What is a frame and bounds of a UIView in swift?

By | February 1, 2024

In iOS development using UIKit, a UIView is a fundamental building block for constructing the user interface. Two important properties of a UIView are its frame and bounds. These properties define the size and location of the view within its superview.


  • The frame of a UIView represents its position and size in the coordinate system of its superview. It is specified using the CGRect structure, which includes the origin (x, y) and size (width, height).
  • Example:
let myView = UIView()
myView.frame = CGRect(x: 50, y: 50, width: 200, height: 100)

In this example, myView is positioned at (50, 50) within its superview, and it has a width of 200 and a height of 100.


  • The bounds of a UIView represents its internal coordinate system. It specifies the size of the view in its own coordinate space but does not include information about the view’s position within its superview.
  • Example:
let myView = UIView()
myView.bounds = CGRect(x: 0, y: 0, width: 200, height: 100)

In this example, myView has a bounds size of 200 by 100 within its internal coordinate system.

In summary:

  • The frame is expressed in the superview’s coordinate system and includes both position and size.
  • The bounds is expressed in the view’s own coordinate system and only includes size.

It’s important to note that changes to the frame property will affect both the position and size of the view, while changes to the bounds property will only affect the size. Additionally, changes to the frame will trigger layout and potentially affect the positions of subviews, whereas changes to the bounds typically do not impact layout. Understanding and appropriately using frame and bounds is crucial for creating responsive and correctly positioned user interfaces in iOS development.

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