How do I make a hollow effect with objective-c?

I found some nice tutorial for drawing from Ray Wenderlich Core Graphics Tutorial. It shows the way "how to draw". An alternative is often the use of an image.

When drawing, than the output is done from background to top. So you would first draw the rectangle and draw the circle over the rectangle. Layering is only needed In cases of high perfomance I would recommend OpenGL. I wrote a article aboutOpenGL and a follow up for Metal.