to_s (PDF::Writer::Object::Catalog)

        # File lib/pdf/writer/object/catalog.rb, line 29
    29:   def to_s
    30:     res = "\n#{@oid} 0 obj\n<< /Type /Catalog"
    31:     res << "\n/Outlines #{@outlines.oid} 0 R" unless @outlines.nil?
    32:     res << "\n/Pages #{@pages.oid} 0 R" unless @pages.nil?
    33:     res << "\n/ViewerPreferences #{@viewer_preferences.oid} 0 R" if @viewer_preferences and @parent.version >= '1.2'
    34:     res << "\n/OpenAction #{@open_here.oid} 0 R" unless @open_here.nil?
    35:     res << "\n/PageMode /#{@page_mode}" unless @page_mode.nil?
    36:     res << "\n/Version /#{@parent.version}" if @parent.version >= '1.4'
    37:     res << ">>\nendobj"
    38:   end