Delaunay Triangulation

This is a port of Mapbox's Delaunator project.

Add this line to your application's Gemfile:

gem 'delaunator'

And then execute:

$ bundle

Or install it yourself as:

$ gem install delaunator

Delaunator.triangulate() returns an array of triangle vertex indices (each group of three numbers forms a triangle). All triangles are directed counterclockwise.

points = [[382, 302], [382, 328], [382, 205], [623, 175], [382, 188], [382, 284], [623, 87], [623, 341], [141, 227]]
triangles = Delaunator.triangulate(points)
# => [2, 3, 4, 2, 5, 3, 5, 7, 3, 3, 6, 4, 0, 7, 5, 1, 7, 0, 0, 8, 1, 5, 8, 0, 2, 8, 5, 4, 8, 2, 6, 8, 4]

You can then use these indices to get the coordinates of each triangle:

(0..triangles.length-1).step(3) do |i|
    ax, ay = points[triangles[i]]
    bx, by = points[triangles[i + 1]]
    cx, cy = points[triangles[i + 2]]
    # (ax, ay), (bx, by), (cx, cy) are your triangle points
    ...

After implementing your own render function you can show the edges of the Delaunay triangulation:

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/hendrixfan/delaunator-ruby.

The gem is available as open source under the terms of the MIT License.