In rstudio/rticles: Article Formats for R Markdown

# this is to generate the GIF and PDF for the gallery
# This is done on GHA and there is a caching mechanism so that a new rendering
# occurs only when needed

library(rticles)
library(magick)

# dir setup
hash_db_dir <- "cache"
if (!dir.exists(hash_db_dir)) dir.create(hash_db_dir)
out_dir <- "resources"
if (!dir.exists(out_dir)) dir.create(out_dir)

# ignore some journals 
to_ignore <- c(
  "ctex", # exclude ctex for now (issue to build)
  "rjournal" # lives in rjtools package now.
)

for (journal in journals()) {
  hash_db_file <- file.path(hash_db_dir, xfun::with_ext(journal, ".rds"))
  out_files <- file.path(out_dir, xfun::with_ext(paste0(journal, "_article"), c("gif", "pdf")))
  # clean for ignored journal
  if (journal %in% to_ignore) {
    # clean files
    to_remove <- xfun::existing_files(c(out_files, hash_db_file))
    if (length(to_remove)) unlink(to_remove)
    next
  }
  # clean cache if no more files
  if (!all(file.exists(out_files))) unlink(hash_db_file)
  # Should we render new resource ? 
  resource_path <- rticles:::pkg_file_template(journal)
  template_files <- list.files(resource_path, recursive = TRUE)
  template_files <- setNames(
    file.path(resource_path, template_files), 
    nm = template_files)
  new_hash_db <- lapply(template_files, function(x) unname(tools::md5sum(x)))
  if (file.exists(hash_db_file)) {
    old_hash_db <- readRDS(hash_db_file)
    if (identical(old_hash_db, new_hash_db)) {
      message("No changes in templates. Skipping ",
              journal, " format.")
      next
    }
  }
  message("Rendering to PDF...")
  out_pdf <- xfun::try_silent(rticles:::render_draft(journal, quiet = TRUE))
  if (inherits(out_pdf, "try-error")) {
    warning("Error with rendering format ", journal,
            immediate. = TRUE)
    next
  }

  message("Converting to GIF...")
  pdf_content <- image_read_pdf(out_pdf, density = 72) %>% image_resize(geometry = "400x")
  out_gif <- image_write_gif(
    image = pdf_content,
    path = xfun::with_ext(out_pdf, "gif"),
    delay = 1)
  message("Retrieving built files.")
  # specific treatment for rjournal name
  if (journal == "rjournal") {
    file.rename(out_pdf, out_pdf <- file.path(dirname(out_pdf), "rjournal_article.pdf"))
    file.rename(out_gif, out_gif <- file.path(dirname(out_gif), "rjournal_article.gif"))
  }
  file.copy(out_pdf, out_dir)
  file.copy(out_gif, out_dir)
  # clean temp dir
  unlink(dirname(out_pdf), recursive = TRUE)
  # saving the new hash
  saveRDS(new_hash_db, hash_db_file)
}