画像をKindle用にトリミング，リサイズ，ガンマ調整

trimming_for_kindle.rb

#!/usr/bin/env ruby

def suffix(file, suffix)
  base = File.basename(file, File.extname(file))
  ext = File.extname(file)
  "#{base}#{suffix}#{ext}"
end

banner = <<EOF
usage
trimming_for_kindle.rb *.jpg
EOF

if ARGV.empty?
  puts banner
  exit(1)
end

ARGV.each{|file|
  puts file
  info = `identify #{file}`
  size = info.scan(/\d+(?:x)\d+/).first
  w, h = *size.split(/x/)
  w = w.to_i
  h = h.to_i
  system "mogrify -crop #{w-40}x#{h-40}+20+20 #{file}" or exit
  system "mogrify -fuzz 15% -trim #{file}" or exit
  system "mogrify -gamma 0.3 -resize 560x742 #{file}" or exit
}