Performance: CSS3 animations vs. HTML5 Canvas

Question

I\'m working on a webapp (will only be running in Chrome 19+) that is currently built with CSS3 transitions. More specifically, I\'m using Jquery Transit to fir

Answer 1

CSS3 will give you fewer headaches and you can change it easily in the future, and it will work gracefully on systems that aren't canvas-enabled.

If you're using text, you should absolutely stick with CSS if you can get away with it. Canvas ruins the accessibility of your app and disallows users from using a carat or highlighting text or using text to speech.

If you're just making a funny sliding button or something then you should also just use CSS as it will probably be much easier to implement and maintain. Redoing CSS is easier than slogging over (what can be complex) JavaScript.

I can't honestly tell you if canvas renderings will be smoother. One plus of the canvas is that you can animate things to a seemingly larger size (while keeping the canvas the same size) without having to cause the DOM to re-layout. On most modern systems this really isn't an issue thought.

Furthermore, if its already done with CSS3, are you actually having performance problems? If nobody has complained about performance yet, why bother rewriting it for canvas? If you aren't encountering any real performance problems so far, why reinvent your app?

Answer 2

The problem I think you might run into with canvas is that it is bitmap based. Therefore scaling up and down after the page is initially rendered will be a problem. Furthermore, line breaks will be painful to deal with potentially. The people who write your site's content might find it challenging to insert line breaks because there is no such thing as a line break using canvas, svg, or vml. In fact you need to pre-compute line breaks. "\n" using raphael.js works, but it isn't great. Furthermore you can't use selectors to target various portions if you in your svg graphics. You may be able to using canvas, maybe.... Canvas probably has a buncha of the same gotchas.

On the image front you will have blurry images if it scales and there are less libraries out there that deal with image resizing for canvas. This may change in the future, but it will still be an ordeal to deal with. I'd just stick with your divs/css3 with jquery fallbacks for older browsers.

From a purely performance perspective, checkout the first comment on your question. It has some nice benchmarks.