Inverted rounded rect mask for a view (content in the middle shown, outside part of rounded rect is set to white)

gistfile1.m

- (void)configureInvertedRoundedRectMaskForView:(UIView *)view
{
    const CGFloat cornerRadius = 5.0f;
    const CGRect rect = CGRectInset(view.bounds, 10.0f, 0.0f);
    
    UIBezierPath *rectPath = [UIBezierPath bezierPathWithRect:view.bounds];
    
    UIBezierPath *roundedRectPath = [UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:cornerRadius];
    [rectPath appendPath:roundedRectPath];
    
    CAShapeLayer *mask = [CAShapeLayer layer];
    mask.path = rectPath.CGPath;
    mask.fillRule = kCAFillRuleEvenOdd;
    
    view.layer.backgroundColor = [UIColor whiteColor].CGColor;
    view.layer.mask = mask;
}