xaringanthemer/R/style_xaringan.R

#' @param text_color Text Color. Defaults to #000. Modifies the `body` element.
#' @param header_color Header Color. Defaults to #000. Modifies the `h1, h2, h3` elements.
#' @param background_color Slide Background Color. Defaults to #FFF. Modifies the `.remark-slide-content` class.
#' @param link_color Link Color. Defaults to rgb(249, 38, 114). Modifies the `a, a > code` elements.
#' @param text_bold_color Bold Text Color. Defaults to `NULL`. Modifies the `strong` element.
#' @param text_slide_number_color Slide Number Color. Defaults to `inverse_background_color`. Modifies the `.remark-slide-number` class.
#' @param padding Slide Padding in `top right [bottom left]` format. Defaults to 16px 64px 16px 64px. Modifies the `.remark-slide-content` class.
#' @param background_image Background image applied to each *and every* slide. Set `title_slide_background_image = "none"` to remove the background image from the title slide. Defaults to `NULL`. Modifies the `.remark-slide-content` class.
#' @param background_size Background image size, requires `background_image` to be set. If `background_image` is set, `background_size` will default to `cover` so the backround fills the screen. If both `background_image` and `background_position` are set, will default to 100 percent. Defaults to `NULL`. Modifies the `.remark-slide-content` class.
#' @param background_position Background image position, requires `background_image` to be set, and it is recommended to adjust `background_size`. Defaults to `NULL`. Modifies the `.remark-slide-content` class.
#' @param code_highlight_color Code Line Highlight. Defaults to rgba(255,255,0,0.5). Modifies the `.remark-code-line-highlighted` class.
#' @param code_inline_color Inline Code Color. Defaults to #000. Modifies the `.remark-inline-code` class.
#' @param code_inline_background_color Inline Code Background Color. Defaults to `NULL`. Modifies the `.remark-inline-code` class.
#' @param code_inline_font_size Inline Code Text Font Size. Defaults to 1rem. Modifies the `.remark-inline-code` class.
#' @param inverse_background_color Inverse Background Color. Defaults to #272822. Modifies the `.inverse` class.
#' @param inverse_text_color Inverse Text Color. Defaults to #d6d6d6. Modifies the `.inverse` class.
#' @param inverse_text_shadow Enables Shadow on text of inverse slides. Defaults to `FALSE`. Modifies the `.inverse` class.
#' @param inverse_header_color Inverse Header Color. Defaults to #f3f3f3. Modifies the `.inverse h1, .inverse h2, .inverse h3` classes.
#' @param title_slide_text_color Title Slide Text Color. Defaults to `inverse_text_color`. Modifies the `.title-slide` class.
#' @param title_slide_background_color Title Slide Background Color. Defaults to `inverse_background_color`. Modifies the `.title-slide` class.
#' @param title_slide_background_image Title Slide Background Image URL. Defaults to `NULL`. Modifies the `.title-slide` class.
#' @param title_slide_background_size Title Slide Background Image Size, defaults to "cover" if background image is set. Defaults to `NULL`. Modifies the `.title-slide` class.
#' @param title_slide_background_position Title Slide Background Image Position. Defaults to `NULL`. Modifies the `.title-slide` class.
#' @param footnote_color Footnote text color (if `NA`, then it will be the same color as `text_color`). Defaults to `NULL`. Modifies the `.footnote` class.
#' @param footnote_font_size Footnote font size. Defaults to 0.9rem. Modifies the `.footnote` class.
#' @param footnote_position_bottom Footnote location from bottom of screen. Defaults to 60px. Modifies the `.footnote` class.
#' @param left_column_subtle_color Left Column Text (not last). Defaults to #777. Modifies the `.left-column h2, .left-column h3` classes.
#' @param left_column_selected_color Left Column Current Selection. Defaults to #000. Modifies the `.left-column h2:last-of-type, .left-column h3:last-child` classes.
#' @param blockquote_left_border_color Blockquote Left Border Color. Defaults to lightgray. Modifies the `blockquote` element.
#' @param table_border_color Table top/bottom border. Defaults to #666. Modifies the `table: border-top, border-bottom` elements.
#' @param table_row_border_color Table row inner bottom border. Defaults to #ddd. Modifies the `table thead th: border-bottom` elements.
#' @param table_row_even_background_color Table Even Row Background Color. Defaults to #eee. Modifies the `thead, tfoot, tr:nth-child(even)` elements.
#' @param base_font_size Base Font Size for All Slide Elements (must be `px`). Defaults to 20px. Modifies the `html` element.
#' @param text_font_size Slide Body Text Font Size. Defaults to 1rem. Modifies the `.remark-slide-content` class.
#' @param header_h1_font_size h1 Header Text Font Size. Defaults to 2.75rem. Modifies the `.remark-slide-content h1` class.
#' @param header_h2_font_size h2 Header Text Font Size. Defaults to 2.25rem. Modifies the `.remark-slide-content h2` class.
#' @param header_h3_font_size h3 Header Text Font Size. Defaults to 1.75rem. Modifies the `.remark-slide-content h3` class.
#' @param header_background_auto Add background under slide title automatically for h1 header elements. If not enabled, use `class: header_background` to enable. Defaults to `FALSE`. 
#' @param header_background_color Background Color for h1 Header with Background. Defaults to `header_color`. Modifies the `.remark-slide-content h1` class.
#' @param header_background_text_color Text Color for h1 Header with Background. Defaults to `background_color`. Modifies the `.remark-slide-content h1` class.
#' @param header_background_padding Padding for h1 Header with Background. Defaults to `NULL`. Modifies the `.remark-slide-content h1` class.
#' @param header_background_content_padding_top Top Padding for Content in Slide with Header with Background. Defaults to 7rem. Modifies the `.remark-slide-content` class.
#' @param header_background_ignore_classes Slide Classes Where Header with Background will not be Applied. Defaults to `c('normal', 'inverse', 'title', 'middle', 'bottom')`. Modifies the `.remark-slide-content` class.
#' @param text_slide_number_font_size Slide Number Text Font Size. Defaults to 0.9rem. Modifies the `.remark-slide-number` class.
#' @param text_font_google Use `google_font()` to specify body font. Defaults to `google_font("Noto Sans", "400", "400i", "700", "700i")`. Modifies the `body` element.
#' @param text_font_family Body Text Font Family (xaringan default is `'Droid Serif'`). Defaults to `NULL`. Modifies the `body` element.
#' @param text_font_weight Body Text Font Weight. Defaults to normal. Modifies the `body` element.
#' @param text_font_url Body Text Font URL(s). Defaults to `NULL`. Modifies the `@import url()` elements.
#' @param text_font_family_fallback Body Text Font Fallbacks. Defaults to 'Palatino Linotype', 'Book Antiqua', Palatino, 'Microsoft YaHei', 'Songti SC'. Modifies the `body` element.
#' @param text_font_base Body Text Base Font (Total Failure Fallback). Defaults to serif. Modifies the `body` element.
#' @param header_font_google Use `google_font()` to specify header font. Defaults to `google_font("Cabin", "600", "600i")`. Modifies the `body` element.
#' @param header_font_family Header Font Family (xaringan default is `'Yanone Kaffeesatz'`). Defaults to `NULL`. Modifies the `h1, h2, h3` elements.
#' @param header_font_weight Header Font Weight. Defaults to normal. Modifies the `h1, h2, h3` elements.
#' @param header_font_url Header Font URL. Defaults to `NULL`. Modifies the `@import url` elements.
#' @param code_font_google Use `google_font()` to specify code font. Defaults to `google_font("Source Code Pro", "400", "700")`. Modifies the `body` element.
#' @param code_font_family Code Font Family. Defaults to `NULL`. Modifies the `.remark-code, .remark-inline-code` classes.
#' @param code_font_size Code Text Font Size. Defaults to 0.9rem. Modifies the `.remark-inline` class.
#' @param code_font_url Code Font URL. Defaults to `NULL`. Modifies the `@import url` elements.
#' @param code_font_family_fallback Code Font Fallback. Defaults to 'Lucida Console', Monaco. Modifies the `.remark-code, .remark-inline-code` classes.
#' @param colors A named vector of custom colors. The names of the colors
#'   become CSS variables and classes that can be used within your slides.
#'   For example, `colors = c(blue = "#bad4ed")` adds a CSS variable
#'   `--blue`, a `.blue` CSS class that applies the color to the text or
#'   foreground color, and a `.bg-blue` CSS class that applies the color
#'   to the background.
#' @template extra_css
#' @param outfile Customized xaringan CSS output file name, default is "xaringan-themer.css"
#' @family themes
#' @template style_xaringan
#' @export
style_xaringan <- function(
  text_color = "#000",
  header_color = "#000",
  background_color = "#FFF",
  link_color = "rgb(249, 38, 114)",
  text_bold_color = NULL,
  text_slide_number_color = inverse_background_color,
  padding = "16px 64px 16px 64px",
  background_image = NULL,
  background_size = NULL,
  background_position = NULL,
  code_highlight_color = "rgba(255,255,0,0.5)",
  code_inline_color = "#000",
  code_inline_background_color = NULL,
  code_inline_font_size = "1rem",
  inverse_background_color = "#272822",
  inverse_text_color = "#d6d6d6",
  inverse_text_shadow = FALSE,
  inverse_header_color = "#f3f3f3",
  title_slide_text_color = inverse_text_color,
  title_slide_background_color = inverse_background_color,
  title_slide_background_image = NULL,
  title_slide_background_size = NULL,
  title_slide_background_position = NULL,
  footnote_color = NULL,
  footnote_font_size = "0.9rem",
  footnote_position_bottom = "60px",
  left_column_subtle_color = "#777",
  left_column_selected_color = "#000",
  blockquote_left_border_color = "lightgray",
  table_border_color = "#666",
  table_row_border_color = "#ddd",
  table_row_even_background_color = "#eee",
  base_font_size = "20px",
  text_font_size = "1rem",
  header_h1_font_size = "2.75rem",
  header_h2_font_size = "2.25rem",
  header_h3_font_size = "1.75rem",
  header_background_auto = FALSE,
  header_background_color = header_color,
  header_background_text_color = background_color,
  header_background_padding = NULL,
  header_background_content_padding_top = "7rem",
  header_background_ignore_classes = c('normal', 'inverse', 'title', 'middle', 'bottom'),
  text_slide_number_font_size = "0.9rem",
  text_font_google = google_font("Noto Sans", "400", "400i", "700", "700i"),
  text_font_family = NULL,
  text_font_weight = "normal",
  text_font_url = NULL,
  text_font_family_fallback = "'Palatino Linotype', 'Book Antiqua', Palatino, 'Microsoft YaHei', 'Songti SC'",
  text_font_base = "serif",
  header_font_google = google_font("Cabin", "600", "600i"),
  header_font_family = NULL,
  header_font_weight = "normal",
  header_font_url = NULL,
  code_font_google = google_font("Source Code Pro", "400", "700"),
  code_font_family = NULL,
  code_font_size = "0.9rem",
  code_font_url = NULL,
  code_font_family_fallback = "'Lucida Console', Monaco",
  colors = NULL,
  extra_css = NULL,
  extra_fonts = NULL,
  outfile = "xaringan-themer.css"
) {
  # DO NOT EDIT - Generated from inst/scripts/generate_theme_functions.R
  # Make sure font names are wrapped in quotes if they have spaces
  f_args <- names(formals(sys.function()))
  for (var in f_args[grepl("font_family$", f_args)]) {
    var_value <- get(var, inherits = FALSE)
    if (!is.null(var_value)) {
      eval(parse(text = paste0(var, "<-quote_elements_w_spaces(", var, ")")))
    }
    # set an is_google flag default of FALSE that is possibly overwritten later
    eval(parse(text = paste0(sub("font_family$", "font_is_google", var), "<-0")))
  }
  
  # Warn if base_font_size isn't absolute
  css_abs_units <- c("cm", "mm", "Q", "in", "pc", "pt", "px")
  if (!grepl(paste(tolower(css_abs_units), collapse = "|"), tolower(base_font_size))) {
    warning(
      glue::glue(
        "Base font size '{base_font_size}' is not in absolute units. ",
        "For best results, specify the `base_font_size` using absolute CSS units: ",
        "{paste(css_abs_units, collapse = ', ')}"
      ),
      call. = FALSE,
      immediate. = TRUE
    )
  }
  
  # Use font_..._google args to overwrite font args
  for (var in f_args[grepl("font_google$", f_args)]) {
    gf <- eval(parse(text = var))
    if (is.null(gf)) next
    if (!inherits(gf, "google_font")) {
      stop("`", var, "` must be set using `google_font()`.")
    }
    group <- strsplit(var, "_")[[1]][1]
    if (group == "text") {
      text_font_family <- quote_elements_w_spaces(gf$family)
      text_font_weight <- gf$weights %||% "normal"
      text_font_weight <- substr(text_font_weight, 1, regexpr(",", text_font_weight)[1] - 1)
      text_font_url <- gf$url
    } else {
      eval(parse(text = paste0(group, "_font_family <- quote_elements_w_spaces(gf$family)")))
      eval(parse(text = paste0(group, "_font_url <- gf$url")))
    }
    eval(parse(text = paste0(group, "_font_is_google <- 1")))
  }
  
  extra_font_imports <- if (is.null(extra_fonts)) "" else list2fonts(extra_fonts)
  extra_font_imports <- paste(extra_font_imports, collapse = "\n")
  
  # convert NA arguments to NULL
  for (var in f_args) {
    val <- eval(parse(text = var))
    if (is.null(val)) next
    val <- val[!is.na(val)]
    is_na <- length(val) == 0
    if (is_na) assign(var, NULL)
  }
  
  # prepare variables for template
  body_font_family <- paste(c(text_font_family, text_font_family_fallback, text_font_base), collapse = ", ")
  background_size_fallback <- if (is.null(background_position)) "cover" else "100%"
  background_size <- background_image %??% (background_size %||% background_size_fallback)
  title_slide_background_size <- title_slide_background_size %||% (
    title_slide_background_image %??% "cover"
  )
  table_row_even_background_color <- table_row_even_background_color %||% background_color
  
  lapply(names(formals()), function(n) assign(n, get(n), envir = xaringanthemer_env))
  
  xaringanthemer_version <- utils::packageVersion("xaringanthemer")
  
  # prepare header background object
  needs_leading_dot <- !grepl("^\\.", header_background_ignore_classes)
  header_background_ignore_classes[needs_leading_dot] <- paste0(
    ".",
    header_background_ignore_classes[needs_leading_dot]
  )
  header_background_ignore_classes <- purrr::map(
    header_background_ignore_classes,
    ~ list(class = .)
  )
  if (is.null(header_background_padding)) {
    slide_padding <- css_get_padding(padding)
    header_background_padding <- paste(
      "2rem", slide_padding$right, "1.5rem", slide_padding$left
    )
  }
  header_background <- list(
    auto = header_background_auto,
    background_color = header_background_color,
    text_color = header_background_text_color,
    padding = header_background_padding,
    content_padding_top = header_background_content_padding_top,
    ignore = header_background_ignore_classes
  )
  
  colors <- prepare_colors(colors)
  
  tf <- system.file("resources", "template.css", package = "xaringanthemer")
  template <- readLines(tf, warn = FALSE)
  template <- paste(template, collapse = "\n")
  x <- whisker::whisker.render(template)
  writeLines(x, con = outfile)
  if (!is.null(extra_css)) style_extra_css(extra_css, outfile)
  outfile
}