In project 10 you learned how to use
UIImagePickerController to select and import a picture from your user's photo library. In this project, we're going to add the reverse: writing images back to the photo library. But because you're here to learn as much as possible, I'm also going to introduce you to another UIKit component,
UISlider, and also a little bit of Core Image, which is Apple's high-speed image manipulation toolkit.
The project we're going to make will let users choose a picture from their photos, then manipulate it with a series of Core Image filters. Once they are happy, they can save the processed image back to their photo library.
To get started, create a new Single View App project in Xcode and name it Project13.
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