R: Markdown HTML rendering options

markdownHTMLOptions {markdown} | R Documentation

## Markdown HTML rendering options

### Description

`markdownHTMLOptions` returns a character vector listing all the options that are available for the HTML renderer in the markdown package. As a convenience, the package default options were chosen to render well-formed stand-alone HTML pages when using `markdownToHTML()`. The default options are `'use_xhtml'`, `'smartypants'`, `'base64_images'`, `'mathjax'`, and `'highlight_code'`.

### Usage

    markdownHTMLOptions(defaults = FALSE)

### Arguments

`defaults` | If `TRUE`, then only the default options are returned. Otherwise all options are returned.

### Details

The HTML renderer provides several options described below. To turn these on globally in the markdown package, simply place some or all of them in a character vector and assign to the global option `markdown.HTML.options` like so:

`options(markdown.HTML.options = markdownHTMLOptions())`

To reset the options to package default, use:

`options(markdown.HTML.options = markdownHTMLOptions(default = TRUE))`

To override the global option, pass the `options` as an argument:

`markdownToHTML(..., options = c('skip_images'))`

Description of all options:

`'skip_html'`

  suppress output of all HTML tags in the document.

`'skip_style'`

  suppress output of HTML style tags.

`'skip_images'`

  suppress output of HTML image tags.

`'skip_links'`

  suppress output of HTML anchor tags.

`'safelink'`

  only create links for known url types, e.g. http, ftp, http, etc.

`'toc'`

  assigns an HTML id to each header of the form 'toc_ where ' (starting at 0), and creates the table of contents.

`'hard_wrap'`

  adds an HTML br tag for every newline (excluding trailing) found within a paragraph.

`'use_xhtml'`

  create XHMTL 1.0 compliant HTML tags.

`'escape'`

  escape all HTML found within the markdown. Overrides all of the `'skip_*'` options mentioned above.

`'smartypants'`

  translates plain ASCII punctuation characters into smart typographic punctuation HTML entities.

`'fragment_only'`

  eliminates the inclusion of any HTML header or body tags, CSS, or Javascript components.

`'base64_images'`

  Any local images linked with the `'<img>'` tag to the output HTML will automatically be converted to base64 and included along with output.

`'mathjax'`

  includes appropriate Javascript libraries to render math markup.

`'highlight_code'`

  includes appropriate Javascript libraries to highlight code chunks.

See the EXAMPLES section to see the output of each option turned on or off.

### Value

A `character` vector listing either all available options or just the default options.

### See Also

markdownToHTML

### Examples

    # List all available extensions:
    markdownHTMLOptions()

    # To turn on all HTML options globally:
    options(markdown.HTML.options = markdownHTMLOptions())

    # To turn off all HTML options globally:
    options(markdown.HTML.options = NULL)

    # To turn on package default HTML options globally:
    options(markdown.HTML.options = markdownHTMLOptions(default = TRUE))

    # HTML OPTIONS

    # The following examples are short, so we allways add the HTML option 'fragment_only'
    tOpt <- "fragment_only"

    # skip_html example
    mkd = '<style></style><img src="http://cran.rstudio.com/Rlogo.jpg"><a href="#">Hello</a>'
    cat(markdownToHTML(text = mkd, options = c(tOpt)))
    cat(markdownToHTML(text = mkd, options = c(tOpt, "skip_html")))

    # skip_style example
    cat(markdownToHTML(text = mkd, options = c(tOpt)))
    cat(markdownToHTML(text = mkd, options = c(tOpt, "skip_style")))

    # skip_images example
    cat(markdownToHTML(text = mkd, options = c(tOpt)))
    cat(markdownToHTML(text = mkd, options = c(tOpt, "skip_images")))

    # skip_links example
    cat(markdownToHTML(text = mkd, options = c(tOpt)))
    cat(markdownToHTML(text = mkd, options = c(tOpt, "skip_links")))

    # safelink example
    cat(markdownToHTML(text = '[foo](http://google.com "baz")', options = c(tOpt)))
    cat(markdownToHTML(text = '[foo](http://google.com "baz")', options = c(tOpt, "safelink")))

    # toc example
    mkd <- paste(c("# Header 1", "p1", "## Header 2", "p2"), collapse = "\n")

    cat(markdownToHTML(text = mkd, options = c(tOpt)))
    cat(markdownToHTML(text = mkd, options = c(tOpt, "toc")))

    # hard_wrap example
    cat(markdownToHTML(text = "foo\nbar\n", options = c(tOpt)))
    cat(markdownToHTML(text = "foo\nbar\n", options = c(tOpt, "hard_wrap")))

    # use_xhtml example
    cat(markdownToHTML(text = "foo\nbar\n", options = c(tOpt, "hard_wrap")))
    cat(markdownToHTML(text = "foo\nbar\n", options = c(tOpt, "hard_wrap", "use_xhtml")))

    # escape example
    mkd = '<style></style><img src="http://cran.rstudio.com/Rlogo.jpg"><a href="#">Hello</a>'
    cat(markdownToHTML(text = mkd, options = c(tOpt, "skip_html")))
    # overrides all 'skip_*' options
    cat(markdownToHTML(text = mkd, options = c(tOpt, "skip_html", "escape")))

    # smartypants example
    cat(markdownToHTML(text = "1/2 (c)", options = c(tOpt)))
    cat(markdownToHTML(text = "1/2 (c)", options = c(tOpt, "smartypants")))

    cat(smartypants(text = "1/2 (c)\n"))

[Package markdown version 0.8 Index]