I use the following code to capture a window screen in python:
def get_screenshot(self):
# get the window image data
wDC = win32gui.GetWindowDC(self.hwnd)
dcObj = win32ui.CreateDCFromHandle(wDC)
cDC = dcObj.CreateCompatibleDC()
dataBitMap = win32ui.CreateBitmap()
dataBitMap.CreateCompatibleBitmap(dcObj, self.w, self.h)
cDC.SelectObject(dataBitMap)
cDC.BitBlt((0, 0), (self.w, self.h), dcObj, (self.cropped_x, self.cropped_y), win32con.SRCCOPY)
# convert the raw data into a format opencv can read
#dataBitMap.SaveBitmapFile(cDC, 'debug.bmp')
signedIntsArray = dataBitMap.GetBitmapBits(True)
img = np.fromstring(signedIntsArray, dtype='uint8')
img.shape = (self.h, self.w, 4)
# free resources
dcObj.DeleteDC()
cDC.DeleteDC()
win32gui.ReleaseDC(self.hwnd, wDC)
win32gui.DeleteObject(dataBitMap.GetHandle())
# drop the alpha channel, or cv.matchTemplate() will throw an error like:
# error: (-215:Assertion failed) (depth == CV_8U || depth == CV_32F) && type == _templ.type()
# && _img.dims() <= 2 in function 'cv::matchTemplate'
img = img[...,:3]
# make image C_CONTIGUOUS to avoid errors that look like:
# File ... in draw_rectangles
# TypeError: an integer is required (got type tuple)
# see the discussion here:
# https://github.com/opencv/opencv/issues/14866#issuecomment-580207109
img = np.ascontiguousarray(img)
return img
I took the code from some YouTube tutorials and the code works perfectly.
However, I'm trying to convert that image into grayscale so I could later use it for Homography without any success.
I tried to use things like cv.cvtColor but nothing worked.
Is there any way to make it grayscale right on the capture?
Thank you
Use the Pillow package img.convert() function to convert to graystyle
from PIL import Image
img = Image.open('download.png')
imgGray = img.convert('L')
imgGray.save('test_gray.png')
Related
im trying to get a screenshot of a window as fast and then inference on yolov5
it works but sometimes it doesnt detect very well compared to using detect.py on the same image. i think its probably because of img shape or array but i dont know where or how to edit those to make it work. can anyone help me with this please?
import torch
import numpy as np
import win32gui
import win32ui
import win32con
w = 800 # set this
h = 600 # set this
bmpfilenamename = "color.bmp" #set this
windowname = 'put windowname'
def screenshot():
hwnd = win32gui.FindWindow(None, windowname)
wDC = win32gui.GetWindowDC(hwnd)
dcObj=win32ui.CreateDCFromHandle(wDC)
cDC=dcObj.CreateCompatibleDC()
dataBitMap = win32ui.CreateBitmap()
dataBitMap.CreateCompatibleBitmap(dcObj, w, h)
cDC.SelectObject(dataBitMap)
cDC.BitBlt((0,0),(w, h) , dcObj, (0,0), win32con.SRCCOPY)
#save the screenshot
#dataBitMap.SaveBitmapFile(cDC, bmpfilenamename)
signedIntsArray = dataBitMap.GetBitmapBits(True)
img = np.frombuffer(signedIntsArray, dtype='uint8')
img.shape = (h,w,4)
# Free Resources
dcObj.DeleteDC()
cDC.DeleteDC()
win32gui.ReleaseDC(hwnd, wDC)
win32gui.DeleteObject(dataBitMap.GetHandle())
#img = img[..., ::-1]
#img = np.ascontiguousarray(img)
return img
#load
model = torch.hub.load('./', 'custom', path='yolov5s.pt', source='local')
#inference
test = screenshot()
results = model(test)
boxes = results.pandas().xyxy[0]
print (boxes)
edit : i figured you can do it by changing the code from this
results = model(test)
to this
results = model(cv.cvtColor(test, cv.COLOR_BGR2RGB))
but isnt this code supposed to do the same? for some reason this one wont work
img[: ,: ,::-1]
I would like to screenshot window in the background (not focused) without saving it as a file so it would be only as a variable. I have code that can screenshot the window but it will save it as .bmp. I can open it with pillow than but it would be better if it was saved in a variable instead of a file.
This is the code I use for the screenshot. I than open it with Image.open("imagename")
def background_screenshot(hwnd, width, height):
wDC = win32gui.GetWindowDC(hwnd)
dcObj=win32ui.CreateDCFromHandle(wDC)
cDC=dcObj.CreateCompatibleDC()
dataBitMap = win32ui.CreateBitmap()
dataBitMap.CreateCompatibleBitmap(dcObj, width, height)
cDC.SelectObject(dataBitMap)
cDC.BitBlt((0,0), (width, height), dcObj, (0,0), win32con.SRCCOPY)
dataBitMap.SaveBitmapFile(cDC, "images\\screenshot.bmp")
dcObj.DeleteDC()
cDC.DeleteDC()
win32gui.ReleaseDC(hwnd, wDC)
win32gui.DeleteObject(dataBitMap.GetHandle())
You can try this, and replace the 'take screenshot' function with your.
import mss import mss.tools
with mss.mss() as sct: # Use the 1st monitor
monitor = sct.monitors[1]
# Grab the picture
im = sct.grab(monitor)
# From now, you have access to different attributes like `rgb`
# See https://python-mss.readthedocs.io/api.html
# mss.tools.ScreenShot.rgb
# `im.rgb` contains bytes of the screen shot in RGB _but_ you will have to
# build the complete image because it does not set needed headers/structures
# for PNG, JPEG or any picture format.
# You can find the `to_png()` function that does this work for you,
# you can create your own, just take inspiration here:
# https://github.com/BoboTiG/python-mss/blob/master/mss/tools.py#L11
# If you would use that function, it is dead simple:
# args are (raw_data: bytes, (width, height): tuple, output: str)
Raw_bytes = mss.tools.to_png(im.rgb, im)
Or you can save the file and write a function that automatically deltes it after use.
os.remove(filepath)
I'm trying to do an exercise of an application windows capture using pywin32, so that I get the exact mirror image of the window(like a video game) The issue is - the below code keep capturing/ keep returning only the first frame/old frame of the window and not the current frame of the window. So there is no change reflecting in the mirror image. I tried changing the pywin32 different version but same problem. Please help is there any issue with the lines of code
Python Version== 3.8.10
pywin32 == 227
Windows 10
import cv2 as cv
import numpy as np
from time import time
import win32gui, win32ui, win32con
def get_screenshot(win_name):
hwnd = win32gui.FindWindow(None, win_name)
print('hwnd',hwnd)
window_rect = win32gui.GetWindowRect(hwnd)
print('window_rec',window_rect)
w = window_rect[2] - window_rect[0]
h = window_rect[3] - window_rect[1]
wDC = win32gui.GetWindowDC(hwnd)
print('wDC',wDC)
dcObj = win32ui.CreateDCFromHandle(wDC)
print('dcObj',dcObj)
cDC = dcObj.CreateCompatibleDC()
print('cDC',cDC)
dataBitMap = win32ui.CreateBitmap()
print('dataBitMap',dataBitMap)
dataBitMap.CreateCompatibleBitmap(dcObj, w, h)
cDC.SelectObject(dataBitMap)
cDC.BitBlt((0, 0), (w, h), dcObj, (0,0), win32con.SRCCOPY)
signedIntsArray = dataBitMap.GetBitmapBits(True)
img = np.fromstring(signedIntsArray, dtype='uint8')
img.shape = (h, w, 4)
dcObj.DeleteDC()
cDC.DeleteDC()
win32gui.ReleaseDC(hwnd, wDC)
win32gui.DeleteObject(dataBitMap.GetHandle())
img = img[...,:3]
return img
loop_time = time()
while(True):
# get an updated image of the window
frame = get_screenshot("<<Window Name>>")
cv.imshow('Computer Vision', frame)
# debug the loop rate
#print('FPS {}'.format(1 / (time() - loop_time)))
loop_time = time()
# press 'q' with the output window focused to exit.
# waits 1 ms every loop to process key presses
if cv.waitKey(1) == ord('q'):
cv.destroyAllWindows()
break
I had the same issue, following the same online tutorial. He covers this issue in the 5th video. see here: https://www.youtube.com/watch?v=7k4j-uL8WSQ&list=PL1m2M8LQlzfKtkKq2lK5xko4X-8EZzFPI&index=5
Instead of:
hwnd = win32gui.FindWindow()
use:
hwnd = win32gui.GetDesktopWindow()
Which unfortunately has the side effect of capturing the whole desktop window, but functions great still.
Answered Edit: Dima solved my issue, I was unnecessarily calling cv2.decode for data that could be passed directly to OpenCV.
First, I'm pretty new to Python and OpenCV so apologies if I'm missing something obvious, which I'm almost certain I am. I'm trying to use Python to grab a screenshot from a specific window then pass that to OpenCV. If I write the screenshot out to disk then read it back, everything is fine, but as I want to be analyzing multiple screenshots per second, waiting on disk IO seems silly. Unfortunately I've spent about 4 hours trying everything I came up with searching around and nothing has solved the problem. Here is my code:
from PIL import ImageGrab
from PIL import Image
import win32gui
import win32ui
from ctypes import windll
import os
import time
import cv2
import numpy as np
from matplotlib import pyplot
def enumHandler(hwnd, lParam):
if win32gui.IsWindowVisible(hwnd):
if 'Sword' in win32gui.GetWindowText(hwnd):
lParam.append(hwnd)
def screenGrab(rect):
im = ImageGrab.grab(rect)
im.save(os.getcwd() + '\\game__' + str(int(time.time())) +
'.png', 'PNG')
def main():
hwnds = []
win32gui.EnumWindows(enumHandler, hwnds)
rect = win32gui.GetWindowRect(hwnds[0])
w = rect[2] - rect[0]
h = rect[3] - rect[1]
hwndDC = win32gui.GetWindowDC(hwnds[0])
mfcDC = win32ui.CreateDCFromHandle(hwndDC)
saveDC = mfcDC.CreateCompatibleDC()
saveBitMap = win32ui.CreateBitmap()
saveBitMap.CreateCompatibleBitmap(mfcDC, w, h)
saveDC.SelectObject(saveBitMap)
result = windll.user32.PrintWindow(hwnds[0], saveDC.GetSafeHdc(), 0)
bmpinfo = saveBitMap.GetInfo()
bmpstr = saveBitMap.GetBitmapBits(True)
im = Image.frombuffer('RGB', (bmpinfo['bmWidth'], bmpinfo['bmHeight']), bmpstr, 'raw', 'BGRX', 0, 1)
im.save('thistest.png')
img = cv2.imread('thistest.png', cv2.IMREAD_UNCHANGED)
if img is not None:
print(img.shape)
print(type(img))
cv2.imshow('FRAME', img)
cv2.waitKey()
im2 = np.frombuffer(bmpstr, dtype='uint8')
im2.shape = (bmpinfo['bmHeight'], bmpinfo['bmWidth'], 4)
img2 = cv2.imdecode(im2, cv2.IMREAD_GRAYSCALE)
if img2 is not None:
print(img2.shape)
print(type(img2))
cv2.imshow('FRAME', img2)
cv2.waitKey()
win32gui.DeleteObject(saveBitMap.GetHandle())
saveDC.DeleteDC()
mfcDC.DeleteDC()
win32gui.ReleaseDC(hwnds[0], hwndDC)
if __name__ == '__main__':
main()
The only piece that sticks out to me is that if I print out the size/shape of bmpstr, it shows something like 1000,1600,3. However, after using numpy.frombuffer I'm unable to reshape to 1000,1600,3 and instead have to use 4 as it will complain about the size. When looking at the len of bmpstr it would show ~6400000 so the math makes sense that you need "4" dimensions, but bmpstr shows the same size with 3. I figured this meant somehow bmpstr was counting from 0, fine, but why can't I do the same with numpy.shape/reshape?
Anyway that's my only guess as to what's going wrong and could be entirely off base. Any help is appreciated.
Edit: I believe Dima is on the right track pointing out I need to convert from RGB to BGR. Unfortunately I tried more than a few methods but still cannot make this work. Here is my current code. If I uncomment im.save, the image is written successfully.
from PIL import Image
import win32gui
import win32ui
from ctypes import windll
import os
import time
import cv2
import numpy as np
from matplotlib import pyplot
def enumHandler(hwnd, lParam):
if win32gui.IsWindowVisible(hwnd):
if 'Sword' in win32gui.GetWindowText(hwnd):
lParam.append(hwnd)
def main():
hwnds = []
win32gui.EnumWindows(enumHandler, hwnds)
rect = win32gui.GetWindowRect(hwnds[0])
w = rect[2] - rect[0]
h = rect[3] - rect[1]
hwndDC = win32gui.GetWindowDC(hwnds[0])
mfcDC = win32ui.CreateDCFromHandle(hwndDC)
saveDC = mfcDC.CreateCompatibleDC()
saveBitMap = win32ui.CreateBitmap()
saveBitMap.CreateCompatibleBitmap(mfcDC, w, h)
saveDC.SelectObject(saveBitMap)
result = windll.user32.PrintWindow(hwnds[0], saveDC.GetSafeHdc(), 0)
if (result):
bmpinfo = saveBitMap.GetInfo()
bmpstr = saveBitMap.GetBitmapBits(True)
im = Image.frombuffer('RGB', (bmpinfo['bmWidth'], bmpinfo['bmHeight']), bmpstr, 'raw', 'BGRX', 0, 1)
#im.save('thistest.png')
im2 = np.array(im)
#im2 = im2[..., :2]
im2 = im2[:, :, ::-1].copy()
img2 = cv2.imdecode(im2, cv2.IMREAD_UNCHANGED)
if img2 is not None:
cv2.imshow('FRAME', img2)
cv2.waitKey()
else:
print('img2 was empty')
win32gui.DeleteObject(saveBitMap.GetHandle())
saveDC.DeleteDC()
mfcDC.DeleteDC()
win32gui.ReleaseDC(hwnds[0], hwndDC)
if __name__ == '__main__':
main()
As soon as you have im, which is of type PIL.Image, you can instantly convert it to numpy and thus OpenCV like this
img = np.array(im)
# In case it is needed to get rid of alpha channel, if it is present
img = img[..., :2]
# To convert RGB to BGR
img = img[:, :, ::-1].copy()
cv2.imshow('FRAME', img)
cv2.waitKey()
In general, using PIL to decode images and then OpenCV to process them is a common practice.
So I originally asked a question here about taking faster screen captures using win api as compared to PIL. I was able to succesfully capture the screen via BitBlt.
Now I am unsure how to convert the bitmap into a form that can be used with OpenCV. OpenCV doesn't have any support for bitmaps, and when I print(im) it is a ~14k long 1D array. OpenCV can't do anything with 1D, and I have tried to reshape it with NUMPY with no success.
def take_screenshot1(hwnd):
wDC = win32gui.GetWindowDC(hwnd)
dcObj=win32ui.CreateDCFromHandle(wDC)
cDC=dcObj.CreateCompatibleDC()
dataBitMap = win32ui.CreateBitmap()
dataBitMap.CreateCompatibleBitmap(dcObj, 765, 503)
cDC.SelectObject(dataBitMap)
cDC.BitBlt((0, 0), (765, 503), dcObj, (0, 0), win32con.SRCCOPY)
im = dataBitMap.GetBitmapBits(False)
#img = np.array(im)
#cv2.cvtColor(img, cv2.COLOR_RGB2BGR)
dcObj.DeleteDC()
cDC.DeleteDC()
win32gui.ReleaseDC(hwnd, wDC)
win32gui.DeleteObject(dataBitMap.GetHandle())
edit:
Here is the working code:
def take_screenshot1(hwnd):
wDC = win32gui.GetWindowDC(hwnd)
dcObj=win32ui.CreateDCFromHandle(wDC)
cDC=dcObj.CreateCompatibleDC()
dataBitMap = win32ui.CreateBitmap()
dataBitMap.CreateCompatibleBitmap(dcObj, 765, 503)
cDC.SelectObject(dataBitMap)
cDC.BitBlt((0, 0), (765, 503), dcObj, (0, 0), win32con.SRCCOPY)
im = dataBitMap.GetBitmapBits(False)
img = np.array(im).astype(dtype="uint8")
img.shape = (503,765,4)
cv2.cvtColor(img, cv2.COLOR_RGB2BGR)
dcObj.DeleteDC()
cDC.DeleteDC()
win32gui.ReleaseDC(hwnd, wDC)
win32gui.DeleteObject(dataBitMap.GetHandle())
GetBitmapBits() in its Python incarnation returns an array of signed ints instead of unsigned bytes. You should first convert it to unsigned bytes and then do as #DanMašek said.