Implemented option_as_alt to allow for ignoring option key characters

[ayax79]

Based off the Fix Alt Modifier on Mac OS PR.

I have tested by rebuilding alacritty here and testing to ensure that alt bindings in zellij work correctly. I have also tested that IME works.

• Tested on all platforms changed
• Added an entry to CHANGELOG.md if knowledge of this change could be valuable to users
• Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior
• Created or updated an example program if it would help users understand this functionality
• Updated feature matrix, if new features were added or implemented

[ayax79]

I reverted back to the version that is roughly the same port as @kjmph's branch. I then disabled IME and everything works correctly. This makes sense as all the IME handling was added after the original fix was created. Now to figure out why...

My test case is:

• Recompile alacritty
• Run Zellij
• Alt+N creates a new pane

[ayax79]

This call unsafe { self.interpretKeyEvents(&events_for_nsview) }; seems to be the problem.. Looking to see if can build a modified event for it.

[ayax79]

This version works and does not break IME (as far I can tell).
To use set option_as_alt to true

[chrisduerr]

Are you still working on this patch? If it's done you should probably ping one of the macOS maintainers, I don't think it's on their radar.

[ayax79]

@madsmtm, this is complete minus updating the feature matrix and documentation. I am not sure this is relevant for the feature matrix, and I was unsure if anymore was needed for documentation beyond the documentation on the trait. thoughts?

[madsmtm]

Thanks for the ping, it was on my radar, I just have a rather long backlog atm.

Haven't looked much at the actual implementation, see my last comment; I'm unsure of what precisely the intended effect is, so I'm unable to ensure it works as expected ;)

[ucabgao]

Thanks for taking a look at this!! How about the use case and where I have utilized the fix...

Basically, when enabled, option should NEVER send an extended character, giving the same behavior as the ALT key on other operating systems. I imagine this feature is really only critical in apps like Alacritty, but it is huge for Alacritty.

I picked up this issue because I use the combination Alacritty and Zellij on linux. I would like to use the same combination on my mac work machine. Zellij is pretty unusable on Alacritty on the mac due to the option key's default behavior of sending extended characters versus just acting as an ALT key. This actually causes a pretty poor experience in a wide range of terminal apps -- anything that requires an ALT key.

Every other terminal on the mac (Terminal.app, Iterm.app, Kitty) have the ability to disable sending extended characters, like this fix implements.

I have been using this fix daily for a while now. If you would like try it, my fork of Alacritty where I have utilized this fix is here: https://github.com/ayax79/alacritty/tree/option_as_alt

Here is my alacritty config: https://github.com/ayax79/config/blob/main/alacritty/alacritty.yml The relevant section is option_as_alt: true under window:

When enabled if you run zellij, OPT+n should open a new terminal pane. When disabled OPT+n should give you ˜.

This has been an outstanding issue in alacritty for a long time: alacritty/alacritty#62

Any update on this PR? Have been waiting for this feature for a long time as an Alacritty user.

[ayax79]

Any update on this PR? Have been waiting for this feature for a long time as an Alacritty user.

I think we are just waiting for feedback from @madsmtm

[madsmtm]

What I was mostly worried about was how this interacts with IME, and as far as I can tell it seems like it doesn't negatively impact that at all, so that's nice!

I looked through the implementation now, looks good, only a few concerns.

Thanks for your patience!

[kchibisov]

I'll add one more note, that such behavior is desired for only e.g. one of the Option modifiers keeping the other one as before. Would it be possible to adjust for that, like say Left as Alt or Right as Alt, so the user could use both at the same time.

[madsmtm]

So something like:

enum OptionAsAlt {
    All,
    OnlyRight,
    OnlyLeft,
    None,
}

Though I suspect it will be a bit tricky to implement, since macOS doesn't easily expose which OPTION button is being held down. (So I'd be fine with deferring that).

[kchibisov]

Though I suspect it will be a bit tricky to implement, since macOS doesn't easily expose which OPTION button is being held down. (So I'd be fine with deferring that).

I think you have that via the raw key event? At least in the past we were able to determine left/right alt?

[madsmtm]

Yeah, it's definitely possible to know when the left or the right ALT button has been pressed, but (at least as far as I know) macOS doesn't track that information for us (like it otherwise does), hence why it might be a bit tricky.

Perhaps we can leave the user to implement it themselves on top of set_option_as_alt? Something like:

let mut set_option_as_lalt = true;

match event {
    WindowEvent::KeyboardInput {
        input: KeyboardInput {
            virtual_keycode: Some(VirtualKeyCode::LAlt),
            state,
            ..
        },
        ..
    } => {
        if set_option_as_lalt {
            window.set_option_as_alt(state == ElementState::Pressed);
        }
    }
    _ => {}
}

(Assuming it works? Would be nice to have the example updated with it if so.)

[saamalik]

@ayax79 - would be great to get this merged in. Sorry, I can't help much =)

[ayax79]

Sorry... I just started a new job and I have been pretty slammed. Hoping to get back to this soon.

[kchibisov]

I've taken the liberty to update this branch and add the requested functionality. I've tested on my macOS machine with the example in the repo, and the events are correct for all left/right/both/none variations.

@madsmtm could you take a look?

[madsmtm]

Implementation looks fine, only a few nits wrt. documentation and such

[kchibisov]

Thanks, @ayax79

[madsmtm]

Perfect, thanks!

[chrisduerr]

Yeah this has been a long standing issue on macOS that wasn't particularly difficult but simply didn't get resolved because there was no macOS developer interested in stepping up and fixing it. So thanks for stepping up.

[kjmph]

Thanks everyone! I can't wait to try this out!

[saamalik]

Woot woot! this is awesome! Thanks team!

[jkp]

Just pulled and built the latest - am unsure how to actually enable this from the config though?

Awesome! read the code and found I I needed this in my config:

window:
  option_as_alt: OnlyLeft

[kchibisov]

Yes, the alacritty.yml has the documentation for that stuff.