fix ob-python

scripts/test/test.org

@@ -1,6 +1,7 @@
 
+* syntax highlighting
 
-* graphviz dot
+** graphviz dot
 #+begin_src dot
 digraph G {
   main -> parse -> execute;
@@ -14,7 +15,7 @@ digraph G {
 }
 #+end_src
 
-* gnuplot
+** gnuplot
 #+begin_src gnuplot :results silent
 reset
 
@@ -35,3 +36,30 @@ h(x) = 10*sqrt(abs(x))
 
 plot f(x) w lp lw 1, g(x) w p lw 2, h(x) w l lw 3
 #+end_src
+
+
+* custom header
+
+** python
+
+- interactive inside org
+- html export creates a svg file
+- latex export creates a pgf file
+
+#+HEADER: :var fname=(mpl-var "img/peltier-characteristic")
+#+HEADER: :epilogue (by-backend (html "fig.savefig(fname);print(fname, end='')") (t "plt.show()"))
+#+HEADER: :results (by-backend (html "output file") (t "none"))
+#+begin_src python :exports results
+import numpy as np
+import matplotlib.pyplot as plt
+x = [-4, -3, -2, -1, 0, 1, 2, 3]
+y1 = [-11.2, -11.6, -7.0, 3.2, 18.3, 39.0, 68.2, 125.0]
+y2 = [-8.2, -8.3, -3.9, 7.3, 22.9, 47.3, 87.1, 136.2]
+fig, ax = plt.subplots(1, 1, dpi=100, layout='constrained', figsize=[6.4*1.5/2, 4.8*1.5/2])
+ax.plot(x, y1, '.-', label='15°C')
+ax.plot(x, y2, '.-', label='20°C')
+ax.legend()
+ax.set_xlabel('Electrical current, A')
+ax.set_ylabel('Temperature, °C')
+ax.set_title('Characteristic curve of the peltier element')
+#+end_src