Getting TeX labeling on graphics

Date: Wed, 24 May 89 12:32:22 PDT
From: KARNEY%PPC.MFENET@CCC.MFECC.LLNL.GOV
Subject: Getting TeX labeling on graphics
Keywords: graphics, TeX

Most of my graphics is generated by scientific programs and so would be
most easily included in a TeX document via a \special which pulled in a
graphics file.  Unfortunately, no scientific graphics packages do their
labeling in TeX.  Furthermore the labeling of most packages is very ugly.

My current solution is to get the graphics package to produce a plot with
NO labels, include this via a \special within a LaTeX picture environment
and use \put (or \multiput for axis labels) to insert the TeX labels.  This
is of course rather labor intensive, and becomes infeasible with
complicated plots where the positions of the labels are variable (for
example, a contour plot with the contours labeled).

A step towards a more streamlined solution is as follows: Assume that the
graphics package can output alphanumeric labels and each label has
associated with it a position on the plot (and possibly a writing direction
if rotated text is to be supported).  Assume also that the DVI driver can
locate these labels and their corresponding positions and directions.  In
the LaTeX file, you would include a series of commands, one for each label:

\plotlabel[positioning]{alphanumeric-label}{TeX-label}

[positioning] is one of the LaTeX positioning commands, e.g., [tl] for
top left.  This governs how the TeX'ed label is positioned relative to the
current location (as given by the graphics file)

{alphanumeric-label} is the label text as it appears in the graphics
file, e.g., {alpha-squared}.

{TeX-label} is the TeX'ed version, e.g., {$\alpha^2$}.

\plotlabel would then do something like:

 \special{plotlabel-start tl alpha-squared}%
 \vbox to 0pt {\hbox to 0pt{$\alpha^2$\hss}\vss}%
 \special{plotlabel-end}

The DVI file on encountering \special{plotlabel-start ...} would NOT
typeset the following TeX box, but squirrel it away in a table under an
index "alpha-squared".  In a following \special calling for the inclusion
of the graphics file, the labels would be looked up in the table and
replaced with their TeX equivalent, correctly positioned (and maybe rotated
appropriatedly).

On complex plots with many numeric labels, I would imagine having a
separate program that could scan the graphics file and extract the
alpha-numeric labels into a file, which could be edited and inserted into
the TeX file.

None of this exists (as far as I know).  And I am not volunteering to
implement it!  But with a committee looking at standards for \special, I
thought it would be a good idea to air these ideas.

    Charles Karney
    Plasma Physics Laboratory   Phone:    +1 609 243 2607
    Princeton University        MFEnet:   Karney@PPC.MFEnet
    PO Box 451                  Internet: Karney%PPC.MFEnet@NMFECC.LLNL.GOV
    Princeton, NJ 08543-0451    Bitnet:   Karney%PPC.MFEnet@LBL.Bitnet