error: (-2:Unspecified error) The function is not implemented. Rebuild the library with Windows, GTK

error: (-2:Unspecified error) The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script in function ‘cvShowImage’

windows,之前用的好好的突然一直在cv.imshow报错，尝试折腾windows的GDI无果，最后发现是因为用的opencv-python-headless所以导致的无法调用imshow。

至于为什么会犯这么低级的错，全是因为fiftyone这个处理数据集的软件，他在安装的时候，哪怕你安装了opencv-python，他也会再装一遍opencv-python-headless，然后import的时候就有可能import到headless版本的opencv，进而引发这个error。解决方法是fiftyone，opencv-python，opencv-python-headless挨个uninstall，然后先装fiftyone(他会默认顺带装opencv的headless版本)，再装opencv-python，这样fiftyone也能用，imshow也正常。

为防以后万一更新了之类的再遇到，mark一下