Can you explain the principle of a frame-based layout system?

In iOS, the layout system using frames is based on defining the position and size of interface elements through rectangular areas — frames (CGRect). Each UIView has its own frame, which specifies the coordinates (x, y) and dimensions (width, height) relative to its parent view.

Working principle:

• When creating or modifying the interface, the developer explicitly sets the frame for each element.
• The frame determines where and what size the element will be displayed.
• When the screen size or orientation changes, the frames need to be manually recalculated and updated so that elements are correctly positioned.

Example in Swift:

let button = UIButton()
button.frame = CGRect(x: 20, y: 50, width: 100, height: 40)
view.addSubview(button)

Thus, the frame-based layout system is a direct control of positioning and sizing of elements through coordinates and dimensions, without automatic adaptive behavior.