[winswitch] auto-repeat keys with xpra

Antoine Martin antoine at nagafix.co.uk
Wed Jul 19 20:44:19 BST 2017


On 19/07/17 23:59, Anthony Stone via shifter-users wrote:
> I have been using xpra for a while to connect from home over broadband
> to my office computer. It's generally fine, and I appreciate the work
> that's gone into it, but there is an irritating feature: if I use the
> auto-repeat by holding down a delete or cursor key, the display doesn't
> keep up with the auto-repeat, so it's impossible to stop at the right
> point.
I guess you're saying that their is a delay between key events and
screen updates.
That is inevitable if your connection has any kind of latency.
The key events have to travel to the server, and the screen updates back
to the client. Those two things happen independently, asynchronously.

> Presumably every repeat has to be sent to the server and
> reflected back before it's displayed.
Sort of. There are two modes: with and without keyboard synchronization.
You can toggle between these modes from xpra's system tray menu.
For more information, see:
https://xpra.org/trac/wiki/Keyboard

> This didn't happen with NX, which
> I used to use, and as xpra is apparently based on NX,
Xpra has absolutely nothing in common whatsoever with NX, thankfully.

The only website that I know of which claims otherwise happens to have a
vested interest in this matter..

> would it be
> possible to echo the cursor position or deletion locally in real time
> even if the server takes a while to catch up?
No, that's absolutely impossible. Tools like mosh can do that for
terminal emulators, but this just cannot be done for GUI applications.

It might be possible to do better at getting the screen updates to your
client, but you would have to give a lot more information on your use
case and bandwidth conditions (preferably in a ticket):
https://www.xpra.org/trac/wiki/ReportingBugs
(and try turning off keyboard-sync first)

Cheers
Antoine


> 
> Thanks,
> Anthony
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> shifter-users at lists.devloop.org.uk
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> 




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