Ruby - HTML Tagcloud with easy changeable formular

README.md

Tagcloud Calculation

Usage

Calculate weight of given array. e.g. %w[ruby ruby ruby rails]

Tagcloud.tagcloudize [ "rails", "ruby", "rails" ...] do |count,max|
 90 + 110 * ( count / max.to_f)
end

results in:

[{:text=>"rails", :count=>1, :size=>126}, {:text=>"ruby", :count=>3, :size=>200}]

Now, one can use some kind of helper to generate html (not included in this gist, to keep independence), or here directly in haml:

Tagcloud.tagcloudize(array).each do |e|
  %span{:style => "font-size: #{e[:size]}%"}
    = link_to e[:text], search_path(:q => e[:text])

just to make the point, Stuff like this should be put into a helper or partial.

Improvements:

• Instead of direct size calculation, calculate levels for css classes. More prettier :)

tagcloud.rb

# from ruby stats
class Array
  def histogram ; self.sort.inject({}){|a,x|a[x]=a[x].to_i+1;a} ; end
end

# Usage:
#   Tagcloud.tagcloudize [ "rails", "ruby", "rails" ...] do |count,max|
#      90 + 110 * ( count / max.to_f)
#   end
#  means: calculate tagcloud. Minsize 90, maxsize 90+110=200
#
#
# Expects [ "rails", "ruby", "rails" ...]
class Tagcloud

  # Expects [ "rails", "ruby", "rails" ...]
  def self.tagcloudize(array)
    return [] if array.blank?
    distribution = array.histogram
    max = distribution.max_by{|a,b|b}[1]
    distribution.map do |text,count|
      if block_given?
        size = yield(count,max)
      else
        size = Tagcloud.default_formula(count,max)
      end
      {:text => text, :count => count, :size => size.to_i}
    end
  end

  def self.default_formula(count,max)
    90 + 110 * ( count / max.to_f)
  end
end