How to change the size of labels in a commutative diagram with tikz-cd

Question

I have made a commutative diagram using the tikz-cd package and cannot figure out how to increase the size of the labels for the arrows. I used [sep=2cm] to space out the rows and columns more, but now the labels look a bit small by comparison. Here is a minimal working example:

\documentclass[a4paper,12pt]{article}
\usepackage{tikz-cd}

\begin{document}

\[\begin{tikzcd}[sep=2cm]
{} & B & {} \\
A_1 \ar{ru}{f_1} & A \ar{l}{\iota_1} \ar{u}{f} \ar{r}{\iota_2} & A_2 \ar{lu}{f_2}
\end{tikzcd}\]

\end{document}

with the following output:

Is there a way to change the size of all labels together, or alternatively just scale the whole diagram proportionately without using [sep=2cm]?

Answer 1

You can use for your labels the \tikzcdset{every label/.append style = {font = \normalsize}} with the option \normalsize leaving [sep=2cm].

\documentclass[a4paper,12pt]{article}
\usepackage{tikz-cd}
\tikzcdset{every label/.append style = {font = \normalsize}}
\begin{document}

\[\begin{tikzcd}[sep=2cm]
{} & B & {} \\
A_1 \ar{ru}{f_1} & A \ar{l}{\iota_1} \ar{u}{f} \ar{r}{\iota_2} & A_2 \ar{lu}{f_2}
\end{tikzcd}\]

\end{document}

Answer 2

I'd do like tikz-cd does, that is, imposing \textstyle instead of \scriptstyle. But, personally, I'd leave them \scriptstyle.

I also suggest some changes to your code, using the \arrow command, which is more flexible. The ' after the label (in double quotes) means swap.

\documentclass[a4paper,12pt]{article}
\usepackage{tikz-cd}

\tikzcdset{
  every label/.append style = {
    font = \everymath\expandafter{\the\everymath\textstyle},
  },
}

\begin{document}

\[
\begin{tikzcd}[sep=2cm]
{} & B & {} \\
A_1 \arrow[ru,"f_1"] &
A \arrow[l,"\iota_1"'] \arrow[u,"f"] \arrow[r,"\iota_2"] &
A_2 \arrow[lu,"f_2"']
\end{tikzcd}
\]

\end{document}