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Images and legends

Download notebookView on GitHubRun when the site was built.

This tutorial covers what a pgfplots axis holds besides lines:

  • A title, and labels with commas in them
  • Ticks at chosen positions, with your own labels
  • Filled polygons and colored points
  • Images placed in data coordinates (add_graphics)
  • Verbatim code in the axis coordinate system (add_raw)
  • Legends that leave some plots out, placed anywhere
  • Saving a figure together with its images
import io


import matplotlib


matplotlib.use("Agg")
import matplotlib.pyplot as plt
import numpy as np


from tikzfigure import TikzFigure

Titles, labels and ticks

Section titled “Titles, labels and ticks”

title= puts a title above the axis. Labels and titles that contain a comma or = are braced for pgfplots automatically. set_ticks places ticks at the given positions, optionally with your own labels.

fig = TikzFigure()
ax = fig.axis2d(
    title="Measurements, first week",
    xlabel="day",
    ylabel="temperature, $^\\circ$C",
    xlim=(0, 6),
    ylim=(10, 25),
)
ax.add_plot([0, 1, 2, 3, 4, 5, 6], [14, 15, 19, 22, 21, 18, 16], color="red", mark="*")
ax.set_ticks("x", [0, 2, 4, 6], ["Mon", "Wed", "Fri", "Sun"])


fig.show()
/home/runner/work/tikzfigure/tikzfigure/.venv/lib/python3.12/site-packages/fitz/__init__.py:17: FutureWarning: The `fitz` API is deprecated and will be removed in future. Use `import pymupdf` instead.
  warnings.warn(
Notebook output
Show the TikZ code
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[title={Measurements, first week}, xlabel=day, ylabel={temperature, $^\circ$C}, xmin=0, xmax=6, ymin=10, ymax=25, xtick={0,2,4,6}, xticklabels={{Mon},{Wed},{Fri},{Sun}}, grid=major]
        \addplot[color=red, mark=*] coordinates {(0,14) (1,15) (2,19) (3,22) (4,21) (5,18) (6,16)};
    \end{axis}
\end{tikzpicture}
Show the standalone LaTeX document
\documentclass[border=10pt]{standalone}
\PassOptionsToPackage{dvipsnames,svgnames,x11names}{xcolor}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{groupplots}
\usetikzlibrary{arrows.meta}
\usepackage{pgfplots}
\begin{document}
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[title={Measurements, first week}, xlabel=day, ylabel={temperature, $^\circ$C}, xmin=0, xmax=6, ymin=10, ymax=25, xtick={0,2,4,6}, xticklabels={{Mon},{Wed},{Fri},{Sun}}, grid=major]
        \addplot[color=red, mark=*] coordinates {(0,14) (1,15) (2,19) (3,22) (4,21) (5,18) (6,16)};
    \end{axis}
\end{tikzpicture}


\end{document}

Filled polygons and colored points

Section titled “Filled polygons and colored points”

cycle=True closes a plot’s path back to its first point, for a polygon. meta= gives every point a value, written as (x,y) [value]; with the pgfplots options scatter and point meta=explicit the points are colored by it through the axis colormap.

fig = TikzFigure()
ax = fig.axis2d(xlim=(0, 4), ylim=(0, 3), colorbar=True)
ax.add_plot([0.5, 2.0, 1.2], [0.5, 0.8, 2.5], cycle=True, fill="blue", fill_opacity=0.2)


x = np.linspace(0.5, 3.5, 12)
ax.add_plot(
    x.tolist(),
    (1.5 + np.sin(2 * x)).tolist(),
    meta=x.tolist(),
    options=["scatter", "only marks", "point meta=explicit"],
)


fig.show()
Notebook output
Show the TikZ code
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[xmin=0, xmax=4, ymin=0, ymax=3, grid=major, colorbar=true]
        \addplot[fill=blue, fill opacity=0.2] coordinates {(0.5,0.5) (2.0,0.8) (1.2,2.5)} -- cycle;
        \addplot[scatter, only marks, point meta=explicit] coordinates {(0.5,2.3414709848078967) [0.5] (0.7727272727272727,2.4996789142433977) [0.7727272727272727] (1.0454545454545454,2.36776314391168) [1.0454545454545454] (1.3181818181818181,1.984007857665163) [1.3181818181818181] (1.5909090909090908,1.4597853190024037) [1.5909090909090908] (1.8636363636363635,0.9472337597608833) [1.8636363636363635] (2.1363636363636362,0.5951042964940122) [2.1363636363636362] (2.409090909090909,0.5055908448925597) [2.409090909090909] (2.6818181818181817,0.7046717199810077) [2.6818181818181817] (2.954545454545454,1.1345702904724295) [2.954545454545454] (3.227272727272727,1.6705227326844927) [3.227272727272727] (3.5,2.156986598718789) [3.5]};
    \end{axis}
\end{tikzpicture}
Show the standalone LaTeX document
\documentclass[border=10pt]{standalone}
\PassOptionsToPackage{dvipsnames,svgnames,x11names}{xcolor}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{groupplots}
\usetikzlibrary{arrows.meta}
\usepackage{pgfplots}
\begin{document}
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[xmin=0, xmax=4, ymin=0, ymax=3, grid=major, colorbar=true]
        \addplot[fill=blue, fill opacity=0.2] coordinates {(0.5,0.5) (2.0,0.8) (1.2,2.5)} -- cycle;
        \addplot[scatter, only marks, point meta=explicit] coordinates {(0.5,2.3414709848078967) [0.5] (0.7727272727272727,2.4996789142433977) [0.7727272727272727] (1.0454545454545454,2.36776314391168) [1.0454545454545454] (1.3181818181818181,1.984007857665163) [1.3181818181818181] (1.5909090909090908,1.4597853190024037) [1.5909090909090908] (1.8636363636363635,0.9472337597608833) [1.8636363636363635] (2.1363636363636362,0.5951042964940122) [2.1363636363636362] (2.409090909090909,0.5055908448925597) [2.409090909090909] (2.6818181818181817,0.7046717199810077) [2.6818181818181817] (2.954545454545454,1.1345702904724295) [2.954545454545454] (3.227272727272727,1.6705227326844927) [3.227272727272727] (3.5,2.156986598718789) [3.5]};
    \end{axis}
\end{tikzpicture}


\end{document}

precision= limits the digits of the written coordinates, which keeps long data series readable: ax.add_plot(x, y, precision=4).

Images in data coordinates

Section titled “Images in data coordinates”

Large colormap data would be slow and memory hungry as pgfplots coordinates. add_graphics places an image instead, its edges at the given data coordinates. Give an existing file as path=, or the image bytes as data=: the figure then writes them next to the TikZ code when it compiles or saves it.

x, y = np.meshgrid(np.linspace(-2, 2, 200), np.linspace(-1, 1, 100))
field = np.exp(-(x**2) - 4 * y**2) * np.cos(4 * x)
png = io.BytesIO()
plt.imsave(png, field, cmap="RdBu_r", origin="lower", format="png")


fig = TikzFigure()
ax = fig.axis2d(xlabel="$x$", ylabel="$y$", xlim=(-2, 2), ylim=(-1, 1), grid=False)
ax.add_graphics(-2, 2, -1, 1, data=png.getvalue(), filename="field.png")
ax.add_plot([-2, 2], [0, 0], color="black", dashed=True)


fig.show()
Notebook output
Show the TikZ code
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[xlabel=$x$, ylabel=$y$, xmin=-2, xmax=2, ymin=-1, ymax=1, grid=none]
        \addplot graphics[xmin=-2.0, xmax=2.0, ymin=-1.0, ymax=1.0] {field.png};
        \addplot[color=black, dashed=true] coordinates {(-2,0) (2,0)};
    \end{axis}
\end{tikzpicture}
Show the standalone LaTeX document
\documentclass[border=10pt]{standalone}
\PassOptionsToPackage{dvipsnames,svgnames,x11names}{xcolor}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{groupplots}
\usetikzlibrary{arrows.meta}
\usepackage{pgfplots}
\begin{document}
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[xlabel=$x$, ylabel=$y$, xmin=-2, xmax=2, ymin=-1, ymax=1, grid=none]
        \addplot graphics[xmin=-2.0, xmax=2.0, ymin=-1.0, ymax=1.0] {field.png};
        \addplot[color=black, dashed=true] coordinates {(-2,0) (2,0)};
    \end{axis}
\end{tikzpicture}


\end{document}

The plots, images and raw code of an axis are drawn in the order they were added, so the dashed line is on top of the image. fig.files() lists the images the figure needs:

list(fig.files())
['field.png']

Raw code in the axis coordinate system

Section titled “Raw code in the axis coordinate system”

add_raw inserts verbatim code inside the axis, where axis cs: refers to data coordinates and axis description cs: to the axis box, (0,0) at its lower left and (1,1) at its upper right.

fig = TikzFigure()
ax = fig.axis2d(xlim=(0, 10), ylim=(0, 1))
ax.add_plot([0, 2, 4, 6, 8, 10], [0.1, 0.5, 0.9, 0.6, 0.3, 0.2], color="teal")
ax.add_raw(r"\draw[->, thick] (axis cs:6,0.9) -- (axis cs:4.3,0.9);")
ax.add_raw(r"\node[anchor=west] at (axis cs:6,0.9) {maximum};")
ax.add_raw(r"\node[anchor=north east] at (axis description cs:0.98,0.98) {(a)};")


fig.show()
Notebook output
Show the TikZ code
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[xmin=0, xmax=10, ymin=0, ymax=1, grid=major]
        \addplot[color=teal] coordinates {(0,0.1) (2,0.5) (4,0.9) (6,0.6) (8,0.3) (10,0.2)};
        \draw[->, thick] (axis cs:6,0.9) -- (axis cs:4.3,0.9);
        \node[anchor=west] at (axis cs:6,0.9) {maximum};
        \node[anchor=north east] at (axis description cs:0.98,0.98) {(a)};
    \end{axis}
\end{tikzpicture}
Show the standalone LaTeX document
\documentclass[border=10pt]{standalone}
\PassOptionsToPackage{dvipsnames,svgnames,x11names}{xcolor}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{groupplots}
\usetikzlibrary{arrows.meta}
\usepackage{pgfplots}
\begin{document}
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[xmin=0, xmax=10, ymin=0, ymax=1, grid=major]
        \addplot[color=teal] coordinates {(0,0.1) (2,0.5) (4,0.9) (6,0.6) (8,0.3) (10,0.2)};
        \draw[->, thick] (axis cs:6,0.9) -- (axis cs:4.3,0.9);
        \node[anchor=west] at (axis cs:6,0.9) {maximum};
        \node[anchor=north east] at (axis description cs:0.98,0.98) {(a)};
    \end{axis}
\end{tikzpicture}


\end{document}

Legends

Section titled “Legends”

Plots with a label get a legend entry. If some plots have none, they are left out of the legend (forget plot) instead of taking the next entry. at= places the legend at a point of the axis box, anchor= says which point of the legend goes there.

fig = TikzFigure()
ax = fig.axis2d(xlabel="$t$", ylabel="signal", xlim=(0, 10), ylim=(-1.5, 1.5))
t = np.linspace(0, 10, 60)
ax.add_plot(
    t.tolist(), np.sin(t).tolist(), label="measured, raw", color="blue", precision=4
)
ax.add_plot([0, 10], [0, 0], color="gray")  # a reference line, not in the legend
ax.add_plot(
    t.tolist(), np.sin(t + 0.2).tolist(), label="model", color="red", precision=4
)
ax.set_legend(at=(0.02, 0.02), anchor="south west", columns=2, style="draw=none")


fig.show()
Notebook output
Show the TikZ code
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[xlabel=$t$, ylabel=signal, xmin=0, xmax=10, ymin=-1.5, ymax=1.5, grid=major, legend style={at={(0.02,0.02)}, anchor=south west, draw=none}, legend columns=2]
        \addplot[color=blue] coordinates {(0,0) (0.1695,0.1687) (0.339,0.3325) (0.5085,0.4868) (0.678,0.6272) (0.8475,0.7496) (1.017,0.8505) (1.186,0.927) (1.356,0.977) (1.525,0.999) (1.695,0.9923) (1.864,0.9572) (2.034,0.8947) (2.203,0.8065) (2.373,0.6952) (2.542,0.564) (2.712,0.4166) (2.881,0.2573) (3.051,0.09062) (3.22,-0.07866) (3.39,-0.2457) (3.559,-0.4057) (3.729,-0.554) (3.898,-0.6865) (4.068,-0.7993) (4.237,-0.8892) (4.407,-0.9537) (4.576,-0.9908) (4.746,-0.9994) (4.915,-0.9795) (5.085,-0.9315) (5.254,-0.8568) (5.424,-0.7575) (5.593,-0.6365) (5.763,-0.4973) (5.932,-0.3438) (6.102,-0.1805) (6.271,-0.012) (6.441,0.1568) (6.61,0.3212) (6.78,0.4763) (6.949,0.6178) (7.119,0.7416) (7.288,0.8441) (7.458,0.9225) (7.627,0.9744) (7.797,0.9984) (7.966,0.9937) (8.136,0.9606) (8.305,0.9) (8.475,0.8135) (8.644,0.7038) (8.814,0.5739) (8.983,0.4275) (9.153,0.2689) (9.322,0.1026) (9.492,-0.0667) (9.661,-0.234) (9.831,-0.3947) (10,-0.544)};
        \addlegendentry{measured, raw}
        \addplot[color=gray, forget plot] coordinates {(0,0) (10,0)};
        \addplot[color=red] coordinates {(0,0.1987) (0.1695,0.3611) (0.339,0.5133) (0.5085,0.6507) (0.678,0.7694) (0.8475,0.8662) (1.017,0.938) (1.186,0.9831) (1.356,0.9999) (1.525,0.9881) (1.695,0.9479) (1.864,0.8806) (2.034,0.7881) (2.203,0.673) (2.373,0.5385) (2.542,0.3887) (2.712,0.2277) (2.881,0.0602) (3.051,-0.109) (3.22,-0.2752) (3.39,-0.4334) (3.559,-0.5792) (3.729,-0.7084) (3.898,-0.8173) (4.068,-0.9028) (4.237,-0.9624) (4.407,-0.9944) (4.576,-0.998) (4.746,-0.9729) (4.915,-0.9199) (5.085,-0.8406) (5.254,-0.7372) (5.424,-0.6127) (5.593,-0.4706) (5.763,-0.315) (5.932,-0.1504) (6.102,0.01851) (6.271,0.1869) (6.441,0.3499) (6.61,0.5029) (6.78,0.6415) (6.949,0.7617) (7.119,0.8601) (7.288,0.9338) (7.458,0.9808) (7.627,0.9996) (7.797,0.9898) (7.966,0.9517) (8.136,0.8862) (8.305,0.7954) (8.475,0.6818) (8.644,0.5486) (8.814,0.3997) (8.983,0.2394) (9.153,0.07217) (9.322,-0.0971) (9.492,-0.2636) (9.661,-0.4225) (9.831,-0.5694) (10,-0.6999)};
        \addlegendentry{model}
    \end{axis}
\end{tikzpicture}
Show the standalone LaTeX document
\documentclass[border=10pt]{standalone}
\PassOptionsToPackage{dvipsnames,svgnames,x11names}{xcolor}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{groupplots}
\usetikzlibrary{arrows.meta}
\usepackage{pgfplots}
\begin{document}
% --------------------------------------------- %
% Tikzfigure generated by tikzfigure v0.5.0     %
% https://github.com/max-models/tikzfigure      %
% --------------------------------------------- %
\begin{tikzpicture}
    \begin{axis}[xlabel=$t$, ylabel=signal, xmin=0, xmax=10, ymin=-1.5, ymax=1.5, grid=major, legend style={at={(0.02,0.02)}, anchor=south west, draw=none}, legend columns=2]
        \addplot[color=blue] coordinates {(0,0) (0.1695,0.1687) (0.339,0.3325) (0.5085,0.4868) (0.678,0.6272) (0.8475,0.7496) (1.017,0.8505) (1.186,0.927) (1.356,0.977) (1.525,0.999) (1.695,0.9923) (1.864,0.9572) (2.034,0.8947) (2.203,0.8065) (2.373,0.6952) (2.542,0.564) (2.712,0.4166) (2.881,0.2573) (3.051,0.09062) (3.22,-0.07866) (3.39,-0.2457) (3.559,-0.4057) (3.729,-0.554) (3.898,-0.6865) (4.068,-0.7993) (4.237,-0.8892) (4.407,-0.9537) (4.576,-0.9908) (4.746,-0.9994) (4.915,-0.9795) (5.085,-0.9315) (5.254,-0.8568) (5.424,-0.7575) (5.593,-0.6365) (5.763,-0.4973) (5.932,-0.3438) (6.102,-0.1805) (6.271,-0.012) (6.441,0.1568) (6.61,0.3212) (6.78,0.4763) (6.949,0.6178) (7.119,0.7416) (7.288,0.8441) (7.458,0.9225) (7.627,0.9744) (7.797,0.9984) (7.966,0.9937) (8.136,0.9606) (8.305,0.9) (8.475,0.8135) (8.644,0.7038) (8.814,0.5739) (8.983,0.4275) (9.153,0.2689) (9.322,0.1026) (9.492,-0.0667) (9.661,-0.234) (9.831,-0.3947) (10,-0.544)};
        \addlegendentry{measured, raw}
        \addplot[color=gray, forget plot] coordinates {(0,0) (10,0)};
        \addplot[color=red] coordinates {(0,0.1987) (0.1695,0.3611) (0.339,0.5133) (0.5085,0.6507) (0.678,0.7694) (0.8475,0.8662) (1.017,0.938) (1.186,0.9831) (1.356,0.9999) (1.525,0.9881) (1.695,0.9479) (1.864,0.8806) (2.034,0.7881) (2.203,0.673) (2.373,0.5385) (2.542,0.3887) (2.712,0.2277) (2.881,0.0602) (3.051,-0.109) (3.22,-0.2752) (3.39,-0.4334) (3.559,-0.5792) (3.729,-0.7084) (3.898,-0.8173) (4.068,-0.9028) (4.237,-0.9624) (4.407,-0.9944) (4.576,-0.998) (4.746,-0.9729) (4.915,-0.9199) (5.085,-0.8406) (5.254,-0.7372) (5.424,-0.6127) (5.593,-0.4706) (5.763,-0.315) (5.932,-0.1504) (6.102,0.01851) (6.271,0.1869) (6.441,0.3499) (6.61,0.5029) (6.78,0.6415) (6.949,0.7617) (7.119,0.8601) (7.288,0.9338) (7.458,0.9808) (7.627,0.9996) (7.797,0.9898) (7.966,0.9517) (8.136,0.8862) (8.305,0.7954) (8.475,0.6818) (8.644,0.5486) (8.814,0.3997) (8.983,0.2394) (9.153,0.07217) (9.322,-0.0971) (9.492,-0.2636) (9.661,-0.4225) (9.831,-0.5694) (10,-0.6999)};
        \addlegendentry{model}
    \end{axis}
\end{tikzpicture}


\end{document}

Saving with images

Section titled “Saving with images”

savefig("figure.tikz") writes the tikzpicture, for \input into a document that loads pgfplots; savefig("figure.tex") a standalone document. Both write the images the figure refers to next to the file. .pdf and .png compile the figure with them.

Part of the max-models projectsSource on GitHub