def draw
get_maximum_by_stack
super
return unless @has_data
@bar_spacing ||= 0.9
@bar_width = @graph_width / @column_count.to_f
padding = (@bar_width * (1 - @bar_spacing)) / 2
@d = @d.stroke_opacity 0.0
height = Array.new(@column_count, 0)
@norm_data.each_with_index do |data_row, row_index|
data_row[DATA_VALUES_INDEX].each_with_index do |data_point, point_index|
@d = @d.fill data_row[DATA_COLOR_INDEX]
label_center = @graph_left + (@bar_width * point_index) + (@bar_width * @bar_spacing / 2.0)
draw_label(label_center, point_index)
next if (data_point == 0)
left_x = @graph_left + (@bar_width * point_index) + padding
left_y = @graph_top + (@graph_height -
data_point * @graph_height -
height[point_index]) + 1
right_x = left_x + @bar_width * @bar_spacing
right_y = @graph_top + @graph_height - height[point_index] - 1
height[point_index] += (data_point * @graph_height )
@d = @d.rectangle(left_x, left_y, right_x, right_y)
end
end
@d.draw(@base_image)
end