Apply blur to a view

gistfile1.m

- (UIView *)applyBlurToView:(UIView *)view withEffectStyle:(UIBlurEffectStyle)style andConstraints:(BOOL)addConstraints {
    //only apply the blur if the user hasn't disabled transparency effects
    if (!UIAccessibilityIsReduceTransparencyEnabled()) {
        UIBlurEffect * blurEffect = [UIBlurEffect effectWithStyle:style];
        UIVisualEffectView * blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
        blurEffectView.frame = view.bounds;
        [view addSubview:blurEffectView];
        blurEffectView.layer.opacity = 0;
        if (addConstraints) {
            //add auto layout constraints so that the blur fills the screen upon rotating device
            [blurEffectView setTranslatesAutoresizingMaskIntoConstraints:NO];
            [view addConstraint:[NSLayoutConstraint constraintWithItem:blurEffectView
                                                             attribute:NSLayoutAttributeTop
                                                             relatedBy:NSLayoutRelationEqual
                                                                toItem:view
                                                             attribute:NSLayoutAttributeTop
                                                            multiplier:1
                                                              constant:0]];

            [view addConstraint:[NSLayoutConstraint constraintWithItem:blurEffectView
                                                             attribute:NSLayoutAttributeBottom
                                                             relatedBy:NSLayoutRelationEqual
                                                                toItem:view
                                                             attribute:NSLayoutAttributeBottom
                                                            multiplier:1
                                                              constant:0]];

            [view addConstraint:[NSLayoutConstraint constraintWithItem:blurEffectView
                                                             attribute:NSLayoutAttributeLeading
                                                             relatedBy:NSLayoutRelationEqual
                                                                toItem:view
                                                             attribute:NSLayoutAttributeLeading
                                                            multiplier:1
                                                              constant:0]];

            [view addConstraint:[NSLayoutConstraint constraintWithItem:blurEffectView
                                                             attribute:NSLayoutAttributeTrailing
                                                             relatedBy:NSLayoutRelationEqual
                                                                toItem:view
                                                             attribute:NSLayoutAttributeTrailing
                                                            multiplier:1
                                                              constant:0]];
        }
        [UIView animateWithDuration: .5 delay: 0 options: UIViewAnimationOptionAllowUserInteraction animations: ^{ blurEffectView.layer.opacity = 1; } completion: nil];
    } else {
        view.backgroundColor = [[UIColor whiteColor] colorWithAlphaComponent:0.7];
    }
    return view;
}