#' Convert to an HTML document
#'
#' Format for converting from R Markdown to an HTML document.
#'
#' @param toc \code{TRUE} to include a table of contents in the output
#' @param toc_depth Depth of headers to include in table of contents
#' @param number_sections \code{TRUE} to number section headings
#' @param fig_width Default width (in inches) for figures
#' @param fig_height Default width (in inches) for figures
#' @param fig_retina Scaling to perform for retina displays (defaults to 2 when
#' \code{fig_caption} is \code{FALSE}, which currently works for all widely
#' used retina displays). Set to \code{NULL} to prevent retina scaling. Note
#' that this will always be \code{NULL} when \code{keep_md} is specified (this
#' is because \code{fig_retina} relies on outputting HTML directly into the
#' markdown document).
#' @param fig_caption \code{TRUE} to render figures with captions
#' @param dev Graphics device to use for figure output (defaults to png)
#' @param smart Produce typographically correct output, converting straight
#' quotes to curly quotes, --- to em-dashes, -- to en-dashes, and ... to
#' ellipses.
#' @param self_contained Produce a standalone HTML file with no external
#' dependencies, using data: URIs to incorporate the contents of linked
#' scripts, stylesheets, images, and videos. Note that even for self
#' contained documents MathJax is still loaded externally (this is
#' necessary because of it's size).
#' @param theme Visual theme ("default", "cerulean", "journal", "flatly",
#' "readable", "spacelab", "united", or "cosmo"). Pass \code{NULL} for
#' no theme (in this case you can use the \code{css} parameter to add your own
#' styles).
#' @param highlight Syntax highlighting style. Supported styles include
#' "default", "tango", "pygments", "kate", "monochrome", "espresso",
#' "zenburn", "haddock", and "textmate". Pass \code{NULL} to prevent syntax
#' highlighting.
#' @param mathjax Include mathjax. The "default" option uses an https URL from
#' the official MathJax CDN. The "local" option uses a local version of
#' MathJax (which is copied into the output directory). You can pass an
#' alternate URL or pass \code{NULL} to exclude MathJax entirely.
#' @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{html_document} won't be available (see the
#' Templates section below for more details).
#' @param css One or more css files to include
#' @param includes Named list of additional content to include within the
#' document (typically created using the \code{\link{includes}} function).
#' @param keep_md Keep the markdown file generated by knitting.
#' @param lib_dir Directory to copy dependent HTML libraries (e.g. jquery,
#' bootstrap, etc.) into. By default this will be the name of the document
#' with \code{_files} appended to it.
#' @param md_extensions Markdown extensions to be added or removed from the
#' default definition or R Markdown. See the \code{\link{rmarkdown_format}}
#' for additional details.
#' @param pandoc_args Additional command line options to pass to pandoc
#' @param ... Additional function arguments to pass to the base R Markdown HTML
#' output formatter
#'
#' @return R Markdown output format to pass to \code{\link{render}}
#'
#' @details
#'
#' See the \href{http://rmarkdown.rstudio.com/html_document_format.html}{online
#' documentation} for additional details on using the \code{html_document} format.
#'
#' R Markdown documents can have optional metadata that is used to generate a
#' document header that includes the title, author, and date. For more details
#' see the documentation on R Markdown \link[=rmd_metadata]{metadata}.
#'
#' R Markdown documents also support citations. You can find more information on
#' the markdown syntax for citations in the
#' \href{http://rmarkdown.rstudio.com/authoring_bibliographies_and_citations.html}{Bibliographies
#' and Citations} article in the online documentation.
#'
#'
#' @section Templates:
#'
#' You can provide a custom HTML template to be used for rendering. The syntax
#' for templates is described in the documentation on
#' \href{http://johnmacfarlane.net/pandoc/demo/example9/templates.html}{pandoc
#' templates}. You can also use the basic pandoc template by passing
#' \code{template = NULL}.
#'
#' Note however that if you choose not to use the "default" HTML template
#' then several aspects of HTML document rendering will behave differently:
#'
#' \itemize{
#' \item{The \code{theme} parameter does not work (you can still
#' provide styles using the \code{css} parameter).
#' }
#' \item{For the \code{highlight} parameter, the default highlighting
#' style will resolve to "pygments" and the "textmate" highlighting
#' style is not available
#' }
#' \item{MathJax will not work if \code{self_contained} is \code{TRUE}
#' (these two options can't be used together in normal pandoc templates).
#' }
#' }
#'
#' Due to the above restrictions, you might consider using the \code{includes}
#' parameter as an alternative to providing a fully custom template.
#'
#' @examples
#' \dontrun{
#'
#' library(rmarkdown)
#'
#' render("input.Rmd", html_document())
#'
#' render("input.Rmd", html_document(toc = TRUE))
#' }
#'
#' @export
html_document <- function(toc = FALSE,
toc_depth = 3,
number_sections = FALSE,
fig_width = 7,
fig_height = 5,
fig_retina = if (!fig_caption) 2,
fig_caption = FALSE,
dev = 'png',
smart = TRUE,
self_contained = TRUE,
theme = "default",
highlight = "default",
mathjax = "default",
template = "default",
css = NULL,
includes = NULL,
keep_md = FALSE,
lib_dir = NULL,
md_extensions = NULL,
pandoc_args = NULL,
...) {
# build pandoc args
args <- c("--standalone")
# use section divs
args <- c(args, "--section-divs")
# table of contents
args <- c(args, pandoc_toc_args(toc, toc_depth))
# template path and assets
if (identical(template, "default"))
args <- c(args, "--template",
pandoc_path_arg(rmarkdown_system_file("rmd/h/default.html")))
else if (!is.null(template))
args <- c(args, "--template", pandoc_path_arg(template))
# numbered sections
if (number_sections)
args <- c(args, "--number-sections")
# 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) {
# use files_dir as lib_dir if not explicitly specified
if (is.null(lib_dir))
lib_dir <- files_dir
# extra args
args <- c()
# highlight
args <- c(args, pandoc_html_highlight_args(highlight,
template,
self_contained,
lib_dir,
output_dir))
# content includes (we do this here so that user include-in-header content
# goes after dependency generated content). make the paths absolute if
# making a Shiny document so we can resolve them even if rendering
# elsewhere.
args <- c(args, includes_to_pandoc_args(includes,
filter = if (identical(runtime, "shiny"))
normalize_path
else
identity))
# return additional args
args
}
# return format
output_format(
knitr = knitr_options_html(fig_width, fig_height, fig_retina, keep_md, dev),
pandoc = pandoc_options(to = "html",
from = from_rmarkdown(fig_caption, md_extensions),
args = args),
keep_md = keep_md,
clean_supporting = self_contained,
pre_processor = pre_processor,
base_format = html_document_base(smart = smart, theme = theme,
self_contained = self_contained,
lib_dir = lib_dir, mathjax = mathjax,
template = template,
pandoc_args = pandoc_args, ...)
)
}
#' Knitr options for an HTML output format
#'
#' Define knitr options for an R Markdown output format that creates
#' HTML output.
#'
#' @inheritParams html_document
#'
#' @return An list that can be passed as the \code{knitr} argument of the
#' \code{\link{output_format}} function.
#'
#' @seealso \link{knitr_options}, \link{output_format}
#'
#' @export
knitr_options_html <- function(fig_width, fig_height, fig_retina, keep_md, dev = 'png') {
opts_chunk <- list(dev = dev,
dpi = 96,
fig.width = fig_width,
fig.height = fig_height,
fig.retina = fig_retina)
if (keep_md)
opts_chunk$fig.retina <- NULL
knitr_options(opts_chunk = opts_chunk)
}
themes <- function() {
c("default",
"cerulean",
"journal",
"flatly",
"readable",
"spacelab",
"united",
"cosmo")
}
html_highlighters <- function() {
c(highlighters(), "textmate")
}
default_mathjax <- function() {
paste("https://cdn.mathjax.org/mathjax/latest/",
mathjax_config(), sep="")
}
mathjax_config <- function() {
"MathJax.js?config=TeX-AMS-MML_HTMLorMML"
}
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