function Text.previous_screen_line(State, pos2)

function Text.previous_screen_line(State, loc2)
  if loc2.screen_line > 1 then
    return {line=loc2.line, screen_line=loc2.screen_line-1, screen_pos=1}
  elseif loc2.line == 1 then
    return loc2
  elseif State.lines[loc2.line-1].mode == 'drawing' then
    return {line=loc2.line-1, screen_line=1, screen_pos=1}