Embed local font in caption text

[datawolf04]

Prework

• Read and abide by gt's code of conduct and contributing guidelines.
• Search for duplicates among the existing issues (both open and closed).

Proposal

I'd like to be able to tag my table with my social media usernames when I do things like #TidyTuesday, or other community participation activities. We are able to do that with figures, and I'm hoping that this functionality can be brought to gt. I will show you what I mean with this MWE:

# Begin setup code
library(tidyverse)
library(gt)
library(sysfonts)
library(ggtext)
library(showtext)

# This is where I have my fontawesome fonts saved
font_add("fa6-brands", 
         "/usr/share/fonts/fontawesome-free-6.6.0-desktop/otfs/Font Awesome 6 Brands-Regular-400.otf")
gh <- str_glue("<span style='font-family: \"fa6-brands\"'>&#xf09b;</span>")
li <- str_glue("<span style='font-family:\"fa6-brands\"'>&#xf08c;</span>")
caption_text <- str_glue("{gh} github_user {li} linkedin_user")

showtext_auto(enable = TRUE)

I'll use the islands data in the gt package:

islands_tbl <- 
  tibble(
    name = names(islands),
    size = islands
  ) |> 
  arrange(desc(size)) |>
  slice(1:10)

And now I will make the world's dumbest plot:

ggplot(islands_tbl, aes(y=name,x=size)) +
  geom_col() + 
  theme(
    axis.title.y = element_blank(),
    axis.text.x = element_text(angle=-45),
    plot.caption = element_markdown(
      family      = "sans",
      color       = "grey40",
    )
  ) +
  labs(
    title="Dumb plot",
    caption = caption_text
  ) 

I can make the table in the documentation, adding in a caption:

# Create a display table showing ten of
# the largest islands in the world
gt_tbl <- gt(islands_tbl)

gt_tbl |>
  tab_header(
    title = "Large Landmasses of the World",
    subtitle = "The top ten largest are presented"
  ) |>
  tab_caption("My caption text") 

But I can't use the same caption object from my plot

gt_tbl |>
  tab_header(
    title = "Large Landmasses of the World",
    subtitle = "The top ten largest are presented"
  ) |>
  tab_caption(md(caption_text))