Hi,

I am posting this here so it can be potentially discussed. The code is based on work done by LemonBoy in #431

I won't have much time so I'm looking for other people who can help out

That said it seems to be working fine, but there are some general trade-offs implemented in this current approach which may need to be decided upon

If you need some help debugging I have a commit in https://github.com/ailin-nemui/irssi/tree/rsplit-debug-code that will print the window sizes to stderr. With that patch applied, you can do irssi 2>windowsizes.log to inspect the screen layout during the resize progress. That may help in better understanding some issues visually

one thing that has come up in discussions is the increase in bandwidth which is caused by sideways splits.

• Irssi updates visible buffers immediately, there is no delayed refresh implemented
• Irssi refuses to start on terminals without DECSTBM support
• For full width buffers, adding a line to a buffer requires ~line-length bytes
• So width×height bytes to fill the screen

For sideways splits we have a problem:

• Most terminals do not support DECSLRM :-(
• Thus, the whole split needs to be redrawn
• That requires ~width×height bytes - per line
• i.e width×height² bytes to fill the screen!

This has been for years the most needed feature in irssi, especially to have a nicklist/chanlist bar on the side. Thanks for implementing it! I wouldn't care too much about the increased bandwidth: in a constrained environment one could chose not to use splits. Or you could enable the feature only in terminals that support DECSLRM.

@irssi/developers