RE: question about "presentation attributes"

On  Wednesday, March 19, 2014 9:45 PM
Tab wrote: (and my response follows)
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On Wed, Mar 19, 2014 at 6:23 PM, David Dailey <ddailey@zoominternet.net> wrote:
> But in the list at
> http://www.w3.org/TR/SVG2/attindex.html#PresentationAttributes , I 
> seem to be missing something.
>
> a)      Am I to understand that as in the above table we might apply, for
> example, the font-stretch attribute to the feColor matrix filter? I’m 
> not sure what that would mean. Maybe I just never thought of 
> differentially applying an feColor filter primitive to things that 
> have had their fonts stretched. It is sort of a fun idea, of course.

Saying "here's all the presentation attributes, and here's all the elements that can take at least one presentation attribute" is just easier than listing everything out individually.  Applying the 'font-stretch' property to <feColorMatrix> doesn't actually do anything.

> b)      When it says that “the plan is to allow all SVG elements to be
> stylable” does this mean that all elements should be selectable by CSS?

All elements are already selectable by CSS - they exist in the DOM, and Selectors can grab any of them.  You might be asking about whether all elements *generate boxes* ("box" being a technical term in CSS for "something that appears in the layout tree, and will probably be rendered", roughly), and the answer is no.

I'm not actually sure what the issue is trying to say - all elements are styleable already, in that they can all receive CSS properties, and you can observe this via inheritance.

> c)        Does it mean that all attributes (presentation or otherwise)
> should be stylable by CSS?

No, but the list of attributes that are "presentational" (meaning, specifying them is identical to just setting a CSS property) is planned to grow.

> d)      Does that mean that all attributes (and their values) should be
> animatable through CSS?

No attributes are animateable through CSS.  All the properties that the presentation attributes map to are, though.

> Ultimately, can the example at 
> http://cs.sru.edu/~ddailey/svg/Stats3.svg be built declaratively, so 
> that the placements of the ellipses as well as their distinct animations can be decided by CSS?

Assuming you're referring to animating the rx/ry and transform of each of the ellipses, yes - 'transform' is already a CSS property, and the rx/ry attributes are on the list of things planned to change to presentation attributes.

~TJ
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Hi Tab,

I can see that I'm not quite clear on the difference between attributes and properties.

How about this question:

Will the list of presentation attributes ever be as large as the list of animatable attributes in SVG? 

Alternatively, are there things in the list of "regular attributes" for which it has been decided that they will never make it into the "presentation attribute" list? Can we expect this transition to take place forever?

Concerning the last part of my question, let's leave that dormant for the time being, since it has to do with how modifiers (like clipPath, filter, mask, gradient, class, and animate) are bulk-modified declaratively. 

Cheers
David

Received on Thursday, 20 March 2014 02:21:06 UTC