Scroll paint is enabled since opengl supports it, but when we turn opengl off we revert back to the cairo backing and get this:
2018-04-26 22:06:03,153 error processing draw packet Traceback (most recent call last): File "/usr/lib64/python3.6/site-packages/xpra/client/mixins/window_manager.py", line 1188, in _draw_thread_loop self._do_draw(packet) File "/usr/lib64/python3.6/site-packages/xpra/client/mixins/window_manager.py", line 1249, in _do_draw window.draw_region(x, y, width, height, coding, data, rowstride, packet_sequence, options, [record_decode_time]) File "/usr/lib64/python3.6/site-packages/xpra/client/client_window_base.py", line 604, in draw_region backing.draw_region(x, y, width, height, coding, img_data, rowstride, options, callbacks) File "/usr/lib64/python3.6/site-packages/xpra/client/window_backing_base.py", line 590, in draw_region self.paint_scroll(img_data, options, callbacks) File "/usr/lib64/python3.6/site-packages/xpra/client/window_backing_base.py", line 545, in paint_scroll raise NotImplementedError("no paint scroll on %s" % type(self)) NotImplementedError: no paint scroll on <class 'xpra.client.gtk3.cairo_backing.CairoBacking'> 2018-04-26 22:06:05,985 Error drawing on window 1
Done in r19085.
Found the magic formulae in this cairo mailing list post from 2005: Scrolling/Copying.
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1821