projects.mako.cc - selectricity/blob - lib/gruff-0.2.8/lib/gruff/spider.rb

   1
   2 require File.dirname(__FILE__) + '/base'
   3
   4 # Experimental!!! See also the Net graph.
   5 #
   6 # Submitted by Kevin Clark http://glu.ttono.us/
   7 class Gruff::Spider < Gruff::Base
   8
   9   # Hide all text
  10   attr_reader :hide_text
  11   attr_accessor :hide_axes
  12   attr_reader :transparent_background
  13
  14   def transparent_background=(value)
  15     @transparent_background = value
  16     @base_image = render_transparent_background if value
  17   end
  18
  19   def hide_text=(value)
  20     @hide_title = @hide_text = value
  21   end
  22
  23   def initialize(max_value, target_width = 800)
  24     super(target_width)
  25     @max_value = max_value
  26     @hide_legend = true;
  27   end
  28
  29   def draw
  30     @hide_line_markers = true
  31
  32     super
  33
  34     return unless @has_data
  35
  36     # Setup basic positioning
  37     diameter = @graph_height
  38     radius = @graph_height / 2.0
  39     top_x = @graph_left + (@graph_width - diameter) / 2.0
  40     center_x = @graph_left + (@graph_width / 2.0)
  41     center_y = @graph_top + (@graph_height / 2.0) - 25 # Move graph up a bit
  42
  43     @unit_length = radius / @max_value
  44
  45
  46     total_sum = sums_for_spider
  47     prev_degrees = 0.0
  48     additive_angle = (2 * Math::PI)/ @data.size
  49
  50     current_angle = 0.0
  51
  52     # Draw axes
  53     draw_axes(center_x, center_y, radius, additive_angle) unless hide_axes
  54
  55     # Draw polygon
  56     draw_polygon(center_x, center_y, additive_angle)
  57
  58
  59     @d.draw(@base_image)
  60   end
  61
  62 private
  63
  64   def normalize_points(value)
  65     value * @unit_length
  66   end
  67
  68   def draw_label(center_x, center_y, angle, radius, amount)
  69     r_offset = 50      # The distance out from the center of the pie to get point
  70     x_offset = center_x      # The label points need to be tweaked slightly
  71     y_offset = center_y + 0  # This one doesn't though
  72     x = x_offset + ((radius + r_offset) * Math.cos(angle))
  73     y = y_offset + ((radius + r_offset) * Math.sin(angle))
  74
  75     # Draw label
  76     @d.fill = @marker_color
  77     @d.font = @font if @font
  78     @d.pointsize = scale_fontsize(legend_font_size)
  79     @d.stroke = 'transparent'
  80     @d.font_weight = BoldWeight
  81     @d.gravity = CenterGravity
  82     @d.annotate_scaled( @base_image,
  83                       0, 0,
  84                       x, y,
  85                       amount, @scale)
  86   end
  87
  88   def draw_axes(center_x, center_y, radius, additive_angle, line_color = nil)
  89     return if hide_axes
  90
  91     current_angle = 0.0
  92
  93     @data.each do |data_row|
  94       @d.stroke(line_color || data_row[DATA_COLOR_INDEX])
  95       @d.stroke_width 5.0
  96
  97       x_offset = radius * Math.cos(current_angle)
  98       y_offset = radius * Math.sin(current_angle)
  99
 100       @d.line(center_x, center_y,
 101               center_x + x_offset,
 102               center_y + y_offset)
 103
 104       draw_label(center_x, center_y, current_angle, radius, data_row[0].to_s) unless hide_text
 105
 106       current_angle += additive_angle
 107     end
 108   end
 109
 110   def draw_polygon(center_x, center_y, additive_angle, color = nil)
 111     points = []
 112     current_angle = 0.0
 113     @data.each do |data_row|
 114       points << center_x + normalize_points(data_row[1][0]) * Math.cos(current_angle)
 115       points << center_y + normalize_points(data_row[1][0]) * Math.sin(current_angle)
 116       current_angle += additive_angle
 117     end
 118
 119     @d.stroke_width 1.0
 120     @d.stroke(color || @marker_color)
 121     @d.fill(color || @marker_color)
 122     @d.fill_opacity 0.4
 123     @d.polygon(*points)
 124   end
 125
 126   def sums_for_spider
 127     @data.inject(0.0) {|sum, data_row| sum += data_row[1][0]}
 128   end
 129
 130 end