epsf-dvipdfmx.tex is a plain TeX file to be \input after epsf.tex when
using plain TeX with dvipdfmx.  As in:

\input epsf
\input epsf-dvipdfmx

It is needed when an .eps file has anything except the origin (0,0) for
the lower-left of its bounding box.  

An alternative is to use the LaTeX graphicx package from your plain TeX
document, as in:
  \input miniltx
  \input graphicx.sty 
  \input dvipdfmx.def % needed tex+dvipdfmx only, omit for xetex
Loading graphicx can also be done through Eplain (http://tug.org/eplain).
Of course graphicx has many more features than epsf.tex.

That's the whole usage.  The rest of this document is the explanation of
why it is necessary.
-----------------------------------------------------------------------------
The ultimate source of the problem is that the dvipdfmx driver has a
feature to autoconvert .eps files to .pdf in order to generate its PDF
output.  By default, the conversion is done using Ghostscript.
Ghostscript forces the lower-left in the output to 0,0 regardless of the
input, and graphics programs (e.g., MetaPost) can create an .eps with a
lower-left that can be anything, depending on what is actually drawn
(e.g., a graph starting at (-10,-10)).

Since this conversion happens at DVI processing time, it conflicts with
what the TeX code sees.  The result is that the output is wrong; part of
the graphic is lost.  Included in this distribution is a trivial TeX
file, graphic, and the bad output by default (the circle is cut off and
misplaced).  You can observe that uncommenting the \input epsf-dvipdfmx
in the input file and rerunning tex+dvipdfmx produces good output (the
whole circle).

This cannot be fixed in epsf.tex, which looks at the graphic as it
exists, with the arbitrary lower-left (and handles it properly), and has
no way of knowing that a driver is going to transform it.  The two
reasonable workarounds for users are given above.

It also cannot be fixed in the dvipdfmx program because the graphic
inclusion in TeX might also use the trim or viewport options, and
sufficient information is not passed through to handle them properly.

The two viable workarounds for the problem that we have found are given above.
-----------------------------------------------------------------------------
This README was originally written in 2014 by Karl Berry.
The epsf-dvipdfmx.tex and test files were originally written in 2014
by Akira Kakuto.
All released to the public domain.