The insets from the view’s frame that define its alignment rectangle.
- iOS 6.0+
- tvOS 9.0+
The default value of this property is an
Edge structure with zero values. Custom views that draw ornamentation around their content should use this property to return insets that align with the edges of the content, excluding the ornamentation. This allows the constraint-based layout system to align views based on their content, rather than just their frame.
Custom views whose content location can’t be expressed by a simple set of insets should override
frame(for to describe their custom transform between alignment rectangle and frame.