Ruby script to generate CSS animation keyframes for a rotating font icon who's text-shadow stays at the same angle

keyframes.rb

L = 0.15
S = 8

(S+1).times do |i|
  time = (100.0 / S) * i
  angle = ((360 / S) * i)
  theta = ((angle % 360) * -1) * Math::PI / 180
  x = L * Math.cos(theta) - L * Math.sin(theta)
  y = L * Math.sin(theta) + L * Math.cos(theta)

  values = {
    step: time,
    angle: angle,
    x: ['%.2g' % x.round(2), ('rem' if x.abs > 0.001)].join,
    y: ['%.2g' % y.round(2), ('rem' if y.abs > 0.001)].join
  }

  keyframe =<<-EOF % values
  %<step>.10g%% {
    transform: rotate(%{angle}deg);
    text-shadow: %{x} %{y} 0 #333;
  }
  EOF

  puts keyframe
end