add org matplotlib example

lisp/my/my-org-article.org

@@ -359,7 +359,7 @@ print(result)
 |---------+-------|
 
 ** Figures
-*** svg
+*** Include svg
 #+NAME: fig-svg
 #+CAPTION: svg figure
 #+ATTR_ORG: :width 100
@@ -367,7 +367,7 @@ print(result)
 [[/usr/share/icons/hicolor/scalable/apps/emacs.svg]]
 
 See figure ref:fig-svg-import as a reference.
-*** png
+*** Include png
 #+NAME: fig-png
 #+CAPTION: png figure
 #+ATTR_ORG: :width 100
@@ -414,6 +414,78 @@ See figure ref:fig-svg-import as a reference.
 [[file:test-tikz.svg]]
 #+end_figure
 
+*** python using matplotlib
+
+SRC block header =:prologue (mpl-prologue)= for non-latex exports (.svg
+exports) to loads my.mplstyle including kpfonts. Other style via
+optional argument, e.g. =:prologue (mpl-prologue "my-tex")= rendering
+via latex including kpfonts.
+
+SRC block header =:var fname=(mpl-var "<file_name>")= to export figure
+as .pgf for latex and .svg otherwise, like HTML.
+
+**** using my.mplstyle
+#+HEADER: :prologue (mpl-prologue)
+#+HEADER: :var fname=(mpl-var "img/figure-matplotlib")
+#+begin_src python :results output file
+import math as m
+import matplotlib as mpl
+
+n = 30
+t = [i/n*m.pi for i in range(n+1)]
+
+fig, ax = plt.subplots()
+[ax.plot(t, [m.sin(i+j/12*m.pi) for i in t], color=f'C{j}', label=f'$C_{j}$') for j in range(10)]
+ax.legend()
+ax.set_title(r'Functions: $\sin(x + \pi \, i/12)$')
+ax.set_xlabel(r'$x ~ \times \pi$')
+ax.set_ylabel('$y$')
+ax.set_xticks([0, m.pi/4, m.pi/2, m.pi*3/4, m.pi])
+ax.set_xticklabels([0.00, 0.25, 0.50, 0.75, 1.00])
+ax.xaxis.set_minor_locator(mpl.ticker.AutoMinorLocator(3))
+ax.grid()
+ax.grid(which='minor', linestyle=':')
+
+fig.savefig(fname)
+plt.close()
+print(fname, end='')
+#+end_src
+
+#+ATTR_ORG: :width 500
+#+RESULTS:
+[[file:img/figure-matplotlib.svg]]
+
+**** using my-tex.mplstyle
+#+HEADER: :prologue (mpl-prologue "my-tex")
+#+HEADER: :var fname=(mpl-var "img-matplotlib-tex")
+#+begin_src python :results output file
+import math as m
+import matplotlib as mpl
+
+n = 30
+t = [i/n*m.pi for i in range(n+1)]
+
+fig, ax = plt.subplots()
+[ax.plot(t, [m.sin(i+j/12*m.pi) for i in t], color=f'C{j}', label=f'$C_{j}$') for j in range(10)]
+ax.legend()
+ax.set_title(r'Functions: $\sin(x + \pi \, i/12)$')
+ax.set_xlabel(r'$x ~ \times \pi$')
+ax.set_ylabel('$y$')
+ax.set_xticks([0, m.pi/4, m.pi/2, m.pi*3/4, m.pi])
+ax.set_xticklabels([0.00, 0.25, 0.50, 0.75, 1.00])
+ax.xaxis.set_minor_locator(mpl.ticker.AutoMinorLocator(3))
+ax.grid()
+ax.grid(which='minor', linestyle=':')
+
+fig.savefig(fname)
+plt.close()
+print(fname, end='')
+#+end_src
+
+#+ATTR_ORG: :width 500
+#+RESULTS:
+[[file:img-matplotlib-tex.svg]]
+
 ** Example / Verbatim
 #+BEGIN_EXAMPLE
   verbatime example