Add magnifier lens (loupe)
As Anchor Points are positioned under your finger you can't set them precisely (especially when you have to trace a background image), a magnifier lens (a circle that enlarge the touch area) help you draw more precisely.
Something like this quick mockup:
http://d.pr/i/I865

Thanks in advance, C.
I'd like to do this. What do you think @sprang?
I'd like to see this as well. Sometimes trying to zoom, I end up moving objects around and have to undo them. I just downloaded this app and I'm exceedingly impressed. It's one of the best apps on the app store!
I'd like to see this too. iOS-MagnifierGlass or iOS-MagnifyingGlass may be used to implement it.
But a memory problem may occurs: Show magnifier content with [CALayer renderInContext:] will make the painting view and subviews to be rasterized and take up a lot of memory (> 70 MB).