Alignment of pgfplot inline legend in body text and caption

Question

I would like to use pgfplots' "legend to name" feature to reference the (named) legend in the caption of the respective figure environment. Additionally, it would be nice to be able to put the legend inline with text, as well.

It works, generally speaking, but the vertical alignment is off in both cases.

I had a look at (amongst others) vertical alignment of tikzpicture with text and TikZ vertical alignment of circled text and the answers didn't really solve the problem.

This is an MWE where the alignment is off:

\documentclass{article}
\usepackage{lipsum}
\usepackage{pgfplots}
\pgfplotsset{
    width=7cm,
    compat=1.18,
    footnotesize,
    samples=10,
    every legend to name picture/.style={
        % baseline={([yshift=+0.55em]current bounding box.south)}
        % baseline={[yshift=+1.65em](current bounding box.base)}
    },
}
\begin{document}
\lipsum[1-2]\ref{named}
\lipsum[3]
\begin{figure}[b]
%
\begin{tikzpicture}
\begin{axis}[
legend columns=-1,
legend entries={$(x+0)^k$;,$(x+1)^k$},
legend to name=named,
every axis legend/.append style={
    draw=none,
},
]
\addplot {x};
\addplot {x+1};
\end{axis}
\end{tikzpicture}
%
\caption{Test: \ref{named}}
\end{figure}
\end{document}

I tried some settings including both commented out using baseline. But manually setting the "correct" yshift seems a bit "hacky".

I hope someone can help me here.

Answer 1

I found that you can name the legend with legend style={name=leg} (or whatever name you like), which allows you to align its inline representation to its own base using every legend to name picture/.style={baseline={(leg.base)}}. You can also align the nodes inside the legend (which are positioned in a matrix) to their base using legend style={nodes={anchor=base}}. So, the trick would be to essentially align everything to the same baseline. This would result in something like the following:

Now, the next step would be to un-align the legend pictures or to shift them a bit upwards. This can be done using legend image post style={yshift=.5ex} for example. The complete code of this approach would be:

\documentclass{article}
\usepackage{lipsum}
\usepackage{pgfplots}
\pgfplotsset{
    width=7cm,
    compat=1.18,
    footnotesize,
    samples=10,
    legend style={
        nodes={anchor=base},
        name=leg,
    },
    legend image post style={yshift=.5ex},
    every legend to name picture/.style={
        baseline={(leg.base)},
    },
}
\begin{document}
\lipsum[1-2]\ref{named}
\lipsum[3]
\begin{figure}[b]
%
\begin{tikzpicture}
\begin{axis}[
legend columns=-1,
legend entries={$(x+0)^k$;,$(x+1)^k$},
legend to name=named,
every axis legend/.append style={
    draw=none,
},
]
\addplot {x};
\addplot {x+1};
\end{axis}
\end{tikzpicture}
%
\caption{Test: \ref{named}}
\end{figure}
\end{document}