Gestures support on MacOS

[pszypowicz]

Hi Everyone,

I spend this week on playing with gestures support for Ghostty, was trying to nail down the feeling of native MacOS app.

I know this is not a real contribution, and it does not reach the quality of the Ghostty yet (but I absolutely from beginning was directing model in the plan phase into "we are building to the upstream standard"), but I had a lot of fun while doing it and had some really interesting issues to solve.

Trackpad Gestures are HARD, proper hard. It was a single most challenging part, to nail down - and even when I though "I got it!" - then I used laptop not on the flat desk but on the chair with legs on the table - and found out that obviously - palm rejection is a thing and not just "nice to have" when Macbooks Trackpads are as enormous as they are.

So I was iterating on the trackpad support so much, that eventually throw it into its own repo, with dedicated tests and versioning to make it's development lifecycle independent from Ghostty.

Then with proven Trackpad lib, I started to integrate it into ghostty - and also - problems. Mainly inertia slipping when jumping from one tab via gesture to other tab. Which required the trackpad monitor to land in the main loop so it could be properly isolated.

I am driving this myself for a couple days already and it feels awesome. I wanted to share and maybe ask for opinions. I would love to prepare it for contribution (This would probably mean that TrackpadKit would get eaten by the ghostty itself).

Defaults:

• double finger swipe (jump between tabs)
• pinch in/out - make font smaller / bigger
• double tap - double fingers - magnify (increase font size by 6)

there is also support for all gestures: 2,3,4 fingers swipes.

Quirks:

• actions like pinching are "continuous" - so if you would like to bind them to issue a single keyboard shortcut - I introduced the keyword once
• if the default 2 finger swipe horizontal is used to jumping between tabs - and you open app that consumes it (vim with no wrap and mouse support) - then app is prioritized and small popup is shown to indicate it. If you would like to bypass that behavior - and say: 2 fingers is only for the ghostty - then you use force
• if you used force for 2 finger horizontal swipe for tab jump - but entered the app like vim and you want to horizontally scroll - you hold shift while swiping (this can be disabled or rebinded)
• For 2 fingers default swipe between tabs - macOS trackpad setting "Swipe between pages" needs to be enabled.
• For 3/4 finger gestures - you need to turn off macos trackpad (Mission Control / Spaces) bindings if they overlap (macos always wins).

Links:

• Draft PR in my own fork: feat: trackpad gesture bindings with raw-touch recognition and scroll arbitration pszypowicz/ghostty#5
• Swift Trackpad lib: https://github.com/pszypowicz/TrackpadKit

If you would like to try it (ad-hoc signed):
brew install --cask pszypowicz/tap/ghostty-gestures

Just remember:

• you need to uninstall your upstream ghostty first
• you need to explicitly disable autoupdate in config (otherwise new releases of ghostty upstream will overwrite it):

  auto-update = off
  

And finally, obviously, I was using LLM/AI - in this case it was Claude - mainly Fable 5