如何使用Python的PIL在特定区域的屏幕上寻找特定像素的颜色？

Question

How can I look for a certain pixel colour on my screen, in a specific area using Python's PIL?

I need a function that will initiate a command in Python 2.7, if a certain pixel colour appears in a pre-designated area. I have tried the following code, with no avail:

def game_one():
box = (x_pad+1, y_pad+1, x_pad+1179, y_pad+474)
im = ImageGrab.grab(box)
return im
rgb_im = im.convert('RGB')
for x in range(1055, 1120, 1):
    for y in range(20, 464, 1):
        pix = rgb_im.getpixel((x, y))
        if pix != (255,0,255):
            startPlaying()
            time.sleep(.2)
            clickbuttonone()
            print "Pixel Found!"
        else:
            print "Waiting for pixel to appear"

(The x_pad and y_pad are predefined screen variables - do not relate to the problem, but help to capture the whole screen)

ImageOps and Image are already imported, as is win32api and win32con.

Many thanks!

Answer 1

To search until the pixel is found, you can use a loop. However, by nature it will be an infinite loop, which is bad practice. I'm adding a timeout of 120 seconds (2 minutes) which you can adjust as is reasonable.

import time
pf = False   #check if pixel was found
start_time = time.time()

def game_one():
    box = (x_pad+1, y_pad+1, x_pad+1179, y_pad+474)
    im = ImageGrab.grab(box)
    # return im
    rgb_im = im.convert('RGB')
    while (pf == False) and ((time.time()-start_time) < 120):
        for x in range(1055, 1120, 1):
            if pf == True:
                break
            for y in range(20, 464, 1):
                pix = rgb_im.getpixel((x, y))
                if pix != (255,0,255):
                    startPlaying()
                    time.sleep(.2)
                    clickbuttonone()
                    print "Pixel Found!"
                    pf = True
                    break
                else:
                    print "Waiting for pixel to appear"

Also, make sure you check your indentation--it's probably just for posting on this site but the function definition should not be on the same line as the rest of the function.

EDIT: Okay I think I found the major issue. Do you see where I commented out return im ? A return statement ends your function and nothing after it will be processed. Your code wasn't even getting to your for loops. Try this. That's why it was printing that weird type thing, because that's what you were returning!