\mathbb plot label in PyX

Question

I am making plot in PyX.

To get (in LaTex language)

\mathrm{a}

you use

\rm{a}

(in PyX language).

I wanna get (in LaTex language)

\mathbb{a}.

How to do it in PyX language? Attempt of

\bb{a}

gives error message.

Answer 1

After looking briefly at the documentation, and the examples section (as you didn't provide an example, which would have been nice):

from pyx import graph, text

text.set(mode="latex")
text.preamble(r"\usepackage{amssymb}")

g = graph.graphxy(width=8, x=graph.axis.linear(min=0, max=1))
g.plot(graph.data.function("y(x) = x**2", points=8))

xax = g.axes['x']
xax.axis.title = '$\mathbb{A}$'

g.writePDFfile("demo")

which makes a PDF looking like

Note that only uppercase blackboard letters are defined by amsfonts, using lower case letters gives various symbols, as you can see if you try

\documentclass{article}
\usepackage{amssymb,pgffor}
\begin{document}
\foreach \i in {a,b,...,z} {$\mathbb{\i}$}

\foreach \i in {A,B,...,Z} {$\mathbb{\i}$}
\end{document}