R/pdf_to_booklet_order.R

In meerapatelmd/secretary: secretary Package

#' #' Converts a pdf file into a version with the pages rearranged for booklet-style printing
#' #' @param path_to_pdf path to a pdf file with a page number that is a multiple of 4
#' #' @importFrom pdftools pdf_length
#' #' @importFrom pdftools pdf_subset
#' #' @export
#'
#'
#' pdf_to_booklet_order <-
#'         function(path_to_pdf) {
#'
#'                 pdf_page_num <- pdftools::pdf_length(path_to_pdf)
#'
#'                 if ((pdf_page_num %% 4) != 0) {
#'                         typewrite_warning(path_to_pdf, "does not have a page length that is a multiple of 4.")
#'                         press_enter()
#'                 }
#'
#'                 page_number_index <- seq(1, pdf_page_num/2, 2)
#'                 max_length <- pdf_page_num
#'
#'
#'                 iteration_number <- length(page_number_index)-1
#'                 a <- rev(seq(max_length-(2*(iteration_number)), max_length, by = 2))
#'                 b <- page_number_index
#'                 c <- b+1
#'                 d <- a-1
#'
#'                 booklet_order_df <-
#'                         tibble(a = a,
#'                                b = b,
#'                                c = c,
#'                                d = d)
#'
#'                 for (i in 1:nrow(booklet_order_df)) {
#'                         if (i == 1) {
#'                                 final_booklet_order <- unlist(booklet_order_df[1,])
#'                         } else {
#'                                 final_booklet_order <-
#'                                         c(final_booklet_order,
#'                                           unlist(booklet_order_df[i,]))
#'                         }
#'                 }
#'
#'                 output_fn <- pdftools::pdf_subset(path_to_pdf,
#'                                              pages = final_booklet_order)
#'
#'                 typewrite(output_fn, "successfully written.")
#'         }