You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: box_drawer.rb
    path of file: ./repos/ruby_jard/lib/ruby_jard
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module RubyJard
  ##
  # Drawer to draw a nice single-line box that maximize screen area
  #
  # Each screen has 4 corners and clock-wise corresponding ID:
  # - Top-left => 1
  # - Top-right => 2
  # - Bottom-right => 3
  # - Bottom-left => 4
  #
  # For each screen, add each point to a coordinator hash.
  # - If a point is occupied by 1 screen, draw normal box corner symbol.
  # - If a point is occupied by 2 screens, look up in a map, and draw corresponding intersection corner symbol.
  # - If a point is occupied by 3 or more screens, it's definitely a + symbol.
  #
  # The corner list at each poi
    
    def calculate_corners
      corners = {}
      @screens.each do |screen|
        mark_corner(
          corners,
          screen.layout.box_x,
          screen.layout.box_y,
          TOP_LEFT
        )
        mark_corner(
          corners,
          screen.layout.box_x + screen.layout.box_width - 1,
          screen.layout.box_y,
          TOP_RIGHT
        )
        mark_corner(
          corners,
          screen.layout.box_x + screen.layout.box_width - 1,
          screen.layout.box_y + screen.layout.box_height - 1,
          BOTTOM_RIGHT
        )
        mark_corner(
          corners,
          screen.layout.box_x,
          screen.layout.box_y + screen.layout.box_height - 1,
          BOTTOM_LEFT
        )
      end
      corners
    end