I am relatively new to the world of programming. I've been using AutoHotkey a lot and came accross a code using WM_NCHITTEST. The code below: When the mouse cursor is above a window Title Bar, Right Click minimizes the window and Middle Click closes it. When the X coordinate of the mouse cursor is > 0, everything works fine (all windows and monitors to the RIGHT of the Main Display). When X < 0, nothing works (everything to the LEFT of the Main Display). Is someone able to explain this?
Specifically, the "WM_NCHITTEST,, x | (y << 16)", I don't quite understand.
Link to the Original Code:
Link to Windows documentation of WM_NCHITTEST:
#If MouseIsOverTitlebar()
RButton::SendMessage 0x112, 0xF020
MButton::WinClose
MouseIsOverTitlebar() { static WM_NCHITTEST := 0x84, HTCAPTION := 2 CoordMode Mouse, Screen MouseGetPos x, y, w if WinExist("ahk_class Shell_TrayWnd ahk_id " w) ; Exclude taskbar. return false SendMessage WM_NCHITTEST,, x | (y << 16),, ahk_id %w% WinExist("ahk_id " w) ; Set Last Found Window for convenience. return ErrorLevel = HTCAPTION
}1 Answer
SendMessage, Msg, wParam, lParam, Control, WinTitleThis is a send message command from AHK. See SendMessage Tutorial and SendMessage.
For a WM_NCHITTEST message, use 0x84 for Msg. See message list.
static WM_NCHITTEST := 0x84
SendMessage, WM_NCHITTEST, wParam, lParam, Control, WinTitleNow the WM_NCHITTEST message require the cursor coordinate for lParam like this
lParam
The low-order word specifies the x-coordinate of the cursor. The coordinate is relative to the upper-left corner of the screen.
The high-order word specifies the y-coordinate of the cursor. The coordinate is relative to the upper-left corner of the screen.
Basically, x | (y << 16) is a way to squeeze 2 variables in one as required. See High-order word, low-order word and Bitwise operations in C.
Now, instead of using x and y as integer directly, we need to take care of the negative value. Use signed 16-bit values (Short) instead.
SendMessage, WM_NCHITTEST,, (x & 0xFFFF) | ((y & 0xFFFF) << 16),, ahk_id %w%
