Gruff::StackedArea

 
               # File lib/gruff/stacked_area.rb, line 9
def draw
  get_maximum_by_stack
  super

  return unless @has_data

  @x_increment = @graph_width / (@column_count - 1).to_f
  @d = @d.stroke 'transparent'

  height = Array.new(@column_count, 0)

  data_points = nil
  iterator = last_series_goes_on_bottom ? :reverse_each : :each
  @norm_data.send(iterator) do |data_row|
    prev_data_points = data_points
    data_points = Array.new
      
    @d = @d.fill data_row[DATA_COLOR_INDEX]

    data_row[DATA_VALUES_INDEX].each_with_index do |data_point, index|
      # Use incremented x and scaled y
      new_x = @graph_left + (@x_increment * index)
      new_y = @graph_top + (@graph_height - data_point * @graph_height - height[index])

      height[index] += (data_point * @graph_height)
      
      data_points << new_x
      data_points << new_y
        
      draw_label(new_x, index)

    end

    if prev_data_points
      poly_points = data_points.dup
      (prev_data_points.length/2 - 1).downto(0) do |i|
        poly_points << prev_data_points[2*i] 
        poly_points << prev_data_points[2*i+1]
      end
      poly_points << data_points[0] 
      poly_points << data_points[1] 
    else
      poly_points = data_points.dup
      poly_points << @graph_right
      poly_points << @graph_bottom - 1
      poly_points << @graph_left
      poly_points << @graph_bottom - 1
      poly_points << data_points[0] 
      poly_points << data_points[1] 
    end
    @d = @d.polyline(*poly_points)

  end

  @d.draw(@base_image)
end