Figure helper

figure-helper — TikZ and PGFPlots authoring

Standard TikZ/PGFPlots preamble

\usepackage{tikz}
\usetikzlibrary{arrows.meta, positioning, calc, shapes.geometric, decorations.pathreplacing, fit, backgrounds}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}                 % or compat=1.18 to pin
\usepgfplotslibrary{groupplots, fillbetween, statistics, dateplot}
% For caching long compiles:
% \usetikzlibrary{external}
% \tikzexternalize[prefix=tikz-cache/]

\pgfplotsset{compat=newest} is required — without it, every minor pgfplots update can shift output. Pin to a specific version (compat=1.18) when reproducibility matters.

Sources: https://ctan.org/pkg/pgfplots, https://tikz.dev/pgfplots.

Flowchart / pipeline diagram

\begin{tikzpicture}[
  node distance=12mm,
  block/.style={rectangle, draw, rounded corners, minimum width=22mm, minimum height=8mm, align=center},
  arrow/.style={-{Latex[length=2mm]}, thick}
]
  \node[block] (in)  {Input};
  \node[block, right=of in]  (proc) {Process};
  \node[block, right=of proc] (out) {Output};
  \draw[arrow] (in) -- (proc);
  \draw[arrow] (proc) -- (out);
\end{tikzpicture}

For more nodes, swap right=of for below=of, above=of, etc. (from positioning lib).

Labeled line plot (PGFPlots)

\begin{tikzpicture}
\begin{axis}[
    width=0.8\linewidth, height=6cm,
    xlabel={Epoch}, ylabel={Loss},
    xmin=1, xmax=10,
    grid=major, grid style={dashed,gray!30},
    legend pos=north east,
    legend cell align=left,
]
\addplot[thick, blue, mark=*]      table {
  1  0.95
  2  0.62
  3  0.41
  4  0.28
  5  0.21
  6  0.18
  7  0.16
  8  0.15
  9  0.14
  10 0.13
};
\addlegendentry{train}
\addplot[thick, red,  mark=square*] table {
  1  1.10
  2  0.78
  3  0.55
  4  0.40
  5  0.30
  6  0.26
  7  0.24
  8  0.23
  9  0.22
  10 0.22
};
\addlegendentry{val}
\end{axis}
\end{tikzpicture}

Mark options: * (filled circle), o (open circle), square*, triangle*, diamond*, +, x, star, none.

Bar chart (PGFPlots)

\begin{tikzpicture}
\begin{axis}[
    ybar, ymin=0,
    width=0.8\linewidth, height=6cm,
    xlabel={Method}, ylabel={Accuracy (\%)},
    symbolic x coords={Baseline, Method A, Method B, Method C},
    xtick=data,
    nodes near coords,
    nodes near coords align={vertical},
    enlarge x limits=0.15,
]
\addplot coordinates {
  (Baseline, 71.2)  (Method A, 78.9)  (Method B, 84.1)  (Method C, 86.4)
};
\end{axis}
\end{tikzpicture}

For grouped bars: \addplot more series; pgfplots handles offset.

Plot from CSV file

% Data in data.csv:
%   epoch,train,val
%   1,0.95,1.10
%   ...
\begin{tikzpicture}
\begin{axis}[xlabel={Epoch}, ylabel={Loss}, legend pos=north east]
\addplot table[x=epoch, y=train, col sep=comma] {data.csv}; \addlegendentry{train}
\addplot table[x=epoch, y=val,   col sep=comma] {data.csv}; \addlegendentry{val}
\end{axis}
\end{tikzpicture}

State machine diagram

\begin{tikzpicture}[
  node distance=18mm, on grid, auto,
  state/.style={circle, draw, minimum size=9mm},
  every edge/.append style={-{Latex[length=2mm]}}
]
  \node[state, initial] (q0) {$q_0$};
  \node[state, right=of q0] (q1) {$q_1$};
  \node[state, accepting, right=of q1] (q2) {$q_2$};
  \path[->]
    (q0) edge node {a} (q1)
    (q1) edge node {b} (q2)
    (q1) edge[loop above] node {c} (q1);
\end{tikzpicture}

Required library: \usetikzlibrary{automata}.

Function plot (analytic)

\begin{tikzpicture}
\begin{axis}[
    domain=-3:3, samples=200,
    xlabel={$x$}, ylabel={$f(x)$},
    axis lines=middle, grid=major,
]
\addplot[thick, blue]   {sin(deg(x))};   \addlegendentry{$\sin x$}
\addplot[thick, red]    {cos(deg(x))};   \addlegendentry{$\cos x$}
\end{axis}
\end{tikzpicture}

Note PGFPlots uses degrees by default — wrap radians input as sin(deg(x)).

Externalize for fast re-compilation

\usetikzlibrary{external}
\tikzexternalize[prefix=tikz-cache/]

Each TikZ figure becomes a separate compile, cached as a PDF. First build is slow; subsequent builds skip unchanged figures. Useful when a thesis has 30+ TikZ figures.

Standalone figure document (compile a figure to its own PDF)

\documentclass[tikz, border=4pt]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
  \node[draw] {Just this figure};
\end{tikzpicture}
\end{document}

Useful when iterating on a single figure without recompiling the whole paper.

Common pitfalls

• Missing \pgfplotsset{compat=newest} → silent layout drift across versions.
• Mixing pgfplots with siunitx — load siunitx first.
• Compile time on large datasets — externalize, or pre-render to PDF and \includegraphics.
• Math in axis labels needs $...$: xlabel={$\theta$ (rad)}, not xlabel={\theta (rad)}.

When uncertain

For non-trivial TikZ libraries or pgfplots options, delegate to /academic-latex:docs-lookup. The pgfplots manual is dense (https://pgfplots.sourceforge.net/pgfplots.pdf) and has the canonical answer.

Last verified

2026-05-09 — pgfplots manual; TikZ documentation at https://tikz.dev/.