Message-Id: <9302060923.AA28511@sc.zib-berlin.dbp.de>
Reply-To: Mailing list for the LaTeX3 project <LATEX-L@vm.urz.Uni-Heidelberg.de>
Date:         Sat, 6 Feb 93 10:15:37 CET
From: Frank Mittelbach <MITTELBACH@MZDMZA.ZDV.UNI-MAINZ.DE>
Sender: Mailing list for the LaTeX3 project <LATEX-L@vm.urz.Uni-Heidelberg.de>
To: Multiple Recipients of <LATEX-L@vm.urz.Uni-Heidelberg.de>
Subject:      Grid layout
Status: R


oh well, the system doesn't like me, so let's try again ...
From:	MZDMZA::MITTELBACH   "Frank Mittelbach"  5-FEB-1993 20:32:14.07
To:	TOLTX
CC:	MITTELBACH
Subj:	Grid layout

Peter and SPQR fighting about grid layout :-)
Here are my comments, I guess I made some of them before.

> I think that is should be possible for rubber space to be introduced in
> the whitespace of headings/images so that baselines remain aligned.

It is sort of hard to introduce `rubber space' that jumps in discrete
values, anybody ever had a try at this? (if so I would like to see it, please)

> Are there any plans for this feature?

yes, as I think grid based layouts are very important we will support
this in LaTeX3, but it isn't easy.

> I use (in this context) A5 pages with 2 columns and point size 9 on 9.67.
> Therefore when I include an image of say 50mm, I can accept a small amount of
> whitespace above or below to ensure the baselines of the two columns are
> aligned.

you can help yourself by turing off every rubber space measuring the
your boxes and insert the missing space yourself after finding out
what is needed. I did this once for the E-TeX paper but this only
solves a restricted class of problems.

> I accept that there are wider issues but would like to think that LaTeX3
> could address the general principle of providing aligned baselines
> (perhaps as on option which can be switched on/off).

we will, but I don't think a switch will make much sense.

> In the general case, LaTeX *does* allow aligned baselines. its up to
> the style designer to use fixed space, not variable bits of rubber,
> between items. since TeX plonks rectangular boxes on the page very
> precisely, its an ideal tool for building aligned baselines. I dont
> quite see what the LaTeX 3 *kernel* needs to add. An example 2 column
> style file with a good implementation of aligned baselines is
> another matter, and it would be lovely to have it.

Well, TeX isn't that ideal for it, for example any large object in a
paragraph throws you out of your grid. As far as the kernel is
concerned, we need to provide the appropriate data structures to make
it possible (and hopefully not too difficult) to achieve such effects.
In general TeX is missing additional alignment points on boxes (and
the TeXbook says why: because Don didn't saw enough applications for
it, sigh) and this means a lot of programming to get it right.

> Would it be possible for an option to be provided in multicol (or whichever
> style file is relevant) such that baselines can be aligned when using
> 2 coumn mode and including images (or other boxes) which are NOT exact
> multiples of baselinskip size?

this is not a question of something like multicol, it have to be
tackled from the other end, ie the stuff that may come in arbitrary.
Eg the figure env, display math, etc have to take care of what they
pass on.

And yes, we will tackle it (one day :-)

Frank