Module for working around Dragonfly issues with custom keyboard layouts

_win32_hkl_switch.py

"""
This command module automatically posts input language change request
messages to all top-level windows as a workaround for keyboard layouts where
Dragonfly's Win32 key input doesn't work properly.

Use this module by loading it as a Dragonfly command module.
"""

import time

import win32con
import win32gui

from dragonfly import RecognitionObserver

PROCESSING_LAYOUT_HKL = 0x8090809  # HKL for English (UK) - QWERTY
NORMAL_LAYOUT_HKL = -0xf3ff7f7  # HKL for English (UK) - Colemak


def postLangChangeReqMsg(hwnd, wParam, lParam):
    """
    Post a WM_INPUTLANGCHANGEREQUEST message with the specified parameters.
    """
    win32gui.PostMessage(hwnd, win32con.WM_INPUTLANGCHANGEREQUEST, wParam,
                         lParam)


class HackyObserver(RecognitionObserver):
    """
    A hacky recognition observer class for setting the keyboard layout
    before and after recognition processing.
    """
    def on_recognition(self, words):
        # Set the keyboard layout for the foreground window.
        hwnd = win32gui.GetForegroundWindow()
        # hwnd = win32con.HWND_BROADCAST  # Use on Windows versions below 8.
        hkl = PROCESSING_LAYOUT_HKL
        # print("Setting layout to %08x." % hkl)
        postLangChangeReqMsg(hwnd, 0, hkl)

        # Wait a moment.
        time.sleep(0.001)

    def on_post_recognition(self, words):
        # Set the keyboard layout for the foreground window.
        hwnd = win32gui.GetForegroundWindow()
        # hwnd = win32con.HWND_BROADCAST  # Use on Windows versions below 8.
        hkl = NORMAL_LAYOUT_HKL
        # print("Setting layout to %08x." % hkl)
        postLangChangeReqMsg(hwnd, 0, hkl)

        # Wait a moment.
        time.sleep(0.001)


# Register the observer.
observer = HackyObserver()
observer.register()
print('Test')


# Unload function which will be called by natlink at unload time.
def unload():
    global observer
    if observer:
        observer.unregister()
    observer = None