screen flickering when nvim window small

[tfriedel]

I start neovim in WSL like this:

NVIM_LISTEN_ADDRESS=127.0.0.1:55432 nvim --clean

Then I start nvim-qt:

"C:\Program Files\neovim-qt 0.2.18\bin\nvim-qt.exe" --server 127.0.0.1:55432 

This now mirrors the nvim in wsl.
If I resize the terminal showing WSL so it's smaller than the nvim-qt window,
the nvim in the terminal is starting to redraw / flicker like crazy.
In nvim-qt everything looks stable though.

What's causing this? Similar behaviour I also saw in goneovim but not in neovide.

[equalsraf]

This is probably related to how resizes are handled internally in the GUI vs the terminal UI - my guess is that it enters a loop where the GUI triggers a resize and then the terminal UI resizes it back (... and this continues in a loop). You can also check cpu usage to see if there is a loop going on.

Resize is handled in a few places, and we try to guard against obvious cases, but if the two UIs disagree on what the size should be they can always conflict:

• https://github.com/equalsraf/neovim-qt/blob/master/src/gui/shell.cpp#L411
• https://github.com/equalsraf/neovim-qt/blob/master/src/gui/shellwidget/shellwidget.cpp#L753
• https://github.com/equalsraf/neovim-qt/blob/master/src/gui/shell.cpp#L1637

There is a particular corner case - we don't resize when the window is maximized

• https://github.com/equalsraf/neovim-qt/blob/master/src/gui/shell.cpp#L418

[tfriedel]

Yes, you are right it's entering a resize loop.
Not sure why I wrote that nvim-qt doesn't flicker. When I just tried it, both instances flicker.
Also cpu usage goes up.

What could be done about it?
Neovide must have solved it somehow.