How to put a picture inside a dvi file?

Question

I want to use Helevetica Neue for producing a dvi file. As this means using a standard system (non LaTex) font, this leave LuaTeX as the only option.

I’m simply using something like this:

\photo{/Users/example/Pictures/identité0001.jpg}

This works nice when using XeTex for any output and even with LuaLateX too in pdf mode.
But if I use dvi mode then it fails:

(/usr/share/texlive/texmf-dist/tex/latex/microtype/mt-mvs.cfg
File: mt-mvs.cfg 2006/07/05 v1.1 microtype config. file: Marvosym Euro (RS)
)
\makecvheadpicturebox=\box62
! String contains an invalid utf-8 sequence.
<read 0> 
   ���xxExif

Where of course Exif means the problem is the binary data of the image.

The man page is maybe spotting the reason why:

All LuaTeX text input and output is considered to be Unicode text.
In DVI mode, luaTeX can be used as a complete replacement for the TeX engine.
In PDF mode, luaTeX can natively handle the PDF, JPG, JBIG2, and PNG graphics formats. luaTeX cannot include PostScript or Encapsulated PostScript (EPS) graphics files; first convert them to PDF using epstopdf (1).

Which hints it doesn’t supports the image format.
If yes, what image format I should use? and how to convert the picture to that image?

Or is there a way to convert directly Extended dvi (.xdv) files produced by XeLaTex to plain dvi files?

Answer 1

The first thing you have to understand about the DVI format is that it's pretty simple and does not have integrated support for many features we expect from formats like PDF. Especially there are no integrated commands for including images.

There is a command which allows for extensions though which corresponds to TeX's \special primitive. This allows to directly pass commands to the program interpreting the DVI file, for example the command to include an image. There are multiple formats for these commands though, so you have to specify which "backend" to use. The right choice depends on the program you want to use the DVI file with. This also means that the TeX engine only passes along this option and never actually reads or interprets your image file, so there is no concept "supporting" an image format on this level. (Effectively you instead need your DVI viewer/converter/etc. and the TeX macos which write the \special to support your image format. In practice, this means that you need an EPS image) To specify this backend, pass an option to the package xcolor, for example by adding (for dvipdfmx)

\PassOptionsToPackage{dvipdfmx}{graphicx}

or by adding the dvipdfmx class option. (The last option also sets the backend for geometry, color, and other packages, so it is often more reliable.) If you do not do this, the dvips backend is the default.

So if you set the right backend and have the image in the right (aka EPS) format, you can just use it to create the DVI file:

%% Copyright 2006-2015 Xavier Danaux ([email protected]).
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License version 1.3c,
% available at http://www.latex-project.org/lppl/.

\documentclass[11pt,a4paper,sans]{moderncv}% For dvips
%\documentclass[11pt,a4paper,sans,dvipdfmx]{moderncv}% For dvipdfmx
%\documentclass[11pt,a4paper,sans,dvisvgm]{moderncv}% For dvisvgm
\moderncvstyle{casual}
\moderncvcolor{blue}
\usepackage[scale=0.75]{geometry}
\name{John}{Doe}
\title{Resumé}
\photo[64pt][0.4pt]{example-image}
\begin{document}
\makecvtitle
\end{document}

This will give you a DVI file, but you will encounter another issue: You use native system fonts instead of regular TFM based TeX fonts. As of TeXLive 2020, none of the included programs can deal with DVI files referencing native system fonts. (This is about to change: dvisvgm will support system font in DVI files written by LuaTeX soon (aka starting with TeXLive 2021).

Also the image is only references by path, no DVI backend I know about supports embedding the image.