take screenshot from background window partitially

gistfile1.txt

import win32gui
import win32ui
import win32con
from PIL import Image
import time
import ctypes
import traceback

'''
you can fastly capture with printwindow by
removimg unuse region from windows.
'''

def get_windows():
    '''Returns windows in z-order (top first)'''
    user32 = ctypes.windll.user32
    lst = []
    top = user32.GetTopWindow(None)
    if not top:
        return lst
    lst.append(top)
    while True:
        next = user32.GetWindow(lst[-1], win32con.GW_HWNDNEXT)
        if not next:
            break
        lst.append(next)
    return lst


tb = time.time()        
for hwnd in get_windows():
    if win32gui.IsWindowVisible(hwnd):
        try:
            left, top, right, bot = win32gui.GetClientRect(hwnd)
            #left, top, right, bot = win32gui.GetWindowRect(hwnd)
            w = right - left
            h = bot - top
            
            hwndDC = win32gui.GetWindowDC(hwnd)
            mfcDC  = win32ui.CreateDCFromHandle(hwndDC)
            saveDC = mfcDC.CreateCompatibleDC()

            saveBitMap = win32ui.CreateBitmap()
            saveBitMap.CreateCompatibleBitmap(mfcDC, w, h)
            saveDC.SelectObject(saveBitMap)
            # you can change w ,h , left , top for geometry you want
            result = saveDC.BitBlt((0, 0), (w, h), mfcDC, (left, top), win32con.SRCCOPY)
            bmpinfo = saveBitMap.GetInfo()
            bmpstr = saveBitMap.GetBitmapBits(True)
            try:
                im = Image.frombuffer(
                        'RGB',
                        (bmpinfo['bmWidth'], bmpinfo['bmHeight']),
                        bmpstr, 'raw', 'BGRX', 0, 1)

                win32gui.DeleteObject(saveBitMap.GetHandle())
                saveDC.DeleteDC()
                mfcDC.DeleteDC()
                win32gui.ReleaseDC(hwnd, hwndDC)
                im.save("./%s.png"%(hwnd))
            except:
                pass
        except:
            print(traceback.format_exc())
print(time.time()-tb)