在新的iOS音乐应用中,我们可以看到一个模糊了的视图后面是一个专辑封面。如何实现这样的效果呢?我已经阅读了文档,但没有找到相关内容。 ![](https://istack.dev59.com/QXEg4m.webp)
![](https://istack.dev59.com/QXEg4m.webp)
采纳的答案是正确的,但这里缺少一个重要的步骤,在这种情况下,你想要模糊背景的视图是使用以下代码呈现的:
[self presentViewController:vc animated:YES completion:nil]
默认情况下,这会取消模糊效果,因为UIKit会移除正在模糊的 presenter 视图。为了避免被移除,请在上一行代码之前添加以下行:
vc.modalPresentationStyle = UIModalPresentationOverFullScreen;
或使用其他 Over
样式。
目标-C
UIVisualEffect *blurEffect;
blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
UIVisualEffectView *visualEffectView;
visualEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
visualEffectView.frame = self.accessImageView.bounds;
[self.accessImageView addSubview:visualEffectView];
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)
如果你想要更多的控制权,可以使用苹果公司提供的UIImageEffects
示例代码。
你可以从苹果开发者文库中复制UIImageEffects
的代码:模糊和着色图像
#import "UIImageEffects.h"
...
self.originalImageView.image = [UIImageEffects imageByApplyingLightEffectToImage:[UIImage imageNamed:@"yourImage.png"]];
func blurBackgroundUsingImage(image: UIImage)
{
var frame = CGRectMake(0, 0, self.view.frame.width, self.view.frame.height)
var imageView = UIImageView(frame: frame)
imageView.image = image
imageView.contentMode = .ScaleAspectFill
var blurEffect = UIBlurEffect(style: .Light)
var blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = frame
var transparentWhiteView = UIView(frame: frame)
transparentWhiteView.backgroundColor = UIColor(white: 1.0, alpha: 0.30)
var viewsArray = [imageView, blurEffectView, transparentWhiteView]
for index in 0..<viewsArray.count {
if let oldView = self.view.viewWithTag(index + 1) {
var oldView = self.view.viewWithTag(index + 1)
// Must explicitly unwrap oldView to access its removeFromSuperview() method as of Xcode 6 Beta 5
oldView!.removeFromSuperview()
}
var viewToInsert = viewsArray[index]
self.view.insertSubview(viewToInsert, atIndex: index + 1)
viewToInsert.tag = index + 1
}
}
@Joey的回答的一个重要补充
这适用于您想要呈现带有UINavigationController
的模糊背景UIViewController
的情况。
// suppose you've done blur effect with your presented view controller
UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController];
// this is very important, if you don't do this, the blur effect will darken after view did appeared
// the reason is that you actually present navigation controller, not presented controller
// please note it's "OverFullScreen", not "OverCurrentContext"
nav.modalPresentationStyle = UIModalPresentationOverFullScreen;
UIViewController *presentedViewController = [[UIViewController alloc] init];
// the presented view controller's modalPresentationStyle is "OverCurrentContext"
presentedViewController.modalPresentationStyle = UIModalPresentationOverCurrentContext;
[presentingViewController presentViewController:nav animated:YES completion:nil];
享受!
我偶然发现了这个,它给我带来了非常好的结果(与苹果公司的几乎相似),并使用了加速框架。-- http://pastebin.com/6cs6hsyQ *不是我写的
import UIKit
//This extension implements a blur to the entire screen, puts up a HUD and then waits and dismisses the view.
extension UIViewController {
func blurAndShowHUD(duration: Double, message: String, completion: @escaping () -> Void) { //with completion block
//1. Create the blur effect & the view it will occupy
let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.light)
let blurEffectView = UIVisualEffectView()//(effect: blurEffect)
blurEffectView.frame = self.view.bounds
blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
//2. Add the effect view to the main view
self.view.addSubview(blurEffectView)
//3. Create the hud and add it to the main view
let hud = HudView.getHUD(view: self.view, withMessage: message)
self.view.addSubview(hud)
//4. Begin applying the blur effect to the effect view
UIView.animate(withDuration: 0.01, animations: {
blurEffectView.effect = blurEffect
})
//5. Halt the blur effects application to achieve the desired blur radius
self.view.pauseAnimationsInThisView(delay: 0.004)
//6. Remove the view (& the HUD) after the completion of the duration
DispatchQueue.main.asyncAfter(deadline: .now() + duration) {
blurEffectView.removeFromSuperview()
hud.removeFromSuperview()
self.view.resumeAnimationsInThisView()
completion()
}
}
}
extension UIView {
public func pauseAnimationsInThisView(delay: Double) {
let time = delay + CFAbsoluteTimeGetCurrent()
let timer = CFRunLoopTimerCreateWithHandler(kCFAllocatorDefault, time, 0, 0, 0, { timer in
let layer = self.layer
let pausedTime = layer.convertTime(CACurrentMediaTime(), from: nil)
layer.speed = 0.0
layer.timeOffset = pausedTime
})
CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, CFRunLoopMode.commonModes)
}
public func resumeAnimationsInThisView() {
let pausedTime = layer.timeOffset
layer.speed = 1.0
layer.timeOffset = 0.0
layer.beginTime = layer.convertTime(CACurrentMediaTime(), from: nil) - pausedTime
}
}
我已确认它可以在iOS 10.3.1和iOS 11上运行
将Kev的答案转换为Swift 3版本以返回模糊图像 -
func blurBgImage(image: UIImage) -> UIImage? {
let radius: CGFloat = 20;
let context = CIContext(options: nil);
let inputImage = CIImage(cgImage: image.cgImage!);
let filter = CIFilter(name: "CIGaussianBlur");
filter?.setValue(inputImage, forKey: kCIInputImageKey);
filter?.setValue("\(radius)", forKey:kCIInputRadiusKey);
if let result = filter?.value(forKey: kCIOutputImageKey) as? CIImage{
let rect = CGRect(origin: CGPoint(x: radius * 2,y :radius * 2), size: CGSize(width: image.size.width - radius * 4, height: image.size.height - radius * 4))
if let cgImage = context.createCGImage(result, from: rect){
return UIImage(cgImage: cgImage);
}
}
return nil;
}
以下是使用了惊人的@AdamBardon技术的更完整的示例。
@IBDesignable class ButtonOrSomethingWithBlur: UIButton {
var ba: UIViewPropertyAnimator?
private lazy var blurry: BlurryBall = { return BlurryBall() }()
override func didMoveToSuperview() {
super.didMoveToSuperview()
// Setup the blurry ball. BE SURE TO TEARDOWN.
// Use superb trick to access the internal guassian level of Apple's
// standard gpu blurrer per stackoverflow.com/a/55378168/294884
superview?.insertSubview(blurry, belowSubview: self)
ba = UIViewPropertyAnimator(duration:1, curve:.linear) {[weak self] in
// note, those duration/curve values are simply unusued
self?.blurry.effect = UIBlurEffect(style: .extraLight)
}
ba?.fractionComplete = live.largeplaybutton_blurfactor
}
override func willMove(toSuperview newSuperview: UIView?) {
// Teardown for the blurry ball - critical
if newSuperview == nil { print("safe teardown")
ba?.stopAnimation(true)
ba?.finishAnimation(at: .current)
}
}
override func layoutSubviews() { super.layoutSubviews()
blurry.frame = bounds, your drawing frame or whatever
}
didMoveToWindow
可能比didMoveToSuperview
更适合您。其次,您可以使用其他方法进行拆卸,但是那里显示的两行代码是拆卸的代码。BlurryBall
只是一个UIVisualEffectView
。请注意视觉效果视图的初始化。如果您需要圆角或其他内容,请在此类中执行。class BlurryBall: UIVisualEffectView {
override init(effect: UIVisualEffect?) { super.init(effect: effect)
commonInit() }
required init?(coder aDecoder: NSCoder) { super.init(coder: aDecoder)
commonInit() }
private func commonInit() {
clipsToBounds = true
backgroundColor = .clear
}
override func layoutSubviews() {
super.layoutSubviews()
layer.cornerRadius = bounds.width / 2
}
}
这是Swift 2.0代码,用于解决已在接受的答案中提供的问题:
//only apply the blur if the user hasn't disabled transparency effects
if !UIAccessibilityIsReduceTransparencyEnabled() {
self.view.backgroundColor = UIColor.clearColor()
let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Dark)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
//always fill the view
blurEffectView.frame = self.view.bounds
blurEffectView.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
self.view.addSubview(blurEffectView) //if you have more UIViews, use an insertSubview API to place it where needed
} else {
self.view.backgroundColor = UIColor.blackColor()
}