Search for WITH_QT and WITH_OPENGL in CMake and check them. Ensure Qt5_DIR or Qt6_DIR points to your Qt installation.
Once downloaded/built, you must link the libraries in your project’s .pro (qmake) or CMakeLists.txt file. For qmake ( .pro file): download opencv for qt
Add the following lines, replacing paths with your actual installation directory: OpenCVhttps://docs.opencv.org Installation in Windows - OpenCV Documentation Search for WITH_QT and WITH_OPENGL in CMake and check them
On Ubuntu/Debian, you can often download via terminal: sudo apt install libopencv-dev . 2. Building OpenCV for Qt (MinGW / macOS) download opencv for qt