[eclipse-incubator-e4-dev] CSS - what do we style?

[Kevin McGuire <Kevin_McGuire@xxxxxxxxxx>]

With respect to this item:
    *  Will CSS styling
be an SWT feature or only available on a higher level? In other words,
can style sheets be applied to plain SWT apps or are extension points etc.
needed? 

    * How to style Workbench
elements? Will CSS styling be applied to the real SWT widgets or to higher
level elements? 

We see conflicting requirements here:
On one hand, the designer (or whoever writes the style sheets) should not
need to know about the exact widget structure. Moreover, the concrete implementation
depends on the presentation being used, maybe also to the size of a view
part, etc. On the other hand, fine-grained styling is not possible without
knowing the widgets and a higher-level styling doesn't seem to make much
sense. 

I'm not sure if you saw my rather (<blush>)
lengthy post:

        http://dev.eclipse.org/mhonarc/lists/eclipse-incubator-e4-dev/msg00528.html

I think we absolutely need to be able
to style at the SWT level.  That's where the properties live and to
not support it would seem odd.

However, I think you'll also want to style at the workbench level because
one can't help but want to think at that level when making look decisions.
 I find that odd though since you then must question (as in the discussion
link) how you know what properties you can style.  It may be that
they act as selectors, not as things which hold properties to be styled.
I can think of a few interesting examples:

        *
jface type (e.g. "CommonViewer", or any sublcass of Viewer)
        *
part type (e.g. "CommonNavigator", or any subclass of WorkbenchPart)
        *
semantic/role type (e.g. "Navigator", which would include the
Project Explorer, the Package Explorer, etc.)

I don't know how we map those to CSS
selectors though.  AFAIK an element can only have a single CSS class,
and a single type (which presumably would be the SWT widget type, not the
jface or part type).  Maybe there exists simultaneously three element
types {SWT, JFace, Part}, each stylable with overlapping properties, and
with some kind of precedence rule if you're say styling background of all
three?  Seems complicated.

Finally, a problem with CSS selectors
is that AFAIK there's no notion of class inheritance except at the element
level (ie. CSS classes don't have subclasses).  So our potential use
of mapping to CSS classes is limited.

Kevin


eclipse-incubator-e4-dev-bounces@xxxxxxxxxxx wrote
on 08/19/2008 09:00:41 AM:

> I had a discussion with Frank and we came across a couple of
> architectural questions that are still unclear to us. As an example,
> which roles will be involved in the development process - I guess
the
> person writing a style sheet is not necessarily a programmer - and
the
> like. I'd like to suggest that we try to clarify those higher-level
> questions before we move on to actually evaluating technologies.
> 
> I added a wrap-up of our questions to my personal wiki page:
> http://wiki.eclipse.org/Ralf_Sternberg
> 
> It's just a rough draft that might serve as a skeleton for the
> discussion. By the way, I wonder: shouldn't we create a wiki page
of its
> own for the CSS topic?
> 
> Best regards,
>  Ralf