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RE: separating svg data from presentation

From: Patrick Schmitz <pschmitz@microsoft.com>
Date: Wed, 9 May 2001 09:54:47 -0700
Message-ID: <6CAC6551F8C10F4C9EC0CF34132F2AAE4FCC70@red-msg-07.redmond.corp.microsoft.com>
To: <mjumbe@electricstoat.com>, <www-svg@w3.org>
Others have addressed most of these questions, so I will answer just one
point:

> 
> here's a question:  why is there an <animateColor> element?  
> it seems to me 
> that svg couldn't care less as to what color any given shape 
> was.  i was 
> under the impression that svg's data was basically concerned 
> with describing 
> the geometry of an image, not the color, font faces, or 
> anything like that.  
> and the same thing can be achieved with <animate attributeType="CSS" 
> attributeName="fill"> anyway.

This cannot be done with generic interpolation, because color is an
abstract/compound type. If you just try to parse the hex values for
color and interpolate a "from" to a "to", you will get garbage. Because
of the specific, non-scalar semantics of motion and color (and
transforms in SVG), we separate these into specific animation elements.
If we did not, we would have to put in a bunch of language saying that
if the target was a color, then interpret all the values differently,
which is messy at best.

============

I think the rest of the question is interesting, and wonder why someone
cannot simply use a CSS stylesheet to control the "presentation" as
described. Does it just need a LINK element to point to the stylesheet?
Remember that I am a SMIL guy, not an SVG guy, so this is a deliberately
naive question.

On a related note, in the world of timing and animation, some of us are
discussing the development of "timesheets", which would pull all timing
(and perhaps animation) out of the document that declares content. Since
timing and animation often operate on and interact with styling, we
separate timing from styling.

Finally, I think it is a bit specious to say that XML is necessarily not
about styling. Language designers are free to choose whatever model they
like - "separation of presentation and content" is simply one
[quasi-religious] viewpoint on this.

Thanks - Patrick
Received on Thursday, 10 May 2001 00:18:08 GMT

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