I just reviewed the code of Pixi.js and I think there's a point that deserve attention. It is much faster to handle an object when it is not rotated/skewed. Its transform matrix is much simpler (doesn't require matrix at all) and lot of computation could be removed. Bounds computing is also much simpler. I wonder if it's not worth implementing an optimization for this. It won't change the API at all, it will add very few code. Just a check for each objects, and saves a lot of code for non rotated objects. I would like to know what people think about that. Do you use rotation on most of your objects or only few of them ?