add_data (SVG::Graph::Plot)

    # File temp/Graph/Plot.rb, line 135
          def add_data data
            @data = [] unless @data

            raise "No data provided by #{conf.inspect}" unless data[:data] and
              data[:data].kind_of? Array
            raise "Data supplied must be x,y pairs!  "+
              "The data provided contained an odd set of "+
              "data points" unless data[:data].length % 2 == 0
            return if data[:data].length == 0

            x = []
            y = []
            data[:data].each_index {|i|
              (i%2 == 0 ? x : y) << data[:data][i]
            }
            sort_two( x, y )
            data[:data] = [x,y]
            @data << data
          end