[whatwg] Counterproposal for canvas in workers

[Robert O'Callahan]

On Fri, Oct 18, 2013 at 4:17 PM, Glenn Maynard <glenn at zewt.org> wrote:

> On Thu, Oct 17, 2013 at 10:25 PM, Robert O'Callahan <robert at ocallahan.org
> >wrote:
> > On Fri, Oct 18, 2013 at 3:10 PM, Glenn Maynard <glenn at zewt.org> wrote:
> >>  Also, with the "transferToImageBuffer" approach, if you want to render
> >> from a worker into multiple canvases in the UI thread, you have to post
> >> those ImageBuffers over to the main thread each frame, which has the
> same
> >> (potential) synchronization issues as the transferDrawingBufferToCanvas
> >> proposal.
> >
> > What are those issues? You can do a single postMessage passing a complete
> > set of ImageBItmaps.
> >
>
> See
> http://lists.w3.org/Archives/Public/public-whatwg-archive/2013Oct/0193.html
> .
> I don't know the answer to this; my feeling is that posting to the UI
> thread and scripts in the UI thread may or may not have
> (performance/smoothness) issues, but doing it all in the worker avoids any
> potential for this issue.
>

I'm confused here. You said "if you want to render from a worker into
multiple canvases in the UI thread", which I took to mean that you wanted
to synchronize canvas updates from workers with DOM changes made by the UI
thread. But now you're saying you don't want to do that. So I don't know
what you meant.

Rob
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