# File lib/text/format.rb, line 728
728:   def center(to_center = nil)
729:     to_center = @text if to_center.nil?
730:     to_center = [to_center].flatten
731: 
732:     tabs = 0
733:     width = @columns - @left_margin - @right_margin
734:     centered = []
735:     to_center.each do |tc|
736:       s = tc.strip
737:       tabs = s.count(TAB)
738:       tabs = 0 if tabs.nil?
739:       ct = ((width - s.size - (tabs * @tabstop) + tabs) / 2)
740:       ct = (width - @left_margin - @right_margin) - ct
741:       centered << "#{s.rjust(ct)}\n"
742:     end
743:     centered.join('')
744:   end