I want to use photo picker view in customized form, such as showing a rectangle in screen to focus on specified area of the picture. However, UIImagePickerController can only offer a normal photo picker view. Is there any other class I can use to replace UIImagePickerController, or should I create a sub class of UIImagePickerController?
You can use ALAsset Library for designing your own ImagePicker. With the help of ALAsset library you can able to extract the photos and videos from the iOS album and use it in your own design.
A good example to start with this is ELCImagePickerController
来源：https://stackoverflow.com/questions/15515407/customized-photo-picker-view