--- /dev/null
+
+require File.dirname(__FILE__) + '/base'
+
+# Experimental!!! See also the Net graph.
+#
+# Submitted by Kevin Clark http://glu.ttono.us/
+class Gruff::Spider < Gruff::Base
+
+ # Hide all text
+ attr_reader :hide_text
+ attr_accessor :hide_axes
+ attr_reader :transparent_background
+
+ def transparent_background=(value)
+ @transparent_background = value
+ @base_image = render_transparent_background if value
+ end
+
+ def hide_text=(value)
+ @hide_title = @hide_text = value
+ end
+
+ def initialize(max_value, target_width = 800)
+ super(target_width)
+ @max_value = max_value
+ @hide_legend = true;
+ end
+
+ def draw
+ @hide_line_markers = true
+
+ super
+
+ return unless @has_data
+
+ # Setup basic positioning
+ diameter = @graph_height
+ radius = @graph_height / 2.0
+ top_x = @graph_left + (@graph_width - diameter) / 2.0
+ center_x = @graph_left + (@graph_width / 2.0)
+ center_y = @graph_top + (@graph_height / 2.0) - 25 # Move graph up a bit
+
+ @unit_length = radius / @max_value
+
+
+ total_sum = sums_for_spider
+ prev_degrees = 0.0
+ additive_angle = (2 * Math::PI)/ @data.size
+
+ current_angle = 0.0
+
+ # Draw axes
+ draw_axes(center_x, center_y, radius, additive_angle) unless hide_axes
+
+ # Draw polygon
+ draw_polygon(center_x, center_y, additive_angle)
+
+
+ @d.draw(@base_image)
+ end
+
+private
+
+ def normalize_points(value)
+ value * @unit_length
+ end
+
+ def draw_label(center_x, center_y, angle, radius, amount)
+ r_offset = 50 # The distance out from the center of the pie to get point
+ x_offset = center_x # The label points need to be tweaked slightly
+ y_offset = center_y + 0 # This one doesn't though
+ x = x_offset + ((radius + r_offset) * Math.cos(angle))
+ y = y_offset + ((radius + r_offset) * Math.sin(angle))
+
+ # Draw label
+ @d.fill = @marker_color
+ @d.font = @font if @font
+ @d.pointsize = scale_fontsize(legend_font_size)
+ @d.stroke = 'transparent'
+ @d.font_weight = BoldWeight
+ @d.gravity = CenterGravity
+ @d.annotate_scaled( @base_image,
+ 0, 0,
+ x, y,
+ amount, @scale)
+ end
+
+ def draw_axes(center_x, center_y, radius, additive_angle, line_color = nil)
+ return if hide_axes
+
+ current_angle = 0.0
+
+ @data.each do |data_row|
+ @d.stroke(line_color || data_row[DATA_COLOR_INDEX])
+ @d.stroke_width 5.0
+
+ x_offset = radius * Math.cos(current_angle)
+ y_offset = radius * Math.sin(current_angle)
+
+ @d.line(center_x, center_y,
+ center_x + x_offset,
+ center_y + y_offset)
+
+ draw_label(center_x, center_y, current_angle, radius, data_row[0].to_s) unless hide_text
+
+ current_angle += additive_angle
+ end
+ end
+
+ def draw_polygon(center_x, center_y, additive_angle, color = nil)
+ points = []
+ current_angle = 0.0
+ @data.each do |data_row|
+ points << center_x + normalize_points(data_row[1][0]) * Math.cos(current_angle)
+ points << center_y + normalize_points(data_row[1][0]) * Math.sin(current_angle)
+ current_angle += additive_angle
+ end
+
+ @d.stroke_width 1.0
+ @d.stroke(color || @marker_color)
+ @d.fill(color || @marker_color)
+ @d.fill_opacity 0.4
+ @d.polygon(*points)
+ end
+
+ def sums_for_spider
+ @data.inject(0.0) {|sum, data_row| sum += data_row[1][0]}
+ end
+
+end