Jixel.js

Jxl.init(function() {
            Jxl.loader.load({
                'animals': ['image', 'examples/assets/animals.png']
            }, function() {
                Jxl.state = new GameState();
            });
            Jxl.start();
        });
        
        var GameState = new Class({
           Extends: Jxl.State,
           create: function() {
                var animal = this.add(new Cat(20, 20));
                Jxl.follow(animal);
            }
        });
        var Cat = new Class({
            Extends: Jxl.Sprite,
            initialize: function(x, y) {
                this.parent({
                    graphic: Jxl.loader.get('animals'),
                    x: x,
                    y: y,
                    animated: true,
                    width: 32,
                    height: 32
                });
                this.addAnimation('run', [72,73,74,73], .30);
                this.addAnimation('idle', [48,49,50,49], .50);
                this.play('idle');
                this.speed = -80;
                this.drag = new Jxl.Point(150,150);
            },
            update: function(delta) {
                if (Jxl.keys.A == true) {
                  this.velocity.x = this.speed;
                  this._flipped = true;
                  this.play('run');
                } else if (Jxl.keys.D == true) {
                  this._flipped = false;
                  this.play('run');
                  this.velocity.x = -1*this.speed;
                } else {
                  this.play('idle');
                }
                this.parent(delta);
            }
        });