R/pdf_article.R

In rmdplugr: Plugins for R Markdown Formats

#' Rmarkdown template for an augmented version of the basic pandoc latex
#' template
#'
#' @param ... arguments passed down to [bookdown::pdf_document2()]
#' @param csl bibliography style in the `.csl` format
#' @param colorlinks should cross-references and links be
#'   colored?
#' @param number_sections whether sections should be numbered
#' @param md_extensions which markdown extensions to add
#' @param indent whether to use paragraph indentation or not. In the latter case
#'   paragraphs are separated by vertical space as in the default rmarkdown
#'   template.
#' @param marginals whether to augment latex template with marginals (header
#'   and footer) code
#' @param author_block whether to augment latex template with author
#'   blocks. The latex package authblk is required.
#' @param template template for latex output. If `NULL`, the default
#'   latex template will be used (obtained from calling `pandoc -D latex`).
#' @param noindentafter whether to augment latex template with
#'   the noindentafter latex package to suppress indentation after
#'   certain environments. Always set to `FALSE` is `indent = FALSE`.
#' @param subfigs whether to use the subfig package for subfig support
#'
#' @return R Markdown output format to pass to [rmarkdown::render()]
#' @examples
#' library(rmarkdown)
#' library(bookdown)
#' tmp <- file.path(tempdir(), "my-article.Rmd")
#' rmarkdown::draft(tmp,
#'                  template = "pdf_article",
#'                  package = "rmdplugr",
#'                  edit = FALSE)
#' unlink(tmp)
#' @export
pdf_article <- function(...,
                        number_sections = TRUE,
                        md_extensions = c("-autolink_bare_uris"),
                        indent = TRUE,
                        marginals = TRUE,
                        author_block = TRUE,
                        noindentafter = TRUE,
                        subfigs = TRUE,
                        template = NULL,
                        csl = NULL,
                        colorlinks = TRUE)
{
  if (!rmarkdown::pandoc_available())
    stop("needs pandoc to work")

  pandoc <- find_pandoc()

  # get template to modify
  if (is.null(template)) {
    template <- get_pandoc_template(pandoc)
  } else {
    template <- readLines(template)
  }

  if (author_block)
    template <- add_author_block(template)

  if (marginals)
    template <- add_marginals(template)

  if (noindentafter && indent)
    template <- add_noindentafter(template)

  if (subfigs)
    template <- add_subfigs(template)

  # write augmented template to temporary file
  tmpfile <- tempfile(fileext = ".latex")
  writeLines(template, tmpfile)

  # base format
  fmt <- bookdown::pdf_document2(...,
                                 number_sections = number_sections,
                                 md_extensions = md_extensions,
                                 template = tmpfile)
  fmt$inherits <- "pdf_document"

  # delete modified latex template
  fmt$on_exit <- function() {
    unlink(tmpfile)
  }

  # add csl to pandoc_args
  if (!is.null(csl)) {
    fmt$pandoc$args <- c(fmt$pandoc$args,
                         "--csl",
                         rmarkdown::pandoc_path_arg(csl))
  }

  # indent by default
  if (isTRUE(indent))
    fmt$pandoc$args <- c(fmt$pandoc$args, "--variable", "indent:yes")

  # always use graphics
  fmt$pandoc$args <- c(fmt$pandoc$args, "--variable", "graphics:yes")

  # use colorlinks by default
  if (isTRUE(colorlinks)) {
    fmt$pandoc$args <- c(fmt$pandoc$args, "--variable", "colorlinks:yes")
  }

  fmt
}