Detect when any application Window is dragged to top of screen - c++

Question

On Windows 10 I have been experimenting with replacing the "Window snap" feature to work better with ultra wide monitors. While I have had no problem capturing the Windows Key+arrow cursors to handle the keyboard shortcut, I now want to detect when another application Window has been dragged to the top/right/left/bottom of the current monitor.
Current code:
#include <iostream>
#include <Windows.h>
HHOOK _hook_keyboard;
KBDLLHOOKSTRUCT kbdStruct;
CONST int HORIZONTAL_SLOTS = 4;
CONST int VERTICAL_SLOTS = 1;
// horizontalPosition/verticalPosition specifies which "slot" starting at 0 to place Window in
// horizontalSlots/verticalSlots specifies how many slots to divide the screen into
void MoveAndResizeActiveWindow(int horizontalPosition, int verticalPosition, int horizontalSlots, int verticalSlots)
{
// get work area on primary monitor
HWND currentWindow = GetForegroundWindow();
if (currentWindow != NULL)
{
HMONITOR currentMonitor = MonitorFromWindow(currentWindow, MONITOR_DEFAULTTONEAREST);
MONITORINFO monitorInfo;
monitorInfo.cbSize = sizeof(MONITORINFO);
if (GetMonitorInfo(currentMonitor, &monitorInfo))
{
long width = monitorInfo.rcWork.right - monitorInfo.rcWork.left;
long height = monitorInfo.rcWork.bottom - monitorInfo.rcWork.top;
long snappedWidth = width / horizontalSlots;
long snappedHeight = height / verticalSlots;
long snappedLeft = (snappedWidth * horizontalPosition) + monitorInfo.rcWork.left;
long snappedTop = (snappedHeight * verticalPosition) + monitorInfo.rcWork.top;
MoveWindow(currentWindow, snappedLeft, snappedTop, snappedWidth, snappedHeight, true);
}
}
}
LRESULT __stdcall HookCallbackKeyboard(int nCode, WPARAM wParam, LPARAM lParam)
{
BOOL bEatkeystroke = false;
short keyState;
if (nCode >= 0)
{
kbdStruct = *((KBDLLHOOKSTRUCT*)lParam);
switch (wParam)
{
case WM_KEYDOWN:
keyState = GetAsyncKeyState(VK_LWIN);
if (keyState)
{
switch (kbdStruct.vkCode)
{
case VK_LEFT:
bEatkeystroke = true;
break;
case VK_RIGHT:
bEatkeystroke = true;
break;
case VK_UP:
bEatkeystroke = true;
break;
case VK_DOWN:
bEatkeystroke = true;
break;
};
};
break;
case WM_KEYUP:
keyState = GetAsyncKeyState(VK_LWIN);
if (keyState)
{
switch (kbdStruct.vkCode)
{
case VK_LEFT:
MoveAndResizeActiveWindow(0, 0, 4, 1);
bEatkeystroke = true;
break;
case VK_RIGHT:
MoveAndResizeActiveWindow(3, 0, 4, 1);
bEatkeystroke = true;
break;
break;
case VK_UP:
MoveAndResizeActiveWindow(1, 0, 4, 1);
bEatkeystroke = true;
break;
case VK_DOWN:
MoveAndResizeActiveWindow(2, 0, 4, 1);
bEatkeystroke = true;
break;
};
}
break;
};
}
if (bEatkeystroke)
{
return 1;
}
else
{
return CallNextHookEx(_hook_keyboard, nCode, wParam, lParam);
}
}
void SetHook()
{
if (!(_hook_keyboard = SetWindowsHookEx(WH_KEYBOARD_LL, HookCallbackKeyboard, NULL, 0)))
{
MessageBox(NULL, L"Failed to install hook on keyboard!", L"Error", MB_ICONERROR);
}
}
int main(int argc, char** argv[])
{
SetHook();
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
Any suggestions how to identify when Windows have been dragged to a particular location on the screen?
As per advice in replies to original question I have tried used SetWinEventHook with the following code, planning to restrict EVENT_MIN and EVENT_MAX once correct events to watch for worked out.
g_hook_winevent = SetWinEventHook(
EVENT_MIN, EVENT_MAX,
NULL, // Handle to DLL.
HandleWinEvent, // The callback.
0, 0, // Process and thread IDs of interest (0 = all)
WINEVENT_OUTOFCONTEXT | WINEVENT_SKIPOWNPROCESS); // Flags.
}
void CALLBACK HandleWinEvent(HWINEVENTHOOK hook, DWORD event, HWND hwnd,
LONG idObject, LONG idChild,
DWORD dwEventThread, DWORD dwmsEventTime)
{
// process event here
}
While this easily tracks start or end of a Windows move with EVENT_SYSTEM_MOVESIZESTART and EVENT_SYSTEM_MOVESIZEEND I can't see an event here that tracks the moving of Window prior to EVENT_SYSTEM_MOVESIZEEND.
While that will work if only good option, ideally I want to be able to detect Window location from start of EVENT_SYSTEM_MOVESIZESTART until EVENT_SYSTEM_MOVESIZEEND completes. Testing with notepad the only event getting raised during the move is EVENT_OBJECT_NAMECHANGE, which seems to constantly trigger during Window move, at least with Notepad. However based on description in documentation I'm not sure if this is suitable for my use case: "An object's Name property has changed. The system sends this event for the following user interface elements: check box, cursor, list-view control, push button, radio button, status bar control, tree view control, and window object. Server applications send this event for their accessible objects."