# File lib/gruff/scatter.rb, line 176
  def normalize(force=@xy_normalize)
    if @norm_data.nil? || force 
      @norm_data = []
      return unless @has_data
      
      @data.each do |data_row|
        norm_data_points = [data_row[DATA_LABEL_INDEX]]
        norm_data_points << data_row[DATA_VALUES_INDEX].map do |r|  
                                (r.to_f - @minimum_value.to_f) / @spread
                            end
        norm_data_points << data_row[DATA_COLOR_INDEX]
        norm_data_points << data_row[DATA_VALUES_X_INDEX].map do |r|  
                                (r.to_f - @minimum_x_value.to_f) / @x_spread 
                            end
        @norm_data << norm_data_points
      end
    end
    #~ @norm_y_baseline = (@baseline_y_value.to_f / @maximum_value.to_f) if @baseline_y_value
    #~ @norm_x_baseline = (@baseline_x_value.to_f / @maximum_x_value.to_f) if @baseline_x_value
  end