The basic special for file inclusion is as follows:
\special{psfile=filename.ps [key=value] ... }
This downloads the PostScript file `filename.ps' such that the current point will be the origin of the PostScript coordinate system. The optional key=value assignments allow you to specify transformations on the PostScript.
The possible keys are:
The dimension parameters are all given in PostScript units. The `hscale' and `vscale' are given in non-dimensioned percentage units, and the rotation value is specified in degrees. Thus
\special{psfile=foo.ps hoffset=72 hscale=90 vscale=90}
will shift the graphics produced by file `foo.ps' right by one inch and will draw it at 0.9 times normal size. Offsets are given relative to the point of the special command, and are unaffected by scaling or rotation. Rotation is counterclockwise about the origin. The order of operations is to rotate the figure, scale it, then offset it.
For compatibility with older PostScript drivers, it is possible to change the units that `hscale' and `vscale' are given in. This can be done by redefining `@scaleunit' in `SDict' by a TeX command such as
\special{! /@scaleunit 1 def}
The `@scaleunit' variable, which is by default 100, is what `hscale' and `vscale' are divided by to yield an absolute scale factor.