colormaps with equal luminance

color.jl

using Pkg
Pkg.activate(".")
using Colors
using Mustache
using Plots
using Clustering

luma(color) = luma(convert(RGB, color))
luma(color::T) where {T <: RGB} = 0.299color.r + 0.587color.g + 0.114color.b

function generate_color(H=30, Y=0.3, S=0.5)
   L = collect(0.0:0.001:1.0)
   colors = map(l -> HSL(H, S, l), L)
   best_match = findmin(abs.(luma.(colors).-Y))
   return colors[last(best_match)]
end

colors = generate_color.(1:360, 0.6, 0.2)
reshape(colors, (20, 18))
D = zeros(Float64, (length(colors),length(colors)))
for (i,c1) in enumerate(colors)
   for (j,c2) in enumerate(colors)
      D[i,j] = colordiff(c1,c2)
   end
end

heatmap(D)