Some PCIe GPU fans spin uncontrollably on macOS computers, and it is very annoying to hear these fans’ buzzing. My computer is built with a Radeon RX 570 and sometimes has the above fan issue, especially after booting.
I searched the internet and found a tricky solution (source) that to install a benchmark software called LuxMark. After opening this software and running for a few seconds, the graphics card fan will magically return to the normal speed.
In macOS, windows created by Tkinter do not automatically get focus. This is annoying when using PyCharm. If you do not take any actions, the created window will be hidden behind PyCharm. An alternative is to set the window to the top and then cancel it (code show as below). This will make the window visible after creation.
This tutorial provides step-by-step instructions to compile OpenCV 4 with Qt 5 for Python 3 and C++ on macOS High Sierra 10.13. For the latest macOS version, I think you can install OpenCV from Homebrew directly. I wrote this tutorial on Dec. 2020 and the High Sierra is a previous macOS system and installing OpenCV directly from Homebrew will fail so I have to compile it manually.