Appendix A — Font Management in R

Font management is often an overlooked or neglected aspect of creating reproducible reports with R. However, it’s a critical consideration when working with flextable and ggplot2, especially in pharmaceutical reporting contexts where documents must be rendered consistently across different machines and environments.

A.1 Why Font Management Matters

We recommand ‘ragg’ and ‘systemfonts’ packages to manage fonts from R.

When you create a ggplot2 graphic on one machine, the rendering engine needs to calculate font metrics, the precise dimensions and spacing of each character.

‘flextable’ may also require access to the actual font files to perform these calculations when function autofit() is called. Fonts used by Word tables are also needed on the machine editing the document (for Word/PowerPoint display and editing).

This because flextable calculates layout during generation, but Word/PowerPoint renders text during editing.

The Challenge

A table or graphic composed on one machine must have the required fonts available on that machine. Without access to the font files, the rendering engine cannot accurately calculate character widths, line heights, and spacing, which can result in:

  • Misaligned columns in tables
  • Text overflow or truncation
  • Inconsistent spacing between elements

This means that reproducibility isn’t just about having the same R code, it also requires having the same fonts available across all machines where the documents will be generated.

A.2 Packages and Functions for Font Management

To use a font in your graphics (or tables), it must be available on your machine. Fonts can be:

  1. System fonts: Installed on your operating system
  2. Downloaded fonts: Obtained from sources like Google Fonts but not necessarily installed system-wide

Not all R graphics engines support all fonts equally. However, engines that use the ‘systemfonts’ package provide robust and easy-to-use font support.

A.3 Working with System Fonts

You can list all fonts available on your system using systemfonts::system_fonts():

Code
library(tidyverse)
system_fonts_available <- systemfonts::system_fonts() |>
  dplyr::select(-path, -index) |>
  dplyr::arrange(family)

head(system_fonts_available, 20)
# A tibble: 20 × 8
   name                      family style weight width italic monospace variable
   <chr>                     <chr>  <chr> <ord>  <ord> <lgl>  <lgl>     <lgl>   
 1 AcademyEngravedLetPlain   Acade… Plain normal norm… FALSE  FALSE     FALSE   
 2 AlBayan-Bold              Al Ba… Bold  bold   norm… FALSE  FALSE     FALSE   
 3 AlBayan                   Al Ba… Plain normal norm… FALSE  FALSE     FALSE   
 4 AlNile                    Al Ni… Regu… normal norm… FALSE  FALSE     FALSE   
 5 AlNile-Bold               Al Ni… Bold  bold   norm… FALSE  FALSE     FALSE   
 6 AlTarikh                  Al Ta… Regu… normal norm… FALSE  FALSE     FALSE   
 7 AmericanTypewriter        Ameri… Regu… normal norm… FALSE  FALSE     FALSE   
 8 AmericanTypewriter-Light  Ameri… Light light  norm… FALSE  FALSE     FALSE   
 9 AmericanTypewriter-Bold   Ameri… Bold  bold   norm… FALSE  FALSE     FALSE   
10 AmericanTypewriter-Conde… Ameri… Cond… light  semi… FALSE  FALSE     FALSE   
11 AmericanTypewriter-Conde… Ameri… Cond… normal semi… FALSE  FALSE     FALSE   
12 AmericanTypewriter-Conde… Ameri… Cond… bold   semi… FALSE  FALSE     FALSE   
13 AmericanTypewriter-Semib… Ameri… Semi… semib… norm… FALSE  FALSE     FALSE   
14 AndaleMono                Andal… Regu… normal norm… FALSE  TRUE      FALSE   
15 AppleBraille              Apple… Regu… normal norm… FALSE  FALSE     FALSE   
16 AppleBraille-Pinpoint8Dot Apple… Pinp… normal norm… FALSE  FALSE     FALSE   
17 AppleBraille-Outline6Dot  Apple… Outl… normal norm… FALSE  FALSE     FALSE   
18 AppleBraille-Outline8Dot  Apple… Outl… normal norm… FALSE  FALSE     FALSE   
19 AppleBraille-Pinpoint6Dot Apple… Pinp… normal norm… FALSE  FALSE     FALSE   
20 Apple-Chancery            Apple… Chan… normal norm… FALSE  FALSE     FALSE

To use a font in your visualization, reference it by the family name from this list:

Code
dat <- mtcars
dat$carname <- row.names(dat)

gg <- ggplot(dat, aes(drat, carname)) +
  geom_point() +
  theme_minimal(base_family = "Arial")
gg

A.4 Using Google Fonts

Google Fonts (https://fonts.google.com/) provides a vast library of freely available fonts. The gdtools package makes it easy to use these fonts in R without installing them system-wide.

The gdtools::register_gfont() function:

  1. Downloads the font to a user-specific directory (if not already downloaded)
  2. Registers it with ‘systemfonts’

Here’s an example using the “Lemon” font from Google Fonts:

Code
gdtools::register_gfont("Lemon")
Code
gg_lemon <- ggplot(dat, aes(drat, carname)) +
  geom_point() +
  theme_minimal(base_family = "Lemon")
gg_lemon

A.5 Our Approach: Using Arial for Maximum Compatibility

A.5.1 Why We Prefer Arial

Throughout this workshop, we use Arial as our standard font. This choice is deliberate and based on practical considerations:

  1. Universal availability: Arial is present on virtually all Windows, macOS, and can be easily deployed on Linux systems
  2. Easy to bundle: The font files can be included in your project for Linux/CI environments

A.5.2 How We Set Up Arial in This Book

Let’s examine how Arial is configured in this book’s _init.qmd file, which is included at the beginning of every chapter:

Code
# From _init.qmd

# Check if Arial is available on the system
if (!font_family_exists("Arial")) {
  # If not, register it from bundled font files
  systemfonts::register_font(
    "Arial",
    plain = "static/fonts/Arial.ttf",
    bold = "static/fonts/Arial Bold.ttf",
    italic = "static/fonts/Arial Italic.ttf",
    bolditalic = "static/fonts/Arial Bold Italic.ttf"
  )
}

# Set Arial as the default font for all flextables
set_flextable_defaults(
  font.family = "Arial",
  font.size = 11,
  padding = 3,
  table.layout = "autofit"
)

This approach ensures that: - On Windows/Mac where Arial is typically installed, the system font is used - On Linux or CI/CD environments, the bundled font files are used - All tables in the book have consistent Arial formatting

A.5.3 Bundling Font Files in Your Project

We include Arial font files directly in the project structure:

r-in-pharma-book/
├── static/
│   └── fonts/
│       ├── Arial.ttf
│       ├── Arial Bold.ttf
│       ├── Arial Italic.ttf
│       └── Arial Bold Italic.ttf
├── _init.qmd
└── [other files...]
  1. Font files location: The font files are stored in static/fonts/ directory
  2. Relative paths: The systemfonts::register_font() call uses relative paths from the working directory (here fonts/ which should point to static/fonts/)
  3. Four variants: We include all four variants (regular, bold, italic, bold-italic) to ensure complete font support
  4. Conditional registration: The if (!font_family_exists("Arial")) check prevents re-registering fonts that are already available system-wide