A linux based learning tutorial and notes, install step by step. If want to use docker file, proceed to end of this document.

1. Install gcc

   # show whether gcc is installed
   gcc -v
   
   # (if not) install gcc in ubuntu
   sudo apt-get update
   
   # install the GNU compiler tools and the GDB debugger with this command
   sudo apt-get install build-essential gdb

2. Test C++ with a project follow Visual Studio Code Example

• create CMakeLists.txt file
• add cmake_minimum_required(), project(), add_executable()
• run

  mkdir build
  cd build
  cmake ..
  make
  # then run the exe by call
  ./your-exectue-file

Refer to ¹ and ².

libgtk2.0-dev and pkg-config are required for OpenCV to show image in linux

1. Install libgtk2.0-dev and pkg-config using sudo apt install libgtk2.0-dev pkg-config

2. Install and build OpenCV

   # Install minimal prerequisites (Ubuntu 18.04 as reference)
   sudo apt update && sudo apt install -y cmake make g++ wget unzip
   # Download and unpack sources
   wget -O opencv.zip https://github.com/opencv/opencv/archive/4.x.zip
   unzip opencv.zip
   # Create build directory
   mkdir -p build && cd build
   # Configure
   cmake  ../opencv-4.x
   # Build
   make -j4
   # Install the OpenCV package
   sudo make install

3. Add "/usr/local/include/opencv4" to Visual Studio Code C++ Extension Settings

   • Go to VS code press CTRL+SHIFT+P search for c/c++ edit configuration.
   • Inside c_cpp_properties.json file under include path add the path "/usr/local/include/opencv4"

using Qt Creator as IDE, since VS code requires too much memory

What I read:

• A website to learn CMake : very basic, or list of things you should know but need to read more to comprehend
• CMake book: Professional CMake: a Practical Guide

The CMake usage and simple tutorial is in folder 3qtCreatorTest, which explains:

• How should the project structure be like?
• How to set CMake for this project?
• How to include files in main.cpp?

4CMakeAndTestCPP demonstrates a simple C++ project managed by CMake with test cpp files in a test folder.

• Test Cpp and head files in test/test.cpp
  • Find the answer in modern-cmake

1. General / Startup
   • https://pabloariasal.github.io/2018/02/19/its-time-to-do-cmake-right/
   • https://www.youtube.com/watch?v=rLopVhns4Zs
   • Cmake example
   • https://stackoverflow.com/questions/26243169/cmake-target-include-directories-meaning-of-scope
   • Cmake offical tutorial
2. CMake & C++ Project / Library Explan
   • https://matgomes.com/add-library-cmake-create-libraries/
   • https://kubasejdak.com/modern-cmake-is-like-inheritance
   • https://crascit.com/professional-cmake/

• Create a Dockerfile: Create a new directory for your project, and inside that directory, create a Dockerfile with the following content, which sets up a Docker image based on Ubuntu 20.04, installs the required packages, and builds OpenCV from source.

  # Use the official Ubuntu image as the base
  FROM ubuntu:20.04
  
  # Set environment variables to avoid interactive prompts during package installation
  ENV DEBIAN_FRONTEND=noninteractive
  
  # Update the package index and install required packages
  RUN apt-get update && apt-get install -y \
      build-essential \
      cmake \
      git \
      libgtk2.0-dev \
      pkg-config \
      libavcodec-dev \
      libavformat-dev \
      libswscale-dev \
      python3-dev \
      python3-numpy \
      libtbb2 \
      libtbb-dev \
      libjpeg-dev \
      libpng-dev \
      libtiff-dev \
      libdc1394-22-dev
  
  # Download and build OpenCV
  RUN cd ~ && \
      git clone https://github.com/opencv/opencv.git && \
      git clone https://github.com/opencv/opencv_contrib.git && \
      cd opencv && \
      mkdir build && \
      cd build && \
      cmake -D CMAKE_BUILD_TYPE=Release \
          -D CMAKE_INSTALL_PREFIX=/usr/local \
          -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules \
          .. && \
      make -j$(nproc) && \
      make install && \
      ldconfig
  
  # Set the default command to run a Bash shell
  CMD ["bash"]

• Build the Docker image: In the terminal, navigate to the directory containing the Dockerfile and build the Docker image using the following command: docker build -t ubuntu-20-opencv .
• Run the Docker container: Run the Docker container using the following command: docker run -it --rm ubuntu-20-opencv
• Mount local directory to docker container: docker run -it --name c11 -v /Users/kexinwei/GitRepos/ImageProcessingOpenCV/:/gitrepo vac611/ubuntu-20-opencv
• Add opencv python linkage (rebuild opencv) and update image: the default python package path is somehow wrong and we need to modify it by using PYTHON3_PACKAGES_PATH=/usr/lib/python3.8/dist-packages in this post