optimize_pngs.rake

task :optimize_pngs => 'optimize_pngs:setup' do
  dir = ENV['DIRECTORY'] || Rails.root.join('app/assets')

  from_extension = ENV['EXTENSION'] || '-optimize'
  to_extension = 'd.png' # -2x-optimize.png => -2x-optimized.png
  speed = ENV['SPEED'] || 1
  files = Dir[dir.join("**/*#{from_extension}.png")]

  options = ["--ext #{to_extension}", "--speed #{speed}"]
  options << '--verbose' if ENV['VERBOSE'] == 'true'
  options << '--force' unless ENV['NO_FORCE'] == 'true'

  `pngquant #{options.join(' ')} #{files.join(' ')}`
end

namespace :optimize_pngs do
  task :setup do
    unless `which pngquant`.length > 0
      puts 'pngquant not found - installing from homebrew ...'
      `brew update && brew install pngquant`
    end
  end
end