Trident

A macOS menu-bar utility that remaps trackpad gestures:

• Three-finger tap → middle click
• Three-finger horizontal swipe → app switch — right = forward (⌘Tab), left = backward (⌘⇧Tab)

A quick swipe switches to the adjacent app instantly; leaving your fingers resting keeps the app-switcher HUD up so you can scrub through several apps, then lift to commit.

Use one or both. Each gesture has its own on/off switch, and swipe sensitivity and palm rejection are adjustable — see Settings.

Install

1. Download the latest Trident.dmg from the Releases page.
2. Open it and drag Trident onto the Applications folder.
3. Launch Trident from Applications. The first time, macOS blocks it with "Apple could not verify 'Trident' is free of malware." — Trident is signed but not notarized by Apple (it's a free, open-source tool). To allow it: open System Settings → Privacy & Security, scroll down to the Trident notice, click Open Anyway, and confirm. You only do this once.
4. Grant Accessibility when prompted (or in System Settings → Privacy & Security → Accessibility) — Trident needs it to read the trackpad and post the remapped events.
5. On first run Trident walks you through one trackpad setting it needs you to change, because macOS uses a three-finger swipe to switch Spaces by default (see Recommended System Settings).

Updates are automatic. Trident checks for new versions in the background and offers to install them; you can also trigger a check from the menu bar via Check for Updates…. Because every release keeps the same signing identity, your Accessibility grant carries across updates — no re-granting.

Settings

Click the menu-bar icon — everything is configured there:

• Tap → Middle Click / Swipe → Switch App — each gesture on or off, independently
• Swipe sensitivity — finger travel per app-switch step; smaller is more sensitive
• Palm rejection — ignores touches that start in a band (width adjustable) along the left, right, and bottom edges, where palm heels and a resting thumb land; oversized contacts are rejected anywhere on the pad
• Haptic Feedback — a tap on each app-switch step
• Enable Trident — master switch; plus Launch at Login, Hide Menu Bar Icon, Check for Updates, and the Setup Assistant

Requirements

• macOS 26 (Tahoe) or later
• A built-in or Magic Trackpad
• Accessibility permission (granted on first launch)

Recommended System Settings

macOS itself uses a three-finger horizontal swipe to switch Spaces / full-screen apps by default, which collides with Trident's app-switch swipe. Trident's first-run assistant detects this and walks you through the fix; to do it manually, set System Settings → Trackpad → More Gestures → Swipe between full-screen applications to a different finger count (e.g. four). Otherwise a three-finger swipe triggers both actions at once.

Support

Trident is free and open source. If it makes your trackpad nicer to live with, you can buy me a coffee on Ko-fi ☕

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For developers

Everything below is for people who want to build Trident themselves or hack on the code.

Build

brew install xcodegen        # one-time
./scripts/setup-signing.sh   # one-time — see "Signing" below
./build.sh                   # Release (or: ./build.sh Debug)

Requires Xcode with the macOS 26 SDK (Swift 6). The build links the private MultitouchSupport framework from /System/Library/PrivateFrameworks to read raw trackpad touches. The app is not sandboxed (required for trackpad access and event synthesis).

Signing

Trident needs Accessibility permission, and macOS ties that grant to the app's code signature. A plain ad-hoc signature changes identity on every build, so the grant would be lost each rebuild. scripts/setup-signing.sh creates a stable self-signed "Trident Dev" certificate in your login keychain; build.sh then signs with it, giving a fixed code requirement so you grant Accessibility once and it survives rebuilds. Without the cert, build.sh falls back to ad-hoc signing (works, but you'll re-grant after each build). To undo: delete the "Trident Dev" certificate in Keychain Access.

Design notes: stray-click suppression

When three fingers don't land or lift perfectly together, the trackpad can briefly see one or two fingers — which, with Tap to click enabled, macOS would turn into a stray left or two-finger secondary (right) click next to Trident's middle click. Trident installs a tightly-scoped event tap that suppresses native left/right mouse clicks only while a three-finger gesture is active (and for ~300 ms after), so those leaks can't fire. Normal clicking is untouched.

Releasing & auto-update (maintainers)

Trident updates itself with Sparkle. Releases are signed with a stable self-signed identity (so Accessibility persists) and an EdDSA key (so Sparkle trusts the update); they are not Apple-notarized, which is why new users see the one-time Gatekeeper step above. The feed (appcast.xml) and the downloads are hosted on this public repo's Releases.

One-time setup:

brew install create-dmg           # designed installer DMG (background, drag-to-Applications layout)
./scripts/setup-signing.sh        # stable "Trident Dev" code-sign identity
./scripts/setup-sparkle-keys.sh   # EdDSA update key → private in keychain, public in Info.plist
.sparkle/bin/generate_keys -x sparkle_private_key.pem   # back up the private key somewhere safe (NOT git)
gh auth login                     # GitHub CLI, if not already

The repo must be public so Sparkle can fetch appcast.xml and the assets without authentication.

Cut a release:

./scripts/release.sh 1.1          # marketing version; build number auto-increments

That builds + signs (including the embedded Sparkle helpers), packages a DMG (for new installs) and a ZIP (what Sparkle downloads to self-update), EdDSA-signs the update, regenerates appcast.xml, commits the version bump + feed, pushes a v1.1 tag, and creates the GitHub Release with both assets. Existing installs pick up the update within a day (or instantly via Check for Updates…).

⚠️ Losing the Sparkle private key means existing installs can no longer verify your updates. Keep the backed-up .pem safe.

Project layout

Sources/TridentCore/   UI-free gesture pipeline (static library)
  MultitouchSupport.swift   private-framework C bindings
  TouchModels.swift         MTTouch / MTPoint / MTVector layout
  DeviceMonitor.swift       device lifecycle + callback guard
  GestureRecognizer.swift   tap + swipe state machine (hot path)
  GestureEventSuppressor.swift  gesture-scoped event tap (stray-click guard, cursor freeze)
  ActionSynthesizer.swift   middle click + held-⌘ app switch
  TridentEngine.swift       wires it together
Sources/TridentApp/    menu-bar accessory app (menu, onboarding, login item)
  Updater.swift             Sparkle auto-update wrapper
Tests/TridentCoreTests/ gesture-recognizer unit tests
project.yml            XcodeGen project spec
build.sh               generate + build (+ stable re-sign incl. Sparkle)
scripts/
  setup-signing.sh          stable code-sign identity (Accessibility persistence)
  setup-sparkle-keys.sh     EdDSA update-signing key + public key into Info.plist
  release.sh                build → package → sign → appcast → GitHub Release
  lib-sparkle.sh            fetches Sparkle's CLI tools on demand
appcast.xml            Sparkle update feed (served from the public repo)

License

MIT

Acknowledgments

• MiddleDrag — a shipping trackpad→middle-click app whose MultitouchSupport plumbing served as a valuable reference for Trident's touch-reading layer.
• Sparkle — the auto-update framework.