Left Lever

Lever.js

!(function () {
	class Lever {
		constructor(data) {
			const lever = this;

			lever.canvas = document.getElementById(data.canvasId);
			lever.context = lever.canvas.getContext('2d');

			lever.canvas.width = data.width;
			lever.canvas.height = data.height;

			lever.objects = [];

			lever.registerBase = new Map;
			lever.register('point', _drawPoint);
			lever.register('line', _drawLine);
		}

		register(typeName, handler) {
			const lever = this;

			lever.registerBase.set(typeName, handler);
		}

		add(data) {
			const lever = this;

			lever.objects.push(data);
		}

		draw() {
			const lever = this;

			for (const data of lever.objects) {
				if (data.type && lever.registerBase.has(data.type)) {
					lever.registerBase.get(data.type)(lever.context, data, lever);
				}
			}
		}

		clear() {
			const lever = this;

			lever.canvas.width = lever.canvas.width;
		}

		interval(loop, timeout) {
			const lever = this;

			const startMoment = Date.now();
			let n = 0;

			return setInterval(() => loop(Date.now() - startMoment, ++n, lever), timeout);
		}
	}

	window.Lever = Lever;

	function _drawPoint(context, data, lever) {
		context.beginPath();
		context.arc(data.x, data.y, data.r, 0, 2 * Math.PI, false);
		context.fillStyle = data.color;
		context.fill();
	}

	function _drawLine(context, data, lever) {
		context.beginPath();
		context.moveTo(data.x1, data.y1);
		context.lineTo(data.x2, data.y2);
		context.stroke();
	}

})();