class PDF::Reader::TextRun

def +(other)
  raise ArgumentError, "#{other} cannot be merged with this run" unless mergable?(other)
  if (other.x - endx) <( font_size * 0.2)
    TextRun.new(x, y, other.endx - x, font_size, text + other.text)
  else
    TextRun.new(x, y, other.endx - x, font_size, "#{text} #{other.text}")
  end
end