Allright:
So slowly working my way through the code,
and looking at your comments, it seems like
the best approach would be to explore the pango
end of it, and find out why figuring out text width is so slow.
I sent an email to the gtk mailing list, and will see if anything
interesting pops up.
I had no idea of the massive and complex nature of wxwidgets!
Best,
Dan
PS In the meantime, goodluck on the book!