Question

With python 3, I’d like to get a handle to another window (not part of my application) such that I can either:

1. directly capture that window as a screenshot, or
2. determine its position and size and capture it some other way

In case it is important, I am using Windows XP (edit: works in Windows 7 also).

I found this solution, but it is not quite what I need since it is full screen and more importantly, PIL to the best of my knowledge does not support 3.x yet.

Answer 1

Ars gave me all the pieces. I am just putting the pieces together here for anyone else who needs to get a screenshot in python 3.x. Next I need to figure out how to work with a win32 bitmap without having PIL to lean on.

Get a Screenshot (pass hwnd for a window instead of full screen):

def screenshot(hwnd = None):
    import win32gui
    import win32ui
    import win32con
    from time import sleep
    if not hwnd:
        hwnd=win32gui.GetDesktopWindow()
    l,t,r,b=win32gui.GetWindowRect(hwnd)
    h=b-t
    w=r-l
    hDC = win32gui.GetWindowDC(hwnd)
    myDC=win32ui.CreateDCFromHandle(hDC)
    newDC=myDC.CreateCompatibleDC()

    myBitMap = win32ui.CreateBitmap()
    myBitMap.CreateCompatibleBitmap(myDC, w, h)

    newDC.SelectObject(myBitMap)

    win32gui.SetForegroundWindow(hwnd)
    sleep(.2) #lame way to allow screen to draw before taking shot
    newDC.BitBlt((0,0),(w, h) , myDC, (0,0), win32con.SRCCOPY)
    myBitMap.Paint(newDC)
    myBitMap.SaveBitmapFile(newDC,'c:\\tmp.bmp')

Get a Window Handle by title (to pass to the above function):

def _get_windows_bytitle(title_text, exact = False):
    def _window_callback(hwnd, all_windows):
        all_windows.append((hwnd, win32gui.GetWindowText(hwnd)))
    windows = []
    win32gui.EnumWindows(_window_callback, windows)
    if exact:
        return [hwnd for hwnd, title in windows if title_text == title]
    else:
        return [hwnd for hwnd, title in windows if title_text in title]