When a European layout is active, and the user presses AltGr, Windows
generates a simulated VK_LCONTROL event alongside the VK_RMENU event.
This was causing the OSK to show LCtrl as depressed alongside RAlt, so
the OSK would show the wrong modifier layer, which was unhelpful and
confusing to the end user.
It is possible to detect the simulated VK_LCONTROL in the WH_KEYBOARD_LL
hook, because the scan code generated is 0x21D, instead of 0x1D.
Warning: this is not a documented value. (But, this 0x21D scan code is
not passed to the WM_KEYDOWN event!) Therefore, we use Keyman's existing
kmnLowLevelKeyboardProc to pass modifier key events on to the visual
keyboard.
This patch handles only this specific scenario, by watching for that
specific scan code in the new handler in the UfrmOSKOnScreenKeyboard
module, together with some minor refactoring so that it fits neatly.
A future improvement would be to have all modifier key processing go
through this new handler, and eliminate the timer-based polling of the
keyboard. However, there is some additional risk around missing events,
leading to 'stuck modifiers'.
Fixes: #14890
Build-bot: skip release:windows
* Remove unused parameters from SendDebugMessage functions
* Add SendDebugEntry and SendDebugExit functions for tracking
function entry/exit
* Add indenting and function names to log entries
* Remove unused debug functions
* Eliminate now-unused hwnd parameter in initialization functions
* Replace Log,LogEntry,LogExit functions with SendDebug equivalents in
kmtip
Many functions now have SendDebugEntry/SendDebugExit (or
return_SendDebugExit) pairs. It is important to SendDebugExit on all
returns from a function to keep the log indent depth consistent. In some
cases I chose not to add these logging calls, e.g. on frequently called
functions such as the message hooks.
add debug log messages in the code that processes modifier
key presses. Will be usefull debuging issues with the
seralized event server and modifer keys.
Just refactoring minor bits and pieces on this PR. Esp: removed the
unnecessary interrogation of TSF (yay!) and cached the debug flag so it
isn't checked on every single keystroke.
[Windows] More tidyup and robustness for metro app support - debug cleanup and serialization of input (not quite finished)
[windows] Refactor serialized input code when used with key event thread model
[windows] Add consistent precompiled headers for other projects
[windows] Merge console window test into metro support
[Windows] Tidy up work and identify additional TODOs for metro-style app support
[Windows] Ensure error case falls through to default hook processing for console windows
[Windows] Refactor shared memory into memory mapped file so we can cross 32-64 bit boundary
[Windows] Tweaks to C++ security calls and parameters
[Windows] Start refactor of SerialKeyEvent* classes
[Windows] Rename to SerialKeyEventServer (refactoring)
[Windows] Complete refactoring of SerialKeyEventClient class
[Windows] Further encapsulation and cleanup with 'interfaces' to reduce header pollution
[Windows] Complete serialization fix with move of modifier state management from client thread to server thread to guarantee consistency
[Windows] Replace atom-based keyboard switching with memory mapped file indexed to avoid security constraints
[Windows] Fixup Left Alt+Shift interaction with serializer
[Windows] Use Windows 8.1 SDK for test
