W3C home > Mailing lists > Public > www-style@w3.org > April 1997

Re: Is DSSSL Hard?

From: Chris Lilley <Chris.Lilley@sophia.inria.fr>
Date: Fri, 25 Apr 1997 00:17:33 +0200 (MET)
Message-Id: <9704250017.ZM10722@grommit.inria.fr>
To: Paul Prescod <papresco@calum.csclub.uwaterloo.ca>, Chris Lilley <Chris.Lilley@sophia.inria.fr>
Cc: Hakon Lie <howcome@w3.org>, www-style@w3.org
On Apr 24, 12:19am, Paul Prescod wrote:

> Once again, you probably have better things to do with
> your time than write a new stylesheet to fix every page that uses a
> .MYGREEN style. I just ran into this problem with the document on the
> W3C that used black underlines for hyperlinks. If I had to work with
> that document for a while, I would have just told my UA "turn off this
> stylesheet, it annoys me." That is very different from using "a cascade"
> and writing my own stylesheet!

That would also have turned off the rest of the formatting. The only
thing you didn't like was the links being in black. A one-line user
stylesheet

a {color: blue}

would fix that. Of course, the UA is free to offer whatever GUI
interface it wants to let readers adjust their reader stylesheets.
But equally, readers can use standard authoring tools to generate them,
or copy other oners that they like.

> If you are blind ... I could go through the same list again, but I'm
> getting very redundant. What does the ability to override styles or
> stylesheets have to do with cascades? I can override stylesheets in Word
> for Windows!!

I think if we are arguing differences between a cascade and a selective
override of part of a stylesheet then we are splitting hairs as these
mean essentially the same thing.


> There's the key! "Well-constructed".

Yes. We cannot legislate against stupidity or ignorance; anything can
be abused including CSS and DSSSL.

> If we can depend on authors to make
> well-constructed stylesheets

We can encourage them but not depend on it. Well-constructed stylesheets are
designed to cascade well and to allow readers to cascade them well.
Paramertrisation is similar except it requires the document author to have
thought of everything that the reader might require; as you say, we cannot
really do that.


> > The reader can then make all the text bigger,
> > or smaller, with a simple one-line stylesheet.
>
> You can do that trivially in DSSSL:
>
> (declare-initial-value font-size: 20pt )
> (declare-initial-value background-color: (rgb 0 0 0) )
>
> You don't need a complex cascading mechanism.

We are down to terminology again; I would say that you just made a
cascading DSSSL stylesheet with your two declarations above. By adding
an extra declaration, to set the foreground color, you could make a
well-constructed cascading DSSSL stylesheet.

> > > - we are back to non-portable and often non-exposed proprietary 'user
> > > preference' files, we are back to 'one size fits all eyes' presentation

> Reader stylesheet files are SGML documents that conform to ISO/IEC
> 10179:1996, Document Style Semantics and Specification Language. Whether
> or not they cascade, they are not proprietary and they are not
> preference files.
>
> On the other hand, the mechanisms I have argued for above would go into
> a preference file,

I think you just argued yourself in a circle

> But you haven't yet explained how I can make a stylesheet that
> will cascade wonderfully and turn all greens into reds.

There is a mechanism but it requires functionality which has not been made
public yet. Sorry I can't say more. The mappings to cope with deuteranomaly
(a type of constant-lightness reduced red-green discrimination) are however
well characterised and it would be fairly straightforward to integrate this
into a special color management step. One of my "if I had time which I don't"
projects is a form that would takesa Web page and display it as if the viewer
had deuteranomaly, which is by far the commnest type of anomalous color vision
(4.5% of caucasian males).


> That could only be done a) with a smart user agent or b) with a
> meta-stylesheet-language that mapped input structure (SGML) to
> intermediate styles (author specified formatting) to output styles (user
> specified overrides based on formatting characteristics). In that case
> the elements in the input document are irrelevant. I would probably
> support a W3C effort to make such a meta-stylesheet-language. It could
> be applied to the output of a DSSSL formatting process or a PDF file or
> whatever. [...] CSS
> cannot do what I am asking it to do. It absolutely cannot turn all
> occurrences of "red" to "blue" or "12pt" to "24pt". A smart user agent
> could do that for me with X resources or something. A
> meta-stylesheet-language could do that for me.

I'm not entirely clear what you are proposing here. Instead of email, if
you think this would be a real help why not write it up when you have time
and make a Web page?




-- 
Chris Lilley, W3C                          [ http://www.w3.org/ ]
Graphics and Fonts Guy            The World Wide Web Consortium
http://www.w3.org/people/chris/              INRIA,  Projet W3C
chris@w3.org                       2004 Rt des Lucioles / BP 93
+33 (0)4 93 65 79 87       06902 Sophia Antipolis Cedex, France
Received on Thursday, 24 April 1997 18:17:40 GMT

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