Images

A Julia Julia set: ColorSchemes and Images

Here's an example of how you can use ColorSchemes when creating images with Images.jl. The code creates a Julia set and uses a pre-defined ColorScheme extracted from Vermeer's painting "Girl with a Pearl Earring" (shown at the right for reference).

using ColorSchemes, Images, FileIO# and possibly QuartzImageIO (macOS) and/or ImageMagick (Linux)function julia(z, c, maxiter::Int64)    for n = 1:maxiter        if abs(z) > 2            return n        end        z = z^2 + c    end    return maxiterend# convert a value between oldmin/oldmax to equivalent value between newmin/newmaxremap(value, oldmin, oldmax, newmin, newmax) = ((value - oldmin) / (oldmax - oldmin)) * (newmax - newmin) + newminfunction draw(c, imsize;      xmin = -1, ymin = -1, xmax  =  1, ymax = 1,      filename = "/tmp/julia-set.png")    imOutput = zeros(RGB{Float32}, imsize, imsize)    maxiterations = 200    for col = range(xmin, stop=xmax, length=imsize)        for row = range(ymin, stop=ymax, length=imsize)            pixelcolor = julia(complex(row, col), c, maxiterations) / 256            xpos = convert(Int, round(remap(col, xmin, xmax, 1, imsize)))            ypos = convert(Int, round(remap(row, ymin, ymax, 1, imsize)))            imOutput[xpos, ypos] = get(ColorSchemes.vermeer, pixelcolor)        end    end    save(filename, imOutput)enddraw(-0.4 + 0.6im, 1200)