Comprehensive Keyboard Handling in Terminals

https://sw.kovidgoyal.net/kitty/keyboard-protocol/

by g0xA52A2A • 3 years ago

166 72 3 years ago

sw.kovidgoyal.net

3np• 3 years ago

I'm not sure I agree that terminal applications should get access to the whole range of modifiers. It's nice having a certain key dedicated to the WM or macros and know there will be no conflicts.

eviks3• 3 years ago

Which certain key? It's different per user, so no way to have a common list to exclude.

Anyway, there are other better mechanisms to resolve the conflict instead of crippling the app

Findecanor• 3 years ago

On Mac, the "Super"/"Command" key controls the terminal app. On Linux, I sometimes wish I had a Command key instead of the Control key being used by both the terminal and programs in the terminal. On X11, "Super" is often mapped to the window manager/the desktop environment, likewise on MS-Windows where it is the Windows key.

BTW. "Hyper" is available also on Mac, by default mapped to Shift+Control+Alt+Command but it can be remapped to another key. That key combination is emitted by the "Office key" on some Microsoft keyboards, and is used in MS-Windows for launching a component in their Office pack, or the Emoji picker.

So, there are lots of opportunities for configuration, and conflicts. IMHO, It would be a "nice thing to have" if users could configure their text-mode programs to use more modifiers, sure ... but as long as they are the only users of that config. I don't think a text-mode program should map Super or Hyper by default.

eviks3• 3 years ago

It's very nice to see some progress in this moldy part of a technology junkyard

galkk3• 3 years ago

Kovid is one of those 10x engineers for me. I love kitty and use it every day, calibre does it job too.

Great, that he tries to make progress in terminal area, that, as for me, is quite archaic as of now.

nextlevelwizard10• 3 years ago

I have never quite understood what the benefit of using kitty is. My default terminal emulator just isn’t using that many resources and I don’t get why I would even want GPU rendering for text.

What problem does it solve for you?

kzrdude3• 3 years ago

Terminals have some infuriating limitations, like imagine not being able to tell the difference between Esc + A or Alt + A as an application. Or that tab and Ctrl + I produce identical input.

Kitty has a new keyboard handling protocol, and Neovim supports it. So if you use kitty, you can use key mappings in neovim in a more predicatable and flexible way.

petepete4• 3 years ago

It's _really_ responsive, whether you're in an editor or accidentally grepped a minified JavaScript file.

I would be capable of working entirely in any modern terminal emulator, but Kitty makes it a pleasure.

leephillips3• 3 years ago

I’ve tried many terminal emulators, probably all available on Linux, and kitty is the best in my experience. Performance is excellent: keyboard latency, catting files. It’s sometimes convenient to use some of its tricks, such as viewing an image right in the terminal through ssh.

ploum• 3 years ago

Also support displaying picture (try chafa with any jpg/png file inside kitty). That makes browsing with offpunk a completely different experience.

seri4l• 3 years ago

You can configure a key combination to run a pager on the last command output, color and everything. You can also configure it so that it pipes the output of a command to a pager automatically whenever it is more than a screen long.

gorgoiler• 3 years ago

In addition to what others have said, it is also freely licensed and open source, with ports to my daily drivers macOS and xorg/Linux. I wonder if a Windows port is in the works too?

nvarsj• 3 years ago

kitty is the most feature complete terminal emulator out there. It’s the only one that properly supports ligatures and variable width characters for instance. If you want faithful terminal reproduction with built in native tmux like functionality (including non broken mouse support), kitty is about the only option.

version_five• 3 years ago

Being able to display inline images in the terminal

toastal2• 3 years ago

Joining in questioning… kitty dev seems to hate tmux since kitty can perform many of it's behaviors. The thing that's most interesting to me is tmux for detaching and persisting a session on a remote host. Does kitty cover this functionality too? Is there like kittyd?

mftb• 3 years ago

Kitty renders more cases correctly, more stable, mainly I appreciate it's overall high quality. I don't use it's tmux-like features.

galkk3• 3 years ago

Kitty is fast, configurable and support ligatures.

Version4672• 3 years ago

I didn't know he also made calibre. That's awesome.

kickaha• 3 years ago

Calibre user. I was like, that’s weird. There’s another Kovid Goyal?

durazabu3• 3 years ago

Glad to see this page featured again.

Is there any advance on that front?

Previous submission was 2 years ago.

https://news.ycombinator.com/item?id=27193661

aumerle22• 3 years ago

The progress is that this protocol has been implemented in many widely used programs, such as vim, neovim, helix, kakoune as well as at least two more terminal emulators, wezterm and foot in addition to kitty.

durazabu3• 3 years ago

It seems like the protocol has not been implemented yet in neovim.

https://github.com/neovim/neovim/issues/14400

zokier• 3 years ago

At some point one might consider if it would be simpler and better to just have some way to pass wayland-compatible events instead of inventing yet another protocol. So much stuff has now been thrown into terminal layer in a way that is not particularly elegant and what we already have perfectly good protocols for.

tyingq• 3 years ago

How would that traverse ssh, tmux, etc?

cellularmitosis• 3 years ago

And what about mac and windows? And X11 for that matter.

hendersoon• 3 years ago

In a development that will surely confuse nobody, the terminal emulator linked in this thread (kitty) is completely separate from another terminal named KiTTY. I assume there's some drama behind this. Anyway, this one is for Linux/MacOS only while KiTTY is a PuTTY fork for Windows only.

gpanders3• 3 years ago

It is briefly mentioned in this post, but this work is based on a proposal by Paul Evans [1] (creator of libtickit and libvterm, among others).

Kovid deserves credit for addressing some of the issues in the original proposal, and for documenting it well. But Evans deserves credit as well for formulating the original idea.

Note also that this is not the only solution to this problem. Xterm has had its own solution for a long time called modifyOtherKeys [2] which has been supported by Vim and iTerm2 for quite some time (I believe foot supports it as well, perhaps others). Of course people have different opinions on which approach is “better”, though empirically it seems like the CSIu/“fixterms”/kitty approach has a lot more momentum at present.

[1] http://www.leonerd.org.uk/hacks/fixterms/

[2] https://invisible-island.net/xterm/modified-keys.html

kps4• 3 years ago

I know mlterm is one that supports modifyOtherKeys.

Fragmentation is unfortunate, especially since there's no termcap/terminfo property that indicates which form(s) a terminal supports, and so many terminals already identify themselves as ‘xterm’ without being remotely close to xterm-compatible.

ibiza2• 3 years ago

There's an even richer protocol, `?9001h`, developed by the Microsoft Terminal team, designed to maintain the fidelity of INPUT_RECORD events. These are the events seen by console programs in Win32. It's quite nice.

https://github.com/microsoft/terminal/blob/main/doc/specs/%2...

eviks3• 3 years ago

In what way is it richer? I've skimmed through the linked doc, saw the mention that it is richer, but didn't see an explanation of the extra functionality is available

ibiza2• 3 years ago

Events include key scan codes for one. The end of the doc contains a pros & cons section of the alternative approaches.

https://github.com/microsoft/terminal/blob/main/doc/specs/%2...

jwr2• 3 years ago

If this were widely adopted, it would do wonders for Emacs. Right now Emacs is unusable in remote terminal connections for many of us, because there is no way to get key combinations like Super-Shift-G to work.

donio3• 3 years ago

I agree that Emacs would greatly benefit from this feature but "unusable" a overly dramatic. It's an inconvenience. I use Super on the desktop as much as anybody but I manage with remote tty sessions (including termux from phone) just fine. I just make sure that I also have a terminal-friendly binding for anything critical that I have on Super.

denotational• 3 years ago

"unusable" a overly dramatic

Disagree. I used to use Emacs with evil-mode, but I gave up because of this issue.

If I entered `ESC` then `k` (i.e. return to normal mode and move up a line) too quickly on an SSH connection, there was a good chance the `read` syscall on the PTTY file descriptor would return two characters (determined via `strace`) instead of two subsequent calls returning a single character each.

This makes it literally impossible for Emacs to distinguish it from `M-k` (i.e. `kill-line`), so I’d “randomly” see lines deleted before I figured out what was going on.

The effect is a lot more pronounced over SSH where a spike in network latency can cause two subsequent TCP segments to reach the host essentially back-to-back (or even be retransmitted as a single segment), leading to this behaviour of `read` returning two characters.

jwr2• 3 years ago

I guess it depends on how many Super shortcuts you use, and for how many years you have been using them. In my case, both numbers are into double digits, so.

ubolonton_• 3 years ago

In Emacs, local-function-key-map has this entry:

    C-x @ s                   event-apply-super-modifier

So to get s-g to work, you'd configure the terminal emulator to convert the Command+G key press to the C-x @ s g sequence.

    # Hex code (iTerm)
    0x18 0x40 0x73 0x67

    # kitty (without Emacs doing the integration)
    map cmd+g send_text all \x18@sg

Konsole somehow seems to have this done for the whole English alphabet, so it just works out of the box there.

For 2-modifier bindings, I guess you can add a creative entry to local-function-key-map. (If the other modifier is Shift, you can just use uppercase letters.)

ithrow• 3 years ago

Does kitty lets you remap modifiers like iterm2? https://i.stack.imgur.com/hd5Yi.png

comfypotato• 3 years ago

Shoutout to Alacritty for having Windows support. Would have adopted kitty at the time for the reasons mentioned in the article (much more mature) but Alacritty does the trick. Not sure how it deals with modifiers etc. in the plumbing, but the configuration is plenty straightforward to access everything from terminal applications that can use lots of bindings.

Comprehensive Keyboard Handling in Terminals

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