I believe this is just a limit on the number of points in a polygon in gdk. Not sure it's readily fixable.

I don't think that is the problem. It crashes the same way (but much quicker) if I set gridsize=5 (and reduce n to 1000).

Still prevalent on master. Interestingly doesn't occur on gtk3 backend.

Gtk+3 completely drops Gdk in favor of Cairo, so it's using a completely different rendering backend. I'm looking at this now.

Fix attached. The problem was actually in _draw_rotated_text when drawing off of the canvas. (So not directly related to hexbin). Underneath this of course is the larger problem that the Gdk backend doesn't support clipping, so the hexbin plot is rather ugly. That's not going to be easy to fix if at all. I'm personally in favor of gracefully deprecating the Gdk backend as Gdk itself is now deprecated as well.

I agree with the idea of phasing out the backend, if possible.

Is there a reason this check for out-of-bounds is needed only in _draw_rotated_text and not in draw_text, which also is already checking for negative x or y?

@efiring: Good point. I have made the analogous fix to _draw_text.