How to display special characters in flextable save_as_image routine

Question

Flextable's save_as_image function seems to only understand ASCII characters. Is there a workaround?

Minimal working example

library(flextable)
library(officer)
ft <- flextable(
  head(mtcars),
  col_keys = c("mpg"))
ft <- set_header_labels(ft, mpg = "n°")
ft

library(webshot)
if( require("webshot") ){
  save_as_image(x = ft, path = "./test.png")
}

Expected output

Actual output

Answer 1

["

use the unicode value for degree<\/i>

library(flextable)
library(officer)
ft <- flextable(
  head(mtcars),
  col_keys = c("mpg"))
ft <- set_header_labels(ft, mpg = "n\u00b0")
ft

library(webshot)
if( require("webshot") ){
  save_as_image(x = ft, path = "./test.png")
}