def font_size_for_tag_cloud( total, lowest, highest, options={} )
 return nil if total.nil? or highest.nil? or lowest.nil?
 #
 # options
 maxf = options.delete( :max_font_size ) || 14
 minf = options.delete( :min_font_size ) || 11
 maxc = options.delete( :max_color ) || [ 0, 0, 0 ]
 minc = options.delete( :min_color ) || [ 156, 156, 156 ]
 hide_sizes = options.delete( :hide_sizes )
 hide_colours = options.delete( :hide_colours )
 #
 # function to work out rgb values
 def rgb_color( a, b, i, x)
  return nil if i <= 1 or x <= 1
  if a > b
   a-(Math.log(i)*(a-b)/Math.log(x)).floor
  else
   (Math.log(i)*(b-a)/Math.log(x)+a).floor
  end
 end
 #
 # work out colours
 c = []
 (0..2).each { |i| c << rgb_color( minc[i], maxc[i], total, highest ) || nil }
 colors = c.compact.empty? ? minc.join(',') : c.join(',')
 #
 # work out the font size
 spread = highest.to_f - lowest.to_f
 spread = 1.to_f if spread <= 0
 fontspread = maxf.to_f - minf.to_f
 fontstep = spread / fontspread
 size = ( minf + ( total.to_f / fontstep ) ).to_i
 size = maxf if size > maxf
 #
 # display the results
 size_txt = "font-size:#{ size.to_s }px;" unless hide_sizes
 color_txt = "color:rgb(#{ colors });" unless hide_colours
 return [ size_txt, color_txt ].join
end

Tag Cloud in Ruby

sql, html, rails, ruby

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