コミックマーケット DVD-ROMカタログのデータをプログラムから利用する（サークルカット編） ref: http://qiita.com/AKB428/items/dbb0e073a9ff50b687d3

circle_cut.rb

require 'pathname'
require 'fileutils'
require 'RMagick'
module ComikeCatalogParser
  class CircleCut

    WORK_FOLDER_NAME = "./circle_cut"

    CIRCLE_CUT_SIZE_WIDTH = 165
    CIRCLE_CUT_SIZE_HEIGHT = 241

    #とりあえず計算せずMAPで持つ 1ページ 6x6=36カット
    H1 = 70
    H2 = 323
    H3 = 575
    H4 = 828
    H5 = 1081
    H6 = 1333

    W1 = 15
    W2 = 192
    W3 = 369
    W4 = 547
    W5 = 724
    W6 = 903


    CIRCLE_CUT_MAP =
        [
            [W1,H1],[W2,H1],[W3,H1], [W4,H1],[W5,H1],[W6,H1],
            [W1,H2],[W2,H2],[W3,H2], [W4,H2],[W5,H2],[W6,H2],
            [W1,H3],[W2,H3],[W3,H3], [W4,H3],[W5,H3],[W6,H3],
            [W1,H4],[W2,H4],[W3,H4], [W4,H4],[W5,H4],[W6,H4],
            [W1,H5],[W2,H5],[W3,H5], [W4,H5],[W5,H5],[W6,H5],
            [W1,H6],[W2,H6],[W3,H6], [W4,H6],[W5,H6],[W6,H6],
        ]


    def initialize(circle_cut_page_file_path)
      @circle_cut_page_file_path = circle_cut_page_file_path
    end

    #対象のサークルカットPNGから1サークルのカットを切り取りファイルパスを返却する
    #すでに切り取っていたらそれを使う
    def individual_cut(position_id)

      circle_cut_page_file_name = Pathname(@circle_cut_page_file_path).basename.to_s
      circle_cut_page_file_name.gsub!("\.PNG", "")
      page_folder_name = Pathname.new(WORK_FOLDER_NAME).join(circle_cut_page_file_name).to_s
      FileUtils.mkdir_p(page_folder_name) unless File.exist?(page_folder_name)

      write_file_path_name = Pathname.new(page_folder_name).join(position_id + ".png").to_s

      #ファイルをすでにカットしていたら処理せず終了
      return write_file_path_name if File.exist?(write_file_path_name)

      image = Magick::Image.read(@circle_cut_page_file_path).first
      image.crop(CIRCLE_CUT_MAP[position_id.to_i - 1][0], CIRCLE_CUT_MAP[position_id.to_i - 1][1], CIRCLE_CUT_SIZE_WIDTH, CIRCLE_CUT_SIZE_HEIGHT).write(write_file_path_name)


      puts "create " + write_file_path_name
      write_file_path_name
    end

  end
end

file1.txt

      image = Magick::Image.read(@circle_cut_page_file_path).first
      image.crop(CIRCLE_CUT_MAP[position_id.to_i - 1][0], CIRCLE_CUT_MAP[position_id.to_i - 1][1], CIRCLE_CUT_SIZE_WIDTH, CIRCLE_CUT_SIZE_HEIGHT).write(write_file_path_name)

sample.rb

require 'circle_cut.rb'
include ComikeCatalogParser
CircleCut.new("/Users/cocoa/PDATA/1093.PNG").individual_cut("32")'