DIY Philips Hue Sync for Linux

hsync.rb

#!/bin/env ruby
# frozen_string_literal: true

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'hue', '~> 0.2'
  gem 'color', '~> 1.8'
end

IMPORT = `which import`.chomp
MONITOR_X_OFFSET = 2560
MONITOR_Y_OFFSET = 0
REFRESH_RATE = 2.0

def import_command(x_offset, y_offset)
  [
    IMPORT,
    '-silent',
    '-window root',
    "-crop 1x1+#{x_offset.to_i}+#{y_offset.to_i}",
    '-depth 8',
    'txt:-'
  ].join(' ')
end

def pixel_colour(x_offset, y_offset)
  m = `#{import_command(x_offset, y_offset)}`.match(/\((\d+),(\d+),(\d+)\)/)

  return @pixel_colour = { r: m[1].to_i, g: m[2].to_i, b: m[3].to_i } if m
  return @pixel_colour unless @pixel_colour.nil?

  raise 'No initial pixel data'
end

client = Hue::Client.new
play_lights = []
target_pixels = []
screen_res = `xrandr | head -n 1`.match(/current (\d+) x (\d+)/)

raise 'No screen resolution data' unless screen_res

client.lights.each do |light|
  play_lights << light if light.name =~ /play/i
  light.on!
end

target_pixels[0] = [
  (
    (screen_res[1].to_i - MONITOR_X_OFFSET) / 3
  ) + MONITOR_X_OFFSET,
  (
    (screen_res[2].to_i - MONITOR_Y_OFFSET) / 2
  ) + MONITOR_Y_OFFSET
]

target_pixels[1] = [
  (
    (screen_res[1].to_i - MONITOR_X_OFFSET) * (2 / 3.0)
  ).to_i + MONITOR_X_OFFSET,
  target_pixels[0][1]
]

begin
  loop do
    play_lights.each_with_index do |light, index|
      rgb = pixel_colour(target_pixels[index][0], target_pixels[index][1])

      xyz = Color::RGB.new(rgb[:r], rgb[:g], rgb[:b]).to_xyz

      x = xyz[:x] / (xyz[:x] + xyz[:y] + xyz[:z])
      y = xyz[:y] / (xyz[:x] + xyz[:y] + xyz[:z])
      light.set_state({ xy: [x, y] }, 400)

      sleep REFRESH_RATE
    end
  end
rescue SystemExit, Interrupt, StandardError => e
  puts e.message
  play_lights.each(&:off!)
end

import.sh