PHImageContentMode
Options for fitting an image’s aspect ratio to a requested size, used by the Requestimage(for:targetsize:contentmode:options:resulthandler:) method.
Declaration
enum PHImageContentModeOverview
With either option, the resulting image may not exactly match the target size, depending on the deliveryMode and resizeMode properties of the image request. To serve your request more quickly, Photos may provide a slightly larger image—one that it can generate more easily or one that is already cached.