Why is PangoCairoRenderer private?

[Peter Frentrup <peter_frentrup gmx de>]

Hello,

I am working on a little text editor using Cairo and Pango (but without
GTK+/GTKTextView, because it does not have a native look-and-feel on
Windows).

At first I thought, I could use the pangocairo API, but it does not give
me the possibility to draw selected text in a different style without
setting the background-attribute (which seems to be slow when changing
the selection range).
So I read a bit about the PangoRenderer class. I could write my own
subclass of PangoRenderer, but this would basically be a copy of the
PangoCairoRenderer code plus a few additions.

So my suggestion is to make PangoCairoRenderer public to let Pango-users
subclass it; or is there another solution for my problem?

Regards,
Peter