Nvim Terminal UI: Built-in Terminfo, Terminal-Dependent Settings, and Input Handling

Y Terminal.app nsterm N tmux tmux, tmux-256color Y Windows/ConEmu conemu Y Windows/Cygwin-built Nvim cygwin Y Windows/Interix interix Y Windows/VTP console vtpcon Y Windows/legacy console win32con Y xterm or compatible xterm, xterm-256color Y < *builtin-terms* *builtin_terms* If a |terminfo| database is not available or there is no entry for the current terminal, Nvim will map |$TERM| to a builtin entry according to the above table, or "ansi" if there is no match. For example "TERM=putty-256color" will be mapped to the builtin "putty" entry. See also |tui-colors|. The builtin terminfo is not combined with any external terminfo database, nor can it be used in preference to one. You can thus entirely override any omissions or out-of-date information in the builtin terminfo database by supplying an external one with entries for the terminal type. Settings depending on terminal *term-dependent-settings* If you want to set terminal-dependent options or mappings, you can do this in your init.vim. Example: >vim if $TERM =~ '^$rxvt\|screen\|interix\|putty$$-.*$\?$' set notermguicolors elseif $TERM =~ '^$tmux\|iterm\|vte\|gnome$$-.*$\?$' set termguicolors elseif $TERM =~ '^$xterm$$-.*$\?$' if $XTERM_VERSION != '' set termguicolors elseif $KONSOLE_PROFILE_NAME != '' set termguicolors elseif $VTE_VERSION != '' set termguicolors else set notermguicolors endif elseif $TERM =~ ... ... and so forth ... endif < *scroll-region* *xterm-scroll-region* Where possible, Nvim will use the terminal's ability to set a scroll region in order to redraw faster when a window is scrolled. If the terminal's terminfo description describes an ability to set top and bottom scroll margins, that is used. This will not speed up scrolling in a window that is not the full width of the terminal. Xterm has an extra ability, not described by terminfo, to set left and right scroll margins as well. If Nvim detects that the terminal is Xterm, it will make use of this ability to speed up scrolling that is not the full width of the terminal. *tui-input* Historically, terminal emulators could not distinguish between certain control key modifiers and other keys. For example, <C-I> and <Tab> are represented in the same way, as are <Esc> and <C-[>, <CR> and <C-M>, and <NL> and <C-J>. Modern terminal emulators are able to distinguish between these pairs of keys by encoding control modifiers differently. There are two common but distinct ways of doing this, known as "modifyOtherKeys" and "CSI u". Nvim supports both encoding methods and at startup will tell the terminal emulator that it understands these key encodings. If your terminal emulator supports it then this will allow you to map the key pairs listed above separately. |<Tab>| Nvim uses libtermkey to convert terminal escape sequences to key codes. |terminfo| is used first, and CSI sequences not in |terminfo| (including extended keys a.k.a. "modifyOtherKeys" or "CSI u") can also be parsed. For example, when running Nvim in tmux, this makes Nvim leave Insert mode and go to the window below: > tmux send-keys 'Escape' [ 2 7 u 'C-W' j Where `'Escape' [ 2 7 u` is an unambiguous "CSI u" sequence for the <Esc> key. The kitty keyboard protocol https://sw.kovidgoyal.net/kitty/keyboard-protocol/ is partially supported, including keypad keys in Unicode Private Use Area. For example, this sequence is recognized by Nvim as <C-kEnter>: > CSI 57414 ; 5 u and can be used differently from <C-CR> in mappings. *tui-modifyOtherKeys* *tui-csiu*

This section covers aspects of Nvim's Terminal UI, including built-in terminfo entries and how they are used when a terminfo database is unavailable. It provides an example of how to set terminal-dependent options in init.vim based on the $TERM variable. It explains how Nvim uses the terminal's scroll region ability for faster redrawing and how it handles terminal input, including the differentiation of control key modifiers and the support for 'modifyOtherKeys' and 'CSI u' encoding methods. Also, it mentions partial support for the Kitty keyboard protocol.