"Can you show me an application that illustrates zooming in on vector imagery in OS X that does use Quartz then? I'd like to be able to see a proper side by side comparison. What about Omni Graffle? Is that using Quartz 2D? That only seems to manage about 4 redraws a second if I hammer on the mouse button using the zoom tool. It's not keeping up with the mouse clicks for a relatively simple drawing. (The terrible horse drawing I posted earlier.) This suggests that it isn't going to be good enough for a smooth (as in full field rate video playback smooth) zooming."
Take a look at my Mac OS X port of Graphviz: http://www.pixelglow.com/graphviz/, a released and production-used app. In particular it uses pure PDF (via Quartz 2D) to draw the graphs, and specifically disables cached bitmaps. As a result rendering is smooth and fast enough to work with a dynamic, live zoom (a slider control).
Try opening graphs with a lot of nodes e.g. awilliams.dot. You can fiddle around with the default colors to get alpha transparency happening and in 10.3 a drop shadow delineates the graph boundary, all within the Quartz 2D/Cocoa API.
The graph PDF is a retained vector representation, of course. As you can see, the Quartz 2D pipeline is pretty good for high performance work!
My main irritation with Quartz PDF is that it's hard to do selective edits of a PDF, since the Quartz model is more a "lay down paint" model like PostScript rather than a full object model.
Glen Low, Pixelglow Software