R/tim_colors.R

In neuroconductor-releases/oro.nifti: Rigorous - 'NIfTI' + 'ANALYZE' + 'AFNI' : Input / Output

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## Copyright (c) 2009, 2015, Brandon Whitcher and Volker Schmid
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#' @title Tim's Useful Color Table
#' 
#' @description A pleasing rainbow style color table patterned after that used 
#' in Matlab.
#' 
#' @details Based on the \code{tim.colors} function in the \pkg{fields} package.  
#' The \code{tim.colors} function here has been modified to break any dependence 
#' on code in the \pkg{fields} package.  Spline interpolation
#' (\code{interpSpline}) is used when the number of requested colors is not the
#' default.
#' 
#' @param n is the number of color levels (default = 64).
#' @return A vector of character strings giving the colors in hexadecimal
#' format.
#' @author Tim Hoar (GSP-NCAR); modified by Brandon Whitcher
#' @seealso \code{\link{hotmetal}}, \code{\link{topo.colors}},
#' \code{\link{terrain.colors}}
#' @keywords aplot
#' @examples
#' 
#' tim.colors(10) 
#' image(outer(1:20, 1:20, "+"), col=tim.colors(75), main="tim.colors")
#' @export 
#' @importFrom splines interpSpline
#' @rdname tim_colors
#' @name tim.colors
tim.colors <- function(n=64) {
  ## Tim Hoar's original 64 color definition:
  orig <- c("#00008F", "#00009F", "#0000AF", "#0000BF",
            "#0000CF", "#0000DF", "#0000EF", "#0000FF",
            "#0010FF", "#0020FF", "#0030FF", "#0040FF",
            "#0050FF", "#0060FF", "#0070FF", "#0080FF",
            "#008FFF", "#009FFF", "#00AFFF", "#00BFFF",
            "#00CFFF", "#00DFFF", "#00EFFF", "#00FFFF",
            "#10FFEF", "#20FFDF", "#30FFCF", "#40FFBF",
            "#50FFAF", "#60FF9F", "#70FF8F", "#80FF80",
            "#8FFF70", "#9FFF60", "#AFFF50", "#BFFF40",
            "#CFFF30", "#DFFF20", "#EFFF10", "#FFFF00",
            "#FFEF00", "#FFDF00", "#FFCF00", "#FFBF00",
            "#FFAF00", "#FF9F00", "#FF8F00", "#FF8000",
            "#FF7000", "#FF6000", "#FF5000", "#FF4000",
            "#FF3000", "#FF2000", "#FF1000", "#FF0000",
            "#EF0000", "#DF0000", "#CF0000", "#BF0000",
            "#AF0000", "#9F0000", "#8F0000", "#800000")
  if (n == 64) {
    return(orig)
  }
  rgb.tim <- t(col2rgb(orig))
  temp <- matrix(NA, ncol=3, nrow=n)
  x <- seq(0, 1, length.out=64)
  xg <- seq(0, 1, length.out=n)
  for (k in 1:3) {
    hold <- splines::interpSpline(x, rgb.tim[, k])
    hold <- predict(hold, xg)$y
    hold[hold < 0] <- 0
    hold[hold > 255] <- 255
    temp[, k] <- round(hold)
  }
  rgb(temp[,1], temp[,2], temp[,3], maxColorValue=255)
}