Chapter 14
Viewing and Editing Photos

People use mobile devices to take pictures and share them with their friends. A lot. No good Twitter app would be complete without this functionality.

Fortunately for us, the iOS SDK offers access to the user’s photo library, meaning we can get pictures taken with the Camera application, as well as add new photos to the library. In addition, the Core Image framework gives us powerful tools to edit the contents of images, so we can improve photos long after they’ve been taken.

PhotoKit is a pair of frameworks introduced in iOS 8: Photos and Photos UI. Photos is the framework that allows us to access photos and videos from the photo library. Photos UI is a paired framework that allows us to create photo-editing app extensions (something we’ll talk about in the next chapter). This allows you to store all of your neat photo-editing effects on your photos in your photo library instead of having them trapped in the application you created them with. If you create a really cool photo in one application, you can now access it with another. This wasn’t possible before.

It is now possible to do anything from simply sharing a photo in a tweet—which is what we will be doing in this chapter—to creating a fully comprehensive photo-editing application on the level of Adobe Photoshop.

It has never been easier to customize your photos on the iPhone. We are just going to scratch the surface of all the awesome things that Apple gives you to express yourself and capture life’s moments.