Reluctantly replying to this, as a complete non-authority on the subject. I like the idea of “in pages that drop below…” part, where we decide between sync and async scrolling based on performance criteria. I don’t know what it would take to implement, but it seems like a reasonable heuristic to try out. After all, we already have heuristics where we decide whether to sync or async scroll.
I really don’t like the idea of exposing this kind of implementation detail to CSS though. I know we’ve already crossed the line in exposing implementation details, and I’m not quite sure why this feels worse than things like “will change”, but for some reason it does. I know I’ve lost the people that go on data, as I’m presenting none, but this seems to be a “force-synchronous-scrolling” property, regardless of how we call it (and I wonder what chance it’d have if that’s what we called it, instead of scroll-blocks-on.) The argument for it also seems a bit handwavy, just like my complaint about it. — - Milan On Feb 15, 2015, at 16:47 , Robert O'Callahan <rob...@ocallahan.org> wrote: > I talked to Chrome devs last week about the issues they have with page > onscroll handlers being used to implement scrolling effects (e.g. sticky > positioning) and how they interact with async scrolling --- something we're > in the process of running into :-). > > Their current idea is to add a new CSS property "scroll-blocks-on" to let a > page opt into sync scrolling: > https://docs.google.com/document/d/1aOQRw76C0enLBd0mCG_-IM6bso7DxXwvqTiRWgNdTn8/edit# > In pages that drop below some performance threshold (e.g. 30fps), the > browser can disable scroll-blocks-on. > > A more general version of the latter is to have the browser maintain a > per-document mode switch that's "green" while the document is hitting > performance targets and "red" when it is not, with an event firing for mode > changes. In red mode, features like "scroll-blocks-on" would be disabled. > We could potentially tie in other things here like will-change disabling. > > Rob > -- > oIo otoeololo oyooouo otohoaoto oaonoyooonoeo owohooo oioso oaonogoroyo > owoiotoho oao oboroootohoeoro oooro osoiosotoeoro owoiololo oboeo > osouobojoeocoto otooo ojouodogomoeonoto.o oAogoaoiono,o oaonoyooonoeo > owohooo > osoaoyoso otooo oao oboroootohoeoro oooro osoiosotoeoro,o o‘oRoaocoao,o’o > oioso > oaonosowoeoroaoboloeo otooo otohoeo ocooouoroto.o oAonodo oaonoyooonoeo > owohooo > osoaoyoso,o o‘oYooouo ofooooolo!o’o owoiololo oboeo oiono odoaonogoeoro > ooofo > otohoeo ofoioroeo ooofo ohoeololo. > _______________________________________________ > dev-platform mailing list > dev-platform@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-platform _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
