Nvim Terminal UI: Cursor Handling in Tmux, Window Size Detection, and Handling Slow Terminals

other environment variables. For the "rxvt", "putty", "linux", "screen", "teraterm", and "iterm" terminal types, or when Konsole, a libvte-based terminal emulator, or genuine Xterm are detected, it will add constructed "Ss" and "Se" capabilities. *tui-cursor-tmux* Within tmux it may appear that Nvim is not changing the cursor, but in fact it is tmux receiving instructions from Nvim to change the cursor and not knowing what to do in turn. tmux must translate what it receives from Nvim into whatever control sequence is appropriate for the host terminal. It shares a common mechanism with Nvim, of using the "Ss" and "Se" capabilities from terminfo (for the output terminal) if they are present. Unlike Nvim, if they are not in terminfo you must add them by setting "terminal-overrides" in ~/.tmux.conf . See the tmux(1) manual page for the details of how and what to do in the tmux configuration file. It will look something like: >bash set -ga terminal-overrides '*:Ss=\E[%p1%d q:Se=\E[ q' or (alas!) for Konsole 18.07.70 or older, something more complex like: >bash set -ga terminal-overrides 'xterm*:\E]50;CursorShape=%?%p1%{3}%<%t%{0}%e%{1}%;%d\007' < ============================================================================== Window size *window-size* [This is about the size of the whole window Vim is using, not a window that is created with the ":split" command.] On Unix systems, three methods are tried to get the window size: - an ioctl call (TIOCGSIZE or TIOCGWINSZ, depends on your system) - the environment variables "LINES" and "COLUMNS" - from the |terminfo| entries "lines" and "columns" If everything fails a default size of 24 lines and 80 columns is assumed. If a window-resize signal is received the size will be set again. If the window size is wrong you can use the 'lines' and 'columns' options to set the correct values. See |:mode|. ============================================================================== Slow and fast terminals *slow-fast-terminal* *slow-terminal* If you have a slow terminal you may want to reset the 'showcmd' and 'ruler' options. The command characters and cursor positions will not be shown in the status line (which involves a lot of cursor motions and attribute changes for every keypress or movement). If the terminal scrolls very slowly, set the 'scrolljump' to 5 or so. If the cursor is moved off the screen (e.g., with "j") Vim will scroll 5 lines at a time. Another possibility is to reduce the number of lines that Vim uses with the command "z{height}<CR>". If the characters from the terminal are arriving with more than 1 second between them you might want to set the 'timeout' and/or 'ttimeout' option. If you are using a color terminal that is slow when displaying lines beyond the end of a buffer, this is because Nvim is drawing the whitespace twice, in two sets of colours and attributes. To prevent this, use this command: >vim hi NonText cterm=NONE ctermfg=NONE This draws the spaces with the default colours and attributes, which allows the second pass of drawing to be optimized away. Note: Although in theory the colours of whitespace are immaterial, in practice they change the colours of cursors and selections that cross them. This may have a visible, but minor, effect on some UIs. vim:et:sw=2:tw=78:ts=8:ft=help:norl:

Nvim constructs 'Ss' and 'Se' cursor capabilities for 'rxvt', 'putty', 'linux', 'screen', 'teraterm', and 'iterm' terminals, or Konsole, libvte, and Xterm. Tmux requires configuration with 'terminal-overrides' in ~/.tmux.conf to handle cursor changes from Nvim correctly. Nvim detects window size via ioctl calls, environment variables, or terminfo entries, defaulting to 24x80 if all fail. Users with slow terminals can disable 'showcmd' and 'ruler', adjust 'scrolljump', or reduce the number of lines Vim uses. Color terminals can be optimized by setting 'hi NonText cterm=NONE ctermfg=NONE' to avoid drawing whitespace twice.