R/plotting.R

In qualpalr: Automatic Generation of Qualitative Color Palettes

#' Multidimensional scaling map of qualitative color palette
#'
#' Uses the colors in a \link{qualpal} object to compute and plot a
#' multidimensional scaling (MDS) map using \code{\link[stats]{cmdscale}} on the
#' Delta E DIN99d distance matrix.
#'
#' @param x An object of class \code{"qualpal"} generated from
#'   \code{\link{qualpal}}.
#' @param \dots Arguments to pass on to \code{\link[graphics]{plot}}.
#' @seealso \code{\link{qualpal}}, \code{\link{pairs.qualpal}},
#'   \code{\link[graphics]{plot}}
#'
#' @examples
#' col_pal <- qualpal(3)
#' plot(col_pal)
#' @export

plot.qualpal <- function(x, ...) {
  args <- list(
    x = stats::cmdscale(x$de_DIN99d, k = if (length(x$hex) == 2) 1 else 2),
    asp = 1,
    col = x$hex,
    cex = 3,
    pch = 19,
    xlab = "dE DIN99d",
    ylab = "dE DIN99d"
  )
  do.call(graphics::plot, utils::modifyList(args, list(...)))
}

#' Scatterplot matrix of qualitative color palette
#'
#' Plots the colors in an object of class  \code{"qualpal"} as a scatterplot
#' matrix on either the DIN99d (the default) or HSL color space.
#'
#' @param x A list object of class \code{"qualpal"} generated from
#'   \code{\link{qualpal}}.
#' @param colorspace The color space in which to plot the colors ("DIN99d",
#'   "HSL", or "RGB").
#' @param \dots Arguments to pass on to \code{\link[graphics]{pairs}}.
#' @seealso
#'   \code{\link{qualpal}},
#'   \code{\link{plot.qualpal}},
#'   \code{\link[graphics]{pairs}}
#'
#' @examples
#' col_pal <- qualpal(3)
#' pairs(col_pal)
#' pairs(col_pal, colorspace = "HSL")
#' @export

pairs.qualpal <- function(x, colorspace = c("DIN99d", "HSL", "RGB"), ...) {
  args <- list(
    x = switch(match.arg(colorspace),
               DIN99d = x$DIN99d,
               HSL = x$HSL,
               RGB = x$RGB),
    col = x$hex,
    cex = 3,
    pch = 19
  )
  do.call(graphics::pairs, utils::modifyList(args, list(...)))
}