No, it's returning a CGContextRef. Here my code:
CGContextRef gc = (CGContextRef) AVPageViewAcquireDrawContext(pv, kMacCGContextType);
AVDevRect r = {0, 0, 0, 0};
AVPageViewGetAperture(pv, &r);
CGContextTranslateCTM(gc, -r.left, r.bottom);
CGContextScaleCTM(gc, 1., -1.);
You then have a graphics context with the origin in the top left corner. Works for me even for iMac 27 Retina.
Hope this helps
Jo