Hull.js - JavaScript library that builds concave hull by set of points.

This library was born in free independent Ukraine, and it has 2 important messages:

• one message for the civilized world: Ukraine and the whole free world is under attack right now, and you can help to defend it by supporting the Armed Forces of Ukraine who are fighting for all of us on the front line. Just donate either here: https://bank.gov.ua/en/news/all/natsionalniy-bank-vidkriv-spetsrahunok-dlya-zboru-koshtiv-na-potrebi-armiyi or here: https://savelife.in.ua/en/donate/
• and one message for russia: Русский военный корабль, иди нахуй!

See live examples here.

var points = [ [236, 126], [234, 115], [238, 109], [247, 102], ... ];
hull(points, 50); // returns points of the hull (in clockwise order)

• 1st param - array of coordinates in format: [[x1, y1], [x2, y2], ..., [xn, yn]];
• 2nd param - concavity. 1 - thin shape. Infinity - convex hull. By default 20;
• 3rd param - points format. For example: ['.lng', '.lat'] if you have {lng: x, lat: y} points. By default you can use [x, y] points.

Let's see step by step what happens when you call hull() function:

1. Hull.js takes your source points of the shape:
   
2. Builds convex hull:
   
3. After that, the edges flex inward (according to the `concavity` param). For example:
   `concavity = 80`
   `concavity = 40`
   `concavity = 20`

This library relies on ES6. The ES6 features used are:

• new Set(null), Set#add, Set#has
• let, const
• Math.trunc (if available)

You may use polyfills for Set and compile with babel to continue to support old browsers.

npm install             # install dependencies
npm test                # build dist file and run tests
npm run-script watch    # watch ./src dir and rebuild dist file

If you want to get involved with Hull.js development, just use github flow and feel free to contribute!

• think about holes;
• think about automatic concavity adjustment based on density.

• Implementation of a fast and efficient concave hull algorithm;
• Computational Geometry: Convex Hulls;
• Andrew's monotone chain convex hull algorithm;
• Line Segment Intersection Algorithm;
• Game Math: "Cross Product" of 2D Vectors;
• Угол между двумя векторами;
• Когда не нужна тригонометрия.

• Clean up .gitignore.
• Add "debug" folder to .npmignore to reduce tarball size.

Introduce fix that avoids hitting stack size limit on large arrays.

• Change language level to ES6.
• Performance improvements.

Return the first point as the last point when fewer than 4 unique points are provided.

Fix missing "var" declaration.

• Fix modification of the initial array.
• Add filtration of the duplicates.

Add edgeSkipList to increase performance of the highly accurate shapes (with the small concavity number) + refactoring.

Fix bower.json.

Fix bower.json.

Bower support.

Minor fixes (copyrights).

Minor fixes (readme, package.json).

Configurable point formats, now you can use points like {x: 10, y: 10} and {lat: 52, lng: 82}.

Some minor updates (doc, package.json, etc.).

Second version with better performance inspired by this article.

First version based on Delaunay triangulation.