_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) .[1]
Creating Settings
_UIBackdropView uses a _UIBackdropViewSettings object for its setup. There are many ways to create it:
_UIBackdropViewSettings *settings = (_UIBackdropViewSettings *)[[[_UIBackdropViewSettingsSemiLight alloc] init] autorelease];
_UIBackdropViewSettings *settings = [_UIBackdropViewSettings settingsForStyle:2070];
_UIBackdropViewSettings *settings = [_UIBackdropViewSettings settingsForPrivateStyle:2070]; //this only calls settingsForStyle internally, so there are no advantages of using it over settingsForStyle
_UIBackdropViewSettings *settings = [[[_UIBackdropViewSettings alloc] initWithDefaultsValue] autorelease];
_UIBackdropViewSettings *settings = [_UIBackdropViewSettings settingsForStyle:2030 graphicsQuality:100] ; //can be either 10 or 100, 100 is better. See notes at the bottom
Available settings classes (styles)
Here's a list with known settings classes (subclasses of _UIBackdropViewSettings) available.
_UIBackdropViewSettingsCombiner
style: 3
_UIBackdropViewSettingsNone
style: -2
_UIBackdropViewSettingsLight
style: 0, 1000, 1003, 2020, 10090, 10100
_UIBackdropViewSettingsDark
style: 0, 1001, 1100, 2030, 11050, 11060
application: Notification Center, Keyboard (Dark), Safari Navigation Bar (Private mode)
_UIBackdropViewSettingsBlur
style: 2
application: Common blurring
_UIBackdropViewSettingsColorSample
style: 2000
_UIBackdropViewSettingsUltraLight
style (iOS 7): 2010
style (iOS 8+): 2010, 10050, 10060, 10070, 10080, 10110
application: Alert views and various UI (White)
comment: fallback of unsupported styles
_UIBackdropViewSettingsLightLow
style: 2029
comment: Optimized version of _UIBackdropViewSettingsLight
_UIBackdropViewSettingsDarkWithZoom
style: 2031
_UIBackdropViewSettingsDarkLow
style: 2039
comment: Optimized version of _UIBackdropViewSettingsDark
_UIBackdropViewSettingsColored
style: 2040
Tint: rgba(0.0196078, 0.0196078, 0.0196078, 1)
style: 10091
Tint (iOS 7): rgba(0.160784, 1, 0.301961, 1)
Tint (iOS 8): rgba(0.160784, 1, 0, 1)
Tint (iOS 9+): rgba(0.160784, 1, 0.301961, 1)
style: 10092
Tint (iOS 7): rgba(1, 0.0980392, 0.0470588, 1)
Tint (iOS 8): rgba(1, 0.098039, 0.047059, 1)
Tint (iOS 9+): rgba(1, 0.0980392, 0.0470588, 1)
style: 10120
Tint (iOS 7): rgba(0.0313725, 0.262745, 0.560784, 1)
Tint (iOS 8): rgba(0.031373, 0.262745, 0.560784, 1)
Tint (iOS 9+): rgba(0.0313725, 0.262745, 0.560784, 1)
_UIBackdropViewSettingsUltraDark
style: 2050, 11070
_UIBackdropViewSettingsAdaptiveLight
style: 2060
application: Control Center
_UIBackdropViewSettingsSemiLight
style: 2070
_UIBackdropViewSettingsFlatSemiLight
style: 2071
_UIBackdropViewSettingsUltraColored
style: 2080
=== iOS 7.1+ ===
_UIBackdropViewSettingsPasscodePaddle
style: 3900
_UIBackdropViewSettingsLightKeyboard
style: 3901
=== iOS 9.0+ ===
_UIBackdropViewSettingsLightEmojiKeyboard
style: 3902
_UIBackdropViewSettingsATVSemiLight
style: 4000
_UIBackdropViewSettingsATVMediumLight
style: 4001
_UIBackdropViewSettingsATVLight
style: 4002
_UIBackdropViewSettingsATVUltraLight
style: 4003
_UIBackdropViewSettingsATVMenuLight
style: 4004
_UIBackdropViewSettingsATVSemiDark
style: 4005
_UIBackdropViewSettingsATVMediumDark
style: 4006
_UIBackdropViewSettingsATVDark
style: 4007
_UIBackdropViewSettingsATVUltraDark
style: 4008
_UIBackdropViewSettingsATVMenuDark
style: 4009
_UIBackdropViewSettingsATVAdaptive
style: 4010
_UIBackdropViewSettingsATVAdaptiveLighten
style: 4011
_UIBackdropViewSettingsATVAccessoryLighten
style: 4012
=== iOS 9.3+ ===
_UIBackdropViewSettingsATVAccessoryDark
style: 4013
Creating Sample
// 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:blurView];
[blurView release];
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:
_UIBackdropViewSettings *settings = [[_UIBackdropViewSettingsColored alloc]init];
[settings setTintColor:[UIColor colorWithRed:1 green:0 blue:0 alpha:1];
//now use it somewhere
For iOS 9
_UIBackdropViewSettings *settings = [_UIBackdropViewSettings settingsForPrivateStyle:2040];
[settings setColorTint:[UIColor colorWithRed:1 green:0 blue:0 alpha:1]];
//now use it somewhere
Blurring Sample
There are only two blur qualities available.
- low
- default (Assumed to be "medium")
They correspend to the kCAFilterGaussianBlur's property "inputQuality"
[blurView setBlurRadiusSetOnce:NO];
[blurView setBlurRadius:10.0];
[blurView setBlurHardEdges:3];
[blurView setBlurWithHardEdges:YES];
[blurView setBlurQuality:@"low"];
Tinting Sample
[blurView setRequiresColorStatistics:YES];
[blurView setUsesColorTintView:YES];
UIColor *color = [UIColor cyanColor];
[blurView setColorTint:color]; // or you may use - (void)transitionToColor:(UIColor *)color;
[blurView setColorTintAlpha:0.8];
[blurView setColorTintMaskAlpha:0.7];
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
[_UIBackdropViewSettings settingsForStyle:2030 arg1 graphicsQuality:100]; //replace 2030 and 100 with whatever you need.
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.
Signature | - (void)transitionIncrementallyToPrivateStyle:(NSInteger)style weighting:(float)weight; |
---|---|
Available in | 7.0 – |
Signature | - (void)transitionIncrementallyToStyle:(NSInteger)style weighting:(float)weight; |
---|---|
Available in | 7.0 – |
Signature | - (void)transitionToSettings:(_UIBackdropViewSettings *)settings; |
---|---|
Available in | 7.0 – |
Signature | - (void)transitionToPrivateStyle:(NSInteger)style; |
---|---|
Available in | 7.0 – |
Signature | - (void)transitionToStyle:(NSInteger)style; |
---|---|
Available in | 7.0 – |
transitionIncrementallyToPrivateStyle and transitionIncrementallyToStyle do the same (transitionIncrementallyToPrivateStyle calls transitionIncrementallyToStyle internally). transitionToSettings and transitionToPrivateStyle are equivalent too.
For example
_UIBackdropViewSettings *newSettings = [_UIBackdropViewSettings settingsForPrivateStyle:0];
// Whatever configuration for the settings
[blurView setInputSettings:newSettings];
Getting/Parsing all _UIBackdropView objects at runtime
NSArray *blurViews = [_UIBackdropView allBackdropViews];
for (_UIBackdropView *view in blurViews) {
NSLog(@"This _UIBackdropView style is: %d", view.style);
// do any _UIBackdropView configuration here
}
References