SetBatchLines, -1
   SetMouseDelay, -1
   CoordMode, Mouse
   OnExit, Exit

   hHook := DllCall("SetWindowsHookEx"
      , Int, WH_MOUSE_LL := 14
      , Int, RegisterCallback("LowLevelMouseProc", "Fast")
      , UInt, DllCall("GetModuleHandle", UInt, 0)
      , UInt, 0)
   Return

Exit:
   DllCall("UnhookWindowsHookEx", UInt, hHook)
   ExitApp

~LCtrl::
   MouseGetPos,, y_prev
   Direction = horizontal
   Return

~LShift::
   MouseGetPos, x_prev
   Direction = vertical
   Return

~LCtrl Up::   Direction =
~LShift Up:: Direction =

LowLevelMouseProc(nCode, wParam, lParam)
{
   global Direction, x_prev, y_prev

   if (nCode < 0 || !Direction || wParam != 0x200)   ; WM_MOUSEMOVE = 0x200
      Return DllCall("CallNextHookEx", UInt, 0, Int, nCode, UInt, wParam, UInt, lParam)

   if Direction = horizontal
      x := NumGet(lParam+0), y := y_prev

   if Direction = vertical
      y := NumGet(lParam+0, 4), x := x_prev

   MouseMove, x, y, 0
   Return 1
}