Re: Fresnel: Styles: summary and unsolved issues

From: Emmanuel Pietriga <>
Date: Wed, 27 Apr 2005 08:21:27 +0200

Ryan Lee wrote:

> If we were to do drop fresnel:Styles, I propose we hang these
> other properties off of :PropertyDescription.
> (derived from
> :myDepicts a fresnel:PropertyDescription ;
> fresnel:property foaf:depiction ;
> fresnel:label "can be seen in" ;
> fresnel:value fresnel:image .
> :FOAFPersonDefaultLens a fresnel:Lens ;
> fresnel:purpose fresnel:defaultLens ;
> fresnel:lensDomain foaf:Person ;
> fresnel:showProperties (foaf:name foaf:mbox :myDepicts) .
> :personsKnowsLens a fresnel:Lens ;
> fresnel:lensDomain foaf:Person ;
> fresnel:showProperties ( foaf:name
> :myDepicts
> [ a fresnel:PropertyDescription ;
> fresnel:property foaf:knows ;
> fresnel:label fresnel:none ;
> fresnel:sublens :FOAFPersonDefaultLens ] ).

If we do that we no longer have a clean seperation between selection and
presentation (in the sense that a PropertyDescription will contain both
selection statements (e.g. sublens) and presentation statements (label,
value, etc.).

And this seems to trigger a new issue: say that for a given property we
have a fresnel:value and a fresnel:sublens, like in:

:myDepicts a fresnel:PropertyDescription ;
   fresnel:property foaf:depiction ;
   fresnel:sublens :ImageMetadataLens ;
   fresnel:label "can be seen in" ;
   fresnel:value fresnel:image .

where :ImageMetadataLens would be a lens that shows information about
the image resource (e.g. its width, height, etc.). Don't we have some
kind of conflict between fresnel:sublens and fresnel:value? How would
you interpret that (I mean, how should a browser behave)?

> The major drawback compared to the former solution is in trying to apply
> the same property manipulations more broadly since only one
> fresnel:property, naming one rdf:Property, can currently be used in a
> fresnel:PropertyDescription (as opposed to the full range of selectors
> in :styleDomain). Considering fresnel:label, though, I don't think
> these manipulations are really that broadly applicable in the first place.

Its impact is limited if you indeed make a heavy use of fresnel:label.
If you don't, this is not so obvious.

> What precisely are we retaining?
> :label (and :LabellingStyles - maybe rename to :LabellingTypes)
> :value (and :PropertyValueStyles - maybe rename to :PropertyValueTypes)
> :contentNoValue
> The remaining :content{First,Last,Before,After} properties seem like
> they could be left to styling instead.

:content{First,Last,Before,After} make sense in Fresnel, because they
are portable across browsers and representation paradigms. Besides they
are closely related to lenses' mergeProperties and alternateProperties.

So I'd rather not drop them. I'm more in favor of keeping as much as we
can in Fresnel, provided that it makes sense. The more we leave to the
non-Fresnel styling part, the less Fresnel is useful.

Emmanuel Pietriga
INRIA Futurs - Projet In Situ    tel : +33 1 69 15 34 66
Bat 490, Université Paris-Sud    fax : +33 1 69 15 65 86
91405 ORSAY Cedex  
Received on Wed Apr 27 2005 - 06:22:22 EDT

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