[FreeNX-kNX] bandwidth used when client is minimized

[Seb Wills]

I've noticed that if I minimize (iconify) my nxclient, significant 
bandwidth between the server and client is still used if there are updates 
being made to the remote desktop (e.g. from clocks, system monitor 
graphs, screensavers and other programs which update the display without 
user interaction).

It would be nice if, when the nxclient's window is not actually visible to 
the user, the traffic between server and client could be reduced the bare 
minimum needed to keep the connection alive. This would allow people who 
have limited bandwidth quotas, or who pay per byte, to keep their nxclient 
sessions running in the background without fear. (The alternative, 
suspending and resuming each time you stop/start using a session, is a bit 
too cumbersome if you frequently dip in and out of a remote session 
throughout the day).

To give an idea of numbers, I found that my remote gnome desktop, the only 
'dynamic' content on which is a tiny system monitor graph in the gnome 
panel, seems to cause roughly 2.5kbytes/sec of NX traffic when the client 
is minimized. If I enable the screensaver (which is stupid, of course) and 
minimize the client, that will saturate my 1Mbit connection displaying 
fireworks to nobody. Even if I remove the system monitor graph so the 
desktop appears entirely static, I get around 500bytes a second of 
traffic. (I'm using the nomachine client on Linux, connecting to Linux 
server - usually FreeNX, but I got the same behaviour connecting to the 
nomachine testdriver server.)

I don't know enough about NX internals to know how hard it would be to 
stop updates when the client window is hidden - I imagine there would be 
issues to do with keeping the client's cache up to date. Just thought I'd 
throw the idea out there.

Seb