Seems like the hard part of this is that you can't predict when JS will modify the DOM or CSS in ways that break you out of a subset. That makes the asm.css idea -- particularly the part about "snapping" into a guaranteed fast path with no fallback once you can prove you're in it for good -- harder, no?
But speculating for high-performance subsets with a fallback to the more general case is tried-and-true. Benjamin, do you have answers for Leo's questions? I don't know epub. Dave On Jul 1, 2013, at 12:09 PM, Leo Meyerovich <lmeye...@berkeley.edu> wrote: > "asm.css" sounds fascinating. > > In the case of epub, are the CSS selectors somehow unique to a subdocument as > well, or is it just the subsequent layout/rendering computation? And how > different is it from, say, an iframe? > > Google and many others preprocess their layouts, so providing fast subsets > sounds reasonable. Subsetting is actually one of items we are especially > excited about with our layout engine generator. E.g., speculating or scanning > for the absence of features with ugly data dependencies. > > - Leo > > > > > On Jul 1, 2013, at 12:00 PM, dev-servo-requ...@lists.mozilla.org wrote: > >> Send dev-servo mailing list submissions to >> dev-servo@lists.mozilla.org >> >> To subscribe or unsubscribe via the World Wide Web, visit >> https://lists.mozilla.org/listinfo/dev-servo >> or, via email, send a message with subject or body 'help' to >> dev-servo-requ...@lists.mozilla.org >> >> You can reach the person managing the list at >> dev-servo-ow...@lists.mozilla.org >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of dev-servo digest..." >> >> >> Today's Topics: >> >> 1. Re: Selector matching in Rust (Benjamin Smedberg) >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Mon, 01 Jul 2013 11:41:46 -0400 >> From: Benjamin Smedberg <benja...@smedbergs.us> >> To: Jet Villegas <j...@mozilla.com> >> Cc: Boris Zbarsky <bzbar...@mit.edu>, >> mozilla-dev-se...@lists.mozilla.org >> Subject: Re: [dev-servo] Selector matching in Rust >> Message-ID: <51d1a33a.2050...@smedbergs.us> >> Content-Type: text/plain; charset=UTF-8; format=flowed >> >> On 6/30/13 2:53 AM, Jet Villegas wrote: >>> I'd love to see us make some bold moves here for application development >>> use cases (think asm.js for CSS.) Can we define a strict subset of CSS >>> syntax with clear semantics for parallel processing, raster caches, >>> hardware acceleration, and general app responsiveness? >> Well, not sure about for *apps*, but there is certainly opportunity for >> improvement if you limit CSS. Specifically, there's the subset of CSS >> used in epub, which disallows absolute or fixed positioning and I think >> other things like negative margins. This allows you to guarantee that >> layout always flows forward and you can easily paginate the document and >> at least in theory allows for a bunch of layout optimizations. It also >> specifically allows you to lay out documents starting "anywhere" (as an >> ebook reader does) without building the entire DOM. >> >> It would be nice if the web could have efficient paginated documents >> without all the horrible positioning added to support "apps". >> >> --BDS >> >> >> ------------------------------ >> >> _______________________________________________ >> dev-servo mailing list >> dev-servo@lists.mozilla.org >> https://lists.mozilla.org/listinfo/dev-servo >> >> >> End of dev-servo Digest, Vol 17, Issue 1 >> **************************************** > > _______________________________________________ > dev-servo mailing list > dev-servo@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-servo _______________________________________________ dev-servo mailing list dev-servo@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-servo
