[TIL][Python] OpenCV with Python2/Python3, dlib for python3

These instructions assume you are on macOS, but basically the same on Linux.

Pre-reqs:

• Have Python 3 installed. On macOS, this could be installed from homebrew or even via standard Python 3.6 downloaded installer from https://www.python.org/download. On Linux, just use your package manager.
• On macOS:
  • Install XCode from the Mac App Store (or install the XCode command line utils).
  • Have homebrew installed
  • Install boost with this command: brew install boost-python --with-python3 --without-python
• On Linux:
  • Install boost. On Ubuntu, that's sudo apt-get install libboost-all-dev
• This assumes you don't have an nVidia GPU and don't have Cuda and cuDNN installed and don't want GPU acceleration (since none of the current Mac models support this).

Clone the code from github:

git clone https://github.com/davisking/dlib.git

Build the main dlib library:

cd dlib
mkdir build; cd build; cmake .. -DDLIB_USE_CUDA=0 -DUSE_AVX_INSTRUCTIONS=1; cmake --build .

Build and install the Python extensions:

cd ..
python3 setup.py install --yes USE_AVX_INSTRUCTIONS --no DLIB_USE_CUDA

At this point, you should be able to run python3 and type import dlib successfully.