windows-trackpad-helper 1.0.0

A native C++ and Python helper for Windows to detect trackpad scrolling with accurate physical touch state.

Windows Trackpad Helper

A small Windows library to help python applications track finger state on precision trackpads, that may not be exposed otherwise. This allows, for example, PyQt apps to know if the trackpad is providing events after the user has lifted their fingers. This is needed because even though the device and the drivers provide this info, it may not trickle down to a framework like Qt.

It interacts directly with the Windows API via ctypes (included in the Python standard library) and can hook any native Win32 window handle (HWND). While the demo uses PyQt6, the library should work with any GUI framework that exposes an HWND handle (such as PySide6, wxPython, Tkinter, GLFW, SDL2, or raw Win32 windows).

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Touch Tracking Algorithm & Heuristics

The library hooks Windows Raw Input (WM_INPUT messages for Digitizer/Touchpad usage pages) to track physical touchpad contact:

1. is_finger_down(system_id: int = 0):
   • When system_id is non-zero (specific device): Returns 1 if raw touchpad contact is active, 0 if inactive (and is a precision touchpad), or -1 if the state is unknown (e.g. non-precision device).
   • When system_id is 0 (global/default): Employs the time heuristic and returns:
     • 1 (Touching): Raw touchpad touch contact is active.
     • 0 (Lifted): Raw contact is inactive, but a touch occurred within the lift threshold window (default 10000 ms).
     • -1 (Unknown): Raw touch is inactive and occurred outside the window (or never touched / non-precision device).
2. get_time_since_last_touch(system_id: int = 0): Returns the precise milliseconds since the last physical contact occurred (-1 if never touched).
3. set_lift_threshold(threshold_ms: int): Configures the time window (in milliseconds) used by global queries to distinguish between Lifted (0) and Unknown/Idle (-1) states.
4. get_lift_threshold(): Returns the currently configured threshold in milliseconds.

Your application can query is_finger_down() inside its own scroll/wheel event loop to determine the physical finger state cleanly and simply.

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Quick Start (Local Run)

To compile the DLL and run the dumper demo locally:

# 1. Compile the C++ DLL locally (requires MSVC or gcc & CMake)
build.bat

# 2. Install package locally in editable mode with optional demo dependencies
py -m pip install -e ".[demo]"

# 3. Run the dumper demo
python -m windows_trackpad_helper.demo_pyqt6

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Direct Integration Example (Generic Win32)

from windows_trackpad_helper import TrackpadHelper

# 1. Initialize the helper
trackpad = TrackpadHelper()

# Explicitly configure the lift threshold window to 10 seconds
trackpad.set_lift_threshold(10000)

# 2. Hook your window using its native HWND handle (from Tkinter, wx, GLFW, etc.)
hwnd = my_window.window_id()  # Replace with your framework's HWND getter
trackpad.init_hwnd(hwnd)

# ... inside your scroll/wheel event handler:
finger_state = trackpad.is_finger_down()

if finger_state == 1:
    state_str = "Touching"
elif finger_state == 0:
    state_str = "Lifted"
else:
    state_str = "Unknown"

print(f"Physical Touch State: {state_str}")

# 3. Cleanly unhook on window close
trackpad.shutdown()