R/revealjs_presentation.R - IDS-Mannheim/revealjs - Gitiles

 #' Convert to a reveal.js presentation
 #'
 #' Format for converting from R Markdown to a reveal.js presentation.
 #'
 #' @inheritParams rmarkdown::beamer_presentation
 #' @inheritParams rmarkdown::pdf_document
 #' @inheritParams rmarkdown::html_document
 #'
 #' @param center \code{TRUE} to vertically center content on slides
 #' @param slide_level Level of heading to denote individual slides. If
 #'   \code{slide_level} is 2 (the default), a two-dimensional layout will be
 #'   produced, with level 1 headers building horizontally and level 2 headers
 #'   building vertically. It is not recommended that you use deeper nesting of
 #'   section levels with reveal.js.
 #' @param theme Visual theme ("simple", "sky", "beige", "serif", "solarized",
 #'   "blood", "moon", "night", "black", "league" or "white").
 #' @param transition Slide transition ("default", "none", "fade", "slide",
 #'   "convex", "concave" or "zoom")
 #' @param background_transition Slide background-transition ("default", "none",
 #'   "fade", "slide", "convex", "concave" or "zoom")
 #' @param reveal_options Additional options to specify for reveal.js (see
 #'   \href{https://github.com/hakimel/reveal.js#configuration}{https://github.com/hakimel/reveal.js#configuration}
 #'    for details).
 #' @param reveal_plugins Reveal plugins to include. Available plugins include
 #'   "notes", "search", "zoom", "chalkboard", and "menu". Note that
 #'   \code{self_contained} must be set to \code{FALSE} in order to use Reveal
 #'   plugins.
 #' @param template Pandoc template to use for rendering. Pass "default" to use
 #'   the rmarkdown package default template; pass \code{NULL} to use pandoc's
 #'   built-in template; pass a path to use a custom template that you've
 #'   created. Note that if you don't use the "default" template then some
 #'   features of \code{revealjs_presentation} won't be available (see the
 #'   Templates section below for more details).
 #' @param extra_dependencies Additional function arguments to pass to the base R
 #'   Markdown HTML output formatter [rmarkdown::html_document_base()].
 #' @param ... Ignored
 #'
 #' @return R Markdown output format to pass to \code{\link{render}}
 #'
 #' @details
 #'
 #' In reveal.js presentations you can use level 1 or level 2 headers for slides.
 #' If you use a mix of level 1 and level 2 headers then a two-dimensional layout
 #' will be produced, with level 1 headers building horizontally and level 2
 #' headers building vertically.
 #'
 #' For additional documentation on using revealjs presentations see
 #' \href{https://github.com/rstudio/revealjs}{https://github.com/rstudio/revealjs}.
 #'
 #' @examples
 #' \dontrun{
 #'
 #' library(rmarkdown)
 #' library(revealjs)
 #'
 #' # simple invocation
 #' render("pres.Rmd", revealjs_presentation())
 #'
 #' # specify an option for incremental rendering
 #' render("pres.Rmd", revealjs_presentation(incremental = TRUE))
 #' }
 #'
 #'
 #' @export
 revealjs_presentation <- function(incremental = FALSE,
                                   center = FALSE,
                                   slide_level = 2,
                                   fig_width = 8,
                                   fig_height = 6,
                                   fig_retina = if (!fig_caption) 2,
                                   fig_caption = FALSE,
                                   smart = TRUE,
                                   self_contained = TRUE,
                                   theme = "simple",
                                   transition = "default",
                                   background_transition = "default",
                                   reveal_options = NULL,
                                   reveal_plugins = NULL,
                                   highlight = "default",
                                   mathjax = "default",
                                   template = "default",
                                   css = NULL,
                                   includes = NULL,
                                   keep_md = FALSE,
                                   lib_dir = NULL,
                                   pandoc_args = NULL,
                                   extra_dependencies = NULL,
                                   md_extensions = NULL,
                                   ...) {

   # function to lookup reveal resource
   reveal_resources <- function() {
     system.file("rmarkdown/templates/revealjs_presentation/resources",
                 package = "revealjs")
   }

   # base pandoc options for all reveal.js output
   args <- c()

   # template path and assets
   if (identical(template, "default")) {
     default_template <- system.file(
       "rmarkdown/templates/revealjs_presentation/resources/default.html",
       package = "revealjs"
     )
     args <- c(args, "--template", pandoc_path_arg(default_template))
   } else if (!is.null(template)) {
     args <- c(args, "--template", pandoc_path_arg(template))
   }

   # incremental
   if (incremental)
     args <- c(args, "--incremental")

   # centering
   jsbool <- function(value) ifelse(value, "true", "false")
   args <- c(args, pandoc_variable_arg("center", jsbool(center)))

   # slide level
   args <- c(args, "--slide-level", as.character(slide_level))

   # theme
   theme <- match.arg(theme, revealjs_themes())
   if (identical(theme, "default"))
     theme <- "simple"
   else if (identical(theme, "dark"))
     theme <- "black"
   if (theme %in% c("blood", "moon", "night", "black"))
     args <- c(args, "--variable", "theme-dark")
   args <- c(args, "--variable", paste("theme=", theme, sep=""))


   # transition
   transition <- match.arg(transition, revealjs_transitions())
   args <- c(args, "--variable", paste("transition=", transition, sep=""))

   # background_transition
   background_transition <- match.arg(background_transition, revealjs_transitions())
   args <- c(args, "--variable", paste("backgroundTransition=", background_transition, sep=""))

   # use history
   args <- c(args, pandoc_variable_arg("history", "true"))

   # additional reveal options
   if (is.list(reveal_options)) {

     add_reveal_option <- function(option, value) {
       if (is.logical(value))
         value <- jsbool(value)
       else if (is.character(value))
         value <- paste0("'", value, "'")
       args <<- c(args, pandoc_variable_arg(option, value))
     }

     for (option in names(reveal_options)) {
       # special handling for nested options
       if (option %in% c("chalkboard", "menu")) {
         nested_options <- reveal_options[[option]]
         for (nested_option in names(nested_options)) {
           add_reveal_option(paste0(option, "-", nested_option),
                             nested_options[[nested_option]])
         }
       }
       # standard top-level options
       else {
         add_reveal_option(option, reveal_options[[option]])
       }
     }
   }

   # reveal plugins
   if (is.character(reveal_plugins)) {

     # validate that we need to use self_contained for plugins
     if (self_contained)
       stop("Using reveal_plugins requires self_contained: false")

     # validate specified plugins are supported
     supported_plugins <- c("notes", "search", "zoom", "chalkboard", "menu")
     invalid_plugins <- setdiff(reveal_plugins, supported_plugins)
     if (length(invalid_plugins) > 0)
       stop("The following plugin(s) are not supported: ",
            paste(invalid_plugins, collapse = ", "), call. = FALSE)

     # add plugins
     sapply(reveal_plugins, function(plugin) {
       args <<- c(args, pandoc_variable_arg(paste0("plugin-", plugin), "1"))
       if (plugin %in% c("chalkboard", "menu")) {
         extra_dependencies <<- append(extra_dependencies,
                                      list(rmarkdown::html_dependency_font_awesome()))

       }
     })
   }

   # content includes
   args <- c(args, includes_to_pandoc_args(includes))

   # additional css
   for (css_file in css)
     args <- c(args, "--css", pandoc_path_arg(css_file))

   # pre-processor for arguments that may depend on the name of the
   # the input file (e.g. ones that need to copy supporting files)
   pre_processor <- function(metadata, input_file, runtime, knit_meta, files_dir,
                             output_dir) {

     # we don't work with runtime shiny
     if (identical(runtime, "shiny")) {
       stop("revealjs_presentation is not compatible with runtime 'shiny'",
            call. = FALSE)
     }

     # use files_dir as lib_dir if not explicitly specified
     if (is.null(lib_dir))
       lib_dir <- files_dir

     # extra args
     args <- c()

     # reveal.js
     revealjs_path <- system.file("reveal.js-3.3.0.1", package = "revealjs")
     if (!self_contained || identical(.Platform$OS.type, "windows"))
       revealjs_path <- relative_to(
         output_dir, render_supporting_files(revealjs_path, lib_dir))
     else
       revealjs_path <- pandoc_path_arg(revealjs_path)
     args <- c(args, "--variable", paste0("revealjs-url=", revealjs_path))

     # highlight
     args <- c(args, pandoc_highlight_args(highlight, default = "pygments"))

     # return additional args
     args
   }

   # return format
   output_format(
     knitr = knitr_options_html(fig_width, fig_height, fig_retina, keep_md),
     pandoc = pandoc_options(to = "revealjs",
                             from = rmarkdown_format(paste0(
                               md_extensions,
                               ifelse(fig_caption, "", "-implicit_figures")
                             )),
                             args = args),
     keep_md = keep_md,
     clean_supporting = self_contained,
     pre_processor = pre_processor,
     base_format = html_document_base(smart = smart, lib_dir = lib_dir,
                                      self_contained = self_contained,
                                      mathjax = mathjax,
                                      pandoc_args = pandoc_args,
                                      extra_dependencies = extra_dependencies,
                                      ...))
 }

 revealjs_themes <- function() {
   c("default",
     "dark",
     "simple",
     "sky",
     "beige",
     "serif",
     "solarized",
     "blood",
     "moon",
     "night",
     "black",
     "league",
     "white")
 }


 revealjs_transitions <- function() {
   c(
     "default",
     "none",
     "fade",
     "slide",
     "convex",
     "concave",
     "zoom"
     )
 }
	#' Convert to a reveal.js presentation
	#'
	#' Format for converting from R Markdown to a reveal.js presentation.
	#'
	#' @inheritParams rmarkdown::beamer_presentation
	#' @inheritParams rmarkdown::pdf_document
	#' @inheritParams rmarkdown::html_document
	#'
	#' @param center \code{TRUE} to vertically center content on slides
	#' @param slide_level Level of heading to denote individual slides. If
	#' \code{slide_level} is 2 (the default), a two-dimensional layout will be
	#' produced, with level 1 headers building horizontally and level 2 headers
	#' building vertically. It is not recommended that you use deeper nesting of
	#' section levels with reveal.js.
	#' @param theme Visual theme ("simple", "sky", "beige", "serif", "solarized",
	#' "blood", "moon", "night", "black", "league" or "white").
	#' @param transition Slide transition ("default", "none", "fade", "slide",
	#' "convex", "concave" or "zoom")
	#' @param background_transition Slide background-transition ("default", "none",
	#' "fade", "slide", "convex", "concave" or "zoom")
	#' @param reveal_options Additional options to specify for reveal.js (see
	#' \href{https://github.com/hakimel/reveal.js#configuration}{https://github.com/hakimel/reveal.js#configuration}
	#' for details).
	#' @param reveal_plugins Reveal plugins to include. Available plugins include
	#' "notes", "search", "zoom", "chalkboard", and "menu". Note that
	#' \code{self_contained} must be set to \code{FALSE} in order to use Reveal
	#' plugins.
	#' @param template Pandoc template to use for rendering. Pass "default" to use
	#' the rmarkdown package default template; pass \code{NULL} to use pandoc's
	#' built-in template; pass a path to use a custom template that you've
	#' created. Note that if you don't use the "default" template then some
	#' features of \code{revealjs_presentation} won't be available (see the
	#' Templates section below for more details).
	#' @param extra_dependencies Additional function arguments to pass to the base R
	#' Markdown HTML output formatter [rmarkdown::html_document_base()].
	#' @param ... Ignored
	#'
	#' @return R Markdown output format to pass to \code{\link{render}}
	#'
	#' @details
	#'
	#' In reveal.js presentations you can use level 1 or level 2 headers for slides.
	#' If you use a mix of level 1 and level 2 headers then a two-dimensional layout
	#' will be produced, with level 1 headers building horizontally and level 2
	#' headers building vertically.
	#'
	#' For additional documentation on using revealjs presentations see
	#' \href{https://github.com/rstudio/revealjs}{https://github.com/rstudio/revealjs}.
	#'
	#' @examples
	#' \dontrun{
	#'
	#' library(rmarkdown)
	#' library(revealjs)
	#'
	#' # simple invocation
	#' render("pres.Rmd", revealjs_presentation())
	#'
	#' # specify an option for incremental rendering
	#' render("pres.Rmd", revealjs_presentation(incremental = TRUE))
	#' }
	#'
	#'
	#' @export
	revealjs_presentation <- function(incremental = FALSE,
	center = FALSE,
	slide_level = 2,
	fig_width = 8,
	fig_height = 6,
	fig_retina = if (!fig_caption) 2,
	fig_caption = FALSE,
	smart = TRUE,
	self_contained = TRUE,
	theme = "simple",
	transition = "default",
	background_transition = "default",
	reveal_options = NULL,
	reveal_plugins = NULL,
	highlight = "default",
	mathjax = "default",
	template = "default",
	css = NULL,
	includes = NULL,
	keep_md = FALSE,
	lib_dir = NULL,
	pandoc_args = NULL,
	extra_dependencies = NULL,
	md_extensions = NULL,
	...) {

	# function to lookup reveal resource
	reveal_resources <- function() {
	system.file("rmarkdown/templates/revealjs_presentation/resources",
	package = "revealjs")
	}

	# base pandoc options for all reveal.js output
	args <- c()

	# template path and assets
	if (identical(template, "default")) {
	default_template <- system.file(
	"rmarkdown/templates/revealjs_presentation/resources/default.html",
	package = "revealjs"
	)
	args <- c(args, "--template", pandoc_path_arg(default_template))
	} else if (!is.null(template)) {
	args <- c(args, "--template", pandoc_path_arg(template))
	}

	# incremental
	if (incremental)
	args <- c(args, "--incremental")

	# centering
	jsbool <- function(value) ifelse(value, "true", "false")
	args <- c(args, pandoc_variable_arg("center", jsbool(center)))

	# slide level
	args <- c(args, "--slide-level", as.character(slide_level))

	# theme
	theme <- match.arg(theme, revealjs_themes())
	if (identical(theme, "default"))
	theme <- "simple"
	else if (identical(theme, "dark"))
	theme <- "black"
	if (theme %in% c("blood", "moon", "night", "black"))
	args <- c(args, "--variable", "theme-dark")
	args <- c(args, "--variable", paste("theme=", theme, sep=""))


	# transition
	transition <- match.arg(transition, revealjs_transitions())
	args <- c(args, "--variable", paste("transition=", transition, sep=""))

	# background_transition
	background_transition <- match.arg(background_transition, revealjs_transitions())
	args <- c(args, "--variable", paste("backgroundTransition=", background_transition, sep=""))

	# use history
	args <- c(args, pandoc_variable_arg("history", "true"))

	# additional reveal options
	if (is.list(reveal_options)) {

	add_reveal_option <- function(option, value) {
	if (is.logical(value))
	value <- jsbool(value)
	else if (is.character(value))
	value <- paste0("'", value, "'")
	args <<- c(args, pandoc_variable_arg(option, value))
	}

	for (option in names(reveal_options)) {
	# special handling for nested options
	if (option %in% c("chalkboard", "menu")) {
	nested_options <- reveal_options[[option]]
	for (nested_option in names(nested_options)) {
	add_reveal_option(paste0(option, "-", nested_option),
	nested_options[[nested_option]])
	}
	}
	# standard top-level options
	else {
	add_reveal_option(option, reveal_options[[option]])
	}
	}
	}

	# reveal plugins
	if (is.character(reveal_plugins)) {

	# validate that we need to use self_contained for plugins
	if (self_contained)
	stop("Using reveal_plugins requires self_contained: false")

	# validate specified plugins are supported
	supported_plugins <- c("notes", "search", "zoom", "chalkboard", "menu")
	invalid_plugins <- setdiff(reveal_plugins, supported_plugins)
	if (length(invalid_plugins) > 0)
	stop("The following plugin(s) are not supported: ",
	paste(invalid_plugins, collapse = ", "), call. = FALSE)

	# add plugins
	sapply(reveal_plugins, function(plugin) {
	args <<- c(args, pandoc_variable_arg(paste0("plugin-", plugin), "1"))
	if (plugin %in% c("chalkboard", "menu")) {
	extra_dependencies <<- append(extra_dependencies,
	list(rmarkdown::html_dependency_font_awesome()))

	}
	})
	}

	# content includes
	args <- c(args, includes_to_pandoc_args(includes))

	# additional css
	for (css_file in css)
	args <- c(args, "--css", pandoc_path_arg(css_file))

	# pre-processor for arguments that may depend on the name of the
	# the input file (e.g. ones that need to copy supporting files)
	pre_processor <- function(metadata, input_file, runtime, knit_meta, files_dir,
	output_dir) {

	# we don't work with runtime shiny
	if (identical(runtime, "shiny")) {
	stop("revealjs_presentation is not compatible with runtime 'shiny'",
	call. = FALSE)
	}

	# use files_dir as lib_dir if not explicitly specified
	if (is.null(lib_dir))
	lib_dir <- files_dir

	# extra args
	args <- c()

	# reveal.js
	revealjs_path <- system.file("reveal.js-3.3.0.1", package = "revealjs")
	if (!self_contained \|\| identical(.Platform$OS.type, "windows"))
	revealjs_path <- relative_to(
	output_dir, render_supporting_files(revealjs_path, lib_dir))
	else
	revealjs_path <- pandoc_path_arg(revealjs_path)
	args <- c(args, "--variable", paste0("revealjs-url=", revealjs_path))

	# highlight
	args <- c(args, pandoc_highlight_args(highlight, default = "pygments"))

	# return additional args
	args
	}

	# return format
	output_format(
	knitr = knitr_options_html(fig_width, fig_height, fig_retina, keep_md),
	pandoc = pandoc_options(to = "revealjs",
	from = rmarkdown_format(paste0(
	md_extensions,
	ifelse(fig_caption, "", "-implicit_figures")
	)),
	args = args),
	keep_md = keep_md,
	clean_supporting = self_contained,
	pre_processor = pre_processor,
	base_format = html_document_base(smart = smart, lib_dir = lib_dir,
	self_contained = self_contained,
	mathjax = mathjax,
	pandoc_args = pandoc_args,
	extra_dependencies = extra_dependencies,
	...))
	}

	revealjs_themes <- function() {
	c("default",
	"dark",
	"simple",
	"sky",
	"beige",
	"serif",
	"solarized",
	"blood",
	"moon",
	"night",
	"black",
	"league",
	"white")
	}


	revealjs_transitions <- function() {
	c(
	"default",
	"none",
	"fade",
	"slide",
	"convex",
	"concave",
	"zoom"
	)
	}