How to make a circular UIView

I can at least show you a shortcut for drawing circles of arbitrary size. No OpenGL, no Core Graphics drawing needed.

Import the QuartzCore framework to get access to the .cornerRadius property of your UIView or UIImageView.

#import <QuartzCore/QuartzCore.h>

Also manually add it to your project's Frameworks folder.

Add this method to your view controller or wherever you need it:

-(void)setRoundedView:(UIImageView *)roundedView toDiameter:(float)newSize;
{
    CGPoint saveCenter = roundedView.center;
    CGRect newFrame = CGRectMake(roundedView.frame.origin.x, roundedView.frame.origin.y, newSize, newSize);
    roundedView.frame = newFrame;
    roundedView.layer.cornerRadius = newSize / 2.0;
    roundedView.center = saveCenter;
}

To use it, just pass it a UIImageView and a diameter. This example assumes you have a UIImageView named "circ" added as a subview to your view. It should have a backgroundColor set so you can see it.

circ.clipsToBounds = YES;
[self setRoundedView:circ toDiameter:100.0];

This just handles UIImageViews but you can generalize it to any UIView.

NOTE: Since iOS 7, clipToBounds need to YES.

A neat, clean and elegant solution is to make a class called RoundedUIView and select it as your UIView element's custom class in Xcode's Identity Inspector like shown in the attached screenshot.

import UIKit

@IBDesignable public class RoundedUIView: UIView {

    override public func layoutSubviews() {
        super.layoutSubviews()

        self.layer.cornerRadius = self.frame.width / 2;
        self.layer.masksToBounds = true
    }
}

I needed to display multiple coloured icons on various screens on white background since the app itself has green theme. So I put my UIImgeView on top of RoundedUIView to make them look like this: