.so /usr/lib/tmac/tmac.pictures
.nr PS 11
.nr VS 13
.TL
MetaPost with troff 
.LP
Since MetaPost is a picture-drawing language that outputs PostScript, it is
necessary to use the
.ft CW
-mpictures
.ft
macro package.  Suppose you have written some figures in MetaPost and placed
the input in a file \f(CWfigures.mp\fR.
Running
.nf
.ft CW
             mp -T figures
.ft
.fi
to invoke the MetaPost interpreter produces output files
\f(CWfigures.1\fR, \f(CWfigures.2\fR, .\|.\|.
via macro calls such as
.nf
.ft CW
            .BP figures.1 height width
.ft
.fi
as explained in the
.ft CW
-mpictures
.ft
documentation. Note that the picture gets rescaled if the height and width
in the \f(CW.BP\fR command don't match \fImp\fR's idea of the picture dimensions.
.PP
For instance,
.BP figs.1 1.08i 1.5i
this figure was derived from a file
.ft CW
figs.mp
.ft
and included at this point by invoking the \f(CW.BP\fR
macro with height 1.08 inches and width 1.5 inches.  The macro tries to run text
around the picture, but this can be stopped
by using the \f(CW.EP\fR macro as was done here.
.EP
The file
.ft CW
figs.mp
.ft
looks like this:
.nf
.ft CW
.nr PS 9
.nr VS 11
prologues:=1;
input boxes
beginfig(1);
pair shadowshift; shadowshift=(1,-1)*bp;

def drawshadowed(text t) =
  forsuffixes $=t:
    fill bpath$ shifted shadowshift;
    unfill bpath$;
    drawboxed($);
  endfor
enddef;

boxit.a(btex \\s8A\\s+2 \\(lh a etex);
circleit.b(btex $e sup {i omega t}$ etex rotated 20);
b.w - a.e = (10bp,0);
drawshadowed(a,b);
draw a.e..b.w;

draw bbox currentpicture dashed evenly;
endfig;
.nr PS 11
.nr VS 13
.ft
.fi
.PP
Note that the typesetting commands in the
\f(CWbtex\fR.\|.\|.\f(CWetex\fR blocks in the above example are processed by
.nf
.ft CW
             eqn -d\\$\\$ | troff;
.ft
.fi
If a different \fItroff\fR pipeline is desired, it can be specified via the
.ft CW
TROFF
.ft
environment variable.  For example,
.nf
.ft CW
             TROFF='tbl | eqn -d\\$\\$ | troff -Tpost'
.ft
.fi
adds \fItbl\fR to the pipeline.
.PP
Macro definitions and such can be added via the standard
\f(CWverbatimtex\fR.\|.\|.\f(CWetex\fR mechanism that adds the given material
to the \fItroff\fR input.  Such material should not generate any output since
this would get mixed up with the next \f(CWbtex\fR.\|.\|.\f(CWetex\fR block.
Thus, newlines between \f(CWverbatimtex\fR and \f(CWetex\fR must be
protected with \f(CW\\\fR.