class PDF::Reader::TextReceiver

def media_box_check (dict)
  corners = (@upper_corners.last || {:urx => 0, :ury => 0}).dup
  if dict.has_key?('MediaBox')
    media_box = dict['MediaBox']
    corners[:urx] = media_box[2] - media_box[0]
    corners[:ury] = media_box[3] - media_box[1]
  end
  corners
end