Dev:UIBackdropView

_UIBackdropView is a private class in UIKit.framework (iOS 7.0+), a subclass of UIView, which is used for the popular blur effects.

It uses a CABackdropLayer with a gaussianBlur CAFilter (kCAFilterGaussianBlur).

Creating Settings
_UIBackdropView uses a _UIBackdropViewSettings object for its setup. There are many ways to create it:

Available settings classes (styles)
Here's a list with known settings classes (subclasses of _UIBackdropViewSettings) available.

About _UIBackdropViewSettingsColored
You can give it a tint color (in fact, it already has a default tint color, and some styles (10091, 10092, 10120) set their own). Example:

For iOS 9

Blurring Sample
There are only two blur qualities available.


 * low
 * default (Assumed to be "medium")

They correspend to the kCAFilterGaussianBlur's property "inputQuality"

About graphics quality
The styles have different graphic qualities. If you don't specify it, the "best matching" quality for your device is used (using [UIDevice _graphicsQuality]). There are two values: 10 and 100. 100 looks better, but needs more resources. On default, iPad2,6, iPad2,7, iPad3,4, iPad3,5, iPad3,6, iPhone4,1, iPhone5,1, iPhone5,2, iPod5,1 get 100, the other devices get 10 (as of iOS 8.1). To manually set a graphic quality to a style, use

If you specify the graphics quality as 10 (or use the default, and it is 10 on the device), the blur quality "low" will be used (if you don't override it).

Applying blur settings/style
There are several ways for doing this by methods.

transitionIncrementallyToPrivateStyle and transitionIncrementallyToStyle do the same (transitionIncrementallyToPrivateStyle calls transitionIncrementallyToStyle internally). transitionToSettings and transitionToPrivateStyle are equivalent too.

For example