QGraphicsScene: OpenGL with fallback

Question

I am writing an application that must display images, and potentially loads of them. So I was wondering if there is a proper way of having a QGraphicsScene use OpenGL, and in case it fails, use a software renderer.

I've read the documentation, but what if setting the viewport fails?

Answer 1

You're talking about more than a gigabyte of textures. OpenGL by itself is of no help here, neither is a raw QGraphicsScene. You'll need to dynamically cache the images, ideally with prediction based on scrolling direction and speed. You'll need a coupling layer between each view and the scene, to keep the scene populated with images that are visible or will be soon visible in each view. Once you do that, OpenGL may help but you absolutely need to profile things and prove to yourself that it helps. Even without OpenGL you can have very decent performance.