iOS: Mask a UIImage using UIBezierPath

I am trying to mask an image so that I can give it only two rounded corners. With the code that I have it just adds the mask in white over the image, but doesn't seem to apply it. What do I need to do different to mask the image corners?

CAShapeLayer *maskLayer = [CAShapeLayer layer];
UIBezierPath *roundedPath = [UIBezierPath bezierPathWithRoundedRect:maskLayer.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCorne开发者_开发技巧rBottomRight cornerRadii:CGSizeMake(16.f, 16.f)];    
maskLayer.fillColor = [[UIColor whiteColor] CGColor];
maskLayer.backgroundColor = [[UIColor clearColor] CGColor];
maskLayer.path = [roundedPath CGPath];

// Add mask
self.imageView.layer.mask = maskLayer;

Round two corners in UIView

As mentioned in the above linked question, you probably need to remove the view from the heirarchy before applying its mask.

[self.imageView removeFromSuperview];
self.imageView.layer.mask = maskLayer;
[self.view addSubview:self.imageView];

Also, your maskLayer has no bounds. You need to set it to the frame (or bounds) of the view you're trying to mask.

CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = self.imageView.frame;