We currently have 2 types of spinners/throbbers: - The one used in splash.css, with 3 squares changing opacity - The one used everywhere else, which comes in multiple sizes, with a rotating circle The splash one is often not animating properly, on both slow desktops and phones. It's painting all the time, and it seems that it doesn't benefit from OMTC as a result. The second one is only rotating and seems like it benefits from OMTC, but uses an image (bug 988674). Also, when it has padding on it (which happens fairly often) we repaint a lot more than what should be necessary (enable paint highlighting in devtools and you'll see it). We should investigate how we can improve this. A couple ideas: - For the splash one, maybe will-change: opacity (bug 940842) will help ? - For the circle, consider rewriting the CSS to make only the circle spin (should be doable without any HTML change, just by moving the animation to ::before)

I tried to get improve the splash one by only changing opacity and adding will-change, but that didn't seem to do the trick: using Firefox OS 2.2, when the app is loading and busy doing a lot of stuff, the animation still suffers :(

Submitted https://github.com/mozilla/fireplace/pull/751 to do experiments there, it'll be easier to follow than in bugzilla.

For the record, will-change is not enabled in privileged apps, only certified, that's why the patch in comment 1 doesn't noticeably improve the situation. I filed bug 1092144.

Branch with my experimentations: https://github.com/diox/fireplace/tree/improve-spinner-animations

While I agree this would be good to do, it's specific to certain devices. I'm removing [ktlo] but leaving [good second bug]. It's a worthy enhancement.