Network disconnect/reconnect issue

[MickM]

I’m using NX to display my Linux box CAD tool windows back onto my Mac (i.e. I’m not viewing the remote linux desktop). On my Linux box I have a .cshrc file that includes the command:

xmodmap ~/.Xmodmap

which I use to remap some keys on my Mac keyboard. When I disconnect from the network and later reconnect to continue my work, all of my key remappings are gone, the graphics in the CAD tool windows is more pixellated than usual, and the colors are all off (like the color space was really culled down). If I close the affected windows with the poor resolution and colors and reopen them they become good again. However, my key remappings never seem to come back unless I specifically re-enter the xmodmap command into the gnome-terminal window that came up when I first connected via NX. It seems NX is not picking up where it left off in an acceptable way after a network disruption.

Is there a way to fix this?

[fra81]

Hi,

keyboard layout is reset at reconnection accordingly to the client side layout. However NoMachine offers the possibility to run custom scripts that will be triggered on specific events, so you can add your xmodmap command to the UserScriptAfterSessionReconnect script in /usr/NX/node.cfg. You can find more info in https://www.nomachine.com/DT04O00139#11.6 and some examples in https://www.nomachine.com/AR02L00787.

Regarding pixelation and colors issue at reconnection, what you see is probably the effect of jpeg compression. If I understand correctly, you’re running custom sessions in floating window mode that use the ‘X11 vector graphics mode’. Being X11 protocol stateless, it may happen that at reconnection windows are redrawn using compressed image instead of vector graphics. Increasing display quality could be enough, or you can try to set a lossless compression method. For example, edit /usr/NX/etc/node.cfg by adding this line:

ProxyExtraOptions pack=16m-png

[MickM]

Regarding pixellation – you’re right in that it is a jpeg compression issue. When I look I can see that the jpeg compression is way lower than what I specified. Wouldn’t the right answer to be to look at the user’s preferences upon reconnection (which specify the desired compression) and just do right thing i.e. I’m saying this unexpected behavior is a bug.

[fra81]

That should already happen, unless you hit a bug or some corner case. What I had supposed is that those windows were originally rendered with “vector graphics” and then compressed as an image upon reconnection (as it can be necessary due to the stateless nature of X11 protocol). And that would be the reason why you see a difference. Can you send a screenshot of the NoMachine window showing the issue and of your Display settings?

[Author]

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