iAds versus widgets

In iAd Producer, the amount of functionality for an iAd versus a widget is pretty extreme. I wanted to know if the iAd features are simply not possible for widgets (for example, accessing the iPad's camera to take photos) or they are possible, but you need to program these features. It seems like widgets are meant to be very simple, but I can't find what's possible and what's not. For example, the Bookry widgets appear to have more functionality (send pictures by email, take photos).

I'm trying to use iAd Producer to create a drawing widget, and have no idea how to code a drawing App in Xcode - but am concerned that using widgets is limiting what I can do.