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Re: exposing CANVAS or something like it to Web Workers

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Mon, 14 May 2012 21:20:15 -0400
Message-ID: <4FB1AF4F.8020902@mit.edu>
To: Charles Pritchard <chuck@jumis.com>
CC: "public-webapps@w3.org" <public-webapps@w3.org>
On 5/14/12 9:15 PM, Charles Pritchard wrote:
> On 5/14/2012 6:08 PM, Boris Zbarsky wrote:
>> On 5/14/12 8:58 PM, Charles Pritchard wrote:
>>> I agree... Can we get this off the main thread?
>> "Maybe".
>> It would be pretty nontrivial in Gecko; last I looked it would be
>> pretty painful in WebKit too. Can't speak for other UAs.
> Can it be pumped through what's essentially an iframe on a null origin?

The issue at least in Gecko is that the DOM uses various 
effectively-global variables (shared caches of various sorts, 
non-threadsafe services, etc).  The origin is irrelevant.

> I'd just assumed that <img src="pic.svg" /> was loaded off-thread /
> async much like <img> calls.

The _loading_ is async.  In Gecko the parsing of the XML, DOM 
construction, style computations, layout are on the main thread, like 
they are for HTML.

It's the "DOM construction, style computations, layout" parts that are 
not so easy to push off to a background thread...

Received on Tuesday, 15 May 2012 01:20:46 UTC

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