IOS: UIImageView border white with radius display a strange dark line in 4 corners

Question

I set the border white and radius for my ImageView. But in 4 corner of the ImageView, some dark line appear.
Here is the code I set the color

Answer 1

Updated code

I tried your code actually your image size is big initially I resized the image based on original Image size

UIImage *myIcon = [self imageWithImage:[UIImage imageNamed:@"abc.jpg"] scaledToSize:CGSizeMake(400, 400)];
self.image.image = myIcon;

sometimes corner radius does not work properly so I used UIBezierPath for this concept

 UIBezierPath *maskPath;
maskPath = [UIBezierPath bezierPathWithRoundedRect:self.image.bounds byRoundingCorners:(UIRectCornerTopLeft | UIRectCornerTopRight | UIRectCornerBottomLeft | UIRectCornerBottomRight) cornerRadii:CGSizeMake(10.0, 10.0)];

CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.frame = self.view.bounds;
maskLayer.path = maskPath.CGPath;
self.image.layer.mask = maskLayer;

for border color and width use this

swift 3

let maskPath = UIBezierPath(roundedRect: imageView.bounds, byRoundingCorners: ([.topLeft, .topRight, .bottomLeft, .bottomRight]), cornerRadii: CGSize(width: 10.0, height: 10.0))


    let borderShape = CAShapeLayer()
    borderShape.frame = self.imageView.bounds
    borderShape.path = maskPath.cgPath
    borderShape.strokeColor = UIColor.white.cgColor
    borderShape.fillColor = nil
    borderShape.lineWidth = 3
    self.imageView.layer.addSublayer(borderShape)

output

Update

CAShapeLayer*   borderShape = [CAShapeLayer layer];
borderShape.frame = self.image.bounds;
borderShape.path = maskPath.CGPath;
borderShape.strokeColor = [UIColor whiteColor].CGColor;
borderShape.fillColor = nil;
borderShape.lineWidth = 3;
[self.image.layer addSublayer:borderShape];

Swift

var borderShape: CAShapeLayer = CAShapeLayer.layer
borderShape.frame = self.image.bounds
borderShape.path = maskPath.CGPath
borderShape.strokeColor = UIColor.whiteColor().CGColor
borderShape.fillColor = nil
borderShape.lineWidth = 3
 self.image.layer.addSublayer(borderShape)

Output

Code for whole project