lila/bin/gen/piece-sprite

#!/usr/bin/env ruby

require 'fileutils'
require 'base64'
include FileUtils

lila_dir = pwd()
source_dir = lila_dir + '/public/piece/'
dest_dir = lila_dir + '/public/piece-css/'

themes = [
  ['alpha', 'svg'],
  ['cburnett', 'svg'],
  ['merida', 'svg'],
  ['pirouetti', 'svg'],
  ['spatial', 'svg'],
  ['chess7', 'svg'],
  ['reillycraig', 'svg'],
  ['fantasy', 'svg'],
  ['shapes', 'svg'],
  ['chessnut', 'svg'],
  ['companion', 'svg'],
  ['letter', 'svg'],
  ['riohacha', 'svg'],
  ['leipzig', 'svg'],
  ['kosal', 'svg'],
  ['pixel', 'svg'],
  ['california', 'svg'],
  ['maestro', 'svg'],
  ['fresca', 'svg']
]
types = {
  'svg' => 'svg+xml;base64,',
  'png' => 'png;base64,'
}
roles = ['pawn', 'knight', 'bishop', 'rook', 'queen', 'king']
colors = ['white', 'black']

# inline SVG
themes.map { |theme|
  name = theme[0]
  ext = theme[1]
  classes = colors.map { |color|
    roles.map { |role|
      piece = color[0] + (role == 'knight' ? 'N' : role.upcase[0])
      file = source_dir + name + '/' + piece + '.' + ext
      File.open(file, 'r') do|image_file|
        image = image_file.read
        base64 = Base64.strict_encode64(image)
        '.is2d .' + role + '.' + color + ' {' +
          "background-image:url('data:image/" + types[ext] + base64 + "')}"
      end
    }
  }.flatten
  File.open(dest_dir + name + '.css', 'w') { |f| f.puts classes.join("\n") }
}

# external SVG
themes.map { |theme|
  name = theme[0]
  ext = theme[1]
  classes = colors.map { |color|
    roles.map { |role|
      piece = color[0] + (role == 'knight' ? 'N' : role.upcase[0])
      '.is2d .' + role + '.' + color + ' {' +
        "background-image:url('/assets/piece/" + name + "/" + piece + "." + ext + "')}"
    }
  }.flatten
  File.open(dest_dir + name + '.external.css', 'w') { |f| f.puts classes.join("\n") }
}