ctwin32

ctwin32

ctwin32 is a pure Python module, that wraps some Windows APIs (win32) by using ctypes. Since it is my personal playground, the selection of supported APIs and the way those are wrapped are solely dictated by my needs and preferences.

ctwin32 is not a replacement for pywin32, although it serves that purpose for me (in conjunction with comtypes). Compared with pywin32 the coverage of ctwin32 is downright tiny.

Here is an example of a classic ‘Hello world’ program:

from ctwin32 import user, gdi, wndcls, wtypes
from ctwin32 import WM_CREATE, WM_PAINT, WM_DESTROY
from ctwin32 import DT_CENTER, DT_SINGLELINE, DT_VCENTER

class HelloWnd(wndcls.SimpleWnd):

    DT_FLAGS = DT_CENTER | DT_SINGLELINE | DT_VCENTER
    MSG = "Hello from ctwin32!"

    def on_message(self, msg, wp, lp):

        if msg == WM_CREATE:
            lf = wtypes.LOGFONT(
                lfHeight=-72,
                lfFaceName = "MS Shell Dlg"
                )
            self.font = gdi.CreateFontIndirect(lf)
            return 0

        if msg == WM_PAINT:
            hdc, ps = self.begin_paint()
            oldfont = gdi.SelectObject(hdc, self.font)
            user.DrawText(hdc, self.MSG, self.client_rect(), self.DT_FLAGS)
            gdi.SelectObject(hdc, oldfont)
            self.end_paint(ps)
            return 0

        if msg == WM_DESTROY:
            gdi.DeleteObject(self.font)
            user.PostQuitMessage(0)
            return 0

        return self.def_win_proc(msg, wp, lp)

if __name__ == "__main__":

    icon = wndcls.load_ctwin32_ico()
    wnd = HelloWnd(wndcls.WndCreateParams("Hello Window", icon))
    wnd.show()

    while msg := user.GetMessage():
        user.TranslateMessage(msg)
        user.DispatchMessage(msg)

See the samples directory for several instances of how ctwin32 can be used.

While there is already another Python module that does something very similar to ctwin32 (pywin32-ctypes), it has a different purpose (namely to serve the internal needs of its creator). However, ctwin32 wraps significantly more API functions than pywin32-ctypes (as of September 2025: 417 / 16).

Note: Even though ctwin32 is a pure Python module, it can of course only be used on Windows. For the first three years or so, packages were tagged with the Windows platform tags to prevent pip from using them on other operating systems. However, it became futile to try to prevent this when after only one year the sdist package was also released. In the absence of suitable wheel packages for other operating systems, this would mean that pip install ctwin32 would now use the sdist package to install ctwin32 anyway. Therefore, a universal wheel is now distributed and it is up to the user to be smart enough to use it on Windows only.