[tex4ht] \usepackage{showframe} error with tex4ht

[Nasser M. Abbasi]

By mistake, I left the command \usepackage{showframe} when
compiling with make4ht. It looks like it is not supported in tex4ht for
obvious reasons.

I wonder if tex4ht could just ignore this package instead
of giving compile error?

===================
\documentclass[10pt]{article}%
\usepackage{showframe}
\begin{document}
test
\end{document}
===================

make4ht -ulm default index.tex
....
(/usr/local/texlive/2019/texmf-dist/tex/latex/eso-pic/showframe.sty
(/usr/local/texlive/2019/texmf-dist/tex/generic/tex4ht/usepackage.4ht
tex4ht warning: package eso-pic was prevented from loading
)
! Undefined control sequence.
\ShowFramePicture ...ethickness }\AtPageLowerLeft
                        {\framebox (\LenToUnit {\p...

l.66 ...rame\AddToShipoutPictureFG{\ShowFramePicture
                        }\fi
?
==================================

Workaround is simple, which is to bypass it explicitly in the code
when using tex4ht

\ifdefined\HCode
\else
\usepackage{showframe}
\fi

--Nasser