The font sizing option preferred by the user.
- iOS 7.0+
- tvOS 9.0+
Users can request that apps display fonts in a size that is larger or smaller than the normal font size defined by the system. For example, a user with a visual impairment might request a larger default font size to make it easier to read text. Font objects returned by the system automatically scale based on the user’s preference. You can use the value of this property to request a font object of the appropriate size.
When the value of this property changes, the app object sends a
UIContent notification so that observers can respond accordingly.
For a list of possible values, see Content Size Category Constants and Accessibility Content Size Category Constants.