189 8069 5689
小编给大家分享一下python下cv.waitKey无响应的原因是什么，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
按下键的时候，焦点要落在窗口上，不能落在cmd窗口上。
另外，一般在imshow()后要使用waitKey()，给图像绘制留下时间，不然窗口会出现无响应情况，并且图像无法显示出来。
int waitKey(int delay=0)
- 延时delay = 0 函数则延时无限长，必须有键按下才继续执行。
- 延时delay > 0 函数返回值为按下的键的ASCII码值，超时则返回-1。
OpenCV: waitKey
waitKey
Waits for a pressed key.
C++: int waitKey(int delay=0)
Python: cv2.waitKey([delay]) → retval
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.
Note
This function is the only method in HighGUI that can fetch and handle events, so it needs to be called periodically for normal event processing unless HighGUI is used within an environment that takes care of event processing.
Note
The function only works if there is at least one HighGUI window created and the window is active. If there are several HighGUI windows, any of them can be active.也就是说必须在有窗口显示的情况下，waitKey才有作用，否则无效。
比如调用cv.waitKey(0)，如果此时没有活动的窗口，该函数立刻返回-1
以上是“python下cv.waitKey无响应的原因是什么”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注创新互联成都网站设计公司行业资讯频道！
另外有需要云服务器可以了解下创新互联scvps.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。