I don't have time to look into this even though it
is probably a simple fix.
If you start up two clients to x11vnc (i.e. libvncserver
app) and then set the ultrascaling to 1/2 in one of
If you move the cursor around in the 1/2 scaled one
it moves around correctly in the unscaled one.
If you move the cursor around in the unscaled one the
motion of the cursor in the 1/2 scaled one seems off
by a factor of two.
Happens for examples/example too, so I don't believe
it is an x11vnc bug...