# File lib/gruff/stacked_area.rb, line 9
 9:   def draw
10:     super
11: 
12:     return unless @has_data
13: 
14:     @x_increment = @graph_width / (@column_count - 1).to_f
15:     @d = @d.stroke 'transparent'
16: 
17:     height = Array.new(@column_count, 0)
18: 
19:     data_points = nil
20:     iterator = last_series_goes_on_bottom ? :reverse_each : :each
21:     @norm_data.send(iterator) do |data_row|
22:       prev_data_points = data_points
23:       data_points = Array.new
24:         
25:       @d = @d.fill data_row[DATA_COLOR_INDEX]
26: 
27:       data_row[1].each_with_index do |data_point, index|
28:         # Use incremented x and scaled y
29:         new_x = @graph_left + (@x_increment * index)
30:         new_y = @graph_top + (@graph_height - data_point * @graph_height - height[index])
31: 
32:         height[index] += (data_point * @graph_height)
33:         
34:         data_points << new_x
35:         data_points << new_y
36:           
37:         draw_label(new_x, index)
38: 
39:       end
40: 
41:       if prev_data_points
42:         poly_points = data_points.dup
43:         (prev_data_points.length/2 - 1).downto(0) do |i|
44:           poly_points << prev_data_points[2*i] 
45:           poly_points << prev_data_points[2*i+1]
46:         end
47:         poly_points << data_points[0] 
48:         poly_points << data_points[1] 
49:       else
50:         poly_points = data_points.dup
51:         poly_points << @graph_right
52:         poly_points << @graph_bottom - 1
53:         poly_points << @graph_left
54:         poly_points << @graph_bottom - 1
55:         poly_points << data_points[0] 
56:         poly_points << data_points[1] 
57:       end
58:       @d = @d.polyline(*poly_points)
59: 
60:     end
61: 
62:     @d.draw(@base_image)
63:   end