Less Blur with 'Visual Effect View with Blur'

Less Blur with `Visual Effect View with Blur`?

The reason you're getting heavy blur is that the blur effect style affects the brightness level of the image, not the amount of blur applied.

Unfortunately, although Apple clearly has the ability to control the amount of blur applied programmatically--try dragging down slowly on the launchpad to watch the Spotlight blurring transition--I don't see any public API to pass a blur amount to UIBlurEffect.

This post claims that adjusting the background color alpha will drive the blur amount. It's worth a try, but I don't see where that is documented: How to fade a UIVisualEffectView and/or UIBlurEffect in and out?

UIVisualEffect view Should not have value less than 1, this interferes with blurring in iOS

The Apple Documentation state :

When using the UIVisualEffectView class, avoid alpha values that are
less than 1

Creating a blurring overlay view

You can use UIVisualEffectView to achieve this effect. This is a native API that has been fine-tuned for performance and great battery life, plus it's easy to implement.

Swift:

//only apply the blur if the user hasn't disabled transparency effects
if !UIAccessibility.isReduceTransparencyEnabled {
    view.backgroundColor = .clear

    let blurEffect = UIBlurEffect(style: .dark)
    let blurEffectView = UIVisualEffectView(effect: blurEffect)
    //always fill the view
    blurEffectView.frame = self.view.bounds
    blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]

    view.addSubview(blurEffectView) //if you have more UIViews, use an insertSubview API to place it where needed
} else {
    view.backgroundColor = .black
}

Objective-C:

//only apply the blur if the user hasn't disabled transparency effects
if (!UIAccessibilityIsReduceTransparencyEnabled()) {
    self.view.backgroundColor = [UIColor clearColor];

    UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
    UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
    //always fill the view
    blurEffectView.frame = self.view.bounds;
    blurEffectView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

    [self.view addSubview:blurEffectView]; //if you have more UIViews, use an insertSubview API to place it where needed
} else {
    self.view.backgroundColor = [UIColor blackColor];
}

If you are presenting this view controller modally to blur the underlying content, you'll need to set the modal presentation style to Over Current Context and set the background color to clear to ensure the underlying view controller will remain visible once this is presented overtop.

Adding blur effect to background in swift

I have tested this code and it's working fine:

let blurEffect = UIBlurEffect(style: UIBlurEffect.Style.dark)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = view.bounds
blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
view.addSubview(blurEffectView)

For Swift 3.0:

let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.dark)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = view.bounds
blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
view.addSubview(blurEffectView)

For Swift 4.0:

let blurEffect = UIBlurEffect(style: UIBlurEffect.Style.dark)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = view.bounds
blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
view.addSubview(blurEffectView)

Here you can see result:

Or you can use this lib for that:

https://github.com/FlexMonkey/Blurable

Visual effect view fine in Interface Builder, incorrect when app runs

Apparently it was just the simulator (for some weird reason). I've tried it on real device and it displays just fine on device.

Create shadow around a UIVisualEffectView without covering the whole view

Ok, so the problem was that my background in the underlying view was white. And with the UIBlurEffect .extraLight used on a background which is lighter than the BlurEffect the shadow beneath a UIVisualView appears darker than with a more vivid background.

Also described in this question:

Fix UIVisualEffectView extra light blur being gray on white background

UPDATE

I found a project explaining how to solve this on Github The solution involves creating a 9-part UIImage to represent the shadow. The creator also explains the underlying layers of the iOS 10 Maps.

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