Python Screenshot of inactive window PrintWindow + win32gui

Question

After hours of googling I managed to "write" this:

import win32gui
from ctypes import windll

hwnd = win32gui.FindWindow(None, 'Steam')

hdc = win32gui.GetDC(hwnd)
hdcMem = win32gui.CreateCompatibleDC(hdc)
    
hbitmap = win32ui.CreateBitmap()
hbitmap = win32gui.CreateCompatibleBitmap(hdcMem, 500, 500)
    
win32gui.SelectObject(hdcMem, hbitmap)
    
windll.user32.PrintWindow(hwnd, hdcMem, 0)

Is this a correct way to do this and how would I save an image?

Answer 1

After lots of searching and trying various different methods, the following worked for me.

import win32gui
import win32ui
from ctypes import windll
import Image

hwnd = win32gui.FindWindow(None, 'Calculator')

# Change the line below depending on whether you want the whole window
# or just the client area. 
#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)

# Change the line below depending on whether you want the whole window
# or just the client area. 
#result = windll.user32.PrintWindow(hwnd, saveDC.GetSafeHdc(), 1)
result = windll.user32.PrintWindow(hwnd, saveDC.GetSafeHdc(), 0)
print result

bmpinfo = saveBitMap.GetInfo()
bmpstr = saveBitMap.GetBitmapBits(True)

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)

if result == 1:
    #PrintWindow Succeeded
    im.save("test.png")