Get Mouse Wheel Scroll using Win32api in Python

Question

I want to read mouse wheel scroll events and then simulate them. I know I can simulate it using below code.

#Scroll one up
win32api.mouse_event(MOUSEEVENTF_WHEEL, x, y, 1, 0)

#Scroll one down
win32api.mouse_event(MOUSEEVENTF_WHEEL, x, y, -1, 0)

However, I couldn't find a way to get whell scroll event using win32api in Python. Is there any way to detect wheel scroll up or down events?

Paul Randleman · Accepted Answer · 2021-08-04 10:47:50Z

2

If you need to get the global WM_MOUSEWHEEL message, you can use the SetWindowsHookEx function and with WH_MOUSE_LL hook.

Then handle the WM_MOUSEWHEEL message in the hook function.

Here is a sample:

import win32api 
import win32con
import ctypes
from ctypes import windll, CFUNCTYPE, POINTER, c_int, c_void_p, byref

user32 = ctypes.windll.user32
kernel32 = ctypes.windll.kernel32

def LowLevelMouseProc(nCode, wParam, lParam):
    if wParam == win32con.WM_MOUSEWHEEL:
        print("mousewheel triggerd!")
    return windll.user32.CallNextHookEx(hook_id, nCode, wParam, lParam)

if __name__ == '__main__':
    CMPFUNC = CFUNCTYPE(c_void_p, c_int, ctypes.wintypes.WPARAM, ctypes.wintypes.LPARAM)

    pointer = CMPFUNC(LowLevelMouseProc)
    hook_id = user32.SetWindowsHookExW(win32con.WH_MOUSE_LL,pointer,c_void_p(win32api.GetModuleHandle(None), 0)
    msg = ctypes.wintypes.MSG()
    while user32.GetMessageW(ctypes.byref(msg), 0, 0, 0) != 0:
        user32.TranslateMessage(msg)
        user32.DispatchMessageW(msg)

It works for me:

Edit

If there are problems like <class'OverflowError'>: int too long to convert, you can try the following code:

import win32api 
import win32con
import ctypes
from ctypes import windll, CFUNCTYPE, c_int, c_void_p, wintypes

 

user32 = ctypes.windll.user32
kernel32 = ctypes.windll.kernel32
user32.CallNextHookEx.argtypes = [ctypes.wintypes.HHOOK,c_int, ctypes.wintypes.WPARAM, ctypes.wintypes.LPARAM]

 

def LowLevelMouseProc(nCode, wParam, lParam):
    if wParam == win32con.WM_MOUSEWHEEL:
        print("mousewheel triggerd!")
    return user32.CallNextHookEx(hook_id, nCode, wParam, lParam)

 

if __name__ == '__main__':
    CMPFUNC = CFUNCTYPE(c_void_p, c_int, ctypes.wintypes.WPARAM, ctypes.wintypes.LPARAM)
    user32.SetWindowsHookExW.argtypes = [c_int,CMPFUNC,ctypes.wintypes.HINSTANCE,ctypes.wintypes.DWORD]
    pointer = CMPFUNC(LowLevelMouseProc)
    hook_id = user32.SetWindowsHookExW(win32con.WH_MOUSE_LL,pointer,win32api.GetModuleHandle(None), 0)
    msg = ctypes.wintypes.MSG()
    while user32.GetMessageW(ctypes.byref(msg), 0, 0, 0) != 0:
        user32.TranslateMessage(msg)
        user32.DispatchMessageW(msg)

edited Aug 4, 2021 at 10:47

Paul Randleman

1241 silver badge8 bronze badges

answered Dec 2, 2020 at 2:16

Zeus

3,9363 gold badges9 silver badges25 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Zeus Over a year ago

Hi,if this answer did help to you, please feel free to mark it to help people with the same issue, and let me know if you have any problem.Thanks.

Basj Over a year ago

How to distinguish up wheelscrolls and down wheelscrolls?

CristiFati Over a year ago

You should delete the 1st snippet, as it's Undefined Behavior ([SO]: C function called from Python via ctypes returns incorrect value (@CristiFati's answer)). 2nd is too, it works by luck (TranslateMessage, DispatchMessageW),

Collectives™ on Stack Overflow

Get Mouse Wheel Scroll using Win32api in Python

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related