A Crystal implementation of the Google polyline algorithm.

Greatly inspired by the Ruby implementation fast-polylines, it is mostly existing for performance comparison between Ruby C extensions and Crystal!

If you are curious: encoding is roughly the same, decoding is way faster in Crystal. If you are even more curious, make benchmark here and in fast-polylines 😉. With a MacBook pro 1,4 GHz i5, here's the result:

——————————————————————————————— ENCODING ————————————————————————————————

CrystalPolylines 706.82k (  1.41µs) (± 4.42%)  466B/op  fastest

———————————————————————————————  DECODING ————————————————————————————————

CrystalPolylines   1.43M (699.73ns) (± 3.21%)  1.62kB/op  fastest

Add the dependency to your shard.yml:

dependencies:
  polylines:
    github: BuonOmo/polylines.cr

Run shards install

require "polylines"

Polylines.encode([{lat: 38.5, lng: -120.2}, {lat: 40.7, lng: -120.95}])
Polylines.encode([[38.5, -120.2], [40.7, -120.95]])
Polylines.encode([{38.5, -120.2}, {40.7, -120.95}])
# => "_p~iF~ps|U_ulLnnqC"

Polylines.decode("_p~iF~ps|U_ulLnnqC")
# => [{lat: 38.5, lng: -120.2}, {lat: 40.7, lng: -120.95}]

Polylines.encode([{lat: 12.1232493, lng: 2.9481493}, {lat: 13.8474392, lng: 16.8373924}], 7)
# => "yemffFi`lfw@uqj{_@}gi|gG"

Polylines.decode("yemffFi`lfw@uqj{_@}gi|gG", 7)
# => [{lat: 12.1232493, lng: 2.9481493}, {lat: 13.8474392, lng: 16.8373924}]

1. Fork it (BuonOmo/polylines.cr/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request