How properly calculate cornerRadius depending on the button frame

Question

How to calculate cornerRadius property based on frame of the button to create rounded corners.

I do not like to redefine each time corner cornerRadius for each button item.

I create extension for the UIButton.

extension UIButton {

    func setRoundedCorners(){
        self.layer.cornerRadius = 10
        self.layer.borderWidth = 1
    }

}

And i would like to know how too calculate dynamically cornerRadius each time i use this function.

The main issue to find function that will calculate .cornerRadius for different button sizes. Example below will show small difference.

Example:

Corner radius is 10:

:

Corner radius is 15:

Is it possible to find function that will calculate proper value that will give corner radius?

Answer 1

This extension may help you -- it computes and sets the corner radius for a given UIView instance based on its frame property:

extension UIView {
    /**
     Magically computes and sets an ideal corner radius.
     */
    public func magicallySetCornerRadius() {
        layer.cornerRadius = 0.188 * min(frame.width, frame.height)
        layer.masksToBounds = true
    }
}

Here's how I've used it in a "ViewController.swift" file for three differently sized UIButtons:

import UIKit

class ViewController: UIViewController {

    private func addButton(frame: CGRect, backgroundColor: UIColor) {
        let button = UIButton(frame: frame)
        button.backgroundColor = backgroundColor
        button.magicallySetCornerRadius()
        button.layer.borderColor = UIColor.black.cgColor
        button.layer.borderWidth = 1.0
        view.addSubview(button)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        addButton(frame: CGRect(x: 40.0, y: 100.0, width: 100.0, height: 300.0), backgroundColor: .blue)
        addButton(frame: CGRect(x: 160.0, y: 180.0, width: 100.0, height: 100.0), backgroundColor: .green)
        addButton(frame: CGRect(x: 160.0, y: 300.0, width: 180.0, height: 100.0), backgroundColor: .red)
        addButton(frame: CGRect(x: 40.0, y: 420.0, width: 300.0, height: 150.0), backgroundColor: .yellow)
    }

}

... and this is what the result looks like:

Answer 2

Try this code:

btn1, btn2 and btnarrival are UIButton instances:

 btn1.setCornerRadius()
 btn2.setCornerRadius()
 btnarrival.setCornerRadius()


extension UIButton {
    func setCornerRadius() {
        layer.cornerRadius = frame.size.height / 2.0
        clipsToBounds = true
    }
}