How to create semi-transparent outside border for UIImageView

Just in case if somebody looks for an UIImage with transparent outside border. If you simply set a layer border, you will get a transparent border, but you will see inside image behind that border, not outside image. I managed to create an ImageView with transparent outside border.

It looks like this:

The idea is simple. I save UIImage from UIImageView. Then I remove UIImage and set initial layer as border layer. Then I put a new smaller sublayer above it and set a saved UIImage as contents of it.

    #import 
    
    @interface SSCircleImageView : UIImageView
    
    
    @end

--------------------

    
    #import "SSCircleImageView.h"
    
    
    
    @implementation SSCircleImageView
    
    
    const CGFloat borderWidth = 5.0f;
    const CGFloat borderAlpha = 0.3f;
    
    
    - (void)awakeFromNib
    {
        UIImage *image = self.image;
        self.image = nil;
        
        self.clipsToBounds = YES;
        self.layer.cornerRadius = self.frame.size.width / 2.0;
        self.layer.borderWidth = borderWidth;
        self.layer.borderColor = [[UIColor colorWithWhite:1.0f alpha:borderAlpha] CGColor];
        
        CALayer *subLayer = [CALayer layer];
        subLayer.frame =  CGRectInset(self.bounds, self.layer.borderWidth, self.layer.borderWidth);
        subLayer.cornerRadius = subLayer.frame.size.width / 2.0;
        subLayer.contents = (id)image.CGImage;
        [self.layer addSublayer:subLayer];
    }
    
    
    
    @end

The same approach can be used for UIButton or UIView.