[Tex/LaTex] pgfplots: tikz-code in xlabel / ylabel

pgfplots

In diagrams, arrows should indicate the direction of increasing values. The DIN461 recommends to place those arrows next to the xlabel / ylabel, which I find a good looking solution. To accomplish this, I tried:

\documentclass[tikz]{standalone}
\usepackage{pgfplots}
\newlength{\txtht}
\newcommand{\diagramarrow}[1]{ %
    \settoheight{\txtht}{#1}%
    \tikz[baseline] { \draw[->,>=latex,inner sep=0pt,outer sep=0pt] (0,0.5\txtht)--++(1.75em,0);}  %
}

\begin{document}
\begin{tikzpicture}
\begin{axis}[ %
    xlabel={Voltage \diagramarrow{X} },
    ylabel={Current \diagramarrow{X} }, 
    ]
\addplot[] coordinates {(0,1) (1,1) (3,10)};
\coordinate (arrowtipX) at (xticklabel cs:0.65,11pt) {};
\end{axis}
\node[red,align=right] at (arrowtipX) {\diagramarrow{X}};
\end{tikzpicture}
\end{document}

resulting plot

However, the resulting arrows (black) are askew. The expected behaviour is the red arrow, which was placed manually using the xticklabel cs.

So here are my questions:

Why are the black arrows not even parallel to the axes, when they where defined –++(1.75em,0)?

How can I achieve a tikz-arrow (arrows like \rightarrow are really ugly…) at the half height of the actual label text?

What are the names of the xlabel/ylabel-nodes? If I knew those names, I could place the arrows outside the axis environment (like the red one) at something like (xlabel.east).

Thank you

ABI

Best Answer

like this:

enter image description here

\documentclass[margin=3mm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.15}

\newcommand{\diagramarrow}{\raisebox{0.5ex}{\tikz\draw[-latex] (0,0) -- (1.75em,0);}}

\begin{document}
\begin{tikzpicture}
\begin{axis}[ %
    xlabel={Voltage \diagramarrow},
    ylabel={Current \diagramarrow},
    no marks
    ]
\addplot    coordinates {(0,1) (1,1) (3,10)};
\end{axis}
\end{tikzpicture}
\end{document}
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