Colorpalette from image: nice to have

[lazarusA]

I do have this script to obtain colorpalettes from images (like the ones for Taylor Swift :D, https://twitter.com/drob/status/1459259255312236547 ). However, probably it will be nice to have a built-in function in ColorSchemes for this. Just in case this is of interest, here the relevant code (probably not the best approach, but it works).

using Clustering, Colors, Random
using Images: load, RGB, channelview, permutedims

function getColorPalette(image; ncolors = 5)
        img_CHWa = channelview(image)
        #img_CHW = permutedims(img_CHWa, (1,3,2))
        testmat = reshape(img_CHWa, (3, size(image)[1]*size(image)[2])) #input shape
        sol = kmeans(testmat, ncolors)
        csize = counts(sol) # get the cluster sizes
        colores = sol.centers # get the cluster centers, dominat colors
        indxc = sortperm(csize)
        colores, indxc
end

[cormullion]

Hi Lazaro! Yes, that's a nice feature!

Some time ago, ColorSchemes.jl was split into two, prompted by the Plots folk: a barebones list of palettes (ColorSchemes.jl), and the various functions for building and modifying images - which eventually ended up in a separate repo, ColorSchemeTools.jl.

It would be interesting to compare the performance and results of your function and the one there : (https://github.com/JuliaGraphics/ColorSchemeTools.jl/blob/51b617c40ae03911e22bcb100b72a3e956e3844f/src/ColorSchemeTools.jl#L55).

I remember having to experiment with the options to get a palette which looks to my eyes a faithful representation of the image - I think clustering is a bit random?

I used to make views of movies with this function: here's the James Bond collection from a few years ago: https://imgur.com/a/AaZMV.

[lazarusA]

As a reference, here are some example of how the colours look like:
https://nextjournal.com/lazarus/extracting-dominant-colours-from-pictures

I will take a look at SchemeTools later (it's also clustering ). Ahh, is the same thing. Good to know that this already there.

Nice James Bond collections :D