MagicMirror

MagicMirror flips an Apple Magic Trackpad for upside-down use on macOS.

It does not warp the cursor, intercept pointer events, or require BetterTouchTool. Instead, it calls Apple's private MultitouchSupport framework to set the trackpad surface orientation directly.

With two trackpads it can keep one normal and the other flipped, durably: a small mt-orient daemon assigns orientation per device by ProductID (the hardware model id, which is stable whether a trackpad is on USB or Bluetooth) and re-applies it across reconnects, wake, and login. See Multiple trackpads.

Why

Apple's Magic Trackpad is physically comfortable upside down in some desk setups, but macOS does not expose a modern setting for mirroring pointer and scroll directions. Event-tap approaches can make the direction correct, but they often cause ghost cursors, jitter, stuck clicks, or jumpy motion.

MagicMirror uses the same class of driver-level orientation path that dedicated tools use, but packages it as a tiny local helper.

Install

git clone https://github.com/smkwray/magicmirror.git
cd magicmirror
./install.sh

The installer compiles src/mt-orientation.m, installs runtime scripts under:

~/.hammerspoon/trackpad-orientation/

and installs a login LaunchAgent:

~/Library/LaunchAgents/com.smkwray.magicmirror.plist

The LaunchAgent reapplies the saved orientation at login.

Usage

Apply upside-down orientation:

~/.hammerspoon/trackpad-orientation/apply-upside-down.sh

Apply normal orientation:

~/.hammerspoon/trackpad-orientation/apply-normal.sh

Toggle saved state:

~/.hammerspoon/trackpad-orientation/toggle.sh

List detected multitouch devices:

~/.hammerspoon/trackpad-orientation/mt-orientation list

Expected output on an external Bluetooth Magic Trackpad:

device 0: transport=4 builtIn=0

Expected output when applying upside-down:

device 0: transport=4 builtIn=0 setOrientation=2 result=0

Normal orientation is 0; upside-down orientation is 2.

Multiple trackpads (durable, per-device)

The original mt-orientation helper flips all external Bluetooth trackpads to the same orientation. That cannot express "trackpad A normal, trackpad B flipped", and it breaks when a device moves between USB and Bluetooth (the device index and transport both change).

mt-orient solves this by keying orientation to each device's ProductID. It correlates every live multitouch device to its IOKit AppleMultitouchDevice record (matching MTDeviceGetDeviceID to the IOKit Multitouch ID) and reads ProductID — a fixed hardware model id that does not change with the cable. Transport, device index, GUID, and the reported serial are all connection-dependent and therefore unsuitable as keys.

Configure the mapping in ~/.hammerspoon/trackpad-orientation/orient.conf:

# <productID> <normal|upside-down>; unlisted devices are left untouched
product 804 normal         # 0x0324  newer Magic Trackpad
product 613 upside-down    # 0x0265  Magic Trackpad 2

# which model toggle.sh / the Hyper+' shortcut flips
toggle-target 613

Find your ProductIDs with mt-orient list. Commands:

mt-orient list     # show devices, ProductIDs, and resolved orientation
mt-orient apply    # apply the config once
mt-orient watch    # daemon: re-apply on reconnect/wake, self-heal every 60s
mt-orient reset    # force all external trackpads back to normal

The installer runs mt-orient watch from the login LaunchAgent with KeepAlive, so the per-device orientation survives reconnect, sleep/wake, and reboot. The toggle.sh / apply-*.sh scripts edit orient.conf and re-apply, so the manual shortcut and the daemon cooperate instead of fighting.

Optional Integrations

Karabiner-Elements:

• Import or copy examples/karabiner-rule.json.
• The example maps Hyper+quote to the installed toggle.sh.

Hammerspoon:

• Copy examples/hammerspoon-menubar.lua into ~/.hammerspoon/init.lua.
• It adds a small TP UD / TP OK menu bar item.

Uninstall

./uninstall.sh

This resets the trackpad to normal, unloads the LaunchAgent, and removes the installed runtime folder.

How It Works

src/mt-orientation.m dynamically loads:

/System/Library/PrivateFrameworks/MultitouchSupport.framework/MultitouchSupport

and calls:

MTDeviceCreateList
MTDeviceGetTransportMethod
MTDeviceIsBuiltIn
MTDeviceSetSurfaceOrientation

The helper targets external Bluetooth multitouch devices:

transport=4 builtIn=0

Caveat

This uses private Apple API. It is free and local, but Apple could rename or remove these symbols in a future macOS release.

Sources

• Ask Different: palm rejection on Apple Trackpad 2
• Ask Different: reverse Magic Trackpad
• Cult of Mac: use Magic Trackpad upside down

License

MIT