In order to generate graphics output from a metafile, one must use a
Metafile Translator to interpret the device independent metafile
commands. The Metafile Translator (GMFPLOT) provided with PGPLOT uses
the PGPLOT subroutines to generate the device-specific output: thus a
metafile may be displayed on any of the devices supported by PGPLOT. (A
metafile may even be translated into another metafile, but this is not
very useful.) To use GMFPLOT, first define a command PLOT
, say, as
follows; this definition may be included in your LOGIN.COM
file if you
make extensive use of it:
$ PLOT == "$PGPLOT_DIR:GMFPLOT"
The PLOT
command takes two arguments: the name of the input metafile,
and the device specification for the output. The following sample
commands display a metafile on a Grinnell and on a Versatec printer:
$ PLOT PLOT17.GMF /GR
$ PLOT PLOT17 DEIMOS::LVA0:/VE
Again, the default file type for the metafile is .GMF
.
At present, it is not possible to edit the metafile before display. This
is a facility which might be added one day. Nor is it possible to change
the scale or aspect ratio (ratio of height/width of the display
surface). When PGPLOT generates a metafile, it does not know the size
or shape of the display surface that it will ultimately be plotted on;
as it has to make some assumption, it assumes that the surface will be
square. The metafile translator displays the metafile in the largest
square available on the output device. Thus a plot which is sent
directly to a terminal may not look exactly the same as one that is
stored in a metafile and subsequently displayed on the terminal. Future
enhancements may allow one to specify the scale and aspect ratio of the
metafile when it is generated.