Displaying MetaPost output in “ghostscript”
MetaPost ordinarily expects its output to be included in some context
where the “standard” MetaFont fonts (that you've specified) are already
defined — for example, as a figure in TeX document. If you're debugging
your MetaPost code, you may want to view it in a
ghostscript-based (or some
other PostScript) previewer, but note that viewers (even
ghostscript) don't ordinarily
have the fonts loaded, and you'll experience an error such as
Error: /undefined in cmmi10
There is provision in MetaPost for avoiding this problem: issue the
command «prologues := 2;» at the start of the mp file.
Unfortunately, the PostScript that MetaPost inserts in its output,
following this command, is incompatible with ordinary use of the
PostScript in inclusions into (La)TeX documents, so it's best to
make the prologues command optional. Furthermore, MetaPost takes a
very simple-minded approach to font encoding: since TeX font
encodings are anything but simple, encoding of text in diagrams are
another source of problems. If you're suffering such problems (the
symptom is that
characters disappear, or are wrongly presented) the solution is
to view the “original” MetaPost output after processing through
LaTeX and dvips.
Conditional compilation may be done either by inputting MyFigure.mp
indirectly from a simple wrapper MyFigureDisplay.mp:
prologues := 2; input MyFigure
or by issuing a shell command such as
mp "\prologues:=2; input MyFigure"
(which will work without the quote marks if you're not using a Unix shell).
A suitable LaTeX route would involve processing
MyFigure.tex, which contains:
- MyFigure.tex
\documentclass{article} \usepackage{graphicx} \begin{document} \thispagestyle{empty} \includegraphics{MyFigure.1} \end{document}
Processing the resulting DVI file with the dvips command
dvips -E -o MyFigure.eps MyFigure
would then give a satisfactory Encapsulated PostScript file. This
procedure may be automated using the Perl script mps2eps,
thus saving a certain amount of tedium.
The Plain TeX user may use an adaptation, by
Dan Luecking, of a jiffy of Knuth's. Dan's version
mpsproof.tex will work under
TeX to produce a DVI file for use with dvips, or
under pdfTeX to produce a PDF file, direct. The output is
set up to look like a proof sheet.
A script application, mptopdf, is available in recent
(La)TeX distributions: it seems fairly reliably to produce
PDF from MetaPost, so may reasonably be considered an answer to
the question…
