comics-cutter

config.yml

setting:
  source:
    dir: src
    format: jpg
  output:
    dir: _output
    format: jpg
  height: 1920
  width: 1350
  digits: 3
default:
  margin:
    top: 0
    bottom: 0
    left: 0
    right: 0
files:
  02.jpg:
    margin:
      top: 3180
    override:
      3:
        height: 1320

cut.rb

#!/usr/bin/env ruby

require 'fileutils'
require 'yaml'

DRYRUN = ENV['DRYRUN']

config = YAML.load(File.read('config.yml'))

source_dir = config['setting']['source']['dir']
output_dir = config['setting']['output']['dir']
source_fmt = config['setting']['source']['format']
output_fmt = config['setting']['output']['format']
img_width  = config['setting']['width']
img_height = config['setting']['height']
digits     = config['setting']['digits']

default_top = config['default']['margin']['top']
default_bottom = config['default']['margin']['bottom']
default_left = config['default']['margin']['left']
default_right = config['default']['margin']['right']
default_height = config['default']['height'] || img_height
default_width = config['default']['width'] || img_width

FileUtils.rm_rf output_dir unless DRYRUN
FileUtils.mkdir_p output_dir unless DRYRUN

counter = 0

def die message
  abort message unless DRYRUN
  puts "[!] #{message}"
end

paths = Dir["#{source_dir}/*.#{source_fmt}"]
paths.each.with_index do |path, i|
  file = File.basename(path)
  puts "[+] processing #{file} [#{i+1}/#{paths.count}]..."

  height, width = `identify -ping -format "%h:%w" #{path}`.split(':').map(&:to_i)
  margin_top = config.dig('files', file, 'margin', 'top') || default_top
  margin_bottom = config.dig('files', file, 'margin', 'bottom') || default_bottom
  margin_left = config.dig('files', file, 'margin', 'left') || default_left
  margin_right = config.dig('files', file, 'margin', 'right') || default_right
  img_height = config.dig('files', file, 'height') || default_height
  img_width = config.dig('files', file, 'width') || default_width

  canvas_width = width - margin_left - margin_right
  canvas_height = height - margin_top - margin_bottom

  overrides = config.dig('files', file, 'override') || {}
  override_height_sum = overrides.map do |_, override|
    override.dig('height') || img_height
  end.sum
  remaining = (canvas_height - override_height_sum) % img_height

  next die "error: wrong canvas width: #{canvas_width}" unless canvas_width == img_width
  next die "error: wrong canvas height: #{remaining} px remaining" unless remaining == 0

  offset = margin_top
  count = (canvas_height - override_height_sum) / img_height + overrides.count
  (1..count).each do |j|
    counter += 1

    output_file = "#{output_dir}/#{"%0#{digits}d" % counter}.#{output_fmt}"
    puts "  [+] generating #{output_file} [#{j}/#{count}]..."

    source_height = config.dig('files', file, 'override', j, 'height') || default_height
    source_width = source_height * default_width / default_height

    command = <<~COMMAND
      convert #{path}
        -crop #{source_width}x#{source_height}+#{margin_left}+#{offset}
        +repage
        -resize #{img_width}x#{img_height}
        #{output_file}
    COMMAND
    command = command.gsub(/\n  /, ' ')
    puts "  [>] #{command}"
    system command unless DRYRUN

    offset += source_height
  end
end

puts '[+] all done'
puts
puts 'press ENTER to exit'
gets