# File lib/gruff/side_stacked_bar.rb, line 62
    def draw
      @has_left_labels = true
      get_maximum_by_stack
      super

      return unless @has_data

      # Setup spacing.
      #
      # Columns sit stacked.
      spacing_factor = 0.9

      @bar_width = @graph_height / @column_count.to_f
      @d = @d.stroke_opacity 0.0
      height = Array.new(@column_count, 0)
      length = Array.new(@column_count, @graph_left)

      @norm_data.each_with_index do |data_row, row_index|
        @d = @d.fill data_row[DATA_COLOR_INDEX]

        data_row[1].each_with_index do |data_point, point_index|

          ## using the original calcs from the stacked bar chart to get the difference between
          ## part of the bart chart we wish to stack.
          temp1 = @graph_left + (@graph_width -
                                      data_point * @graph_width - 
                                      height[point_index]) + 1
          temp2 = @graph_left + @graph_width - height[point_index] - 1
          difference = temp2 - temp1

          left_x = length[point_index] #+ 1
                left_y = @graph_top + (@bar_width * point_index)
          right_x = left_x + difference
                right_y = left_y + @bar_width * spacing_factor
          length[point_index] += difference
          height[point_index] += (data_point * @graph_width - 2)

          @d = @d.rectangle(left_x, left_y, right_x, right_y)

          # Calculate center based on bar_width and current row
          label_center = @graph_top + (@bar_width * point_index) + (@bar_width * spacing_factor / 2.0)
          draw_label(label_center, point_index)
        end

      end

      @d.draw(@base_image)    
    end