mfpic-doc.pdf.

4.9 PICTURE FRAMES. 55
ment, \newsavepic is actually defined to be \newsavebox.
\savepic saves the next \mfpic picture in the named box, which should have been previously
allocated with \newsavepic. (This command should not be used inside an mfpic environment.)
The next picture will not be placed, but saved in the box for later use. This is primarily intended as
a convenience. One could use
\savebox{〈picname〉}{〈entire mfpic environment〉},
but \savepic avoids having to place the mfpic environment in braces, and avoids one extra level
of TEX grouping. It also avoids reading the entire mfpic environment as a parameter, which would
nullify MFPIC’s efforts to preserve line breaks in parameters written to the METAFONT output file. If
you repeat \savepic with the same 〈picname〉, the old contents are replaced with the next picture.
\usepic copies the picture that had been saved in the named box. This may be repeated as often
as liked to create multiple copies of one picture. The \usepic command is essentially a clone of
the LATEX \usebox command. Since the contents of the saved picture are only defined during the
TEX run, \usebox cannot be used in the TEX-commands argument of the \tlabel command while
mplabels is in effect.
4.9 Picture Frames.
When TEX is run but before METAFONT or METAPOST has been run on the output file, MFPIC detects
that the .tfm file is missing or that the first METAPOST figure file 〈file〉.1 is missing. In these cases,
the mfpic environment draws only a rectangular frame with dimensions equal to the nominal size of
the picture, containing the figure number (and any text placed by \tlabel and its relatives without
mplabels in effect). The command(s) used internally to do this are made available to the user.
\mfpframe[〈fsep〉]〈 material-to-be-framed 〉\endmfpframe
\mfpframed[〈fsep〉]{〈material-to-be-framed〉}
These commands surround their contents with a rectangular frame consisting of lines with thickness
\mfpframethickness separated from the contents by the 〈fsep〉 if specified, otherwise by the
value of the dimension \mfpframesep. The default value of the TEX dimensions \mfpframesep
and \mfpframethickness are 2pt and 0.4pt, respectively. The \mfpframe ... \endmfpframe
version is preferred around mfpic environments or verbatim material since it avoids reading the
enclosed material before appropriate \catcode changes go into effect. In LATEX, one can also use
environment syntax: \begin{mfpframe} ... \end{mfpframe}.
An alternative way to frame mfpic pictures is to save them with \savepic (see previous section)
and issue a corresponding \usepic command inside any framing environment or command of the
user’s choice or devising.
4.10 Affine Transforms.
Coordinate transformations that keep parallel lines in parallel are called affine transforms. These include
translation, rotation, reflection, scaling and skewing (slanting). For the METAFONT coordinate
system only (that is, for paths, but not for \tlabel nor \tcaption) MFPIC provides the ability to
apply METAFONT affine transforms.
4.10.1 TRANSFORMING THE METAFONT COORDINATE SYSTEM
\coords . . . \endcoords
All affine transforms are restricted to the innermost enclosing \coords...\endcoords pair. If
there is no such enclosure, then the transforms will apply to the rest of the mfpic environment. In
LATEX, one can use the environment named coords.