Message-Id: <9212011346.AB17008@sc.zib-berlin.dbp.de>
Reply-To: Mailing list for the LaTeX3 project <LATEX-L@vm.urz.Uni-Heidelberg.de>
In-Reply-To:  David_Rhead%vme.nott.ac.uk@uk.ac.essex.mailhost's message of Wed,
              25 Nov 92 12:46:49 +0100
Date:         Tue, 1 Dec 92 11:54:29 GMT
From: Adrian F Clark <alien@SX.AC.UK>
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:      Re: LaTeX 3 floating strategy: plates
Status: R


I haven't seen any discussion of David Rhead's interesting message of
25th November regarding plates.  Since most of my `real' work is
concerned with pictures, this is a subject close to my heart; so here
are some comments and suggestions concerned with floating inserts in
general and pictures (images, not line-drawings) in particular.

WHERE PLATES APPEAR.  As far as I can tell, having just looked closely
   at a few books, plates are typically inserted between signatures in
   older (dare I say more carefully prepared?) books, or in a separate
   signature at the end.  I only have two books in which colour plates
   appear as floating inserts on `normal' pages -- both these books
   were very expensive (and produced by Springer-Verlag).

WHAT PLATES CONTAIN.  The tendency is to produce grey-scale pictures
   (halftones) as `conventional' floats, with only colour plates pushed
   into strange places in the document.  The use of PostScript for
   rendering grey-scale pictures means that the tedious messing around
   with process cameras is no longer needed.  (Having said that, the
   quality from PostScript halftones doesn't match that from a process
   camera; but that's another matter.)

DIFFERENT TYPES OF FLOATS.  David's message implies that plates
   require a separate numbering sequence from figures and tables.  I
   can think of several other cases in which things that one might
   wish to have float would also require separate numbering: for
   example, sections of code ("Listing 4.2: The radix-2 Cooley-Tukey
   fast Fourier transform"), grey-scale images ("Image 4.2: Result of
   applying the program of Listing 4.2 to out test image"), colour
   images, and `pictures' of a user's screen ("...after running this
   command, your terminal screen should look like that in Screen
   4.2").  I have seen separate floats of all these kinds in books.

A SUGGESTION.  Just as there are \newcommand and friends, surely it is
   possible to produce a \newfloat command?  I'm thinking along the
   lines of

      \newfloat[\placement]{listing}{chapter}

   As well as the name of the floating entity, this would require
   indication of when the associated counter has to be reset
   (`chapter' in the above example).  Of course, \newfloat would also
   have to define an appropriate \listoflistings command.  Since I
   recall Frank saying that he is moving towards a single auxiliary
   file to hold all cross-referencing and contents information, this
   shouldn't result in an explosion of new files!  Perhaps, as the
   example shows, it would also be possible to present a macro to
   determine the placement of the class of float --- if this is
   feasible, it would allow a different placement policy to be used
   for colour plates from other floats...and allow for special
   requirements, as in David Rogers' memorable (but plain) floating
   challenge.

   Of course, LaTeX could pre-define floats called `plate'
   `colorplate' (yes, with American spelling), and `listing' in
   addition to the current `figure' and `table' in terms of the more
   primitive macros in a manner analogous to \section.


CHANGE OF BEHAVIOUR FOR [h].  Might I also suggest that a change of
   behaviour of the [h] option for figure placement is also worthy of
   consideration?  On a number of occasions, I have been writing
   documents that use explicit placement of a figure or table to come out
   between paragraphs.  When there is insufficient room for the unfloated
   float to appear on the current page, it is retained until the end of
   the chapter, dragging all other floats with it.  Could I suggest that,
   if feasible, a new page is started and the [h] float rendered at the
   top of it?  This is similar in concept to the `.ne' directive in olde
   worlde text formatters.

   Oh, and one last thing regarding tables, or more precisely
   tabulars.  When preparing overheads with \raggedright in effect,
   shouldn't p{<size>} cause paragraphs to be produced ragged-right
   too?

I hope this is  of interest/help.

..Adrian

 Dr Adrian F. Clark                                   JANET: alien@uk.ac.essex
 INTERNET: alien%uk.ac.essex@nsfnet-relay.ac.uk          FAX: (+44) 206-872900
 BITNET: alien%uk.ac.essex@ac.uk              PHONE: (+44) 206-872432 (direct)
 Dept ESE, University of Essex, Wivenhoe Park, Colchester, Essex, C04 3SQ, UK.