Use HammerSpoon to capture screenshots, then ImageMagick to compile

gistfile1.txt

require 'mini_magick'

# HammerSpoon config
# function takeScreenshot(window)
#   window:snapshot():saveToFile(os.getenv("HOME") .. "/Desktop/chrome-images/" .. os.time() .. ".png")
# end
#
# local wf=hs.window.filter
# wf_chrome = wf.new{'Google Chrome'}
# wf_chrome:subscribe(wf.windowFocused,takeScreenshot)

#MiniMagick.logger.level = Logger::DEBUG

images = Dir['/users/simon.hildebrandt/Desktop/chrome-images/*']
output = File.expand_path('../output', __FILE__)

images.each do |path|
  image = MiniMagick::Image.open(path)
  image.crop "x36+0"
  pieces = path.match /\/(\d+.png)\Z/
  image.write File.join(output, pieces[1])
end

images = Dir['output/*']

x = ""
images.each_slice(10).with_index do |slice, i|
  MiniMagick::Tool::Montage.new do |out|
    slice.each do |image|
      out << image
    end
    out.geometry '+0+0'
    out.tile '1x'
    out << "out#{i}.png"
    x << "<img src='out#{i}.png'>"
  end
end

File.open("x.html", 'w') { |f| f.write x }