ktl@wag.caltech.edu (Kian-Tat Lim) (03/07/91)
One of our users is attempting to use large vertical braces in
LaTeX. His code looks like this:
\documentstyle[12pt]{article}
\newcommand{\bdm}{\begin{displaymath}}
\newcommand{\edm}{\end{displaymath}}
\newcommand{\RM}[1]{{\rm #1}}
\begin{document}
\bdm
\begin{array}{c}
\RM{Pair\;3} \\
\RM{Pair\;1} \left\{ \begin{array}{c}
\overbrace{ H_a\frac{\;\;\;\;\;}{\;}H_b } \\[1in]
H_c
\end{array} \right\} \RM{Pair\;2}
\end{array}
\edm
\end{document}
The problem is that there is a thin break between the central part of
each brace (the "point") and the extended straight piece below it.
This problem was first noticed using the U Toronto TeX
distribution for SGI machines, dvi2ps 3.13, and a write-white printer
(Ricoh engine). We suspected that it was due to fonts designed for a
write-black printer, but using a write-white mode_def and adjusting
blacker, fillin, and o_correction led nowhere.
We then tried the same file on our VAX running a VMS version
of TeX from Talaris with their own printer software, writing to a
write-black printer (Canon engine). The resulting braces looked good
until they were inspected closely -- there is also a (very fine) break
in this output, though it is well-hidden (by write-black overshoot?).
Is this a known problem with cmex10.mf? A kludge workaround
seems to be to generate a 308 dpi font and use it in place of the 300
dpi font, but this is hardly elegant.
Thank you for any assistance you can provide.
--
Kian-Tat Lim (ktl@wag.caltech.edu, KTL @ CITCHEM.BITNET, GEnie: K.LIM1)