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Re: Utility of background-composite and background-blend-mode?

From: Robert O'Callahan <robert@ocallahan.org>
Date: Thu, 14 Mar 2013 23:53:34 +1300
Message-ID: <CAOp6jLbj0fSWKLXq3PGS5p=GCWdfgE-sMVrdOeobytdHOgZsPA@mail.gmail.com>
To: Rik Cabanier <cabanier@gmail.com>
Cc: public-fx@w3.org
On Thu, Mar 14, 2013 at 5:00 PM, Rik Cabanier <cabanier@gmail.com> wrote:

> I create a jsfiddle testcase: http://jsfiddle.net/vSjXM/5/
> and attached the rendering of WebKit and Firefox that has the blending
> patch. (https://bugzilla.mozilla.org/show_bug.cgi?id=841601)
> The behavior you described indeed happens. As soon as an element is
> scrolled, it goes to an offscreen bitmap (ffox_scrolling vs
> ffox_no_scrolling).
> Webkit does not seems to suffer from this.

You mean "Webkit doesn't do this optimization" :-).

> Is this something we can detect and disable if we detect blending in the
> element?
Another difference is that 'position: fixed' didn't create a buffer in
> Firefox, but it did in WebKit.
> It does create a buffer is the scrollable div goes under it; just like you
> said :-)
> These differences should all be fixed so blending and filter chains that
> access the background can work.

I'm not sure what you're suggesting. Are you suggesting we write Webkit's
buffer-creation rules into a spec and modify other browsers to follow those
rules if blending is detected in the page?

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bire gurz. Abg fb jvgu lbh. Vafgrnq, jubrire jnagf gb orpbzr terng nzbat
lbh zhfg or lbhe freinag, naq jubrire jnagf gb or svefg zhfg or lbhe fynir
— whfg nf gur Fba bs Zna qvq abg pbzr gb or freirq, ohg gb freir, naq gb
tvir uvf yvsr nf n enafbz sbe znal.” [Znggurj 20:25-28]
Received on Thursday, 14 March 2013 10:54:05 UTC

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