R/drawScale.R

In bryanhanson/ChemoSpec2D: Exploratory Chemometrics for 2D Spectroscopy

#'
#' Draw the Scale
#'
#' @export
#' @noRd
#' @importFrom graphics plot.new mtext rect
#'

.drawScale <- function(cscale, orient) {
  nc <- length(cscale)

  if (orient == "horizontal") {
    plot(1:nc, rep(1.0, nc),
      type = "n", bty = "n",
      yaxt = "n", xaxt = "n", main = "", xlab = "", ylab = ""
    )
    for (i in 1:nc) {
      rect(i - 0.5, 0.5, i + 0.5, 1.5, border = NA, col = cscale[i])
    }
  } # end of orient == "horizontal"

  if (orient == "vertical") {
    op <- par(no.readonly = TRUE) # save to restore later (must call before layout)
    par(mai = c(0.75, 3.4, 0.75, 3.4))

    plot(rep(1.0, nc), 1:nc,
      type = "n", bty = "n",
      yaxt = "n", xaxt = "n", main = "", xlab = "", ylab = ""
    )
    for (i in 1:nc) {
      rect(0.5, i - 0.5, 1.5, i + 0.5, border = NA, col = cscale[i])
    }
    mtext("low", side = 1)
    mtext("high", side = 3)
    on.exit(par(op)) # restore original values
  } # end of orient == "vertical"
}