OpenCV on wheels

Work in progress!

The aim of this repository is to provide means to package each new OpenCV release for the most used Python versions and platforms.

At the same time it allows anyone to build a custom version of OpenCV for any Python version: just fork this repo and modify the appveyor.yml (I'll add Travis later for OS X and Linux) to fit your needs.

Why?

1. Installation of OpenCV for Python is pretty hideous:
   1. Download OpenCV
   2. Find cv2.pyd from the package
      • If it exists, copy it to the root of Python site-packages
      • If it does not exist for some reason for your setup, you have to setup the build environment and compile it manually
   3. Try to import cv2 and hope it works
2. Everyone should be able to install OpenCV (or any package for that matter) with pip with a single command without building anything
3. Python wheels are nice, we should use them more

Documentation

The project is structured like a normal Python package with a standard setup.py file. The build process is as follows (see appveyor.yml):

1. Checkout OpenCV (to do: pull only latest tag)
2. Upgrade pip and install numpy for each Python version
3. Build OpenCV
   • tests are disabled, otherwise build time increases too much
   • build runs twice, once for 32bit and once for 64bit
     • both of these builds produce two .pyd files, one for py2 and one for py3
4. Copy each .pyd file one by one to cv2 folder of this project and generate wheel
5. Install the generated wheels for each Python version
6. Tests that the Python versions can import them
7. To do: upload the wheels to GitHub releases and PyPi

Currently the setup.py file parses OpenCV version information from the OpenCV sources. OpenCV depends on numpy, so setup.py checks the numpy version also with the help of pip.

As described earlier, the .pyd file is normally copied to site-packages. I don't want to pollute the root folder, so the __init__.py file in cv2 folder handles the import logic correctly by importing the actual .pyd module and replacing the imported cv2 package in sys.modudes with the .pyd module.