Support for Synchronized Output (Mode 2026)

[talios]

Is your feature request related to a problem? Please describe.

Recently I've been beta testing the new Ghostty terminal (https://mitchellh.com/ghostty), whose super fast performance has started revealing various refresh/tearing issues in other applications.

When running the Dagger (dagger.io) CI tool locally, and more so using experimental UI, I noticed A LOT of screen flicker, after discussing this on both the Ghostty and Dagger discords, I was pointed here.

Ghostty supports the Synchronized Output spec (https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036, inspired from iTerm) which aims to provide a contract between terminals and applications to reduce screen tearing and apparent UI flickering.

Describe the solution you'd like

I'm not a bubbletea user myself, but a user of tools using bubbletea, but I'd love to see the library adopt support for Synchronised Output and makes many users a lot less... tearful.

[meowgorithm]

Hi! Thanks for filing; this makes sense to me. No ETA on when we can commit to it, though at first read it looks like implementation would be pretty straightforward.

We're actually also Ghostty users, though I personally haven't seen much jank yet. I will say that traditionally you'll see some lag when redrawing very large TUIs on very large windows, and we do plan to address that in other ways as well.

Few more questions, which will help us measure results a bit:

1. Are you using very large terminal?
2. Any chance you upload a screencast of the behavior?
3. Which OS are you using?
4. Are you seeing this with any other tools built on Bubble Tea? Asking mostly because at first glance Dagger looks like it may take a degree of setup before we can actually see some UI from it (I could be wrong through).

[talios]

Hi, just a quick response and its 3:30am (I couldn't sleep).

This is a link to my ghostty discord message/video: https://discord.com/channels/1005603569187160125/1005603569711452192/1168783411968745482 - I can post that elsewhere in the morning if not accessible.

The terminal window isn’t that large even even small term sizes produce the effect.

This is on macOS Sonoma (Intel).

[meowgorithm]

Got it, thank you. Attaching the video here for reference. It looks like the top and bottom are both different builds of Ghostty. Is that correct?

Hope you get some sleep!

Ghostty_-__I_s_s_smx3-integration.mp4

[muesli]

I do have a patch implementing synchronized output. I've never followed up on it, as so far I had not seen a terminal where it would make a difference, but if ghostty benefits from this, I'll happily open a PR.

[talios]

@meowgorithm the bottom version was WezTerm, with Ghostty at the top - which as Mitchel pointed out, still shows some tearing but not as much as Ghostty - mostly cause Ghostty is much more responsive.

[ctrox]

@muesli Would you mind posting that patch or is it already pushed somewhere? I observed similar issues in Alacritty on Linux, which apparently should support synchronized output and I would be very interested to see if this helps.