UIBackdropView

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Revision as of 08:10, 18 May 2014 by PoomSmart (talk | contribs) (Better explaination.)
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_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.[1]

_UIBackdropView uses the settings for its setup. Here's all settings class available in iOS 7.0

Class name Style number Comments/Used by
_UIBackdropViewSettingsBlur 0 Common blurring
_UIBackdropViewSettingsUltraLight 2010 Some alert views in Settings app & many white UIs
_UIBackdropViewSettingsLight 2020
_UIBackdropViewSettingsDark 2030 iOS 7 Notification Center (?)
_UIBackdropViewSettingsDarkLow 2039
_UIBackdropViewSettingsColored 2040
_UIBackdropViewSettingsUltraDark 2050
_UIBackdropViewSettingsAdaptiveLight 2060 iOS 7 Control Center
_UIBackdropViewSettingsSemiLight 2070
_UIBackdropViewSettingsUltraColored 2080

There are many ways to create the settings object

_UIBackdropViewSettings *settings = (_UIBackdropViewSettings *)[[[_UIBackdropViewSettingsSemiLight alloc] init] autorelease];

_UIBackdropViewSettings *settings = [_UIBackdropViewSettings settingsForStyle:2070];

_UIBackdropViewSettings *settings = [_UIBackdropViewSettings settingsForPrivateStyle:2070];

_UIBackdropViewSettings *settings = [[[_UIBackdropViewSettings alloc] initWithDefaultsValue] autorelease];

Creating _UIBackdropView (Blur view) object

// Creating blur view using settings object
_UIBackdropViewSettings *settings = [_UIBackdropViewSettings settingsForStyle:2060];

// initialization of the blur view
_UIBackdropView *blurView = [[_UIBackdropView alloc] initWithFrame:CGRectZero
                                              autosizesToFitSuperview:YES settings:settings];
// another way for initialization
_UIBackdropView *blurView = [[_UIBackdropView alloc] initWithSettings:settings];

// or without settings object implementation
_UIBackdropView *blurView = [[_UIBackdropView alloc] initWithStyle:2060];

[someView addSubview:backView];
[blurView release];

Blur Quality

There are only two qualities available.

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

You can set it like this:

[blurView setBlurQuality:@"low"];

Tinting blur view

[blurView setRequiresColorStatistics:YES];
[blurView setColorTint:[UIColor cyanColor]];
[blurView setColorTintAlpha:0.8];
[blurView setColorTintMaskAlpha:0.7];

Applying blur settings

You can config the settings parameter then apply and update the blur view.

_UIBackdropViewSettings *newSettings = [_UIBackdropView settingsForPrivateStyle:0];

// Whatever configuration for the settings

[blurView applySettings:newSettings];
// or
[blueView computeAndApplySettings:newSettings];

Getting/Parsing all _UIBackdropView objects at runtime

NSArray *blurViews = [_UIBackdropView allBackdropViews];

for (_UIBackdropView *view in blurViews) {
     // do any _UIBackdropView configuration here
}

References