How to render to an QOffscreenSurface?

[likewise]

I would like to render to an QOffscreenSurface, i.e. not rendering for a display but for an image file with much larger resolution. What needs to be changed to do so?

[QUItCoding]

You can render with QNanoPainter into offscreen FBO using QOpenGLFramebufferObject and then use QNanoImage::fromFrameBuffer() to get paintable image from FBO handle. Gallery qnanopainter_features contains example of this, see commit d5ab8f3

If something else is needed regarding this please explain or preferably even provide a patch =)

[daljit97]

@QUItCoding is it possible to still antialiasing with QOpenGLFrameBufferObject? Currently QNanoImage::fromFrameBuffer() requires that the buffer object is without multisampling. I have tried to call QOpenGLFramebufferObject::blitFramebuffer without success.

[QUItCoding]

I think you can't use multisampled QOpenGLFrameBufferObject for texture images. But you can paint antialiased paths also into FBOs using QNanoPainter setAntialias(float).