Adjust / and \backslash symbols in Fourier

Question

In Fourier, the non-sized slashes / and \backslash are, in my opinion, too small and does not tilt enough compared to their sized version. For example, writing a / b and a \big/ b, we obtain something like below:

Perhaps it is not very easy to see just like this, but the first slash does not tilt as much as the second one.

I know that in fourier.sty, we have

\DeclareMathDelimiter{/}{\mathord}{operators}{047}{largesymbols}{177}

which explains why / behaves different compared to \big/, as they point to different symbols (similar for \backslash). Perhaps one could change this to

\DeclareMathDelimiter{/}{\mathord}{largesymbols}{177}{largesymbols}{177}

such that they point to the same symbol, and then in some way rescale and reposition it. Changing only this line, however, we get

where first and foremost the slash is at a very bad position, and secondly has the same size as \big/.

How can I make the non-sized slashes tilt as much as their sized versions, and make them slightly bigger than what they currently are? I still want to be able to simply write a / b, but where the slashes are coherent to their sized versions.

Update: mathdesign's slashes looks good. However, I don't know how to substitute Fourier's with these. Perhaps this post can be of help.

Note: This seems to be very much related to this closed post. Hopefully this can be remained open, as I'm trying to work on a solution.

Answer 1

As mathdesign's slashes are very similar, it was somewhat easy to replace these two slashes with their counterpart in the Utopia part of mathdesign.

What I obtained was

Here is the corresponding code on how to generate this:

\documentclass[12pt,oneside]{scrartcl}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage[draft=false]{scrlayer-scrpage}
\usepackage{mathtools}
\usepackage{fourier}

\makeatletter
% slash
\DeclareFontFamily{OT1}{mdput}{\hyphenchar \font =45}
\DeclareFontShape{OT1}{mdput}{m}{n}{
   <->s * [0.94]  mdputr7t
}{}
\DeclareFontShape{OT1}{mdput}{b}{n}{
   <->s * [0.94]  mdputb7t
}{}
\DeclareSymbolFont{newoperators}{OT1}{mdput}{m}{n}
\SetSymbolFont{newoperators}{bold}{OT1}{mdput}{b}{n}
\DeclareMathDelimiter{/}{\mathord}{newoperators}{047}{largesymbols}{177}

% backslash
\DeclareFontFamily{OMS}{mdput}{\skewchar \font =48}
\DeclareFontShape{OMS}{mdput}{m}{n}{
   <->s * [0.94]  mdputr7y
}{}
\DeclareFontShape{OMS}{mdput}{b}{n}{
   <->s * [0.94]  mdputb7y
}{}
\DeclareSymbolFont{newsymbols}{OMS}{mdput}{m}{n}
\SetSymbolFont{newsymbols}{bold}{OMS}{mdput}{b}{n}
\DeclareMathDelimiter{\backslash}{\mathord}{newsymbols}{110}{largesymbols}{178}

% just to patch sized delimiters in the Fourier font
\def\resetMathstrut@{%
  \setbox\z@\hbox{%
    \mathchardef\@tempa\mathcode`\(\relax
    \def\@tempb##1"##2##3{\the\textfont"##3\char"}%
    \expandafter\@tempb\meaning\@tempa \relax
  }%
  \ht\Mathstrutbox@1.2\ht\z@ \dp\Mathstrutbox@1.2\dp\z@
}
\makeatother

\begin{document}
This is a demonstration of slash:~$a / b = (a / b)$.

This is a demonstration of backslash:~$a \backslash b = (a \backslash b)$.
\begin{gather*}
  a / b
\;=\;
  a \big/ b
\\
  a \backslash b
\;=\;
  a \big\backslash b
\\
  / \mspace{-6mu} \big/
\\
  \backslash \mspace{-6mu} \big\backslash
\end{gather*}
\end{document}

This was achieved by looking at how mathdesign's Utopia loads the symbol fonts operator and symbol and port it here.