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Re: presentational attributes

From: Sigurd Lerstad <sigler@bredband.no>
Date: Thu, 13 Mar 2003 14:33:39 +0100
Message-ID: <01e401c2e965$2871f1c0$5d1273d5@mmstudio>
To: <www-svg@w3.org>

> On Wednesday, March 12, 2003, 1:48:13 AM, Sigurd wrote:
> SL> Hello,
> SL> I'm implementing SVG and CSS.. And I'm about to implement
> SL> presentational attributes and
> SL> SVGStylable::getPresentationAttribute()
> SL> Are the presentational attributes separate from the CSS properties
> SL> on that element?
> Depends what you mean.
> SL> I mean, if you have
> SL> <svg fill="#000000" style="fill:#ffffff">
> SL> If you call element.getPresentationAttribute("fill") and you call
> SL> element.style.getPropertyValue("fill")
> SL> Do you get two separate objects in return? or do you get the same
> Separate, with different values.
> SL> I understand the spec as two different objects, just want to make
> getPresentationAttribute
> Returns the base (i.e., static) value of a given presentation
> attribute as an object of type CSSValue
> That will return a CSSValue with white (there is no canonical form
> yet, though clearly rgb (100%, 100%, 100%) can express any of the other
> forms.

I don't understand what you mean, fill was just an example. I'm thinking of
implementing it like this:

SVGStylable    // implemented on an element
    CSSStyleDeclaration m_style; // CSS style property declarations (done)

    CSSStyleDeclaration m_presentationAttributes;

    CSSValue getPresentationAttribute(name)
        return m_presentationAttributes.getPropertyValue(name);

    OnChangedAttribute(name, value)    // Some attribute has been
        if (IsPresentationAttribute(name))
            m_presentationAttributes.setPropertyValue(name, value);

Would this be correct?

> getPropertyValue will, in the case of an implementation that
> understands CSS, return a CSSValue most likely with the value black
> unless there is a higher-specificity selector in a rule that sets it
> to a different value. Which is possible, in CSS2, for example using
> two id selectors, or an id and a class.

Are you now talking about the computed property value?, because if you call
element.style.getPropertyValue() that should as far as I know return the
property value in that style declaration (i.e. the style attribute),
regardless of other rules, selectors or specificity. If not, I'm seriously

Sigurd Lerstad
Received on Wednesday, 12 March 2003 16:30:25 UTC

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