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#!/usr/bin/ruby # daltonize an image with ruby-vips # based on # http://scien.stanford.edu/pages/labsite/2005/psych221/projects/05/ofidaner/colorblindness_project.htm # see # http://libvips.blogspot.co.uk/2013/05/daltonize-in-ruby-vips-carrierwave-and.html # for a discussion of this code require "vips" # Vips.set_debug true # matrices to convert D65 XYZ to and from bradford cone space xyz_to_brad = [ [0.8951, 0.2664, -0.1614], [-0.7502, 1.7135, 0.0367], [0.0389, -0.0685, 1.0296] ] brad_to_xyz = [ [0.987, -0.147, 0.16], [0.432, 0.5184, 0.0493], [-0.0085, 0.04, 0.968] ] im = Vips::Image.new_from_file ARGV[0] # remove any alpha channel before processing alpha = nil if im.bands == 4 alpha = im[3] im = im.extract_band 0, n: 3 end begin # import to XYZ with lcms # if there's no profile there, we'll fall back to the thing below xyz = im.icc_import embedded: true, pcs: :xyz rescue Vips::Error # nope .. use the built-in converter instead xyz = im.colourspace :xyz end brad = xyz.recomb xyz_to_brad # through the Deuteranope matrix # we need rows to sum to 1 in Bradford space --- the matrix in the original # Python code sums to 1.742 deut = brad.recomb [ [1, 0, 0], [0.7, 0, 0.3], [0, 0, 1] ] xyz = deut.recomb brad_to_xyz # .. and back to sRGB rgb = xyz.colourspace :srgb # so this is the colour error err = im - rgb # add the error back to other channels to make a compensated image im += err.recomb([[0, 0, 0], [0.7, 1, 0], [0.7, 0, 1]]) # reattach any alpha we saved above if alpha im = im.bandjoin(alpha) end im.write_to_file ARGV[1]
Version data entries
14 entries across 13 versions & 4 rubygems