Change tikz-cd arrow 'background color' in beamer

Question

I'm typesetting a diagram in beamer. It renders like this:

EDIT: the problem appears to be just the background color of the arrow. It's white and not transparent, therefore stands out on the black background.

This is the result I want:

Here's a MWE:

\documentclass[10pt, notheorems]{beamer}
\usepackage{tikz}
\usetikzlibrary{cd, arrows, decorations.pathmorphing}
\definecolor{colornormaltext}{HTML}{e5e8f8}
\definecolor{colorbg}{HTML}{101316}
\definecolor{colorgold}{HTML}{db9a46}
\setbeamercolor{background canvas}{bg=colorbg}
\setbeamercolor{normal text}{fg=colornormaltext}
\begin{document}
    \begin{frame}
        \begin{equation}
            \begin{tikzcd}[ampersand replacement=&]
                Sh_ W &[-3ex] &[-3ex] Sh_ V\
                & Msbl
                \arrow[""{name=0, anchor=center, inner sep=0}, "{f_}"', shift right=2, from=1-1, to=1-3]
                \arrow[""{name=1, anchor=center, inner sep=0}, "{f^*}"', shift right=2, from=1-3, to=1-1]
                \arrow["{O_W}", from=2-2, to=1-1]
                \arrow[""{name=2, anchor=center, inner sep=0}, "{O_V}"', from=2-2, to=1-3]
                \arrow["\dashv"{anchor=center, rotate=-90}, draw=none, from=1, to=0]
                \arrow[shift left=2, Rightarrow, "\hat f", from=2, to=1-1]
            \end{tikzcd}
        \end{equation*}
    \end{frame}
\end{document}

The incriminated arrow is the very last one in the code:

\arrow[shift left=2, Rightarrow, "\hat f", from=2, to=1-1]

Answer 1

Besides setting the background color to colorbg which is also necessary for other things (crossing over and description nodes), the great nfold library can be used that doesn't draw a thick line with the background color.

Code

\documentclass[10pt, notheorems]{beamer}
\usepackage{tikz}
\usetikzlibrary{cd, decorations.pathmorphing, nfold}
\definecolor{colornormaltext}{HTML}{e5e8f8}
\definecolor{colorbg}{HTML}{101316}
\definecolor{colorgold}{HTML}{db9a46}
\setbeamercolor{background canvas}{bg=colorbg}
\setbeamercolor{normal text}{fg=colornormaltext}
\tikzcdset{
  diagrams={/tikz/double/.append style=/tikz/nfold},% every cd should use nfold
  background color=colorbg
}
\begin{document}
\begin{frame}
\begin{equation*}
\begin{tikzcd}[column sep=small, ampersand replacement=\&]
Sh_W \&      \& Sh_V\\
     \& Msbl
\arrow["f_*"', shift right=2, from=1-1, to=1-3]
\arrow[from=1-1, to=1-3, draw=none, "\dashv" {rotate=-90, auto=false}]
\arrow["f^*"', shift right=2, from=1-3, to=1-1]
\arrow["{O_W}"  name=OW, from=2-2, to=1-1]
\arrow["{O_V}"' name=OV, from=2-2, to=1-3]
\arrow[Rightarrow, "\hat f" near start, from=OV, to=1-1, bend left=10]
\end{tikzcd}
\end{equation*}
\end{frame}
\end{document}

Output

Answer 2

Found the answer in a different thread.

The tikz-cd environment has a setting for the background color, which you would need to set to black in your case, i.e. simply change

\begin{tikzcd}[ampersand replacement=\&]

to

\begin{tikzcd}[ampersand replacement=\&, background color=black]

and it gives the desired result.

Answer 3

• You should provide complete MWE, not just fragment diagram code.
• Your code fragment is a bit strange, so it is hart to understand what is your problem.
• I just clean-up your code and try to reproduce showed image (without thick arrows which purpose is not clear)

\documentclass{beamer}
\usepackage{tikz-cd}
\usetikzlibrary{arrows.meta}
\begin{document}
\begin{frame}[fragile]
\frametitle{tikz-cd diagram}
[
    \begin{tikzcd}[
    row sep = large,
arrow style = tikz,
          > = {Straight Barb[scale=0.8]}

                    ]
Sh_{\mathrm{a.e.}}W_{\infty} \ar[rr,shift right=0.5em, "1_t" ', "\bot"]
    &   & Sh_{\mathrm{a.e.}}W_t  \ar[ll,shift right=0.5em,"1^t" ']    \
    & \mathsf{Msbl} \ar[ul, "\mathcal{O}{\infty}"]
                    \ar[ur, "\mathcal{O}_t" ']
        &
\end{tikzcd}
]
\end{frame}
\end{document}

Addendum:

It is still (unfortunately) not clear where arrow in the middle of diagram should be. Also if it need to be Rightarrow In case that it need to cross arrows from node 2-2 to 1-3 result can be ugly (to my opinion). So below are two examples of:

\documentclass{beamer}
\usepackage{tikz-cd}
\usetikzlibrary{arrows.meta}
\begin{document}
\begin{frame}[fragile]
\frametitle{tikz-cd diagram}
[
    \begin{tikzcd}[
    row sep = large,
arrow style = tikz,
          > = {Straight Barb[scale=0.8]},
                    ]
Sh_{\mathrm{a.e.}}W_{\infty} \ar[rr,shift right=0.5em, "1_t" ', "\bot"]
    &   & Sh_{\mathrm{a.e.}}W_t  \ar[ll,shift right=0.5em,"1^t" ']    \
    & \mathsf{Msbl} \ar[ul, "\mathcal{O}{\infty}"]
                    \ar[ur, ""{name=Ot,right}]
                    \ar[ur, "\mathcal{O}_t" ']
                    \ar[dashrightarrow, from=Ot, to=1-1,yshift=-1ex]
        &
\end{tikzcd}
]
\end{frame}
\end{document}

or (only diagram code):

Sh_{\mathrm{a.e.}}W_{\infty} \ar[rr,shift right=0.5em, "1_t*" ', "\bot"]
    &   & Sh_{\mathrm{a.e.}}W_t  \ar[ll,shift right=0.5em,"1^*_t" ']    \\
    & \mathsf{Msbl} \ar[ul, "\mathcal{O}_{\infty}"]
                    \ar[ur, draw=none, ""{name=Ot,right}]
                    \ar[ur, "\mathcal{O}_t" ']
                    \ar[Rightarrow, crossing over, from=Ot, to=1-1,yshift=-1ex]
        &

or with Rightarrow inside diagram:

Sh_{\mathrm{a.e.}}W_{\infty} \ar[rr,shift right=0.5em, "1_t*" ', "\bot"]
    &   & Sh_{\mathrm{a.e.}}W_t  \ar[ll,shift right=0.5em,"1^*_t" ']    \\
    & \mathsf{Msbl} \ar[ul, "\mathcal{O}_{\infty}"]
                    \ar[ur, "\mathcal{O}_t" ', ""{name=Ot}]
                    \ar[Rightarrow,  from=Ot, to=1-1,yshift=-1ex]
        &

Answer 4

I am not going to create MWE but have you tried adding \usetikzlibrary{arrows.meta} to your preamble? Then, try this:

\arrow[""{name=0, anchor=center, inner sep=0,latex-}, "{f_*}"', shift right=2, from=1-1, to=1-3]