require 'gnuplotrb'

include GnuplotRB

titles = %w{decade Austria Hungary Belgium}

data = [

['1891-1900', 234081, 181288, 18167],

['1901-1910', 668209, 808511, 41635],

['1911-1920', 453649, 442693, 33746],

['1921-1930', 32868, 30680, 15846],

['1931-1940', 3563, 7861, 4817],

['1941-1950', 24860, 3469, 12189],

['1951-1960', 67106, 36637, 18575],

['1961-1970', 20621, 5401, 9192],

]

x = data.map(&:first)

datasets = (1..3).map do |col|

y = data.map { |row| row[col] }

Dataset.new([x, y], using: '2:xtic(1)', title: titles[col], file: true)

end

plot = Plot.new(*datasets, title: 'Histogram example', style: 'data histograms', xtics: 'nomirror rotate by -45')

plot.to_png('./gnuplot_gem.png', size: [600, 600])