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: scroll_mode.rb
    path of file: ./repos/sup/lib/sup/modes
    
    the code of the file until where you have to start completion: module Redwood

class ScrollMode < Mode
  ## we define topline and botline as the top and bottom lines of any
  ## content in the currentview.

  ## we left leftcol and rightcol as the left and right columns of any
  ## content in the current view. but since we're operating in a
  ## line-centric fashion, rightcol is always leftcol + the buffer
  ## width. (whereas botline is topline + at most the buffer height,
  ## and can be == to topline in the case that there's no content.)

  attr_reader :status, :topline, :botline, :leftcol

  register_keymap do |k|
    k.add :line_down, "Down one line"
    
  def initialize opts={}
    @topline, @botline, @leftcol = 0, 0, 0
    @slip_rows = opts[:slip_rows] || 0 # when we pgup/pgdown,
                                       # how many lines do we keep?
    @twiddles = opts.member?(:twiddles) ? opts[:twiddles] : true
    @search_query = nil
    @search_line = nil
    @status = ""
    super()
  end

  def rightcol; @leftcol + buffer.content_width; end

  def draw
    ensure_mode_validity
    (@topline ... @botline).each { |ln| draw_line ln, :color => :text_color }
    ((@botline - @topline) ... buffer.content_height).each do |ln|
      if @twiddles
        buffer.write ln, 0, "~", :color => :twiddle_color
      else
        buffer.write ln, 0, "", :color => :text_color
      end
    end
    @status = "lines #{@topline + 1}:#{@botline}/#{lines}"
  end

  def in_search?; @search_line end
  def cancel_search!; @search_line = nil end

  def continue_search_in_buffer
    unless @search_query
      BufferManager.flash "No current search!"
      return
    end

    start = @search_line || search_start_line
    line, col = find_text @search_query, start
    if line.nil? && (start > 0)
      line, col = find_text @search_query, 0
      BufferManager.flash "Search wrapped to top!" if line
    end
    if line
      @search_line = line + 1
      search_goto_pos line, col, col + @search_query.display_length
      buffer.mark_dirty
    else
      BufferManager.flash "Not found!"
    end
  end