Helper and model methods for creating GoogleVisualr charts

googlevisualr-helper.rb

# This is a Rails helper for generating a single chart for a column from a data set.
# blood_tests is the data set, and column_name is the column from the set to use.
# It calls generate_chart_row for each record, passing the column_name argument.
# It also does some stuff with vertical axis labels and chart options.

  def generateChart(blood_tests, column_name)
    data_table = GoogleVisualr::DataTable.new

    # Add Column Headers
    data_table.new_column('string', 'Date' )
    data_table.new_column('number', column_name.to_s.capitalize)
    data_table.new_column('boolean' , nil, nil, 'scope')
    data_table.new_column('string' , nil, nil, 'tooltip')

    chart_entries = Array.new
    # Add Rows and Values
    blood_tests.each do |test|
      chart_entries.concat(test.generate_chart_row(column_name))
    end
    data_table.add_rows(chart_entries)

    if(column_name == :hba1c) then
      vaxes = [{:format => "#'%'"}]
    else
      vaxes = [{:format => "# 'mg/dL'"}]
    end

    option = { :width => 800, :height => 100, :areaOpacity => 0, :vAxes => vaxes, :colors => ['red'], :legend => {:position => 'none'}, :title => column_name.to_s.capitalize}
    chart = GoogleVisualr::Interactive::AreaChart.new(data_table, option)
    return chart
  end
# END HELPER

googlevisualr-model.rb

# This goes in the model of the item to be charted. 
# It's set up for blood tests right now but could do anything based on the column names you specify. 
# These methods are all called via the helper above.

  def generate_chart_row(column_name)
    return [[self.date.to_s,
      self[column_name], range(column_name), tooltip(column_name)]]
  end

  def range(column_name)
    case column_name
    when :triglycerides
      tri_range(self[column_name])
    when :cholesterol
      cho_range(self[column_name])
    when :hdl
      hdl_range(self[column_name])
    when :ldl
      ldl_range(self[column_name])
    when :glucose
      glu_range(self[column_name])
    when :hba1c
      hba_range(self[column_name])
    end
  end

  def tooltip(column_name)
    case column_name
    when :hba1c
      column_name.to_s.capitalize+':\r\n'+self[column_name].to_s+"%"
    else
      column_name.to_s.capitalize+':\r\n'+self[column_name].to_s+" mg/dL"
    end
  end


  def tri_range(val)
    if(val > 200)
      return true
    else
      return false
    end
  end

# END MODEL

googlevisualr-view.html.erb

<!-- This is a Rails view for generating multiple charts, one per column, for a given Rails data set using the helper and model methods below. -->
<!-- This all relies on the GoogleVisualr gem. -->

<div id='chart1'></div>
<div id='chart2'></div>
<div id='chart3'></div>
<div id='chart4'></div>
<div id='chart5'></div>
<div id='chart6'></div>
<%= render_chart(generateChart(@blood_tests, :triglycerides), 'chart1') %>
<%= render_chart(generateChart(@blood_tests, :cholesterol), 'chart2') %>
<%= render_chart(generateChart(@blood_tests, :hdl), 'chart3') %>
<%= render_chart(generateChart(@blood_tests, :ldl), 'chart4') %>
<%= render_chart(generateChart(@blood_tests, :glucose), 'chart5') %>
<%= render_chart(generateChart(@blood_tests, :hba1c), 'chart6') %>

<!-- END VIEW -->