https://github.com/mikolalysenko/compare-slope

Checks if a pair of 2D vectors are oriented CW/CCW relatively
https://github.com/mikolalysenko/compare-slope

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Checks if a pair of 2D vectors are oriented CW/CCW relatively

• Host: GitHub
• URL: https://github.com/mikolalysenko/compare-slope
• Owner: mikolalysenko
• License: mit
• Created: 2013-04-01T18:53:12.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2013-05-14T00:11:26.000Z (over 11 years ago)
• Last Synced: 2024-10-10T21:42:47.580Z (3 months ago)
• Language: JavaScript
• Size: 105 KB
• Stars: 5
• Watchers: 4
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
compare-slope

=============

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.

Use

===

First install using npm:

    npm install compare-slope

    

Then use as follows:

```javascript

var compareSlope = require("compare-slope")

console.log(compareSlope([0, 1], [1, 2]))

```

### `require("compare-slope")(a, b)`

Checks whether `a` comes before `b` in a counter-clockwise ordering.

* `a` and `b` are both represented by arrays of at least length 2

**Returns:**

* `> 0` if `b` is clockwise from `a`

* `< 0` if `a` is clockwise from `b`

* `0` if `a` and `b` are collinear

**Note:** Somewhat arbitrarily, the degenerate point at the origin is ranked before all other points.

Credits

=======

(c) 2013 Mikola Lysenko. MIT License