For usage on my blog Le Quant 40 together with the Highcharts graphical library, I required a Javascript implementation of a fast algorithm to calculate a convex hull from a set of points in x,y coordinates (Graham's Scan then).
I found what I needed on brian3kb's Github, although this implementation lacked the capability of managing points with labels, which I added.
The minified source code, for immediate usage in a browser, is available here.
The following commands produce the minified file graham_scan.min.js and launch the unit tests with QUnit:
npm install
grunt deliver
The QUnit unit tests are located in the file tests/index.html.
Straightforward:
// Create a new instance.
var aConvexHull = new ConvexHullGrahamScan();
// Points addition, one by one, with an optional label
aConvexHull.addPoint(1.5, 3.1);
aConvexHull.addPoint(1.6, 3.2, 'my label');
// Computation of the convex hull
// The returned array is in JSON format: [{x: x coordinate, y: y coordinate, name: point label }, ...]
var hullPoints = convexHull.getHull();