hex_color_mix.rb

hex_colors=["1f77b4", "ff7f0e", "2ca02c", "d62728", "9467bd", "8c564b", "e377c2", "7f7f7f", "bcbd22", "17becf", "1f77b4", "ff7f0e", "2ca02c"]
values = hex_colors.collect do |hex|
  (0..2).collect do |cindex| # collect components (r,g,b)
    chex = hex[(cindex*2)..(cindex*2+1)]
    c = chex.to_i(16) # convert from hex
    mix = c * 0.25 + 255 * 0.75 # mix original color with white (equivalent to 0.25 opacity)
    mix.to_i.to_s(16) # convert to hex
  end.join()
end
p values