python3 按任意键退出 python按esc键退出程序

文章目录

• python代码
• 代码解读
• 接口回顾

python代码

While:
    k = cv2.waitKey()
    if k==27:    # Esc key to stop
        break

代码解读

选中OpenCV已弹出的窗口，按下Esc，循环结束。

接口回顾

Waits for a pressed key.
C++: int waitKey(int delay=0)
Python: cv2.waitKey([delay]) → retval
C: int cvWaitKey(int delay=0 )
Python: cv.WaitKey(delay=0) → int
Parameters: delay – Delay in milliseconds. 0 is the special value that means “forever”.
The function waitKey waits for a key event infinitely (when \texttt{delay}\leq 0 ) or for delay milliseconds, when it is positive. Since the OS has a minimum time between switching threads, the function will not wait exactly delay ms, it will wait at least delay ms, depending on what else is running on your computer at that time. It returns the code of the pressed key or -1 if no key was pressed before the specified time had elapsed.
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