class PDF::Reader::PageLayout

def interesting_rows(rows)


=> [ "one", "two" ]
interesting_rows([ "", "one", "two", "" ])

beginning and end removed.
given an array of strings, return a new array with empty rows from the 
def interesting_rows(rows)
  line_lengths = rows.map { |l| l.strip.length }
  return [] if line_lengths.all?(&:zero?)
  first_line_with_text = line_lengths.index { |l| l > 0 }
  last_line_with_text  = line_lengths.size - line_lengths.reverse.index { |l| l > 0 }
  interesting_line_count = last_line_with_text - first_line_with_text
  rows[first_line_with_text, interesting_line_count].map
end