Render text in color for Markdown / Quarto | Format refs to packages in inline text

colorize.R

#' Render text in color for Markdown / Quarto documents using LaTeX or CSS styles
#' 
#' This function uses `\textcolor{}{}` from the `xcolor` package for LaTeX output
#' or a CSS `<span>` for HTML output.
#' 
#' Note that a color not defined in the `xcolor` package will trigger a latex error.
#' e.g., `darkgreen` is not defined but can use:
#'    \definecolor{darkgreen}{RGB}{1,50,32}
#'
#' @param text  Text to display, a character string
#' @param color Color to use, a valid color designation
#'
#' @return A character string with color-encoded text
#' @export
#'
#' @examples
#' # None yet
#' 
colorize <- function(text, color) {
  if (missing(color)) color <- text
  if (knitr::is_latex_output()) {
    sprintf("\\textcolor{%s}{%s}", color, text)
  } else if (knitr::is_html_output()) {
    sprintf("<span style='color: %s;'>%s</span>", color, text)
  } else text
}

# Define some color names for use in figure captions.
# use as: 
#    #| fig-cap: !expr glue::glue("Some points are ", {red}, " some are ", {blue}, "some are ", {green})

red <- colorize('red')
pink <- colorize("pink")
blue <- colorize('blue')
green <- colorize("green")
lightgreen <- colorize("lightgreen")
darkgreen <- colorize("darkgreen")


if (knitr::is_latex_output()) {
  # options(crayon.enabled = FALSE)
  # options(cli.unicode = TRUE)
}

pkgrefs.R

# References to package inline in text
#   Use as: `r pkg("lattice")` or `r pkg("lattice", cite=TRUE)`
#
#   Assumes the bibtex key will be of the form: R-package
# * Produces appropriate markup for HTML and PDF
# * Allows package names to be printed in color and in different font styles (bold, ital, ...)
#
#
# See: Demonstration of how to use other fonts in an Rmarkdown document 
#      https://gist.github.com/richarddmorey/27e74bcbf28190d150d266ae141f5117

# attributes for displaying the package name
pkgname_font = "bold"    # or: plain, ital, boldital
pkgname_color ="brown"   # uses colorize()
pkgname_face = "mono"    # not implemented

pkg <- function(package, cite=FALSE) {
  if (knitr::is_latex_output()) {
      pkgname <- dplyr::case_when(
      pkgname_font == "ital"      ~ paste0("\\texttt{\\textit{", package, "}}"),
      pkgname_font == "bold"      ~ paste0("\\texttt{\\textbf{", package, "}}"),
      pkgname_font == "boldital"  ~ paste0("\\texttt{\\textit{\\textbf{", package, "}}}"),
      .default = paste0("\\texttt{", package, "}}")
    )
  }
  # HTML output
  else {
    pkgname <- dplyr::case_when(
      pkgname_font == "ital"      ~ paste0("_", package, "_"),
      pkgname_font == "bold"      ~ paste0("**", package, "**"),
      pkgname_font == "boldital"  ~ paste0("***", package, "***"),
      .default = package
    )
  }

  ref <- pkgname
  if (!is.null(pkgname_color)) ref <- colorize(pkgname, pkgname_color)
  if (cite) ref <- paste0(ref, " [@R-", package, "]")
  if (knitr::is_latex_output()) {
    ref <- paste0(ref, "\n\\index{`", pkgname, " package`}",
                        "\n\\index{packages!", pkgname, "}")
  }
  ref
}

# Same, but say "`pkgname` package cite"
package <- function(package, cite=FALSE) {
  if (knitr::is_latex_output()) {
    pkgname <- dplyr::case_when(
      pkgname_font == "ital"      ~ paste0("\\texttt{\\textit{", package, "}}"),
      pkgname_font == "bold"      ~ paste0("\\texttt{\\textbf{", package, "}}"),
      pkgname_font == "boldital"  ~ paste0("\\texttt{\\textit{\\textbf{", package, "}}}"),
      .default = paste0("\\texttt{", package, "}}")
    )
  }
  # HTML output
  else {
    pkgname <- dplyr::case_when(
      pkgname_font == "ital"      ~ paste0("_", package, "_"),
      pkgname_font == "bold"      ~ paste0("**", package, "**"),
      pkgname_font == "boldital"  ~ paste0("***", package, "***"),
      .default = package
    )
  }
  
  ref <- pkgname
  if (!is.null(pkgname_color)) ref <- colorize(pkgname, pkgname_color)
  if (cite) ref <- paste0(ref, " package [@R-", package, "]")
  if (knitr::is_latex_output()) {
    ref <- paste0(ref, "\n\\index{`", pkgname, " package`}",
                  "\n\\index{packages!", pkgname, "}")
  }
  ref
}