code: def to_rtf
          text  = StringIO.new
          count = 0
    
          #text << '{\pard{\*\shppict{\pict'
          text << '{\*\shppict{\pict'
          text << "\\picscalex#{@x_scaling}" if @x_scaling != nil
          text << "\\picscaley#{@y_scaling}" if @y_scaling != nil
          text << "\\piccropl#{@left_crop}" if @left_crop != nil
          text << "\\piccropr#{@right_crop}" if @right_crop != nil
          text << "\\piccropt#{@top_crop}" if @top_crop != nil
          text << "\\piccropb#{@bottom_crop}" if @bottom_crop != nil
          text << "\\picwgoal#{@displayed_width}" if @displayed_width != nil
          text << "\\pichgoal#{@displayed_height}" if @displayed_height != nil        
          text << "\\picw#{@width}\\pich#{@height}\\bliptag#{@id}"
          text << "\\#{@type.id2name}\n"
    
          open_file do |file|
            file.each_byte do |byte|
              hex_str = byte.to_s(16)
              hex_str.insert(0,'0') if hex_str.length == 1
              text << hex_str    
              count += 1
              if count == 40
                text << "\n"
                count = 0
              end
            end
          end
          #text << "\n}}\\par}"
          text << "\n}}"
  
          text.string
        end
docs: This method generates the RTF for an ImageNode object.