okcupidlabz / node-geom2d

2d vectors, geometry, and affine transformations for nodejs

Explanation

A very alpha version of a JS Library for doing affine transformations and (coming soon) other simple transformations I need for a bigger project. My first node module. Written in IcedCoffeeScript. affine and polygon are currently the two big exports.

Browser Use

For your convenience, this project is stitched into one JS file, geom2d.js. The stitched file provides a way of requiring components. Here's an example:

<script src="geom2d.js"></script>
<script>
 var affine  = require('affine');
 var polygon = require('polygon');

 var rot_left  = new affine.rotation(  Math.PI / 4);
 var rot_right = new affine.rotation( -Math.PI / 4);
 var go_big    = new affine.scaling (  2,   4);
 var go_small  = new affine.scaling (  0.5, 0.25);
 
 var t = rot_left.copy();
 // rightComposing a transform A with another, A'
 // desctructively replaces A with A'(A)
 t.rightComposeWith(rot_right);
 t.rightComposeWith(go_big);
 t.rightComposeWith(go_small);
 
 var square = polygon.factory.unitSquare();
 
 document.write("<h3>Square before</h3>");
 document.write(JSON.stringify(square));
 
 document.write("<h3>Square after (should be the same)</h3>");
 square.transform(t);
 document.write(JSON.stringify(square));
</script>

Node Installation

npm install -g geom2d

Usage (CoffeeScript example)

{affine, polygon} = require 'geom2d'

rot_left  = new affine.rotation  Math.PI / 4
rot_right = new affine.rotation -Math.PI / 4
go_big    = new affine.scaling   2,   4
go_small  = new affine.scaling   0.5, 0.25


# rightComposing a transform A with another, A'
# desctructively replaces A with A'(A)
t = rot_left.copy()
t.rightComposeWith rot_right
t.rightComposeWith go_big
t.rightComposeWith go_small

square = polygon.factory.unitSquare()
square.transform t

# square should be the same, as the 4 affines 
# cancel each other out.
console.log square

Contributing

All .js and .json files are auto-generated. Please edit the appropropriate .iced files and run cake build before committing.

geom2d is written in an improved version of CoffeeScript called "IcedCoffeeScript".