draw (Gruff::SideBar)

    # File lib/gruff/side_bar.rb, line 8
      def draw
        @has_left_labels = true
        super

        return unless @has_data

        # Setup spacing.
        #
        spacing_factor = 0.9

        @bars_width = @graph_height / @column_count.to_f
        @bar_width = @bars_width * spacing_factor / @norm_data.size
        @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[DATA_VALUES_INDEX].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])
            temp2      = @graph_left + @graph_width - height[point_index]
            difference = temp2 - temp1

            left_x     = length[point_index] - 1
            left_y     = @graph_top + (@bars_width * point_index) + (@bar_width * row_index)
            right_x    = left_x + difference
            right_y    = left_y + @bar_width

            height[point_index] += (data_point * @graph_width)

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

            # Calculate center based on bar_width and current row
            label_center = @graph_top + (@bars_width * point_index + @bars_width / 2)
            draw_label(label_center, point_index)
          end

        end

        @d.draw(@base_image)
      end