R/make_color_scale.R

In milescsmith/bubbleplot: Create bubble plot of scRNAseq expression data from Seurat

#' @title make_color_scale
#'
#' @description Using a list of colors, create a gradient of a discrete number of colors.
#'
#' @param palette One of the palettes in RColorBrewer, viridis, or a list of
#'   colors understood by colors()
#' @param gradations The number of colors to return
#'
#' @return A list of hexidecimal numbers.
#' @export
#'
#' @importFrom RColorBrewer brewer.pal.info brewer.pal
#' @importFrom viridis viridis
#' @importFrom grDevices colorRampPalette
#'
#' @examples
make_color_scale <- function(palette = "viridis", gradations = 10) {
  if (length(palette) == 1) {
    if (palette %in% rownames(brewer.pal.info)) {
      pal <- colorRampPalette(brewer.pal(
        brewer.pal.info[palette, ]$maxcolors,
        palette
      ))(gradations)
    } else if (palette %in% c(
      "viridis",
      "inferno",
      "magma",
      "plasma",
      "cividis"
    )) {
      pal <- viridis(n = gradations, option = palette)
    } else {
      stop("That is not a valid palette")
    }
  } else {
    pal <- colorRampPalette(palette)(gradations)
  }
  
  pal
}