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Re: Some practical issues integrating the SVG transform attribute with CSS transform properties

From: Robert O'Callahan <robert@ocallahan.org>
Date: Sat, 26 Mar 2011 10:51:57 +1300
Message-ID: <AANLkTinGTGM=cMJ0703aYp_38TcX_BqxfksdC7wUETQF@mail.gmail.com>
To: Anthony Grasso <Anthony.Grasso@cisra.canon.com.au>
Cc: Jonathan Watt <jwatt@jwatt.org>, Cameron McCormack <cam@mcc.id.au>, "public-fx@w3.org" <public-fx@w3.org>
On Fri, Mar 25, 2011 at 7:50 PM, Anthony Grasso <
Anthony.Grasso@cisra.canon.com.au> wrote:

>  I remember from past discussions in the FX Group that the “transform”
> attribute and “transform” property behave differently. At least for
> “transform-origin” it’s currently defined that way [1] . We originally
> decided that the CSS property will override the SVG attribute (which is how
> it works with current SVG I think).
>

Have you got a reference to those discussions? It's not clear to me what
"CSS property overrides the SVG attribute" would actually mean. Does it mean
something different from the way presentational attributes normally map into
CSS?

 People have commented to me that would like the current proposal changed
> such that CSS transform property is additive to the SVG transform attribute.
> That is, the CSS transform property will apply to SVG elements based on the
> bounding box of the SVG element with respect to the top-level document. This
> differs from the current proposal for the CSS transform property to override
> the SVG transform attribute. It resolves the syntax/parsing issue and makes
> sense in developer scenarios, particularly concerning animation.
>

Can you be more specific? This would mean an element actually has two
transforms: an SVG transform and a separate CSS transform on top. I guess
that would work. However, it means that setting an SVG transform attribute
behaves differently to setting the CSS transform property.

I'd be reluctant to do something different to the normal way presentational
attributes are mapped into CSS.

 One question that we need to answer with both options below is, what
> happens if the “transform-origin” is already specified on an SVG element?
> Does the UA style rule (1a) or the transform mapping (1b) override what is
> defined? Or do the value(s) of the “transform-origin” override the style
> rule/mapping?
>

Author-specified transform-origin would override the UA style rule or the
presentational attribute, as normal for CSS.

Rob
-- 
"Now the Bereans were of more noble character than the Thessalonians, for
they received the message with great eagerness and examined the Scriptures
every day to see if what Paul said was true." [Acts 17:11]
Received on Friday, 25 March 2011 21:52:31 GMT

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