xem

Conventions

• A = [xA, yA] is a point on the 2D plane. Same for B, C, ...
• lengths are in any unit (ex: pixels)
• code snippets are in JavaScript

Degrees to radians

angleRad = angleDeg * Math.PI / 180;

paulirish

/* bling.js */
window.$ = document.querySelector.bind(document);
window.$$ = document.querySelectorAll.bind(document);
Node.prototype.on = window.on = function(name, fn) { this.addEventListener(name, fn); };
NodeList.prototype.__proto__ = Array.prototype;
NodeList.prototype.on = function(name, fn) { this.forEach((elem) => elem.on(name, fn)); };