def visible_pages
      visible = []
      last_inserted = 0
      splited = false
      (1..pages).each do |page|
        # insert
        if visible? page
          visible << page
          last_inserted = page
          splited = false
        else
          # need splitter
          if not splited and outer > 0 and last_inserted < page
            visible << nil
            splited = true
          end
        end
      end
      visible
    end
def visible_pages
      visible = []
      last_inserted = 0
      splited = false
      (1..pages).each do |page|
        # insert
        if visible? page
          visible << page
          last_inserted = page
          splited = false
        else
          # need splitter
          if not splited and outer > 0 and last_inserted < page
            visible << nil
            splited = true
          end
        end
      end
      visible
    end
build array with all visible pages