在新iOS的音乐应用程序中,我们可以看到一个模糊的视图后面有一个专辑封面。
这样的事情是如何完成的呢?我看了文件,但什么都没发现。
在新iOS的音乐应用程序中,我们可以看到一个模糊的视图后面有一个专辑封面。
这样的事情是如何完成的呢?我看了文件,但什么都没发现。
当前回答
为了帮助大家,下面是我根据Jordan h的回答创建的一个快速扩展。它是用swift 5编写的,可以在Objective C中使用。
extension UIView {
@objc func blurBackground(style: UIBlurEffect.Style, fallbackColor: UIColor) {
if !UIAccessibility.isReduceTransparencyEnabled {
self.backgroundColor = .clear
let blurEffect = UIBlurEffect(style: style)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
//always fill the view
blurEffectView.frame = self.self.bounds
blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
self.insertSubview(blurEffectView, at: 0)
} else {
self.backgroundColor = fallbackColor
}
}
}
注意:如果你想在不影响文本的情况下模糊UILabel的背景,你应该创建一个容器UIView,将UILabel作为子视图添加到容器UIView,将UILabel的backgroundColor设置为UIColor。clear,然后调用blurBackground(style: UIBlurEffect。样式,fallbackColor: UIColor)的容器UIView。下面是用Swift 5写的一个简单的例子:
let frame = CGRect(x: 50, y: 200, width: 200, height: 50)
let containerView = UIView(frame: frame)
let label = UILabel(frame: frame)
label.text = "Some Text"
label.backgroundColor = UIColor.clear
containerView.addSubview(label)
containerView.blurBackground(style: .dark, fallbackColor: UIColor.black)
其他回答
你可以使用UIVisualEffectView来实现这个效果。这是一个本地API,经过了性能和电池寿命的微调,而且很容易实现。
迅速:
//only apply the blur if the user hasn't disabled transparency effects
if !UIAccessibility.isReduceTransparencyEnabled {
view.backgroundColor = .clear
let blurEffect = UIBlurEffect(style: .dark)
let blurEffectView = UIVisualEffectView(effect: blurEffect)
//always fill the view
blurEffectView.frame = self.view.bounds
blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
view.addSubview(blurEffectView) //if you have more UIViews, use an insertSubview API to place it where needed
} else {
view.backgroundColor = .black
}
objective - c:
//only apply the blur if the user hasn't disabled transparency effects
if (!UIAccessibilityIsReduceTransparencyEnabled()) {
self.view.backgroundColor = [UIColor clearColor];
UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
//always fill the view
blurEffectView.frame = self.view.bounds;
blurEffectView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[self.view addSubview:blurEffectView]; //if you have more UIViews, use an insertSubview API to place it where needed
} else {
self.view.backgroundColor = [UIColor blackColor];
}
如果你以模态方式呈现这个视图控制器来模糊底层内容,你需要将模态呈现风格设置为Over Current Context,并将背景颜色设置为clear,以确保底层视图控制器在顶部呈现时仍然可见。
下面是Swift中使用CIGaussianBlur的快速实现:
func blur(image 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);
let result = filter?.valueForKey(kCIOutputImageKey) as! CIImage;
let rect = CGRectMake(radius * 2, radius * 2, image.size.width - radius * 4, image.size.height - radius * 4)
let cgImage = context.createCGImage(result, fromRect: rect);
let returnImage = UIImage(CGImage: cgImage);
return returnImage;
}
下面是一个简单的方法来添加自定义模糊,而不用与私有api讨价还价使用UIViewPropertyAnimator:
首先,声明class属性:
var blurAnimator: UIViewPropertyAnimator!
然后在viewDidLoad()中设置你的模糊视图:
let blurEffectView = UIVisualEffectView()
blurEffectView.backgroundColor = .clear
blurEffectView.frame = view.bounds
blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
view.addSubview(blurEffectView)
blurAnimator = UIViewPropertyAnimator(duration: 1, curve: .linear) { [blurEffectView] in
blurEffectView.effect = UIBlurEffect(style: .light)
}
blurAnimator.fractionComplete = 0.15 // set the blur intensity.
注意:此解决方案不适用于UICollectionView/UITableView单元格
Swift 3版本的凯文的答案返回模糊的图像-
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Swift 2.0解决方案的代码,已经在接受的答案中提供:
//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()
}