I've created a block diagram and want to add a legend to it which should be positioned in the very top left corner.
I've setup a custom environment for the legend according to the answer to this question. Without the legend, this is my result:
However, when adding the legend at current bounding box.north west the whole thing gets shifted for some reason:
This is the code:
\documentclass[tikz]{standalone}
\usepackage{pgfplots}
\usetikzlibrary{positioning}
% setup the custom legend stuff
% argument #1: any options
\makeatletter
\newenvironment{customlegend}[1][]{%
\begingroup
% inits/clears the lists (which might be populated from previous
% axes):
\pgfplots@init@cleared@structures
\pgfplotsset{#1}%
}{%
% draws the legend:
\pgfplots@createlegend
\endgroup
}%
% makes \addlegendimage available (typically only available within an
% axis environment):
\def\addlegendimage{\pgfplots@addlegendimage}
\makeatother
\begin{document}
\begin{tikzpicture}
[
node distance=50pt
]
\newcommand{\nodesize}{12pt}
\linespread{0.8}
\node (S0) [circle,draw,inner sep=\nodesize,very thick]
{$$\mbox{\Large $0$}$$};
\node (S1) [circle,draw,inner sep=\nodesize, right =of S0 ,very thick]
{$$\mbox{\Large $1$}$$};
\node(S2A) [circle,draw,inner sep=\nodesize, above right =of S1 ,very thick]
{$$\mbox{\Large $2^a$}$$};
\node(S2B) [circle,draw,inner sep=\nodesize, below right =of S1 ,very thick]
{$$\mbox{\Large $2^b$}$$};
\node (S3) [circle,draw,inner sep=\nodesize, below right =of S2A,very thick]
{$$\mbox{\Large $3$}$$};
\node (S4) [circle,draw,inner sep=\nodesize, right =of S3,very thick]
{$$\mbox{\Large $4$}$$};
\draw[->, gray] (S0.10) -- (S1.170);
\draw[->, gray] (S1.190) -- (S0.350);
\draw[->, gray] (S1.90) -- (S2A.180);
\draw[->, gray] (S1.290) -- (S2B.160);
\draw[->, gray] (S2B.180) -- (S1.270);
\draw[->, gray] (S2A.260) -- (S2B.100);
\draw[->, gray] (S2B.80) -- (S2A.280);
\draw[->, gray] (S2A.0) -- (S3.90);
\draw[->, gray] (S2B.20) -- (S3.250);
\draw[->, gray] (S3.270) -- (S2B.0);
\draw[->, gray] (S4.190) -- (S3.350);
\draw[->, gray] (S0) to [in=80,out=30,looseness=4.5] (S0);
\draw[->, gray] (S1) to [in=100,out=150,looseness=4.5] (S1);
\draw[->, gray] (S2B) to [in=350,out=300,looseness=4.5] (S2B);
\draw[->, gray] (S3) to [in=80,out=30,looseness=4.5] (S3);
\draw[->, gray] (S1) to [in=280,out=260,looseness=2.3] (S3);
\draw[->, gray] (S3) to [in=240,out=300,looseness=2.7] (S1);
\draw[->] (S3.10) edge node[sloped, anchor=center, above,align=center]
{$t_m$ \\ $$\mbox{\tiny $\mathtt{[0,0,-,1]}$}$$} (S4.170);
\draw[->] (S4) to [in=80,out=30,looseness=4.5] node [above,xshift=-7pt,yshift=2pt,align=center] {$t_{m+1}...t_{n-1}$ \\ $$\mbox{\tiny $\mathtt{[0,0,-,-]}$}$$} (S4);
\draw[->, dashed]
(S2A.200) edge node[sloped, anchor=center, below,align=center] {$t_n$ \\ $$\mbox{\tiny $\mathtt{[1,0,-,-]}$}$$} (S1.70)
(S3.110) edge node[sloped, anchor=center, below,align=center] {$t_m$ \\ $$\mbox{\tiny $\mathtt{[0,0,-,-]}$}$$} (S2A.340)
(S2A) to [in=80,out=30,looseness=4.5] node [right,xshift=2pt,align=center] {$t_{m+1}...t_{n-1}$ \\ $$\mbox{\tiny $\mathtt{[0,0,-,-]}$}$$} (S2A);
% the next few lines add the legend:
\begin{customlegend}[legend style={at={(current bounding box.north west)}}, anchor=north west, legend entries={\textbf{Transitions}, valid, invalid, corrected}]
\addlegendimage{empty legend}
\addlegendimage{black}
\addlegendimage{dotted}
\addlegendimage{dashed}
\end{customlegend}
\end{tikzpicture}
\end{document}
Why is adding the custom legend changing the bounding box and how can I position the legend at the top left corner of the first image? I know I could fiddle around with legend style={at={x,y)} but I feel like there should be a more elegant solution which actually lines up the legend with my diagram.
$$...$$construct, I initially tried$...$but this did not apply\tiny. I found this construct with \mbox somewhere on tex.stackexchange which allows me to change text size inside the math environment. – Dominic Mar 30 '20 at 14:52\tinyinside$ .. $, but if you place it before it changes the font size. See the code in my answer, where I changed$$\mbox{\tiny $ .. $}$$to\tiny $ .. $. (In fact, if you did$$ \tiny a $$then that wouldn't work either, as that would be using the font size macro in math mode, and they only work in text mode, I think.) – Torbjørn T. Mar 30 '20 at 14:59