Q. Why don’t many iPhone applications implement the upside-down portrait mode?
A. Although there is no problem implementing the upside-down portrait orientation using the approaches described in this hour, it isn’t recommended. When the iPhone is upside-down, the Home button and sensors are not in the “normal” location. If a call comes in or the user needs to interact with the phone’s controls, the user will need to rotate the phone 180 degrees—a somewhat complicated action to perform with one hand.
Q. How do I get the controls in application XYZ to behave using Auto Layout?
A. This is a difficult question with no clear answer because there may be dozens of ways of implementing constraints that have the desired effect. I have implemented Auto Layout constraints for 3.5” and 4” iPhone displays in all my sample projects. You may want to take a look at those to get an idea of how I solved resizing problems (landscape, however, is up to you!).