将UIImage切成圆形

我想将UIImage剪切成圆形，然后我可以将它用作注释。 我发现这个网站上的每个答案都描述了创建一个UIImageView ，然后修改它并显示它，但你不能将注释的图像设置为UIImageView ，只能是UIImage 。 我该怎么办呢？

如果需要，请务必导入QuarzCore。 

  func maskRoundedImage(image: UIImage, radius: CGFloat) -> UIImage { let imageView: UIImageView = UIImageView(image: image) let layer = imageView.layer layer.masksToBounds = true layer.cornerRadius = radius UIGraphicsBeginImageContext(imageView.bounds.size) layer.render(in: UIGraphicsGetCurrentContext()!) let roundedImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return roundedImage! }

Xcode 8.2•Swift 3.0.2 

 extension UIImage { var isPortrait: Bool { return size.height > size.width } var isLandscape: Bool { return size.width > size.height } var breadth: CGFloat { return min(size.width, size.height) } var breadthSize: CGSize { return CGSize(width: breadth, height: breadth) } var breadthRect: CGRect { return CGRect(origin: .zero, size: breadthSize) } var circleMasked: UIImage? { UIGraphicsBeginImageContextWithOptions(breadthSize, false, scale) defer { UIGraphicsEndImageContext() } guard let cgImage = cgImage?.cropping(to: CGRect(origin: CGPoint(x: isLandscape ? floor((size.width - size.height) / 2) : 0, y: isPortrait ? floor((size.height - size.width) / 2) : 0), size: breadthSize)) else { return nil } UIBezierPath(ovalIn: breadthRect).addClip() UIImage(cgImage: cgImage, scale: 1, orientation: imageOrientation).draw(in: breadthRect) return UIGraphicsGetImageFromCurrentImageContext() } }

游乐场测试 

 let profilePicture = UIImage(data: try! Data(contentsOf: URL(string:"http://i.stack.imgur.com/Xs4RX.jpg")!))! profilePicture.circleMasked

UIImage扩展： 

 extension UIImage { func circularImage(size size: CGSize?) -> UIImage { let newSize = size ?? self.size let minEdge = min(newSize.height, newSize.width) let size = CGSize(width: minEdge, height: minEdge) UIGraphicsBeginImageContextWithOptions(size, false, 0.0) let context = UIGraphicsGetCurrentContext() self.drawInRect(CGRect(origin: CGPoint.zero, size: size), blendMode: .Copy, alpha: 1.0) CGContextSetBlendMode(context, .Copy) CGContextSetFillColorWithColor(context, UIColor.clearColor().CGColor) let rectPath = UIBezierPath(rect: CGRect(origin: CGPoint.zero, size: size)) let circlePath = UIBezierPath(ovalInRect: CGRect(origin: CGPoint.zero, size: size)) rectPath.appendPath(circlePath) rectPath.usesEvenOddFillRule = true rectPath.fill() let result = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return result } }

用法：

的UIImageView： 

 @IBDesignable class CircularImageView: UIImageView { override var image: UIImage? { didSet { super.image = image?.circularImage(size: nil) } } }

的UIButton： 

 @IBDesignable class CircularImageButton: UIButton { override func setImage(image: UIImage?, forState state: UIControlState) { let circularImage = image?.circularImage(size: nil) super.setImage(circularImage, forState: state) } }

Xcode 8.1，Swift 3.0.1

我的代码看起来像这样： 

 let image = yourImage.resize(CGSize(width: 20, height: 20))?.circled(forRadius: 20)

添加UIImage扩展，然后： 

 func resize(_ size: CGSize) -> UIImage? { let rect = CGRect(origin: .zero, size: size) return redraw(in: rect) } func redraw(in rect: CGRect) -> UIImage? { UIGraphicsBeginImageContextWithOptions(rect.size, false, UIScreen.main.scale) guard let context = UIGraphicsGetCurrentContext(), let cgImage = cgImage else { return nil } let rect = CGRect(origin: .zero, size: size) let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: rect.size.height) context.concatenate(flipVertical) context.draw(cgImage, in: rect) let image = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return image } func circled(forRadius radius: CGFloat) -> UIImage? { let rediusSize = CGSize(width: radius, height: radius) let rect = CGRect(origin: .zero, size: size) UIGraphicsBeginImageContextWithOptions(size, false, UIScreen.main.scale) guard let context = UIGraphicsGetCurrentContext(), let cgImage = cgImage else { return nil } let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: rect.size.height) context.concatenate(flipVertical) let bezierPath = UIBezierPath(roundedRect: rect, byRoundingCorners: [.allCorners], cornerRadii: rediusSize) context.addPath(bezierPath.cgPath) context.clip() context.drawPath(using: .fillStroke) context.draw(cgImage, in: rect) let image = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return image }

我设法通过找到BezierPath的使用来回答我自己的问题！ 

 if let xyz = UIImage(contentsOfFile: readPath) { var Rect: CGRect = CGRectMake(0, 0, xyz.size.width, xyz.size.height) var x = UIBezierPath(roundedRect: Rect, cornerRadius: 200).addClip() UIGraphicsBeginImageContextWithOptions(xyz.size, false, xyz.scale) xyz.drawInRect(Rect) var ImageNew = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() annotation.image = ImageNew }

您可以使用此代码圈出图像 

 extension UIImage { func circleImage(_ cornerRadius: CGFloat, size: CGSize) -> UIImage? { let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height) UIGraphicsBeginImageContextWithOptions(size, false, 0) if let context = UIGraphicsGetCurrentContext() { var path: UIBezierPath if size.height == size.width { if cornerRadius == size.width/2 { path = UIBezierPath(arcCenter: CGPoint(x: size.width/2, y: size.height/2), radius: cornerRadius, startAngle: 0, endAngle: 2.0*CGFloat(Double.pi), clockwise: true) }else { path = UIBezierPath(roundedRect: rect, cornerRadius: cornerRadius) } }else { path = UIBezierPath(roundedRect: rect, cornerRadius: cornerRadius) } context.addPath(path.cgPath) context.clip() self.draw(in: rect) // 从上下文上获取剪裁后的照片guard let uncompressedImage = UIGraphicsGetImageFromCurrentImageContext() else { UIGraphicsEndImageContext() return nil } // 关闭上下文UIGraphicsEndImageContext() return uncompressedImage }else { return nil } }}

swift 3符合MVC模式创建外部文件 

 @IBDesignable class RoundImage: UIImageView{ @IBInspectable var cornerRadius: CGFloat = 0 { didSet{ self.layer.cornerRadius = cornerRadius } } // set border width @IBInspectable var borderWidth: CGFloat = 0 { didSet{ self.layer.borderWidth = borderWidth } } // set border color @IBInspectable var borderColor: UIColor = UIColor.clear { didSet{ self.layer.borderColor = borderColor.cgColor } } override func awakeFromNib() { self.clipsToBounds = true } }// class

在故事板上的IB中调用类

在故事板上的IB中调用类

随便设置cornerradius（如果需要圆圈的宽度的1/2）

设置属性

完成！

对于直接的解决方案，所有这些答案都非常复杂。 我只是复制了我的Objective-C代码并针对Swift进行了调整。 

 self.myImageView?.layer.cornerRadius = (self.myImageView?.frame.size.width)! / 2; self.myImageView?.clipsToBounds = true

基于Nikos答案： 

 public extension UIImage { func roundedImage() -> UIImage { let imageView: UIImageView = UIImageView(image: self) let layer = imageView.layer layer.masksToBounds = true layer.cornerRadius = imageView.frame.width / 2 UIGraphicsBeginImageContext(imageView.bounds.size) layer.render(in: UIGraphicsGetCurrentContext()!) let roundedImage = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() return roundedImage! } } //Usage let roundedImage = image.roundedImage()
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