Re: Fresnel: Styles: summary and unsolved issues

From: Emmanuel Pietriga <>
Date: Mon, 25 Apr 2005 17:25:13 +0200

Jacco van Ossenbruggen wrote:
> Emmanuel Pietriga wrote:
>> Me: I see your point. But that seems to be were we diverge. I do not
>> consider the CSS/SVG/whatever part of Fresnel styles to play a central
>> role. That is not the most interesting part of Fresnel styles. In my
>> opinion, Fresnel is not about defining how to layout data, or even how
>> to *precisely* style it with instructions such as:
>> "display:table-cell;padding-top:1em;border-bottom: 1px solid black".
>> For me, Fresnel is about encoding display *knowledge*, not precise
>> instructions. We are not inventing a new styling/layout language such as
>> CSS, or even adapting it to RDF.
> This is good to hear, but it is not the impression I got from reading
> the paper and the manual document.

Forget about this part of the manual and paper. We failed to convey this
idea properly. And that is entirely our fault.

> Maybe you should emphasize this more in the paper.
> For example, by
> using the external CSS stylesheet with
> the fresnel:styleClass as the main example instead of the current
> fresnel:valueStyle and propertyStyle. The latter could just be mentioned
> in the text. Maybe the role of the box model should also be de-emphasized.
> But most important, you should state very carefully what part of the
> styling is the core of fresnel, and what is left for the application.
> Again, the description of the box model and detailed CSS style property
> specification in the example gave me the impression you are aiming for a
> "complete" style solution that leaves very little or nothing to style
> for the application.

We have decided to postpone the submission of a paper on Fresnel until
we reach broad consensus on the style part. But you are 100% right.

>> I am more interested in more abstract
>> parts of fresnel styles, such as fresnel:contentBefore, fresnel:label,
>> fresnel:value, etc., i.e. the part of Fresnel styles that are RDF
>> specific. This is what counts for me, and this part *is* portable across
>> representation paradigms. I find it to be useful. At least that is what
>> I think.
> I agree. And even in Stefano's lens-only model, you would need the
> label part because once you are in XML-tree world you don't want to (or
> cannot) query the RDF for the labels anymore.


>> Besides, I do not reject Stefano's proposal of an intermediate tree as
>> the result of the selection process. I don't think this format has
>> been clearly defined and I'd like to hear more about it. However I do
>> have an question about what I've heard: this <div>-based tree
>> structure just looks already too Longwell/CSS-oriented to me. Stefano,
>> you've been arguing that Fresnel should not define an implicit layout
>> method. I entirely agre with you. But doesn't this tree structure
>> already goes down this path? I'm not saying it does; it is just the
>> impression I get from it.
> Maybe <div> has just too much HTML/CSS layout associations, what about
> <g> (a la SVG)?


> For me, and I assume Stefano agrees (lets hear it if he's not), the key
> idea is that a lens can output an ordered tree. Graph-based tools may
> choose to ignore the tree and just build a graph as theyt would from a
> flattended output structure (but I can easily envision a graph tool that
> uses the tree structure to allow folding and unfolding of subgraphs!).

Yes. Actually, I am not against a structured output from the selection
process. I may have sounded like I am, but I'm not. I agree with you
that it is useful, even for graph layouts, just because it gives you
grouping information which is valuable. I was more worrying about this
tree structure having to be interpreted necessarily as nested boxes. It
looks like it is not the case, so that's fine with me.

> But other tools may use the tree structure for building sections and
> subsections etc in a document model or CSS-like box model.


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 Mon Apr 25 2005 - 15:26:22 EDT

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