A UIVisual​Effect​View object gives you an easy way implement some complex visual effects. Depending on the desired effect, the effect may affect content layered behind the view or content added to the visual effect view’s content​View.


Apply a visual effect view to an existing view and then apply a UIBlur​Effect or UIVibrancy​Effect object to apply a blur or vibrancy effect to the existing view. After you add the visual effect view to the view hierarchy, add any subviews to the content​View property of the visual effect view. Do not add subviews directly to the visual effect view itself.

Setting the Correct Alpha Value

When using the UIVisual​Effect​View class, avoid alpha values that are less than 1. Creating views that are partially transparent causes the system to combine the view and all the associated subviews during an offscreen render pass. UIVisual​Effect​View objects need to be combined as part of the content they are layered on top of in order to look correct. Setting the alpha to less than 1 on the visual effect view or any of its superviews causes many effects to look incorrect or not show up at all.

Using Masks with a UIVisualEffectView

Masks directly applied to a UIVisual​Effect​View are forwarded to the internal views that provide the visual effect, including the content​View itself. You can also apply masks directly to the content​View. Applying a mask to a superview of a UIVisual​Effect​View object causes the effect to fail, and an exception is thrown.

Any mask provided to UIVisual​Effect​View is not the view that actually performs the mask. UIKit makes a copy of the view and applies it to each subview. To reflect a size change to the mask, you must apply the change to the original mask and reset it on the effect view.

Capturing a Snapshot of a UIVisualEffectView

Many effects require support from the window that hosts the UIVisual​Effect​View. Attempting to take a snapshot of only the UIVisual​Effect​View will result in a snapshot that does not contain the effect. To take a snapshot of a view hierarchy that contains a UIVisual​Effect​View, you must take a snapshot of the entire UIWindow or UIScreen that contains it.


Retrieving View Information

var content​View:​ UIView

A UIView object that can have a visual effect view added to it.

var effect:​ UIVisual​Effect?

The visual effect provided by the view.

Creating a New Visual Effect View

init(effect:​ UIVisual​Effect?)

Creates a new visual effect view with the designated visual effect.