R/epi_plot_cow_save.R

In AntonioJBT/episcout: Quickly Clean, Explore and Visualise Large Epidemiological Datasets

#' @title Save a grid of plots
#'
#' @description epi_plot_cow_save() A light wrapper to save plots to disk with
#' cowplot::save_plot()
#'
#' @param file_name Name of the file to save
#' @param plot_grid plot to save, more often expecting a grid.
#' @param base_height Height in inches of the plot. Default is 11.69 (A4 size)
#' @param base_width Width in inches of the plot. Default is 8.27 (A4 size)
#' @param ... Pass any other parameter from cowplot::save_plot()
#'
#' @return None, file saved to disk.
#'
#' @author Antonio Berlanga-Taylor <\url{https://github.com/AntonioJBT/episcout}>
#'
#' @seealso \code{\link{epi_plot_list}},
#' \code{\link{epi_plots_to_grid}},
#' \code{\link[cowplot]{plot_grid}},
#' \code{\link[cowplot]{save_plot}}.
#'
#' @note height and width are for A4 size.
#' See also ggplot2 wrappers epi_plot_*().
#'
#' @examples
#'
#' \dontrun{
#' set.seed(12345)
#' n <- 20
#' df <- data.frame(var_id = rep(1:(n / 2), each = 2),
#'                  var_to_rep = rep(c("Pre", "Post"), n / 2),
#'                  x = rnorm(n),
#'                  y = rbinom(n, 1, 0.50),
#'                  z = rpois(n, 2)
#' )
#' df
#' df[, 'var_id'] <- as.character(df[, 'var_id'])
#' vars_to_plot <- df %>%
#'   select_if(epi_clean_cond_numeric) %>%
#'   names()
#' my_plot_list <- epi_plot_list(vars_to_plot)
#' my_plot_list
#' # Generate plots:
#' for (i in names(my_plot_list)) {
#'   print(i)
#'   my_plot_list[[i]] <- ggplot2::ggplot(df, aes_string(y = i)) + geom_boxplot()
#' }
#' # Pass to a grid and save to file:
#' # length(my_plot_list)
#' my_plot_grid <- epi_plots_to_grid(my_plot_list[1:length(my_plot_list)])
#' epi_plot_cow_save(file_name = 'plots_1.pdf', plot_grid = my_plot_grid)
#'
#' }
#'
#' @export
#'

epi_plot_cow_save <- function(file_name = NULL,
                              plot_grid = NULL,
                              base_height = 11.69, # A4
                              base_width = 8.27, # A4
                              ...
                              ) {
  if (!requireNamespace('cowplot', quietly = TRUE)) {
    stop("Package cowplot needed for this function to work. Please install it.",
         call. = FALSE)
  }
  cowplot::save_plot(filename = file_name,
                     plot = plot_grid,
                     # the ratio can be very skewed with many plots
                     # axis labels appear out of proportion and not scaled
                     # base_aspect_ratio = 3,
                     base_height = base_height,
                     base_width = base_width,
                     ...
  )
}