tikz pgf hide or show legend, colorbar, plot lines - similar to hide axis

Question

If you have a complex tikzpicture with many \addplot commands and \addlegendentry commands, references to many datasets, probably also a colorbar, and so on: is there a convenient way to only hide/show the legend or only hide/show the colorbar, or to hide all the plot lines while keeping the legend?

I want to avoid having to uncomment and edit many things and there is for example a very convenient way to hide the axis by using hide axis, somewhere within the axis options of the tikzpicture. I am looking for similar commands to hide the legend or to hide the colorbar or to hide the actual line data (plots) while still showing the correct legend (with correct colors, entries etc.).

The goal is for example to be able to create a pdf, which just shows the cropped legend (with all the correct lines in the corresponding colors of the plots and with the correct legend entries) but hides all of the rest of the figure's elements (colorbar, axis, plot lines...). Is something like this possible? I would like to avoid to create the legend manually as mentioned here: 54794

Answer 1

As I already stated in the comments below the question, you can externalize the legend to a PDF. For that have a look at the following example (including the comments).

% use this document to externalize the legend of the plot
% (it is important that the `--shell-escape' feature is enabled)
\documentclass[border=2mm]{standalone}
\usepackage{pgfplots}
    % load `external' library from PGFPlots and not TikZ,
    % because its newer and some bugs are fixed
    \usetikzlibrary{
        pgfplots.external,
    }
    % when you are new to LaTeX/PGFPlots then you should use
    % the newest `compat' level to use all new features
    \pgfplotsset{
        compat=newest,
    }
    % activate externalization
    \tikzexternalize[
        % with the following key you can define where to store the
        % externalized files. Otherwise they will be stored in the
        % main/\jobname folder
        prefix=Pics/pgf-export/,
        % only externalize stuff that is "named" with `\tikzsetnextfilename'
        only named=true,
%        % if you have to force to reexternalize stuff, uncomment the next line
%        force remake,
    ]
\begin{document}
% if you (also) want to externalize the plot, give him a name
% (uncomment the next line)
%    \tikzsetnextfilename{linear_plots}
    \begin{tikzpicture}
        \begin{axis}[
            legend columns=-1,
            legend entries={
                $(x+0)^k$;,
                $(x+1)^k$;,
                $(x+2)^k$;,
                $(x+3)^k$
            },
            legend to name=legend:linear_plots,
        ]
            \addplot {x};
            \addplot {x+1};
            \addplot {x+2};
            \addplot {x+3};
        \end{axis}
    \end{tikzpicture}

    bla
    % to externalize the (external) legend, give it a name with the
    % following command
    \tikzsetnextfilename{linear_plots_legend}
    % then reference the legend, so it is drawm and thus externalized
    \ref{legend:linear_plots}
    blub
\end{document}

Then you can simply use \includegraphics in your real document to show the legend anywhere you want.

% in your "real" document you can then include the externalized plot/legend
\documentclass[border=2mm]{standalone}
\usepackage{graphicx}
    % also add the externalize path (from above)
    % to the `\graphicspath'
    \graphicspath{{Pics/pgf-export/}}
\begin{document}
    bla \includegraphics{linear_plots_legend} blub
\end{document}