R/utils.R

In USAID-OHA-SI/glitr: Adorned SI style plots

.onLoad <- function (libname, pkgname)
{
  check_fonts()

  choose_font()

  invisible()
}


#' Check if font exists
#'
#' @param font typeface to check, defaults to Source Sans 3 and Pro
#'
#' @keywords internal

font_exists <- function(font = c("Source Sans 3", "Source Sans Pro")){
  #list of all fonts available
  localfonts <- unique(systemfonts::system_fonts()$family)
  #check if any of the fonts exists
  any(font %in% localfonts)
}

#' Check for Imported Fonts
#'
#' @keywords internal

check_fonts <- function(){

  #list of all fonts available
    localfonts <- unique(systemfonts::system_fonts()$family)

  #check if font (Source Sans Pro) is installed
    if(!font_exists())
      cli::cli_alert_warning("Before proceeding, we recommend installing the {.strong Source Sans 3} or {.strong Source Sans Pro} from USAID Software Center or {.href [Google Fonts](https://fonts.google.com/specimen/Source+Sans+3)}. In the absense of Source Sans 3 or Pro, we will default to using {.strong Arial}")

}


#' Check for Imported Fonts
#'
#' @keywords internal
#'
choose_font <- function(){

  ss_fonts <- c("Source Sans 3", "Source Sans Pro", "sans")
  localfonts <- unique(systemfonts::system_fonts()$family)
  preferred_font <- localfonts[localfonts %in% ss_fonts]
  preferred_font <- factor(preferred_font, ss_fonts) %>% sort() %>% as.character()
  preferred_font <- preferred_font[1]

  options(glitr_font = preferred_font)

}