QOpenGL exclusively for off-screen drawing...
I want to do some image processing using OpenGL shader language programming. So I'm creating a QGLWidget. Does anyone know how can I get the widget to execute its initialize, resize, or update functions without actually showing the widget on-screen?
You don't need QGLWidget and friends. Just use QOpenGLContext, QOffscreenSurface and QOpenGLFramebufferObject. All your rendering should target the framebuffer object, without anything going to an actual window.