julia-climate.jl

using Luxor, Colors

function main(fname)
    Drawing(600, 600, fname)
    origin()
    circle(O, 290, :clip)
    sethue("white")
    paint()

    colors = [Luxor.julia_blue, Luxor.julia_red, Luxor.julia_green, Luxor.julia_purple]

    # make a table with rows smaller in the middle
    progression = [70, 55, 47, 40, 30, 20, 14]
    fatrows = vcat(progression, reverse(progression))
    # every other row is blank
    thinrows = fill(12, 2 * length(progression))
    table = Table(collect(Iterators.flatten(zip(fatrows, thinrows))), [500])
    L = length(table)
    wavelength = 70
    for (pos, n) in table
        table.rowheights[n] < minimum(progression) && continue # skip thin rows
        # march through the four Julia colors
        col = convert(Int, min(1 + floor((n - 1) / L * 4), 4))
        sethue(colors[col])
        @layer begin
            translate(pos)
            # amplitude of sine scales by y coordinate
            sf = rescale(abs(pos.y), 0, 300, 5, 32)
            pts = [Point(x, sf * sin(x * 1/wavelength)) for x = -300:300]
            setline(table.rowheights[n])
            poly(pts, :stroke)
        end
    end

    # outer ring
    @layer begin
        setcolor("#635")
        setline(30)
        circle(O, 291, :stroke)
        end
    finish()
    preview()
end

main("/tmp/juliaclimate.png")