rudimentary solution for generating non-similar colors

plot.rb

@@ -6,8 +6,23 @@ log_dir = LOG_DIR
 
 colors  = {}
 
+def rand_color
+  "%06x" % (rand * 0xffffff)
+end
+
+def color_dist (c1, c2)
+  (c1[0..1].hex - c2[0..1].hex).abs +
+    (c1[2..3].hex - c2[2..3].hex).abs +
+    (c1[4..5].hex - c2[4..5].hex).abs
+end
+
 users.each do |user|
-  colors[user] = "%06x" % (rand * 0xffffff)
+  tentative_color = rand_color
+  while (colors.detect {|k,v| color_dist(v,tentative_color) < 200}) do
+    tentative_color = rand_color
+  end
+
+  colors[user] = tentative_color
 end
 
 plotstring = %Q[set terminal 'svg' size 800,400 fname 'Verdana, Helvetica, Arial, sans-serif' \