W3C home > Mailing lists > Public > www-style@w3.org > April 2005

Re: User constant declarations in style sheets

From: Werner Donné <werner.donne@re.be>
Date: Tue, 26 Apr 2005 23:12:07 +0200
Message-ID: <426EAEA7.9080301@re.be>
To: David Woolley <david@djwhome.demon.co.uk>
Cc: www-style@w3.org

David Woolley wrote:
>>You have really understood nothing of this thread.
> Your English was not very clear, and I think you confused leading and
> line height.

It is not my English. According to the specification this qualifies
indeed as a confusion. However, some books on typography refer to
leading as the distance between one baseline to the next. What the
CSS specification calls "leading" is  called "lead" in such books.

The confusion is, however, totally irrelevant to the topic of the thread,
AND at least two earlier postings in this thread show the confusion was

>>The line height example is just an example. Once the line height is
> I don't believe it is a good enough example to establish a use case.

Would you care to elaborate?

>>p { line-height: 1.2em; }
> Please only use pure numeric line heights.  Others tend to produce unreadable
> text when users override font  sizes.

I can't see why. In the example the lines would always be in proportion
to the font. If you use absolute measures, increasing the font size could
make the lines overlap. Perhaps there is a catch you might care to explain.

>>h1 { margin-top: 2lh; margin-bottom: 1lh; }
> This syntax wouldn't be acceptable because it would conflict with newly
> defined units.  You would have to make constant support mandatory on
> any browser with new units (or vendor specific ones) to ensure the browser
> understood that lh wasn't the new lh unit.

Well, that is what grammars are for, isn't it? They are with us since quite
a while now.

> It would only be better than em in the rare cases when integral multiples
> of line height were used (these margins are normally less than 1 em).

Absolutely not. If you want to keep the text in phase, you must make sure
that after an area which is out of phase, you get back in phase again. So
the total of the intermediate area must be an integral multiple of the line
height, but the constituent parts don't have to be.

> As noted previously, this is easy to do in the server or authoring tool 
> without causing the page to break for the next ten years in browsers that
> didn't support the proposed feature, and from the number of times it has been
> rejected before, I think it unlikely to happen.  (There is also a fear that
> this is the thin end of the edge of full scripting.)

If every proposed feature is going to be rejected purely on the basis of
browsers being immobile, then why bother with CSS3 at all? On this list
we are discussing matters about the CSS specification. We are not describing
the state of affairs of browsers.

Werner Donné  --  Re BVBA
Engelbeekstraat 8
B-3300 Tienen
tel: (+32) 486 425803	e-mail: werner.donne@re.be
Received on Tuesday, 26 April 2005 21:12:14 UTC

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