A script to convert JPEG and PNG images in desired folders to WebP

convert_to_webp

#!/usr/bin/env ruby

def process_folders(message, *folders, &block)
  root = File.expand_path('../..', __FILE__)

  puts message
  puts

  total_old = 0
  total_new = 0

  folders.map{|f| Dir[File.join(root, f)] }.flatten.sort.each do |file|
    old_size, new_size = yield(file)

    next unless old_size && new_size

    puts "%70s: %7d -> %7d (%0.1f%% less)" % [
      file.sub(root, ''),
      old_size,
      new_size,
      (1 - new_size.to_f / old_size) * 100
    ]

    if old_size > new_size
      total_old += old_size
      total_new += new_size
    end
  end

  puts
  puts "Done! Total save: %d of %d (%01.f%%)" % [
    total_old - total_new,
    total_old,
    (1 - total_new.to_f / total_old) * 100
  ]
  puts
end

process_folders("Converting PNG images to WebP...",
  'public/assets/**/*.png',
  'public/images/**/*.png'
) do |file|
  next if File.file?("#{file}.webp") && File.mtime("#{file}.webp") > File.mtime(file)

  result = `cwebp -short -alpha_method 1 -lossless #{ file } -o #{ file }.webp 2>&1`

  old_size = File.size(file)
  new_size = result.split(' ').first.to_i

  [old_size, new_size]
end


process_folders("Converting JPG images to WebP...",
  'public/assets/**/*.jpg',
  'public/images/**/*.jpg'
) do |file|
  next if File.file?("#{file}.webp") && File.mtime("#{file}.webp") > File.mtime(file)

  result = `cwebp -short #{ file } -o #{ file }.webp 2>&1`

  old_size = File.size(file)
  new_size = result.split(' ').first.to_i

  [old_size, new_size]
end