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Tag Cloud for Octopress
# tag_cloud.rb
#
# Copyright (C) 2011 Anurag Priyam - MIT License
module Jekyll
# Jekyll plugin to generate tag clouds.
#
# The plugin defines a `tag_cloud` tag that is rendered by Liquid into a tag
# cloud:
#
# <div class='cloud'>
# {% tag_cloud %}
# </div>
#
# The tag cloud itself is a collection of anchor tags, styled dynamically
# with the `font-size` CSS property. The range of values, and unit to use for
# `font-size` can be specified with a very simple syntax:
#
# {% tag_cloud font-size: 16 - 28px %}
#
# The output is automatically formatted to use the same number of decimal
# places as used in the argument:
#
# {% tag_cloud font-size: 0.8 - 1.8em %} # => 1
# {% tag_cloud font-size: 0.80 - 1.80em %} # => 2
#
# Tags that have been used less than a certain number of times can be
# filtered out from the tag cloud with the optional `threshold` parameter:
#
# {% tag_cloud threshold: 2%}
#
# Both the parameters can be easily clubbed together:
#
# {% tag_cloud font-size: 50 - 150%, threshold: 2%}
#
# The plugin randomizes the order of tags every time the cloud is generated.
class TagCloud < Liquid::Tag
safe = true
# tag cloud variables - these are setup in `initialize`
attr_reader :size_min, :size_max, :precision, :unit, :threshold
def initialize(name, params, tokens)
# initialize default values
@size_min, @size_max, @precision, @unit = 70, 170, 0, '%'
@threshold = 1
# process parameters
@params = Hash[*params.split(/(?:: *)|(?:, *)/)]
process_font_size(@params['font-size'])
process_threshold(@params['threshold'])
super
end
def render(context)
# get category directory of category page
config = context.registers[:site].config
dir = config['root'] + config['category_dir']
# get an Array of [tag name, tag count] pairs
count = context.registers[:site].categories.map do |name, posts|
[name, posts.count] if posts.count >= threshold
end
# clear nils if any
count.compact!
# get the minimum, and maximum tag count
min, max = count.map(&:last).minmax
# map: [[tag name, tag count]] -> [[tag name, tag weight]]
weight = count.map do |name, count|
# logarithmic distribution
weight = (Math.log(count) - Math.log(min))/(Math.log(max) - Math.log(min))
[name, weight]
end
# shuffle the [tag name, tag weight] pairs
weight.sort_by! { rand }
# reduce the Array of [tag name, tag weight] pairs to HTML
weight.reduce("") do |html, tag|
name, weight = tag
size = size_min + ((size_max - size_min) * weight).to_f
size = sprintf("%.#{@precision}f", size)
html << "<a style='font-size: #{size}#{unit}' href='#{dir}/#{name.downcase}/'>#{name}</a>\n"
end
end
private
def process_font_size(param)
/(\d*\.{0,1}(\d*)) *- *(\d*\.{0,1}(\d*)) *(%|em|px)/.match(param) do |m|
@size_min = m[1].to_f
@size_max = m[3].to_f
@precision = [m[2].size, m[4].size].max
@unit = m[5]
end
end
def process_threshold(param)
/\d*/.match(param) do |m|
@threshold = m[0].to_i
end
end
end
end
Liquid::Template.register_tag('tag_cloud', Jekyll::TagCloud)
Owner

tokkonopapa commented Jan 8, 2012

Original Code:
yeban/yeban.github.com

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