Ranks the slope of a pair of vectors through the origin in clockwise order. This is more robust than comparing their arc tangents using atan2.
First install using npm:
npm install compare-slope
Then use as follows:
var compareSlope = require("compare-slope")
console.log(compareSlope([0, 1], [1, 2]))
Checks whether a
comes before b
in a counter-clockwise ordering.
-
a
andb
are both represented by arrays of at least length 2
Returns:
-
> 0
ifb
is clockwise froma
-
< 0
ifa
is clockwise fromb
-
0
ifa
andb
are collinear
Note: Somewhat arbitrarily, the degenerate point at the origin is ranked before all other points.
(c) 2013 Mikola Lysenko. MIT License