R/colorpanel.R

In NormalizeMets: Analysis of Metabolomics Data

#colorpanel function from gplots
#n Desired number of color elements in the panel.
#low, mid, high: Colors to use for the Lowest, middle, and highest values. mid may be ommited.
colorpanel<-function (n, low, mid, high) 
{
  if (missing(mid) || missing(high)) {
    low <- col2rgb(low)
    if (missing(high)) 
      high <- col2rgb(mid)
    else high <- col2rgb(high)
    red <- seq(low[1, 1], high[1, 1], length = n)/255
    green <- seq(low[3, 1], high[3, 1], length = n)/255
    blue <- seq(low[2, 1], high[2, 1], length = n)/255
  }
  else {
    isodd <- odd(n)
    if (isodd) {
      n <- n + 1
    }
    low <- col2rgb(low)
    mid <- col2rgb(mid)
    high <- col2rgb(high)
    lower <- floor(n/2)
    upper <- n - lower
    red <- c(seq(low[1, 1], mid[1, 1], length = lower), seq(mid[1, 
                                                                1], high[1, 1], length = upper))/255
    green <- c(seq(low[3, 1], mid[3, 1], length = lower), 
               seq(mid[3, 1], high[3, 1], length = upper))/255
    blue <- c(seq(low[2, 1], mid[2, 1], length = lower), 
              seq(mid[2, 1], high[2, 1], length = upper))/255
    if (isodd) {
      red <- red[-(lower + 1)]
      green <- green[-(lower + 1)]
      blue <- blue[-(lower + 1)]
    }
  }
  rgb(red, blue, green)
}