chart
plots a column for each series.
#
# You can use the :type
option to plot a point chart instead.
filename = File.basename(__FILE__).gsub('.rb', '.pdf')
Prawn::ManualBuilder::Example.generate(filename) do
data = {views: {2013 => 182, 2014 => 46, 2015 => 88},
uniques: {2013 => -104, 2014 => 27, 2015 => 14}}
chart data, type: :point, labels: [false, true], formats: []
end