CoffeeScript code to pan and zoom using the mouse wheel for paper.js, see app/scripts/pan_and_zoom.coffee.
The code is explained in Stable Zooming and Panning in paper.js.
Run
$ npm install
$ grunt serve
Then open http://127.0.0.1:9000
Documentation and running examples are generated from CoffeeScript source by running Docco, including live reload in the browser, see Mixing Documentation and Live Code in CoffeeScript.