iOS Swift3.0异步设置任意弧度高性能圆角图片

写一个UIImage的分类,方便调用

import UIKit extension UIImage { /// 异步设置圆角图片 /// /// - Parameters: /// - size: 图片大小 /// - radius: 圆角值 /// - fillColor: 裁切区域填充颜色 /// - completion: 回调裁切结果图片 func cornerImage(size:CGSize, radius:CGFloat, fillColor: UIColor, completion:@escaping ((_ image: UIImage)->())) -> Void { //异步绘制裁切 DispatchQueue.global().async { //利用绘图建立上下文 UIGraphicsBeginImageContextWithOptions(size, true, 0) let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height) //设置填充颜色 fillColor.setFill() UIRectFill(rect) //利用贝塞尔路径裁切 let path = UIBezierPath.init(roundedRect: rect, cornerRadius: radius) path.addClip() self.draw(in: rect) //获取结果 let resultImage = UIGraphicsGetImageFromCurrentImageContext() //关闭上下文 UIGraphicsEndImageContext() //主队列回调 DispatchQueue.main.async { completion(resultImage!) } } } }

调用绘制方法

let image = UIImage(named: "imageName") image?.cornerImage(size: CGSize(width: 200, height: 200), radius:30, fillColor: UIColor.white) { (resultImage: UIImage) in self.imageView.image = resultImage }