MultitouchKit

A Swift wrapper for macOS MultitouchSupport private framework, providing easy access to raw trackpad touch data.

Installation

Swift Package Manager

Add to your Package.swift:

dependencies: [
    .package(url: "https://github.com/akinazuki/MultitouchKit", from: "1.0.0")
]

Or in Xcode:

1. File → Add Package Dependencies
2. Enter the repository URL
3. Add to your target

Local Development

dependencies: [
    .package(path: "../MultitouchKit")
]

Usage

Basic Example

import MultitouchKit

// Start monitoring single-touch events
MultitouchManager.shared.startMonitoring(
    onTouchMove: { touch in
        print("Touch at: \(touch.percentX)%, \(touch.percentY)%")
        print("Pressure: \(touch.pressure)")
        print("State: \(touch.state)")
    }
)

// Stop monitoring when done
MultitouchManager.shared.stopMonitoring()

Multi-Touch Example

import MultitouchKit

MultitouchManager.shared.startMonitoring(
    onTouchMove: { touch in
        // Single finger touch
        print("Single touch: (\(touch.normalizedX), \(touch.normalizedY))")
    },
    onMultiTouch: { touches in
        // Multiple fingers
        print("Multi-touch: \(touches.count) fingers")
        for (index, touch) in touches.enumerated() {
            print("  Finger \(index): \(touch.percentX)%, \(touch.percentY)%")
        }
    }
)

Touch Data Properties

public struct TouchData {
    // Normalized coordinates (0.0 - 1.0)
    public let normalizedX: Float  // 0=left, 1=right
    public let normalizedY: Float  // 0=top, 1=bottom

    // Velocity
    public let velocityX: Float
    public let velocityY: Float

    // Pressure (0.0 - 1.0+)
    public let pressure: Float

    // Touch state
    public let state: TouchState

    // Identifiers
    public let fingerID: Int32
    public let pathIndex: Int32

    // Convenience properties
    public var percentX: Int        // 0-100
    public var percentY: Int        // 0-100
    public var isLeftSide: Bool
    public var sideDescription: String  // "LEFT" or "RIGHT"
}

Touch States

public enum TouchState: UInt32 {
    case TouchStateNotTracking = 0
    case TouchStateStartInRange = 1
    case TouchStateHoverInRange = 2
    case TouchStateMakeTouch = 3
    case TouchStateTouching = 4
    case TouchStateBreakTouch = 5
    case TouchStateLingerInRange = 6
    case TouchStateOutOfRange = 7
}

Requirements

• macOS 11.0+
• Swift 5.9+
• Xcode 15.0+

How It Works

MultitouchKit links to /System/Library/PrivateFrameworks/MultitouchSupport.framework and provides:

1. Device enumeration and filtering (excludes Magic Mouse, older devices)
2. Touch event callbacks with raw trackpad data
3. Automatic coordinate normalization and conversion
4. Thread-safe event dispatching

Disclaimer

This library uses undocumented private APIs. Use at your own risk. The API may change or be removed in future macOS versions without notice.