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Re: [css3-images] Referencing <svg> element directly with element()

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Mon, 27 Feb 2012 16:16:04 -0800
Message-ID: <CAAWBYDAhaH2KH1YEsqdKZ7jpgAcwfVBWQppfAtOp=nr-LZ+SFA@mail.gmail.com>
To: Boris Zbarsky <bzbarsky@mit.edu>
Cc: www-style@w3.org
On Fri, Feb 24, 2012 at 1:32 PM, Boris Zbarsky <bzbarsky@mit.edu> wrote:
> On 2/24/12 4:04 PM, Tab Atkins Jr. wrote:
>> Hm, why do you say that?  Inheritance is well-defined even if it's not
>> in the document
> But rule application is not.
> Specifically, if you have a disconnected document fragment, which rules
> should be applying to the elements in it?  Should inline styles be applying?
>  None of that stuff is really defined anywhere.
> getComputedStyle sort of makes up something, but it involves applying
> applying rules across documents and whatnot.  It's also not really all that
> workable in the face of dynamic changes.
>> Rendering an SVG paint server shouldn't require any information gained
>> from being in a displayed document, either.
> SVG assumes that styles can be computed in a sane way for all elements.
> Other specs don't define such sane ways of computing styles, yet.
> Maybe they should....  There are a lot of details to work out, though
> (scoped stylesheets in disconnected fragments; how should those work?).

For now, I've deleted the previous totally unnecessary paragraph about
cutting off inheritance, and added the following to the Paint Sources

Because paint sources have an intrinsic appearance, it's not necessary
for the element providing them to be in a document - for example, one
can simply create an element with JavaScript and directly assign it to
the CSSElementMap in HTML. However, some paint sources (such as an SVG
<pattern>) depend on style information for their appearance, and it's
currently largely undefined how styling information is assigned to an
element fragment that's not part of a document. (For example, does the
fragment receive styles from the active document? What if it has its
own <style> or <link rel=stylesheet> in it?) This specification
explicitly does not define how such a fragment is styled; it is
expected that CSS will define it in sufficient detail in the future.

For now, it is recommended that such fragments be inserted into a
document before being referenced. For example, a <pattern> element may
be placed into a ‘display:none’ <svg> element's <defs> element within
a document; this has no rendering or layout effects on the document,
but the style inheritance is well-defined.

I'm not totally happy about leaving this undefined, but this spec
*really* isn't the place to define it, and I'm not happy with simply
disallowing this case in the spec, since there are definitely cases
where there isn't any ambiguity.  For example, a disconnected
<pattern> that used nothing but attributes for styling would work just

Is this acceptable?

Received on Tuesday, 28 February 2012 00:16:51 UTC

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