R/ptol.R

In ggthemes: Extra Themes, Scales and Geoms for 'ggplot2'

#' Color Palettes from Paul Tol's "Colour Schemes"
#'
#' Qualitative color palettes from Paul Tol,
#' \href{https://personal.sron.nl/~pault/}{"Colour Schemes"}.
#'
#' Incorporation of the palette into an R package was originally inspired by
#' Peter Carl's [Paul Tol 21 Gun Salute](https://tradeblotter.wordpress.com/2013/02/28/the-paul-tol-21-color-salute/)
#'
#' @export
#' @family colour ptol
#' @references
#' Paul Tol. 2012. "Colour Schemes." SRON Technical Note, SRON/EPS/TN/09-002.
#'  \url{https://personal.sron.nl/~pault/data/colourschemes.pdf}
#' @example inst/examples/ex-ptol_pal.R
ptol_pal <- function() {
  colors <- ggthemes::ggthemes_data[["ptol"]][["qualitative"]]
  max_n <- length(colors)
  f <- function(n) {
    check_pal_n(n, max_n)
    colors[[n]]
  }
  attr(f, "max_n") <- max_n
  f
}

#' Color Scales from Paul Tol's "Colour Schemes
#'
#' See \code{\link{ptol_pal}()}. These palettes support up to 12 values.
#'
#' @inheritParams ggplot2::scale_colour_hue
#' @inheritParams ptol_pal
#' @family colour ptol
#' @rdname scale_ptol
#' @export
#' @example inst/examples/ex-scale_colour_ptol.R
scale_colour_ptol <- function(...) {
  discrete_scale("colour", "ptol", ptol_pal(), ...)
}

#' @export
#' @rdname scale_ptol
scale_color_ptol <- scale_colour_ptol

#' @export
#' @rdname scale_ptol
scale_fill_ptol <- function(...) {
  discrete_scale("fill", "ptol", ptol_pal(), ...)
}