gistfile1.rb

    def pie(data_array)
        @labels = ""
        @data_str = ""
        @data = []
        @sum = 0
        data_array.find().to_a.each do |f|
            @labels += "#{f['_id']}|"
            @sum += f['value']['count'].to_i
            @data.push(f['value']['count'].to_i)
        end
        @data.each do |d|
            @num = d/(@sum + 0.0) * 100
            @data_str += "#{@num.round},"
        end
        @labels = @labels[0..@labels.length-2]
        @data_str = @data_str[0..@data_str.length-2]
        return <<-HTML
            <img src="http://chart.apis.google.com/chart?chs=450x200&chd=t:#{@data_str}&cht=p3&chl=#{@labels}" />
        HTML
    end