How to scale the bar in tikz-cd mapsto arrow?

Question

After setting

\tikzcdset{
arrow style=tikz,
diagrams={>={Straight Barb[scale=0.7]}}
}

the bar tail of the arrow gets bigger than the tip.

I thought perhaps I could scale the tail in a similar manner, by specifying something like |={Bar[scale=0.7] in the diagrams options, but that was to no effect. I did not find further information on the tikz-cd manual.

Answer 1

I am not entirely convinced that it is a good idea to use scale here but I keep it and focus on the bar. The bar gets called in mapsto, so here I am going to define a variation, my mapsto, which differs in the bar that is going to be used, named my bar. The bar is now much longer than what you want it to be, but this is just to illustrate which parameter you need to adjust. BTW, this kind of stuff is not so much described in the tikz-cd manual, rather the foundations can be found in section 16 of the pgf manual.

\documentclass{article}
\usepackage{tikz-cd} 
% the original bar has 8.2 instead of 20.2
\pgfset{my bar/.tip={Bar[width=+0pt 20.2 0.89,line cap=round]}}
\tikzcdset{my mapsto/.code={\pgfsetarrows{my bar-tikzcd to}},
arrow style=tikz,
diagrams={>={Straight Barb[scale=0.7]}}}
\begin{document}
\begin{tikzcd}
 A \arrow[r,my mapsto]& B
\end{tikzcd}
\end{document}