AFAICT backend_ps + usetex is perfectly happy to output to an in-memory
buffer, as shown by

from pylab import *
from io import BytesIO
rcParams["text.usetex"] = True
xlabel("hello")
ylabel("$world$")
buf = BytesIO()
savefig(buf, format="eps", bbox_inches="tight")
print(buf.getvalue())
buf = BytesIO()
savefig(buf, format="ps", bbox_inches="tight")
print(buf.getvalue())

PR Summary

PR Checklist

• Has Pytest style unit tests
• Code is PEP 8 compliant
• New features are documented, with examples if plot related
• Documentation is sphinx and numpydoc compliant
• Added an entry to doc/users/next_whats_new/ if major new feature (follow instructions in README.rst there)
• Documented in doc/api/api_changes.rst if API changed in a backward-incompatible way