python3 ctype CreateWindowEx simple example

Question

I have googled for some time but could not find simple example of python3 ctypes and Win32 API for creating and showing window. Please point me to good link or show code her

Answer 1

This is most easy to do with the win32gui module and its friends, win32api and win32con. There's no need to write your own ctypes wrappers to the Windows API. The simplest Petzold style app comes out something like this:

import win32api, win32con, win32gui

class MyWindow:

    def __init__(self):
        win32gui.InitCommonControls()
        self.hinst = win32api.GetModuleHandle(None)
        className = 'MyWndClass'
        message_map = {
            win32con.WM_DESTROY: self.OnDestroy,
        }
        wc = win32gui.WNDCLASS()
        wc.style = win32con.CS_HREDRAW | win32con.CS_VREDRAW
        wc.lpfnWndProc = message_map
        wc.lpszClassName = className
        win32gui.RegisterClass(wc)
        style = win32con.WS_OVERLAPPEDWINDOW
        self.hwnd = win32gui.CreateWindow(
            className,
            'My win32api app',
            style,
            win32con.CW_USEDEFAULT,
            win32con.CW_USEDEFAULT,
            300,
            300,
            0,
            0,
            self.hinst,
            None
        )
        win32gui.UpdateWindow(self.hwnd)
        win32gui.ShowWindow(self.hwnd, win32con.SW_SHOW)

    def OnDestroy(self, hwnd, message, wparam, lparam):
        win32gui.PostQuitMessage(0)
        return True

w = MyWindow()
win32gui.PumpMessages()

Answer 2

Found this nice little trinket and took the time to get it working on nothing but the standard library of vanilla python 3.4.0:
(for those who wish to use natives over PyWin32)
http://code.activestate.com/recipes/208699-calling-windows-api-using-ctypes-and-win32con/

import sys
from ctypes import *

kernel32 = windll.kernel32
user32 = windll.user32
gdi32 = windll.gdi32

NULL = 0
CW_USEDEFAULT = -2147483648
IDI_APPLICATION = 32512
WS_OVERLAPPEDWINDOW = 13565952

CS_HREDRAW = 2
CS_VREDRAW = 1

IDC_ARROW = 32512
WHITE_BRUSH = 0

SW_SHOWNORMAL = 1

WNDPROC = WINFUNCTYPE(c_long, c_int, c_uint, c_int, c_int)

class WNDCLASS(Structure):
    _fields_ = [('style', c_uint),
                ('lpfnWndProc', WNDPROC),
                ('cbClsExtra', c_int),
                ('cbWndExtra', c_int),
                ('hInstance', c_int),
                ('hIcon', c_int),
                ('hCursor', c_int),
                ('hbrBackground', c_int),
                ('lpszMenuName', c_char_p),
                ('lpszClassName', c_char_p)]

class RECT(Structure):
    _fields_ = [('left', c_long),
                ('top', c_long),
                ('right', c_long),
                ('bottom', c_long)]

class PAINTSTRUCT(Structure):
    _fields_ = [('hdc', c_int),
                ('fErase', c_int),
                ('rcPaint', RECT),
                ('fRestore', c_int),
                ('fIncUpdate', c_int),
                ('rgbReserved', c_char * 32)]

class POINT(Structure):
    _fields_ = [('x', c_long),
                ('y', c_long)]

class MSG(Structure):
    _fields_ = [('hwnd', c_int),
                ('message', c_uint),
                ('wParam', c_int),
                ('lParam', c_int),
                ('time', c_int),
                ('pt', POINT)]

def ErrorIfZero(handle):
    if handle == 0:
        raise WinError
    else:
        return handle

def MainWin():
    global NULL
    CreateWindowEx          = user32.CreateWindowExA
    CreateWindowEx.argtypes = [c_int, c_char_p, c_char_p, c_int, c_int, c_int, c_int, c_int, c_int, c_int, c_int, c_int]
    CreateWindowEx.restype  = ErrorIfZero

    # Define Window Class
    wndclass = WNDCLASS()
    wndclass.style          = CS_HREDRAW | CS_VREDRAW
    wndclass.lpfnWndProc    = WNDPROC(WndProc)
    wndclass.cbClsExtra = wndclass.cbWndExtra = 0
    wndclass.hInstance      = kernel32.GetModuleHandleA(c_int(NULL))
    wndclass.hIcon          = user32.LoadIconA(c_int(NULL), c_int(IDI_APPLICATION))
    wndclass.hCursor        = user32.LoadCursorA(c_int(NULL), c_int(IDC_ARROW))
    wndclass.hbrBackground  = gdi32.GetStockObject(c_int(WHITE_BRUSH))
    wndclass.lpszMenuName   = None
    wndclass.lpszClassName  = b"MainWin"
    # Register Window Class
    if not user32.RegisterClassA(byref(wndclass)):
        raise WinError()
    # Create Window
    hwnd = CreateWindowEx(0,
                          wndclass.lpszClassName,
                          b"Python Window",
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          CW_USEDEFAULT,
                          NULL,
                          NULL,
                          wndclass.hInstance,
                          NULL)
    # Show Window
    user32.ShowWindow(c_int(hwnd), c_int(SW_SHOWNORMAL))
    user32.UpdateWindow(c_int(hwnd))
    # Pump Messages
    msg = MSG()
    pMsg = pointer(msg)
    NULL = c_int(NULL)

    while user32.GetMessageA( pMsg, NULL, 0, 0) != 0:
        user32.TranslateMessage(pMsg)
        user32.DispatchMessageA(pMsg)

    return msg.wParam

WM_PAINT = 15
WM_DESTROY = 2

DT_SINGLELINE = 32
DT_CENTER = 1
DT_VCENTER = 4
def WndProc(hwnd, message, wParam, lParam):
    ps = PAINTSTRUCT()
    rect = RECT()

    if message == WM_PAINT:
        hdc = user32.BeginPaint(c_int(hwnd), byref(ps))
        user32.GetClientRect(c_int(hwnd), byref(rect))
        user32.DrawTextA(c_int(hdc),
                         b"Python Powered Windows" ,
                         c_int(-1), byref(rect), 
                         DT_SINGLELINE|DT_CENTER|DT_VCENTER)
        user32.EndPaint(c_int(hwnd), byref(ps))
        return 0
    elif message == WM_DESTROY:
        user32.PostQuitMessage(0)
        return 0

    return user32.DefWindowProcA(c_int(hwnd), c_int(message), c_int(wParam), c_int(lParam))

if __name__=='__main__':
    sys.exit(MainWin())