# File lib/pdf/writer/object/viewerpreferences.rb, line 66
66:   def to_s
67:     res = "\n#{@id} 0 obj\n<< "
68:     Preferences.each do |s|
69:       v = __send__("#{s.downcase}".intern)
70:       res << "\n/#{s} /#{v}" unless v.nil?
71:     end
72:     res << "\n>>\n"
73:   end