[Tex/LaTex] How to use Iwona as sans serif font

Question

I feel stupid. The Iwona package seems to load Iwona as \rmfamily font but I want to use it as sans serif font, after all it is a sans serif font… How do I get it as the \sffamily font?

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Example for clarification:

\documentclass{article}

\usepackage{iwona}

\begin{document}
This should be Computer Modern but is Iwona

\sffamily
This should be Iwona but is Computer Modern Sans Serif
\end{document}

Answer 1

Prepare a file sansiwona.sty

\ProvidesPackage{sansiwona}

\DeclareOption{regular}{\renewcommand{\sfdefault}{iwona}}
\DeclareOption{light}{\renewcommand{\sfdefault}{iwonal}}
\DeclareOption{condensed}{\edef\sfdefault{\sfdefault c}}
%\DeclareOption{mathnoalias}{\let\define@iwona@mathversions\relax}
\DeclareOption{math}{%
  \let\define@iwona@mathversions a%
  \PassOptionsToPackage{mathnoalias}{iwona}%
}

\ExecuteOptions{regular}
\ProcessOptions

\let\sansiwona@saved@rmdefault\rmdefault
\let\sansiwona@saved@bfdefault\bfdefault

\RequirePackage[mathnoalias]{iwona}

\let\rmdefault\sansiwona@saved@rmdefault
\let\bfdefault\sansiwona@saved@bfdefault
\mathversion{normal}

\endinput

Then the document

\documentclass{article}
\usepackage[math]{sansiwona}

\begin{document}

What font will this be?

{\sffamily And this? \bfseries And this?}

$a+b=\sum$

\mathversion{iwona}

$a+b=\sum$

\end{document}

will do the right thing, because the “wrong” settings made by iwona.sty are reverted.

Put sansiwona.sty where TeX will find it, see Adding style files

The math option is needed only if you need Iwona Math.