Python win32con.CS_VREDRAW Examples

def _CreateMainWindow(self, prev, settings, browser, rect):
        # Creates a parent window that hosts the view window.  This window
        # gets the control notifications etc sent from the child.
        style = win32con.WS_CHILD | win32con.WS_VISIBLE #
        wclass_name = "ShellViewDemo_DefView"
        # Register the Window class.
        wc = win32gui.WNDCLASS()
        wc.hInstance = win32gui.dllhandle
        wc.lpszClassName = wclass_name
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        try:
            win32gui.RegisterClass(wc)
        except win32gui.error, details:
            # Should only happen when this module is reloaded
            if details[0] != winerror.ERROR_CLASS_ALREADY_EXISTS:
                raise 

def __init__(self):
    message_map = {
      win32con.WM_DEVICECHANGE : self.onDeviceChange
    }
    
    wc = win32gui.WNDCLASS ()
    hinst = wc.hInstance = win32api.GetModuleHandle (None)
    wc.lpszClassName = "DeviceChangeDemo"
    wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW;
    wc.hCursor = win32gui.LoadCursor (0, win32con.IDC_ARROW)
    wc.hbrBackground = win32con.COLOR_WINDOW
    wc.lpfnWndProc = message_map
    classAtom = win32gui.RegisterClass (wc)
    style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
    self.hwnd = win32gui.CreateWindow (
      classAtom,
      "Device Change Demo",
      style,
      0, 0,
      win32con.CW_USEDEFAULT, win32con.CW_USEDEFAULT,
      0, 0,
      hinst, None
    ) 

def __init__(self):
        msg_TaskbarRestart = win32gui.RegisterWindowMessage("TaskbarCreated");
        message_map = {
                msg_TaskbarRestart: self.OnRestart,
                win32con.WM_DESTROY: self.OnDestroy,
                win32con.WM_COMMAND: self.OnCommand,
                win32con.WM_USER+20 : self.OnTaskbarNotify,
        }
        # Register the Window class.
        wc = win32gui.WNDCLASS()
        hinst = wc.hInstance = win32api.GetModuleHandle(None)
        wc.lpszClassName = "PythonTaskbarDemo"
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW;
        wc.hCursor = win32api.LoadCursor( 0, win32con.IDC_ARROW )
        wc.hbrBackground = win32con.COLOR_WINDOW
        wc.lpfnWndProc = message_map # could also specify a wndproc.

        # Don't blow up if class already registered to make testing easier
        try:
            classAtom = win32gui.RegisterClass(wc)
        except win32gui.error, err_info:
            if err_info.winerror!=winerror.ERROR_CLASS_ALREADY_EXISTS:
                raise

        # Create the Window. 

def __init__(self):
        message_map = {
            win32con.WM_DEVICECHANGE: self.onDeviceChange
        }

        wc = win32gui.WNDCLASS()
        hinst = wc.hInstance = win32api.GetModuleHandle(None)
        wc.lpszClassName = "DeviceChangeDemo"
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        wc.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        wc.hbrBackground = win32con.COLOR_WINDOW
        wc.lpfnWndProc = message_map
        classAtom = win32gui.RegisterClass(wc)
        style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
        self.hwnd = win32gui.CreateWindow(
            classAtom,
            "Device Change Demo",
            style,
            0, 0,
            win32con.CW_USEDEFAULT, win32con.CW_USEDEFAULT,
            0, 0,
            hinst, None
        ) 

def _dialog_register_windowclass(cls, instance, name):
        if not cls._dialog_registered_windowclass:
            wc = win32gui.WNDCLASS()
            wc.SetDialogProc()
            wc.hInstance = instance
            wc.lpszClassName = name
            wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
            wc.hCursor = win32gui.LoadCursor( 0, win32con.IDC_ARROW )
            wc.hbrBackground = win32con.COLOR_WINDOW + 1
            wc.lpfnWndProc = {}

            # C code: wc.cbWndExtra = DLGWINDOWEXTRA + sizeof(HBRUSH) + (sizeof(COLORREF));
            wc.cbWndExtra = win32con.DLGWINDOWEXTRA + struct.calcsize("Pi")

            cls._dialog_atom = win32gui.RegisterClass(wc)
            cls._dialog_registered_windowclass = True

        return cls._dialog_atom


    #----------------------------------------------------------------------- 

def _RegisterWndClass(self):
        message_map = {}
        wc = win32gui.WNDCLASS()
        wc.SetDialogProc()  # Make it a dialog class.
        wc.hInstance = self.hinst
        wc.lpszClassName = self.className
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        wc.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        wc.hbrBackground = win32con.COLOR_WINDOW + 1
        wc.lpfnWndProc = message_map  # could also specify a wndproc.
        wc.cbWndExtra = win32con.DLGWINDOWEXTRA + struct.calcsize("Pi")

        try:
            self.classAtom = win32gui.RegisterClass(wc)
        except win32gui.error, err_info:
            if err_info.winerror != winerror.ERROR_CLASS_ALREADY_EXISTS:
                raise 

def initialize(klass):
        WM_RESTART = win32gui.RegisterWindowMessage('TaskbarCreated')
        klass.WM_NOTIFY = win32con.WM_USER+1
        klass.WNDCLASS = win32gui.WNDCLASS()
        klass.WNDCLASS.hInstance = win32gui.GetModuleHandle(None)
        klass.WNDCLASS.lpszClassName = 'Py_'+klass.__name__
        klass.WNDCLASS.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW;
        klass.WNDCLASS.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        klass.WNDCLASS.hIcon = win32gui.LoadIcon(0, win32con.IDI_APPLICATION)
        klass.WNDCLASS.hbrBackground = win32con.COLOR_WINDOW
        klass.WNDCLASS.lpfnWndProc = {
            WM_RESTART: klass._restart,
            klass.WM_NOTIFY: klass._notify,
            win32con.WM_CLOSE: klass._close,
            win32con.WM_DESTROY: klass._destroy,
            win32con.WM_COMMAND: klass._command,
            }
        klass.CLASS_ATOM = win32gui.RegisterClass(klass.WNDCLASS)
        klass._instance = {}
        return 

def _RegisterWndClass(self):
        message_map = {}
        wc = win32gui.WNDCLASS()
        wc.SetDialogProc()  # Make it a dialog class.
        wc.hInstance = self.hinst
        wc.lpszClassName = self.className
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        wc.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        wc.hbrBackground = win32con.COLOR_WINDOW + 1
        wc.lpfnWndProc = message_map  # could also specify a wndproc.
        wc.cbWndExtra = win32con.DLGWINDOWEXTRA + struct.calcsize("Pi")

        try:
            self.classAtom = win32gui.RegisterClass(wc)
        except win32gui.error, err_info:
            if err_info.winerror != winerror.ERROR_CLASS_ALREADY_EXISTS:
                raise 

def _CreateMainWindow(self, prev, settings, browser, rect):
        # Creates a parent window that hosts the view window.  This window
        # gets the control notifications etc sent from the child.
        style = win32con.WS_CHILD | win32con.WS_VISIBLE #
        wclass_name = "ShellViewDemo_DefView"
        # Register the Window class.
        wc = win32gui.WNDCLASS()
        wc.hInstance = win32gui.dllhandle
        wc.lpszClassName = wclass_name
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        try:
            win32gui.RegisterClass(wc)
        except win32gui.error, details:
            # Should only happen when this module is reloaded
            if details[0] != winerror.ERROR_CLASS_ALREADY_EXISTS:
                raise 

def _register_wnd_class(self, message_map):
        # Register the Window class.
        window_class = win32gui.WNDCLASS()
        self.hinst = window_class.hInstance = win32gui.GetModuleHandle(None)
        window_class.lpszClassName = self.window_class_name
        window_class.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        window_class.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        window_class.hbrBackground = win32con.COLOR_WINDOW
        window_class.lpfnWndProc = message_map  # could also specify a wndproc.
        return win32gui.RegisterClass(window_class) 

def register_wnd_class(self, message_map):
        # Register the Window class.
        window_class = win32gui.WNDCLASS()
        self.hinst = window_class.hInstance = win32gui.GetModuleHandle(None)
        window_class.lpszClassName = self.window_class_name
        window_class.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        window_class.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        window_class.hbrBackground = win32con.COLOR_WINDOW
        window_class.lpfnWndProc = message_map  # could also specify a wndproc.
        return win32gui.RegisterClass(window_class) 

def _RegisterWndClass(self):
        message_map = {}
        wc = win32gui.WNDCLASS()
        wc.SetDialogProc()  # Make it a dialog class.
        wc.hInstance = self.hinst
        wc.lpszClassName = self.className
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        wc.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        wc.hbrBackground = win32con.COLOR_WINDOW + 1
        wc.lpfnWndProc = message_map    # could also specify a wndproc.

        # C code: wc.cbWndExtra = DLGWINDOWEXTRA + sizeof(HBRUSH) +
        #                         (sizeof(COLORREF));
        wc.cbWndExtra = win32con.DLGWINDOWEXTRA + struct.calcsize("Pi")

        #  py.ico went away in python 2.5, load from executable instead
        this_app = win32api.GetModuleHandle(None)
        try:
            # python.exe and pythonw.exe
            wc.hIcon = win32gui.LoadIcon(this_app, 1)
        except win32gui.error:
            # pythonwin's icon
            wc.hIcon = win32gui.LoadIcon(this_app, 135)
        try:
            self.classAtom = win32gui.RegisterClass(wc)
        except win32gui.error, err_info:
            if err_info.winerror != winerror.ERROR_CLASS_ALREADY_EXISTS:
                raise 

def _RegisterWndClass(self):
        className = "PythonDocSearch"
        message_map = {}
        wc = win32gui.WNDCLASS()
        wc.SetDialogProc() # Make it a dialog class.
        wc.hInstance = self.hinst
        wc.lpszClassName = className
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        wc.hCursor = win32gui.LoadCursor( 0, win32con.IDC_ARROW )
        wc.hbrBackground = win32con.COLOR_WINDOW + 1
        wc.lpfnWndProc = message_map # could also specify a wndproc.
        # C code: wc.cbWndExtra = DLGWINDOWEXTRA + sizeof(HBRUSH) + (sizeof(COLORREF));
        wc.cbWndExtra = win32con.DLGWINDOWEXTRA + struct.calcsize("Pi")
        icon_flags = win32con.LR_LOADFROMFILE | win32con.LR_DEFAULTSIZE

        ## py.ico went away in python 2.5, load from executable instead
        this_app=win32api.GetModuleHandle(None)
        try:
            wc.hIcon=win32gui.LoadIcon(this_app, 1)    ## python.exe and pythonw.exe
        except win32gui.error:
            wc.hIcon=win32gui.LoadIcon(this_app, 135)  ## pythonwin's icon
        try:
            classAtom = win32gui.RegisterClass(wc)
        except win32gui.error, err_info:
            if err_info.winerror!=winerror.ERROR_CLASS_ALREADY_EXISTS:
                raise 

def Create(self, title, style, rect, parent):
		classStyle = win32con.CS_HREDRAW | win32con.CS_VREDRAW
		className = win32ui.RegisterWndClass(classStyle, 0, win32con.COLOR_WINDOW+1, 0)
		self._obj_ = win32ui.CreateWnd()
		self._obj_.AttachObject(self)
		self._obj_.CreateWindow(className, title, style, rect, parent, win32ui.AFX_IDW_PANE_FIRST)
		self.HookMessage (self.OnSize, win32con.WM_SIZE)
		self.HookMessage (self.OnPrepareToClose, WM_USER_PREPARE_TO_CLOSE)
		self.HookMessage (self.OnDestroy, win32con.WM_DESTROY)
		self.timerid = timer.set_timer (100, self.OnTimer)
		self.InvalidateRect() 

def __init__(self,
                 icon,
                 hover_text,
                 menu_options,
                 on_quit=None,
                 default_menu_index=None,
                 window_class_name=None, ):

        self.icon = icon
        self.hover_text = hover_text
        self.on_quit = on_quit

        menu_options = menu_options + (('Quit', None, self.QUIT),)
        self._next_action_id = self.FIRST_ID
        self.menu_actions_by_id = set()
        self.menu_options = self._add_ids_to_menu_options(list(menu_options))
        self.menu_actions_by_id = dict(self.menu_actions_by_id)
        del self._next_action_id

        self.default_menu_index = (default_menu_index or 0)
        self.window_class_name = window_class_name or "SysTrayIconPy"

        message_map = {win32gui.RegisterWindowMessage("TaskbarCreated"): self.restart,
                       win32con.WM_DESTROY: self.destroy,
                       win32con.WM_COMMAND: self.command,
                       win32con.WM_USER + 20: self.notify, }
        # Register the Window class.
        window_class = win32gui.WNDCLASS()
        hinst = window_class.hInstance = win32gui.GetModuleHandle(None)
        window_class.lpszClassName = self.window_class_name
        window_class.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        window_class.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        window_class.hbrBackground = win32con.COLOR_WINDOW
        window_class.lpfnWndProc = message_map  # could also specify a wndproc.
        classAtom = win32gui.RegisterClass(window_class)
        # Create the Window.
        style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
        self.hwnd = win32gui.CreateWindow(classAtom,
                                          self.window_class_name,
                                          style,
                                          0,
                                          0,
                                          win32con.CW_USEDEFAULT,
                                          win32con.CW_USEDEFAULT,
                                          0,
                                          0,
                                          hinst,
                                          None)
        win32gui.UpdateWindow(self.hwnd)
        self.notify_id = None
        self.refresh_icon()

        win32gui.PumpMessages() 

def __init__(self, menu_options, program_name='Python Taskbar', window_name=None):

        self.logger = logging.getLogger("tray")
        self.cache = {}
        self._commands = {'OnMenuOpen': [],
                          'OnMenuClose': [],
                          'OnWindowHide': [],
                          'OnWindowRestore': []}
        self.program_name = program_name
        try:
            self.console_hwnd = WindowHandle(parent=False, console=True)
        except NameError:
            self.console_hwnd = None
        self._refresh_menu(menu_options)
        if window_name is None:
            window_name = program_name

        #Set up callbacks
        msg_TaskbarRestart = win32gui.RegisterWindowMessage('TaskbarCreated')
        message_map = {
            msg_TaskbarRestart: self.OnRestart,
            win32con.WM_DESTROY: self.OnDestroy,
            win32con.WM_COMMAND: self.OnCommand,
            TRAY_EVENT: self.OnTaskbarNotify,
        }
        #Register the Window class.
        wc = win32gui.WNDCLASS()
        hinst = wc.hInstance = win32api.GetModuleHandle(None)
        wc.lpszClassName = window_name
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        wc.hCursor = win32api.LoadCursor(0, win32con.IDC_ARROW)
        wc.hbrBackground = win32con.COLOR_WINDOW
        wc.lpfnWndProc = message_map # could also specify a wndproc.

        #Don't blow up if class already registered to make testing easier
        try:
            classAtom = win32gui.RegisterClass(wc)
        except (win32gui.error, err_info):
            if err_info.winerror!=winerror.ERROR_CLASS_ALREADY_EXISTS:
                raise

        #Create the Window.
        style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
        self.hwnd = win32gui.CreateWindow(wc.lpszClassName, window_name, style, \
                0, 0, win32con.CW_USEDEFAULT, win32con.CW_USEDEFAULT, \
                0, 0, hinst, None)
        win32gui.UpdateWindow(self.hwnd)
        self._set_icon()
        self.logger.info('Window created.') 

def __init__(self,
                 icon,
                 hover_text,
                 menu_options,
                 on_quit=None,
                 default_menu_index=None,
                 window_class_name=None, ):

        self.logger = logging.getLogger("root.SysIcon")

        self.icon = icon
        self.hover_text = hover_text
        self.on_quit = on_quit

        menu_options = menu_options + (('Quit', None, self.QUIT),)
        self._next_action_id = self.FIRST_ID
        self.menu_actions_by_id = set()
        self.menu_options = self._add_ids_to_menu_options(list(menu_options))
        self.menu_actions_by_id = dict(self.menu_actions_by_id)
        del self._next_action_id

        self.default_menu_index = (default_menu_index or 0)
        self.window_class_name = window_class_name or "SysTrayIconPy"

        message_map = {win32gui.RegisterWindowMessage("TaskbarCreated"): self.restart,
                       win32con.WM_DESTROY: self.destroy,
                       win32con.WM_COMMAND: self.command,
                       win32con.WM_USER + 20: self.notify, }
        # Register the Window class.
        window_class = win32gui.WNDCLASS()
        hinst = window_class.hInstance = win32gui.GetModuleHandle(None)
        window_class.lpszClassName = self.window_class_name
        window_class.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW;
        window_class.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        window_class.hbrBackground = win32con.COLOR_WINDOW
        window_class.lpfnWndProc = message_map  # could also specify a wndproc.
        classAtom = win32gui.RegisterClass(window_class)
        # Create the Window.
        style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
        self.hwnd = win32gui.CreateWindow(classAtom,
                                          self.window_class_name,
                                          style,
                                          0,
                                          0,
                                          win32con.CW_USEDEFAULT,
                                          win32con.CW_USEDEFAULT,
                                          0,
                                          0,
                                          hinst,
                                          None)
        win32gui.UpdateWindow(self.hwnd)
        self.notify_id = None
        self.refresh_icon()

        win32gui.PumpMessages() 

def new_icon(hdesk,desktop_name):
    """ Runs as a thread on each desktop to create a new tray icon and handle its messages """ 
    global id
    id=id+1
    hdesk.SetThreadDesktop()
    ## apparently the threads can't use same hinst, so each needs its own window class
    windowclassname='PythonDesktopManager'+desktop_name
    wc = win32gui.WNDCLASS()
    wc.hInstance = win32api.GetModuleHandle(None)
    wc.lpszClassName = windowclassname
    wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW | win32con.CS_GLOBALCLASS
    wc.hCursor = win32gui.LoadCursor( 0, win32con.IDC_ARROW )
    wc.hbrBackground = win32con.COLOR_WINDOW
    wc.lpfnWndProc = icon_wndproc
    windowclass = win32gui.RegisterClass(wc)
    style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
    hwnd = win32gui.CreateWindow(windowclass, 'dm_'+desktop_name, win32con.WS_SYSMENU,
                    0, 0, win32con.CW_USEDEFAULT, win32con.CW_USEDEFAULT,
                    0, 0, wc.hInstance, None)
    win32gui.UpdateWindow(hwnd)
    flags = win32gui.NIF_ICON | win32gui.NIF_MESSAGE | win32gui.NIF_TIP
    notify_info = (hwnd, id, flags, win32con.WM_USER+20, hicon, 'Desktop Manager (%s)' %desktop_name)
    window_info[hwnd]=notify_info
    ## wait for explorer to initialize system tray for new desktop
    tray_found=0
    while not tray_found:
        try:
            tray_found=win32gui.FindWindow("Shell_TrayWnd",None)
        except win32gui.error:
            traceback.print_exc
            time.sleep(.5)
    win32gui.Shell_NotifyIcon(win32gui.NIM_ADD, notify_info)
    win32gui.PumpMessages() 

def __init__(self, apiServer):
        
        self.apiServer = apiServer
        
        self.icon = AppFolders.imagePath("trout.ico")
        self.hover_text = "ComicStreamer"
        self.on_quit = self.bye    
            
        menu_options = (
                        ('Show ComicStreamer UI', None, self.show),
                       )
        
        menu_options = menu_options + (('Quit', None, self.QUIT),)
        self._next_action_id = self.FIRST_ID
        self.menu_actions_by_id = set()
        self.menu_options = self._add_ids_to_menu_options(list(menu_options))
        self.menu_actions_by_id = dict(self.menu_actions_by_id)
        del self._next_action_id
        
        
        self.default_menu_index = 1
        self.window_class_name = "ComicStreamerTrayIcon"
        
        message_map = {win32gui.RegisterWindowMessage("TaskbarCreated"): self.restart,
                       win32con.WM_DESTROY: self.destroy,
                       win32con.WM_COMMAND: self.command,
                       win32con.WM_USER+20 : self.notify,}
        # Register the Window class.
        window_class = win32gui.WNDCLASS()
        hinst = window_class.hInstance = win32gui.GetModuleHandle(None)
        window_class.lpszClassName = self.window_class_name
        window_class.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW;
        window_class.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        window_class.hbrBackground = win32con.COLOR_WINDOW
        window_class.lpfnWndProc = message_map # could also specify a wndproc.
        classAtom = win32gui.RegisterClass(window_class)
        # Create the Window.
        style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
        self.hwnd = win32gui.CreateWindow(classAtom,
                                          self.window_class_name,
                                          style,
                                          0,
                                          0,
                                          win32con.CW_USEDEFAULT,
                                          win32con.CW_USEDEFAULT,
                                          0,
                                          0,
                                          hinst,
                                          None)
        win32gui.UpdateWindow(self.hwnd)
        self.notify_id = None
        self.refresh_icon() 

def __init__(self, iconPath=None):

        self.iconPath = iconPath
        self.status = []

        msg_TaskbarRestart = \
            win32api.RegisterWindowMessage('TaskbarCreated')
        message_map = {
            msg_TaskbarRestart: self.OnRestart,
            win32con.WM_DESTROY: self.OnDestroy,
            win32con.WM_COMMAND: self.OnCommand,
            win32con.WM_USER + 20: self.OnTaskbarNotify,
        }

        # Register the Window class.

        wc = win32gui.WNDCLASS()
        hinst = wc.hInstance = win32api.GetModuleHandle(None)
        wc.lpszClassName = 'web2pyTaskbar'
        wc.style = win32con.CS_VREDRAW | win32con.CS_HREDRAW
        wc.hCursor = win32gui.LoadCursor(0, win32con.IDC_ARROW)
        wc.hbrBackground = win32con.COLOR_WINDOW
        wc.lpfnWndProc = message_map  # could also specify a wndproc.
        classAtom = win32gui.RegisterClass(wc)

        # Create the Window.

        style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
        self.hwnd = win32gui.CreateWindow(
            classAtom,
            'web2pyTaskbar',
            style,
            0,
            0,
            win32con.CW_USEDEFAULT,
            win32con.CW_USEDEFAULT,
            0,
            0,
            hinst,
            None,
        )
        win32gui.UpdateWindow(self.hwnd)
        self.SetServerStopped() 

def _WindowsShutdownBlocker(title='Python script'):
    """
    Block Windows shutdown when you do something important.
    """
    from ctypes import CFUNCTYPE, c_bool, c_uint, c_void_p, c_wchar_p, windll
    import win32con
    import win32gui

    def WndProc(hWnd, message, wParam, lParam):
        if message == win32con.WM_QUERYENDSESSION:
            return False
        else:
            return win32gui.DefWindowProc(hWnd, message, wParam, lParam)

    CALLBACK = CFUNCTYPE(c_bool, c_void_p, c_uint, c_void_p, c_void_p)

    wc = win32gui.WNDCLASS()
    wc.style = win32con.CS_GLOBALCLASS | win32con.CS_VREDRAW | win32con.CS_HREDRAW
    wc.lpfnWndProc = CALLBACK(WndProc)
    wc.hbrBackground = win32con.COLOR_WINDOW + 1
    wc.lpszClassName = "block_shutdown_class"
    win32gui.RegisterClass(wc)

    hwnd = win32gui.CreateWindow(wc.lpszClassName, title,
                                 win32con.WS_OVERLAPPEDWINDOW, 50,
                                 50, 100, 100, 0, 0,
                                 win32gui.GetForegroundWindow(), None)

    win32gui.ShowWindow(hwnd, win32con.SW_HIDE)

    windll.user32.ShutdownBlockReasonCreate.argtypes = [c_void_p, c_wchar_p]
    windll.user32.ShutdownBlockReasonCreate.restype = c_bool
    windll.user32.ShutdownBlockReasonCreate(
        hwnd, "Important work in processing, don't shutdown :-(")

    yield

    windll.user32.ShutdownBlockReasonDestroy.argtypes = [c_void_p]
    windll.user32.ShutdownBlockReasonDestroy.restype = c_bool
    windll.user32.ShutdownBlockReasonDestroy(hwnd)
    win32gui.DestroyWindow(hwnd)
    win32gui.UnregisterClass(wc.lpszClassName, None) 

def __init__(self, title, style,
                 size = (win32con.CW_USEDEFAULT,
                         win32con.CW_USEDEFAULT),
                 messages = {}):
        '''Setup a window class and a create window'''
        self.layers = []
        self.module_handle = win32gui.GetModuleHandle(None)
        self.systray = False
        self.systray_map = {
            win32con.WM_RBUTTONDOWN: self._show_menu
            }
        
        # Setup window class
        #
        self.window_class_name = self._make_window_class_name()
        self.message_map = {
             win32con.WM_PAINT: self._on_paint,
             win32con.WM_CLOSE: self._on_close,
             win32con.WM_COMMAND: self._on_command,
             self._notify_event_id: self._on_notify,
             }
        self.message_map.update( messages )
        self.window_class = win32gui.WNDCLASS()
        self.window_class.style = win32con.CS_HREDRAW | win32con.CS_VREDRAW
        self.window_class.lpfnWndProc = self.message_map
        self.window_class.hInstance = self.module_handle
        self.window_class.hCursor = win32gui.LoadCursor( None, win32con.IDC_ARROW )
        self.window_class.hbrBackground = win32con.COLOR_WINDOW
        self.window_class.lpszClassName = self.window_class_name
            
        self.window_classHandle = win32gui.RegisterClass( self.window_class )

        self.window_handle = win32gui.CreateWindow(
            self.window_class_name,
            title,
            style,
            win32con.CW_USEDEFAULT,
            win32con.CW_USEDEFAULT,
            size[ 0 ],
            size[ 1 ],
            None,
            None,
            self.module_handle,
            None )