--
-- We won't care too much about long, wrapped lines. If they lines get too
-- long to manage, you need a better, graphical rendering for them.

  -- move
  if chord == 'up' then
    if State.screen_top1.line > 1 then
      State.screen_top1.line = State.screen_top1.line-1
    end
  elseif chord == 'down' then
    if State.screen_top1.line < #State.lines then
      State.screen_top1.line = State.screen_top1.line+1
    end
  elseif chord == 'pageup' then
    local y = 0
    while State.screen_top1.line > 1 and y < App.screen.height - 100 do
      State.screen_top1.line = State.screen_top1.line - 1
      y = y + tenonauger.height(State, State.screen_top1.line)
    end
  elseif chord == 'pagedown' then
    local y = 0
    while State.screen_top1.line < #State.lines and y < App.screen.height - 100 do
      y = y + tenonauger.height(State, State.screen_top1.line)
      State.screen_top1.line = State.screen_top1.line + 1
    end
  end

function tenonauger.height(State, line_index)
  return State.line_height
end