi of 300.
• If you are using showtext in RMarkdown documents you don’t have to use showtext_auto(). That will set up the wrong dpi and the text will look too small. You need to add fig.showtext=TRUE to the chunk settings as shown here.
• For more information about these issues see here.

Custom fonts with ragg

This solution provided in this section is quite different from the solution above. Instead of using a library to install and manage fonts that are accesible by R, this solution is based on using a different graphic device provided by ragg.

Among other very nice features, using ragg gives access to all system fonts, which means that custom fonts can be used without having to install other package in R.

Assuming RStudio is used to work with R, ragg can be set up as the graphic back-end to the Rstudio device (for RStudio >= 1.4) by choosing AGG as the backend in the graphics pane in general options (see screenshot)

Also, ragg can be used with RMarkdown documents. knitr supports png output from ragg by setting dev = "ragg_png" in the chunk settings or globally with knitr::opts_chunk$set(dev = "ragg_png").

Finally, if you are going to export your plot with ggsave(), you can simply pass device functions from ragg into the device argument as ggsave("image.png", device=ragg::agg_png).

In practice, you need to download and install the fonts in your system manually. This is usually done by opening the font file and clicking on the install button in the window that pops up. One of its advantages is that this procedure is required only once per font. After a font is installed in your system it can be used anywhere in your R plots without having to use any external packages such as showtext.

Let’s generate the same plot than above, but using the ragg::agg_png backend.

library(ragg)

# Quick notes:
# * No "showtext_auto()" or similar calls
# * Full names must be used for the fonts because they are now 
#   searched in the system

data <- data.frame(x = 1:4, y = 1:4)

ggplot(data) +
  geom_point(aes(x, y), size = 10, color = "cadetblue4") +
  geom_label(
    aes(x, y), 
    data = data.frame(x = 3, y = 2), 
    label = "This is Hydrophilia Iced!",
    family = "Hydrophilia Iced",
    size = 7
  ) + 
  labs(
    x = "Horizontal Label",
    y = "Vertical label too!",
    title = "Do you like titles with nice-looking fonts?"
  ) +
  theme(
    axis.title = element_text(family = "Special Elite"),
    title = element_text(family = "Special Elite")
  )