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

From: Robert O'Callahan <robert@ocallahan.org>
Date: Tue, 5 Mar 2013 17:44:29 +1300
Message-ID: <CAOp6jLZEp0Awb0p6wpL=OBjscouTFkamDbez7Aat5gzkVpVq9w@mail.gmail.com>
To: Rik Cabanier <cabanier@gmail.com>
Cc: public-fx@w3.org
On Fri, Feb 1, 2013 at 10:52 AM, Rik Cabanier <cabanier@gmail.com> wrote:

> On Thu, Jan 31, 2013 at 1:41 PM, Robert O'Callahan <robert@ocallahan.org>wrote:
>> What is the difference between background-blend-mode:<MODE> and
>> mix-blend-mode: background <MODE>?
> 'background-blend-mode' specifies how the background images blend with
> each other. Conceptually, the background blend and composite with each
> other and the resulting bitmap is then used as the element's background.
> 'mix-blend-mode: background <MODE>' allows you to specify the blend mode
> on that background image.

Was this answer correct? It looks to me like "background-composite"
specifies "how the background images blend with each other".

In fact, I am completely confused. background-blend-mode says "Each
background image will blend with the element's background and the
background images at a lower z-index." So if there's just one background
image, which of mix-blend-mode:background <mode>" and
"background-blend-mode" controls how that image blends with the element's
background (which I assume means "backdrop"?)?

A description of the processing model --- a pseudo-algorithm for drawing
--- would be really helpful.

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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 Tuesday, 5 March 2013 04:44:57 UTC

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