- From: Anne van Kesteren <annevk@annevk.nl>
- Date: Fri, 22 Aug 2014 11:10:42 +0200
- To: James Robinson <jamesr@google.com>
- Cc: Elliott Sprehn <esprehn@gmail.com>, "www-dom@w3.org" <www-dom@w3.org>, "public-web-perf@w3.org" <public-web-perf@w3.org>, "www-style@w3.org" <www-style@w3.org>, Ian Hickson <ian@hixie.ch>, "public-fx@w3.org" <public-fx@w3.org>, Yehuda Katz <wycats@gmail.com>, Rafael Weinstein <rafaelw@google.com>, Adam Klein <adamk@google.com>, Adam Barth <w3c@adambarth.com>
On Fri, Aug 22, 2014 at 8:07 AM, James Robinson <jamesr@google.com> wrote: > HTML defines the event loop and it defines (as much as anything does) when > the 'update the rendering' step happens, which is I think when all of this > should be tied to. Specifically I think we should extend Step 8 of the > processing model: > > http://www.whatwg.org/specs/web-apps/current-work/multipage/webappapis.html#processing-model-9 > > 8.) Update the rendering: If this event loop is a browsing context event > loop (as opposed to a worker event loop), then, if necessary, update the > rendering or user interface of anyDocument or browsing context to reflect > the current state. > > To say something like: > > To update the rendering, run these steps: > 1.) Run tasks in the bag-of-stuff-to-run-before RAF in some order (probably > FIFO). This includes the set of things Elliot mentioned (scroll updates, > media queries, etc etc) and anything else we want to put in other than the > requestAnimationFrame events themselves > 2.) Run the 'Sample all animations' task: > https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/RequestAnimationFrame/Overview.html#processingmodel > 3.) Render the document to reflect the current state > > I think it's important that rAF callbacks be the last script thing that runs > here so the author has a chance to get everything ship-shape before > rendering actually happens, else you get flashes and inconsistencies like > the ones in the test case Elliot demonstrated. I'm not sure if we need the > step in (1) to be hookable by other specs or not but it might be useful. Yes we should make that extensible. > If we want to define that to be FIFO then we have to strictly define when > items in that queue are added to the queue, which for things like media > queries and other CSS/layout-driven tasks might be hard. This will end up being required I think. The more we make this extensible, the more observable and painful it will get for developers if we do not fix this. I filed https://www.w3.org/Bugs/Public/show_bug.cgi?id=26636 on HTML pointing to your email as a start towards fixing this. -- http://annevankesteren.nl/
Received on Friday, 22 August 2014 09:11:09 UTC